# Copyright 2012-2016 The Meson development team

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at

#     http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from . import mparser
from . import environment
from . import coredata
from . import dependencies
from . import mlog
from . import build
from . import optinterpreter
from . import compilers
from .wrap import wrap
from . import mesonlib
from mesonbuild.interpreterbase import InterpreterBase
from mesonbuild.interpreterbase import InterpreterException, InvalidArguments, InvalidCode
from mesonbuild.interpreterbase import InterpreterObject, MutableInterpreterObject

import os, sys, subprocess, shutil, uuid, re
from functools import wraps

import importlib

run_depr_printed = False

# Decorators for method calls.

def check_stringlist(a, msg='Arguments must be strings.'):
    if not isinstance(a, list):
        mlog.debug('Not a list:', str(a))
        raise InvalidArguments('Argument not a list.')
    if not all(isinstance(s, str) for s in a):
        mlog.debug('Element not a string:', str(a))
        raise InvalidArguments(msg)

def noPosargs(f):
    @wraps(f)
    def wrapped(self, node, args, kwargs):
        if len(args) != 0:
            raise InvalidArguments('Function does not take positional arguments.')
        return f(self, node, args, kwargs)
    return wrapped

def noKwargs(f):
    @wraps(f)
    def wrapped(self, node, args, kwargs):
        if len(kwargs) != 0:
            raise InvalidArguments('Function does not take keyword arguments.')
        return f(self, node, args, kwargs)
    return wrapped

def stringArgs(f):
    @wraps(f)
    def wrapped(self, node, args, kwargs):
        assert(isinstance(args, list))
        check_stringlist(args)
        return f(self, node, args, kwargs)
    return wrapped

def stringifyUserArguments(args):
    if isinstance(args, list):
        return '[%s]' % ', '.join([stringifyUserArguments(x) for x in args])
    elif isinstance(args, int):
        return str(args)
    elif isinstance(args, str):
        return "'%s'" % args
    raise InvalidArguments('Function accepts only strings, integers, lists and lists thereof.')

class TryRunResultHolder(InterpreterObject):
    def __init__(self, res):
        super().__init__()
        self.res = res
        self.methods.update({'returncode' : self.returncode_method,
                             'compiled' : self.compiled_method,
                             'stdout' : self.stdout_method,
                             'stderr' : self.stderr_method,
                            })

    def returncode_method(self, args, kwargs):
        return self.res.returncode

    def compiled_method(self, args, kwargs):
        return self.res.compiled

    def stdout_method(self, args, kwargs):
        return self.res.stdout

    def stderr_method(self, args, kwargs):
        return self.res.stderr

class RunProcess(InterpreterObject):

    def __init__(self, command_array, source_dir, build_dir, subdir, in_builddir=False):
        super().__init__()
        pc = self.run_command(command_array, source_dir, build_dir, subdir, in_builddir)
        (stdout, stderr) = pc.communicate()
        self.returncode = pc.returncode
        if sys.stdout.encoding:
            self.stdout = stdout.decode(encoding=sys.stdout.encoding, errors='ignore').replace('\r\n', '\n')
        else:
            self.stdout = stdout.decode(errors='ignore').replace('\r\n', '\n')
        if sys.stderr.encoding:
            self.stderr = stderr.decode(encoding=sys.stderr.encoding, errors='ignore').replace('\r\n', '\n')
        else:
            self.stderr = stderr.decode(errors='ignore').replace('\r\n', '\n')
        self.methods.update({'returncode' : self.returncode_method,
                             'stdout' : self.stdout_method,
                             'stderr' : self.stderr_method,
                            })

    def run_command(self, command_array, source_dir, build_dir, subdir, in_builddir):
        cmd_name = command_array[0]
        env = {'MESON_SOURCE_ROOT' : source_dir,
               'MESON_BUILD_ROOT' : build_dir,
               'MESON_SUBDIR' : subdir}
        if in_builddir:
            cwd = os.path.join(build_dir, subdir)
        else:
            cwd = os.path.join(source_dir, subdir)
        child_env = os.environ.copy()
        child_env.update(env)
        mlog.debug('Running command:', ' '.join(command_array))
        try:
            return subprocess.Popen(command_array, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                                    env=child_env, cwd=cwd)
        except FileNotFoundError:
            pass
        # Was not a command, is a program in path?
        exe = shutil.which(cmd_name)
        if exe is not None:
            command_array = [exe] + command_array[1:]
            return subprocess.Popen(command_array, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                                    env=child_env, cwd=cwd)
        # No? Maybe it is a script in the source tree.
        fullpath = os.path.join(source_dir, subdir, cmd_name)
        command_array = [fullpath] + command_array[1:]
        try:
            return subprocess.Popen(command_array, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
                                    env=child_env, cwd=cwd)
        except FileNotFoundError:
            raise InterpreterException('Could not execute command "%s".' % cmd_name)

    def returncode_method(self, args, kwargs):
        return self.returncode

    def stdout_method(self, args, kwargs):
        return self.stdout

    def stderr_method(self, args, kwargs):
        return self.stderr

class ConfigureFileHolder(InterpreterObject):

    def __init__(self, subdir, sourcename, targetname, configuration_data):
        InterpreterObject.__init__(self)
        self.held_object = build.ConfigureFile(subdir, sourcename, targetname, configuration_data)


class EnvironmentVariablesHolder(MutableInterpreterObject):
    def __init__(self):
        super().__init__()
        self.held_object = build.EnvironmentVariables()
        self.methods.update({'set': self.set_method,
                             'append': self.append_method,
                             'prepend' : self.prepend_method,
                            })

    @stringArgs
    def add_var(self, method, args, kwargs):
        if not isinstance(kwargs.get("separator", ""), str):
            raise InterpreterException("EnvironmentVariablesHolder methods 'separator'"
                                       " argument needs to be a string.")
        if len(args) < 2:
            raise InterpreterException("EnvironmentVariablesHolder methods require at least"
                                       "2 arguments, first is the name of the variable and"
                                       " following one are values")
        self.held_object.envvars.append((method, args[0], args[1:], kwargs))

    def set_method(self, args, kwargs):
        self.add_var(self.held_object.set, args, kwargs)

    def append_method(self, args, kwargs):
        self.add_var(self.held_object.append, args, kwargs)

    def prepend_method(self, args, kwargs):
        self.add_var(self.held_object.prepend, args, kwargs)


class ConfigurationDataHolder(MutableInterpreterObject):
    def __init__(self):
        super().__init__()
        self.used = False # These objects become immutable after use in configure_file.
        self.held_object = build.ConfigurationData()
        self.methods.update({'set': self.set_method,
                             'set10': self.set10_method,
                             'set_quoted': self.set_quoted_method,
                             'has' : self.has_method,
                            })

    def is_used(self):
        return self.used

    def mark_used(self):
        self.used = True

    def validate_args(self, args, kwargs):
        if len(args) != 2:
            raise InterpreterException("Configuration set requires 2 arguments.")
        if self.used:
            raise InterpreterException("Can not set values on configuration object that has been used.")
        name = args[0]
        val = args[1]
        desc = kwargs.get('description', None)
        if not isinstance(name, str):
            raise InterpreterException("First argument to set must be a string.")
        if desc is not None and not isinstance(desc, str):
            raise InterpreterException('Description must be a string.')

        return (name, val, desc)

    def set_method(self, args, kwargs):
        (name, val, desc) = self.validate_args(args, kwargs)
        self.held_object.values[name] = (val, desc)

    def set_quoted_method(self, args, kwargs):
        (name, val, desc) = self.validate_args(args, kwargs)
        if not isinstance(val, str):
            raise InterpreterException("Second argument to set_quoted must be a string.")
        escaped_val = '\\"'.join(val.split('"'))
        self.held_object.values[name] = ('"' + escaped_val + '"', desc)

    def set10_method(self, args, kwargs):
        (name, val, desc) = self.validate_args(args, kwargs)
        if val:
            self.held_object.values[name] = (1, desc)
        else:
            self.held_object.values[name] = (0, desc)

    def has_method(self, args, kwargs):
        return args[0] in self.held_object.values

    def get(self, name):
        return self.held_object.values[name]     # (val, desc)

    def keys(self):
        return self.held_object.values.keys()

# Interpreter objects can not be pickled so we must have
# these wrappers.

class DependencyHolder(InterpreterObject):
    def __init__(self, dep):
        InterpreterObject.__init__(self)
        self.held_object = dep
        self.methods.update({'found' : self.found_method,
                             'type_name': self.type_name_method,
                             'version': self.version_method,
                             'version': self.version_method,
                             'get_pkgconfig_variable': self.pkgconfig_method,
                             })

    def type_name_method(self, args, kwargs):
        return self.held_object.type_name

    def found_method(self, args, kwargs):
        if self.held_object.type_name == 'internal':
            return True

        return self.held_object.found()

    def version_method(self, args, kwargs):
        return self.held_object.get_version()

    def pkgconfig_method(self, args, kwargs):
        if not isinstance(args, list):
            args = [args]
        if len(args) != 1:
            raise InterpreterException('get_pkgconfig_variable takes exactly one argument.')
        varname = args[0]
        if not isinstance(varname, str):
            raise InterpreterException('Variable name must be a string.')
        return self.held_object.get_pkgconfig_variable(varname)

class InternalDependencyHolder(InterpreterObject):
    def __init__(self, dep):
        InterpreterObject.__init__(self)
        self.held_object = dep
        self.methods.update({'found' : self.found_method,
                             'version': self.version_method,
                             })

    def found_method(self, args, kwargs):
        return True

    def version_method(self, args, kwargs):
        return self.held_object.get_version()

class ExternalProgramHolder(InterpreterObject):
    def __init__(self, ep):
        InterpreterObject.__init__(self)
        self.held_object = ep
        self.methods.update({'found': self.found_method,
                             'path': self.path_method})

    def found_method(self, args, kwargs):
        return self.found()

    def path_method(self, args, kwargs):
        return self.get_command()

    def found(self):
        return self.held_object.found()

    def get_command(self):
        return self.held_object.fullpath

    def get_name(self):
        return self.held_object.name

class ExternalLibraryHolder(InterpreterObject):
    def __init__(self, el):
        InterpreterObject.__init__(self)
        self.held_object = el
        self.methods.update({'found': self.found_method})

    def found(self):
        return self.held_object.found()

    def found_method(self, args, kwargs):
        return self.found()

    def get_filename(self):
        return self.held_object.fullpath

    def get_name(self):
        return self.held_object.name

    def get_compile_args(self):
        return self.held_object.get_compile_args()

    def get_link_args(self):
        return self.held_object.get_link_args()

    def get_exe_args(self):
        return self.held_object.get_exe_args()

class GeneratorHolder(InterpreterObject):
    def __init__(self, interpreter, args, kwargs):
        super().__init__()
        self.interpreter = interpreter
        self.held_object = build.Generator(args, kwargs)
        self.methods.update({'process' : self.process_method})

    def process_method(self, args, kwargs):
        check_stringlist(args)
        extras = mesonlib.stringlistify(kwargs.get('extra_args', []))
        gl = GeneratedListHolder(self, extras)
        [gl.add_file(os.path.join(self.interpreter.subdir, a)) for a in args]
        return gl

class GeneratedListHolder(InterpreterObject):
    def __init__(self, arg1, extra_args=[]):
        super().__init__()
        if isinstance(arg1, GeneratorHolder):
            self.held_object = build.GeneratedList(arg1.held_object, extra_args)
        else:
            self.held_object = arg1

    def add_file(self, a):
        self.held_object.add_file(a)

class BuildMachine(InterpreterObject):
    def __init__(self, compilers):
        self.compilers = compilers
        InterpreterObject.__init__(self)
        self.methods.update({'system' : self.system_method,
                             'cpu_family' : self.cpu_family_method,
                             'cpu' : self.cpu_method,
                             'endian' : self.endian_method,
                            })

    def cpu_family_method(self, args, kwargs):
        return environment.detect_cpu_family(self.compilers)

    def cpu_method(self, args, kwargs):
        return environment.detect_cpu(self.compilers)

    def system_method(self, args, kwargs):
        return environment.detect_system()

    def endian_method(self, args, kwargs):
        return sys.byteorder

# This class will provide both host_machine and
# target_machine
class CrossMachineInfo(InterpreterObject):
    def __init__(self, cross_info):
        InterpreterObject.__init__(self)
        minimum_cross_info = {'cpu', 'cpu_family', 'endian', 'system'}
        if set(cross_info) < minimum_cross_info:
            raise InterpreterException(
                'Machine info is currently {}\n'.format(cross_info) +
                'but is missing {}.'.format(minimum_cross_info - set(cross_info)))
        self.info = cross_info
        self.methods.update({'system' : self.system_method,
                             'cpu' : self.cpu_method,
                             'cpu_family' : self.cpu_family_method,
                             'endian' : self.endian_method,
                            })

    def system_method(self, args, kwargs):
        return self.info['system']

    def cpu_method(self, args, kwargs):
        return self.info['cpu']

    def cpu_family_method(self, args, kwargs):
        return self.info['cpu_family']

    def endian_method(self, args, kwargs):
        return self.info['endian']

class IncludeDirsHolder(InterpreterObject):
    def __init__(self, idobj):
        super().__init__()
        self.held_object = idobj

class Headers(InterpreterObject):

    def __init__(self, src_subdir, sources, kwargs):
        InterpreterObject.__init__(self)
        self.sources = sources
        self.source_subdir = src_subdir
        self.install_subdir = kwargs.get('subdir', '')
        self.custom_install_dir = kwargs.get('install_dir', None)
        if self.custom_install_dir is not None:
            if not isinstance(self.custom_install_dir, str):
                raise InterpreterException('Custom_install_dir must be a string.')

    def set_install_subdir(self, subdir):
        self.install_subdir = subdir

    def get_install_subdir(self):
        return self.install_subdir

    def get_source_subdir(self):
        return self.source_subdir

    def get_sources(self):
        return self.sources

    def get_custom_install_dir(self):
        return self.custom_install_dir

class DataHolder(InterpreterObject):
    def __init__(self, sources, install_dir):
        super().__init__()
        if not isinstance(install_dir, str):
            raise InterpreterException('Custom_install_dir must be a string.')
        self.held_object = build.Data(sources, install_dir)

    def get_source_subdir(self):
        return self.held_object.source_subdir

    def get_sources(self):
        return self.held_object.sources

    def get_install_dir(self):
        return self.held_object.install_dir

class InstallDir(InterpreterObject):
    def __init__(self, source_subdir, installable_subdir, install_dir):
        InterpreterObject.__init__(self)
        self.source_subdir = source_subdir
        self.installable_subdir = installable_subdir
        self.install_dir = install_dir

class Man(InterpreterObject):

    def __init__(self, source_subdir, sources, kwargs):
        InterpreterObject.__init__(self)
        self.source_subdir = source_subdir
        self.sources = sources
        self.validate_sources()
        if len(kwargs) > 1:
            raise InvalidArguments('Man function takes at most one keyword arguments.')
        self.custom_install_dir = kwargs.get('install_dir', None)
        if self.custom_install_dir is not None and not isinstance(self.custom_install_dir, str):
            raise InterpreterException('Custom_install_dir must be a string.')

    def validate_sources(self):
        for s in self.sources:
            try:
                num = int(s.split('.')[-1])
            except (IndexError, ValueError):
                num = 0
            if num < 1 or num > 8:
                raise InvalidArguments('Man file must have a file extension of a number between 1 and 8')

    def get_custom_install_dir(self):
        return self.custom_install_dir

    def get_sources(self):
        return self.sources

    def get_source_subdir(self):
        return self.source_subdir

class GeneratedObjectsHolder(InterpreterObject):
    def __init__(self, held_object):
        super().__init__()
        self.held_object = held_object

class BuildTargetHolder(InterpreterObject):
    def __init__(self, target, interp):
        super().__init__()
        self.held_object = target
        self.interpreter = interp
        self.methods.update({'extract_objects' : self.extract_objects_method,
                             'extract_all_objects' : self.extract_all_objects_method,
                             'get_id': self.get_id_method,
                             'outdir' : self.outdir_method,
                             'full_path' : self.full_path_method,
                             'private_dir_include' : self.private_dir_include_method,
                             })

    def is_cross(self):
        return self.held_object.is_cross()

    def private_dir_include_method(self, args, kwargs):
        return IncludeDirsHolder(build.IncludeDirs('', [], False,
                    [self.interpreter.backend.get_target_private_dir(self.held_object)]))

    def full_path_method(self, args, kwargs):
        return self.interpreter.backend.get_target_filename_abs(self.held_object)

    def outdir_method(self, args, kwargs):
        return self.interpreter.backend.get_target_dir(self.held_object)

    def extract_objects_method(self, args, kwargs):
        gobjs = self.held_object.extract_objects(args)
        return GeneratedObjectsHolder(gobjs)

    def extract_all_objects_method(self, args, kwargs):
        gobjs = self.held_object.extract_all_objects()
        return GeneratedObjectsHolder(gobjs)

    def get_id_method(self, args, kwargs):
        return self.held_object.get_id()

class ExecutableHolder(BuildTargetHolder):
    def __init__(self, target, interp):
        super().__init__(target, interp)

class StaticLibraryHolder(BuildTargetHolder):
    def __init__(self, target, interp):
        super().__init__(target, interp)

class SharedLibraryHolder(BuildTargetHolder):
    def __init__(self, target, interp):
        super().__init__(target, interp)

class JarHolder(BuildTargetHolder):
    def __init__(self, target, interp):
        super().__init__(target, interp)

class CustomTargetHolder(InterpreterObject):
    def __init__(self, object_to_hold, interp):
        super().__init__()
        self.held_object = object_to_hold
        self.interpreter = interp
        self.methods.update({'full_path' : self.full_path_method,
                             })

    def full_path_method(self, args, kwargs):
        return self.interpreter.backend.get_target_filename_abs(self.held_object)

class RunTargetHolder(InterpreterObject):
    def __init__(self, name, command, args, dependencies, subdir):
        self.held_object = build.RunTarget(name, command, args, dependencies, subdir)

class Test(InterpreterObject):
    def __init__(self, name, suite, exe, is_parallel, cmd_args, env, should_fail, valgrind_args, timeout, workdir):
        InterpreterObject.__init__(self)
        self.name = name
        self.suite = suite
        self.exe = exe
        self.is_parallel = is_parallel
        self.cmd_args = cmd_args
        self.env = env
        self.should_fail = should_fail
        self.valgrind_args = valgrind_args
        self.timeout = timeout
        self.workdir = workdir

    def get_exe(self):
        return self.exe

    def get_name(self):
        return self.name

class SubprojectHolder(InterpreterObject):

    def __init__(self, subinterpreter):
        super().__init__()
        self.held_object = subinterpreter
        self.methods.update({'get_variable' : self.get_variable_method,
                            })

    def get_variable_method(self, args, kwargs):
        if len(args) != 1:
            raise InterpreterException('Get_variable takes one argument.')
        varname = args[0]
        if not isinstance(varname, str):
            raise InterpreterException('Get_variable takes a string argument.')
        return self.held_object.variables[varname]

class CompilerHolder(InterpreterObject):
    def __init__(self, compiler, env):
        InterpreterObject.__init__(self)
        self.compiler = compiler
        self.environment = env
        self.methods.update({'compiles': self.compiles_method,
                             'links': self.links_method,
                             'get_id': self.get_id_method,
                             'sizeof': self.sizeof_method,
                             'has_header': self.has_header_method,
                             'has_header_symbol': self.has_header_symbol_method,
                             'run' : self.run_method,
                             'has_function' : self.has_function_method,
                             'has_member' : self.has_member_method,
                             'has_members' : self.has_members_method,
                             'has_type' : self.has_type_method,
                             'alignment' : self.alignment_method,
                             'version' : self.version_method,
                             'cmd_array' : self.cmd_array_method,
                             'find_library': self.find_library_method,
                             'has_argument' : self.has_argument_method,
                             'first_supported_argument' : self.first_supported_argument_method,
                             'unittest_args' : self.unittest_args_method,
                            })

    def version_method(self, args, kwargs):
        return self.compiler.version

    def cmd_array_method(self, args, kwargs):
        return self.compiler.exelist

    def determine_args(self, kwargs):
        nobuiltins = kwargs.get('no_builtin_args', False)
        if not isinstance(nobuiltins, bool):
            raise InterpreterException('Type of no_builtin_args not a boolean.')
        args = []
        if not nobuiltins:
            opts = self.environment.coredata.compiler_options
            args += self.compiler.get_option_compile_args(opts)
            args += self.compiler.get_option_link_args(opts)
        args += mesonlib.stringlistify(kwargs.get('args', []))
        return args

    def determine_dependencies(self, kwargs, allowed_dep_types=None):
        deps = kwargs.get('dependencies', None)
        if allowed_dep_types is None:
            allowed_dep_types = (dependencies.Dependency, dependencies.ExternalLibrary)
        if deps is not None:
            if not isinstance(deps, list):
                deps = [deps]
            final_deps = []
            for d in deps:
                try:
                    d = d.held_object
                except Exception:
                    pass
                if not isinstance(d, allowed_dep_types):
                    raise InterpreterException('Dependencies must be external deps')
                final_deps.append(d)
            deps = final_deps
        return deps

    def alignment_method(self, args, kwargs):
        if len(args) != 1:
            raise InterpreterException('Alignment method takes exactly one positional argument.')
        check_stringlist(args)
        typename = args[0]
        extra_args = mesonlib.stringlistify(kwargs.get('args', []))
        result = self.compiler.alignment(typename, self.environment, extra_args)
        mlog.log('Checking for alignment of "', mlog.bold(typename), '": ', result, sep='')
        return result

    def run_method(self, args, kwargs):
        if len(args) != 1:
            raise InterpreterException('Run method takes exactly one positional argument.')
        code = args[0]
        if isinstance(code, mesonlib.File):
            code = mesonlib.File.from_absolute_file(
                code.rel_to_builddir(self.environment.source_dir))
        elif not isinstance(code, str):
            raise InvalidArguments('Argument must be string or file.')
        testname = kwargs.get('name', '')
        if not isinstance(testname, str):
            raise InterpreterException('Testname argument must be a string.')
        extra_args = self.determine_args(kwargs)
        deps = self.determine_dependencies(kwargs)
        result = self.compiler.run(code, self.environment, extra_args, deps)
        if len(testname) > 0:
            if not result.compiled:
                h = mlog.red('DID NOT COMPILE')
            elif result.returncode == 0:
                h = mlog.green('YES')
            else:
                h = mlog.red('NO (%d)' % result.returncode)
            mlog.log('Checking if "', mlog.bold(testname), '" runs : ', h, sep='')
        return TryRunResultHolder(result)

    def get_id_method(self, args, kwargs):
        return self.compiler.get_id()

    def unittest_args_method(self, args, kwargs):
        # At time, only D compilers have this feature.
        if not hasattr(self.compiler, 'get_unittest_args'):
            raise InterpreterException('This {} compiler has no unittest arguments.'.format(self.compiler.language))
        return self.compiler.get_unittest_args()

    def has_member_method(self, args, kwargs):
        if len(args) != 2:
            raise InterpreterException('Has_member takes exactly two arguments.')
        check_stringlist(args)
        typename = args[0]
        membername = args[1]
        prefix = kwargs.get('prefix', '')
        if not isinstance(prefix, str):
            raise InterpreterException('Prefix argument of has_member must be a string.')
        extra_args = self.determine_args(kwargs)
        deps = self.determine_dependencies(kwargs, allowed_dep_types=(dependencies.Dependency,))
        had = self.compiler.has_members(typename, [membername], prefix,
                                        self.environment, extra_args, deps)
        if had:
            hadtxt = mlog.green('YES')
        else:
            hadtxt = mlog.red('NO')
        mlog.log('Checking whether type "', mlog.bold(typename),
                 '" has member "', mlog.bold(membername), '": ', hadtxt, sep='')
        return had

    def has_members_method(self, args, kwargs):
        check_stringlist(args)
        typename = args[0]
        membernames = args[1:]
        prefix = kwargs.get('prefix', '')
        if not isinstance(prefix, str):
            raise InterpreterException('Prefix argument of has_members must be a string.')
        extra_args = self.determine_args(kwargs)
        deps = self.determine_dependencies(kwargs, allowed_dep_types=(dependencies.Dependency,))
        had = self.compiler.has_members(typename, membernames, prefix,
                                        self.environment, extra_args, deps)
        if had:
            hadtxt = mlog.green('YES')
        else:
            hadtxt = mlog.red('NO')
        members = mlog.bold(', '.join(['"{}"'.format(m) for m in membernames]))
        mlog.log('Checking whether type "', mlog.bold(typename),
                 '" has members ', members, ': ', hadtxt, sep='')
        return had

    def has_function_method(self, args, kwargs):
        if len(args) != 1:
            raise InterpreterException('Has_function takes exactly one argument.')
        check_stringlist(args)
        funcname = args[0]
        prefix = kwargs.get('prefix', '')
        if not isinstance(prefix, str):
            raise InterpreterException('Prefix argument of has_function must be a string.')
        extra_args = self.determine_args(kwargs)
        deps = self.determine_dependencies(kwargs)
        had = self.compiler.has_function(funcname, prefix, self.environment, extra_args, deps)
        if had:
            hadtxt = mlog.green('YES')
        else:
            hadtxt = mlog.red('NO')
        mlog.log('Checking for function "', mlog.bold(funcname), '": ', hadtxt, sep='')
        return had

    def has_type_method(self, args, kwargs):
        if len(args) != 1:
            raise InterpreterException('Has_type takes exactly one argument.')
        check_stringlist(args)
        typename = args[0]
        prefix = kwargs.get('prefix', '')
        if not isinstance(prefix, str):
            raise InterpreterException('Prefix argument of has_type must be a string.')
        extra_args = self.determine_args(kwargs)
        deps = self.determine_dependencies(kwargs)
        had = self.compiler.has_type(typename, prefix, self.environment, extra_args, deps)
        if had:
            hadtxt = mlog.green('YES')
        else:
            hadtxt = mlog.red('NO')
        mlog.log('Checking for type "', mlog.bold(typename), '": ', hadtxt, sep='')
        return had

    def sizeof_method(self, args, kwargs):
        if len(args) != 1:
            raise InterpreterException('Sizeof takes exactly one argument.')
        check_stringlist(args)
        element = args[0]
        prefix = kwargs.get('prefix', '')
        if not isinstance(prefix, str):
            raise InterpreterException('Prefix argument of sizeof must be a string.')
        extra_args = self.determine_args(kwargs)
        deps = self.determine_dependencies(kwargs, allowed_dep_types=(dependencies.Dependency,))
        esize = self.compiler.sizeof(element, prefix, self.environment, extra_args, deps)
        mlog.log('Checking for size of "%s": %d' % (element, esize))
        return esize

    def compiles_method(self, args, kwargs):
        if len(args) != 1:
            raise InterpreterException('compiles method takes exactly one argument.')
        code = args[0]
        if isinstance(code, mesonlib.File):
            code = mesonlib.File.from_absolute_file(
                code.rel_to_builddir(self.environment.source_dir))
        elif not isinstance(code, str):
            raise InvalidArguments('Argument must be string or file.')
        testname = kwargs.get('name', '')
        if not isinstance(testname, str):
            raise InterpreterException('Testname argument must be a string.')
        extra_args = self.determine_args(kwargs)
        deps = self.determine_dependencies(kwargs, allowed_dep_types=(dependencies.Dependency,))
        result = self.compiler.compiles(code, self.environment, extra_args, deps)
        if len(testname) > 0:
            if result:
                h = mlog.green('YES')
            else:
                h = mlog.red('NO')
            mlog.log('Checking if "', mlog.bold(testname), '" compiles : ', h, sep='')
        return result

    def links_method(self, args, kwargs):
        if len(args) != 1:
            raise InterpreterException('links method takes exactly one argument.')
        code = args[0]
        if isinstance(code, mesonlib.File):
            code = mesonlib.File.from_absolute_file(
                code.rel_to_builddir(self.environment.source_dir))
        elif not isinstance(code, str):
            raise InvalidArguments('Argument must be string or file.')
        testname = kwargs.get('name', '')
        if not isinstance(testname, str):
            raise InterpreterException('Testname argument must be a string.')
        extra_args = self.determine_args(kwargs)
        deps = self.determine_dependencies(kwargs)
        result = self.compiler.links(code, self.environment, extra_args, deps)
        if len(testname) > 0:
            if result:
                h = mlog.green('YES')
            else:
                h = mlog.red('NO')
            mlog.log('Checking if "', mlog.bold(testname), '" links : ', h, sep='')
        return result

    def has_header_method(self, args, kwargs):
        if len(args) != 1:
            raise InterpreterException('has_header method takes exactly one argument.')
        check_stringlist(args)
        hname = args[0]
        prefix = kwargs.get('prefix', '')
        if not isinstance(prefix, str):
            raise InterpreterException('Prefix argument of has_header must be a string.')
        extra_args = self.determine_args(kwargs)
        deps = self.determine_dependencies(kwargs, allowed_dep_types=(dependencies.Dependency,))
        haz = self.compiler.has_header(hname, prefix, self.environment, extra_args, deps)
        if haz:
            h = mlog.green('YES')
        else:
            h = mlog.red('NO')
        mlog.log('Has header "%s":' % hname, h)
        return haz

    def has_header_symbol_method(self, args, kwargs):
        if len(args) != 2:
            raise InterpreterException('has_header_symbol method takes exactly two arguments.')
        check_stringlist(args)
        hname = args[0]
        symbol = args[1]
        prefix = kwargs.get('prefix', '')
        if not isinstance(prefix, str):
            raise InterpreterException('Prefix argument of has_header_symbol must be a string.')
        extra_args = self.determine_args(kwargs)
        deps = self.determine_dependencies(kwargs, allowed_dep_types=(dependencies.Dependency,))
        haz = self.compiler.has_header_symbol(hname, symbol, prefix, self.environment, extra_args, deps)
        if haz:
            h = mlog.green('YES')
        else:
            h = mlog.red('NO')
        mlog.log('Header <{0}> has symbol "{1}":'.format(hname, symbol), h)
        return haz

    def find_library_method(self, args, kwargs):
        # TODO add dependencies support?
        if len(args) != 1:
            raise InterpreterException('find_library method takes one argument.')
        libname = args[0]
        if not isinstance(libname, str):
            raise InterpreterException('Library name not a string.')
        required = kwargs.get('required', True)
        if not isinstance(required, bool):
            raise InterpreterException('required must be boolean.')
        search_dirs = mesonlib.stringlistify(kwargs.get('dirs', []))
        for i in search_dirs:
            if not os.path.isabs(i):
                raise InvalidCode('Search directory %s is not an absolute path.' % i)
        linkargs = self.compiler.find_library(libname, self.environment, search_dirs)
        if required and not linkargs:
            l = self.compiler.language.capitalize()
            raise InterpreterException('{} library {!r} not found'.format(l, libname))
        # If this is set to None, the library and link arguments are for
        # a C-like compiler. Otherwise, it's for some other language that has
        # a find_library implementation. We do this because it's easier than
        # maintaining a list of languages that can consume C libraries.
        lang = None
        if self.compiler.language == 'vala':
            lang = 'vala'
        lib = dependencies.ExternalLibrary(libname, linkargs, language=lang)
        return ExternalLibraryHolder(lib)

    def has_argument_method(self, args, kwargs):
        args = mesonlib.stringlistify(args)
        if len(args) != 1:
            raise InterpreterException('Has_arg takes exactly one argument.')
        result = self.compiler.has_argument(args[0], self.environment)
        if result:
            h = mlog.green('YES')
        else:
            h = mlog.red('NO')
        mlog.log('Compiler for {} supports argument {}:'.format(self.compiler.language, args[0]), h)
        return result

    def first_supported_argument_method(self, args, kwargs):
        for i in mesonlib.stringlistify(args):
            if self.compiler.has_argument(i, self.environment):
                mlog.log('First supported argument:', mlog.bold(i))
                return [i]
        mlog.log('First supported argument:', mlog.red('None'))
        return []

class ModuleState:
    pass

class ModuleHolder(InterpreterObject):
    def __init__(self, modname, module, interpreter):
        InterpreterObject.__init__(self)
        self.modname = modname
        self.held_object = module
        self.interpreter = interpreter

    def method_call(self, method_name, args, kwargs):
        try:
            fn = getattr(self.held_object, method_name)
        except AttributeError:
            raise InvalidArguments('Module %s does not have method %s.' % (self.modname, method_name))
        if method_name.startswith('_'):
            raise InvalidArguments('Function {!r} in module {!r} is private.'.format(method_name, self.modname))
        state = ModuleState()
        state.build_to_src = os.path.relpath(self.interpreter.environment.get_source_dir(),
                                             self.interpreter.environment.get_build_dir())
        state.subdir = self.interpreter.subdir
        state.environment = self.interpreter.environment
        state.project_name = self.interpreter.build.project_name
        state.project_version = self.interpreter.build.dep_manifest[self.interpreter.active_projectname]
        state.compilers = self.interpreter.build.compilers
        state.targets = self.interpreter.build.targets
        state.data = self.interpreter.build.data
        state.headers = self.interpreter.build.get_headers()
        state.man = self.interpreter.build.get_man()
        state.global_args = self.interpreter.build.global_args
        state.project_args = self.interpreter.build.projects_args.get(self.interpreter.subproject, {})
        value = fn(state, args, kwargs)
        return self.interpreter.module_method_callback(value)

class MesonMain(InterpreterObject):
    def __init__(self, build, interpreter):
        InterpreterObject.__init__(self)
        self.build = build
        self.interpreter = interpreter
        self.methods.update({'get_compiler': self.get_compiler_method,
                             'is_cross_build' : self.is_cross_build_method,
                             'has_exe_wrapper' : self.has_exe_wrapper_method,
                             'is_unity' : self.is_unity_method,
                             'is_subproject' : self.is_subproject_method,
                             'current_source_dir' : self.current_source_dir_method,
                             'current_build_dir' : self.current_build_dir_method,
                             'source_root' : self.source_root_method,
                             'build_root' : self.build_root_method,
                             'add_install_script' : self.add_install_script_method,
                             'add_postconf_script' : self.add_postconf_script_method,
                             'install_dependency_manifest': self.install_dependency_manifest_method,
                             'project_version': self.project_version_method,
                             'version': self.version_method,
                             'project_name' : self.project_name_method,
                             'get_cross_property': self.get_cross_property_method,
                            })

    def add_install_script_method(self, args, kwargs):
        if len(args) != 1:
            raise InterpreterException('Set_install_script takes exactly one argument.')
        check_stringlist(args)
        scriptbase = args[0]
        scriptfile = os.path.join(self.interpreter.environment.source_dir,
                                  self.interpreter.subdir, scriptbase)
        if not os.path.isfile(scriptfile):
            raise InterpreterException('Can not find install script %s.' % scriptbase)
        self.build.install_scripts.append(build.InstallScript([scriptfile]))

    def add_postconf_script_method(self, args, kwargs):
        if len(args) < 1:
            raise InterpreterException('Not enough arguments')
        check_stringlist(args, 'add_postconf_script arguments must be strings.')
        scriptbase = args[0]
        search_dir = os.path.join(self.interpreter.environment.source_dir,
                                  self.interpreter.subdir)
        exe = dependencies.ExternalProgram(scriptbase, search_dir=search_dir)
        extras = args[1:]
        self.build.postconf_scripts.append({'exe': exe, 'args': extras})

    def current_source_dir_method(self, args, kwargs):
        src = self.interpreter.environment.source_dir
        sub = self.interpreter.subdir
        if sub == '':
            return src
        return os.path.join(src, sub)

    def current_build_dir_method(self, args, kwargs):
        src = self.interpreter.environment.build_dir
        sub = self.interpreter.subdir
        if sub == '':
            return src
        return os.path.join(src, sub)

    def source_root_method(self, args, kwargs):
        return self.interpreter.environment.source_dir

    def build_root_method(self, args, kwargs):
        return self.interpreter.environment.build_dir

    def has_exe_wrapper_method(self, args, kwargs):
        if self.is_cross_build_method(None, None) and \
           'binaries' in self.build.environment.cross_info.config and \
           self.build.environment.cross_info.need_exe_wrapper():
            exe_wrap = self.build.environment.cross_info.config['binaries'].get('exe_wrapper', None)
            if exe_wrap is None:
                return False
        # We return True when exe_wrap is defined, when it's not needed, and
        # when we're compiling natively. The last two are semantically confusing.
        # Need to revisit this.
        return True

    def is_cross_build_method(self, args, kwargs):
        return self.build.environment.is_cross_build()

    def get_compiler_method(self, args, kwargs):
        if len(args) != 1:
            raise InterpreterException('get_compiler_method must have one and only one argument.')
        cname = args[0]
        native = kwargs.get('native', None)
        if native is None:
            if self.build.environment.is_cross_build():
                native = False
            else:
                native = True
        if not isinstance(native, bool):
            raise InterpreterException('Type of "native" must be a boolean.')
        if native:
            clist = self.build.compilers
        else:
            clist = self.build.cross_compilers
        for c in clist:
            if c.get_language() == cname:
                return CompilerHolder(c, self.build.environment)
        raise InterpreterException('Tried to access compiler for unspecified language "%s".' % cname)

    def is_unity_method(self, args, kwargs):
        return self.build.environment.coredata.get_builtin_option('unity')

    def is_subproject_method(self, args, kwargs):
        return self.interpreter.is_subproject()

    def install_dependency_manifest_method(self, args, kwargs):
        if len(args) != 1:
            raise InterpreterException('Must specify manifest install file name')
        if not isinstance(args[0], str):
            raise InterpreterException('Argument must be a string.')
        self.build.dep_manifest_name = args[0]

    def project_version_method(self, args, kwargs):
        return self.build.dep_manifest[self.interpreter.active_projectname]['version']

    def version_method(self, args, kwargs):
        return coredata.version

    def project_name_method(self, args, kwargs):
        return self.interpreter.active_projectname

    def get_cross_property_method(self, args, kwargs):
        if len(args) < 1 or len(args) > 2:
            raise InterpreterException('Must have one or two arguments.')
        propname = args[0]
        if not isinstance(propname, str):
            raise InterpreterException('Property name must be string.')
        try:
            props = self.interpreter.environment.cross_info.get_properties()
            return props[propname]
        except Exception:
            if len(args) == 2:
                return args[1]
            raise InterpreterException('Unknown cross property: %s.' % propname)

class Interpreter(InterpreterBase):

    def __init__(self, build, backend, subproject='', subdir='', subproject_dir='subprojects'):
        super().__init__(build.environment.get_source_dir(), subdir)
        self.build = build
        self.environment = build.environment
        self.coredata = self.environment.get_coredata()
        self.backend = backend
        self.subproject = subproject
        self.subproject_dir = subproject_dir
        option_file = os.path.join(self.source_root, self.subdir, 'meson_options.txt')
        if os.path.exists(option_file):
            oi = optinterpreter.OptionInterpreter(self.subproject, \
                                                  self.build.environment.cmd_line_options.projectoptions)
            oi.process(option_file)
            self.build.environment.merge_options(oi.options)
        self.load_root_meson_file()
        self.sanity_check_ast()
        self.builtin.update({'meson': MesonMain(build, self)})
        self.generators = []
        self.visited_subdirs = {}
        self.args_frozen = False
        self.subprojects = {}
        self.subproject_stack = []
        self.build_func_dict()
        self.parse_project()
        self.builtin['build_machine'] = BuildMachine(self.coredata.compilers)
        if not self.build.environment.is_cross_build():
            self.builtin['host_machine'] = self.builtin['build_machine']
            self.builtin['target_machine'] = self.builtin['build_machine']
        else:
            cross_info = self.build.environment.cross_info
            if cross_info.has_host():
                self.builtin['host_machine'] = CrossMachineInfo(cross_info.config['host_machine'])
            else:
                self.builtin['host_machine'] = self.builtin['build_machine']
            if cross_info.has_target():
                self.builtin['target_machine'] = CrossMachineInfo(cross_info.config['target_machine'])
            else:
                self.builtin['target_machine'] = self.builtin['host_machine']
        self.build_def_files = [os.path.join(self.subdir, environment.build_filename)]

    def build_func_dict(self):
        self.funcs.update({'project' : self.func_project,
                      'message' : self.func_message,
                      'error' : self.func_error,
                      'executable': self.func_executable,
                      'dependency' : self.func_dependency,
                      'static_library' : self.func_static_lib,
                      'shared_library' : self.func_shared_lib,
                      'library' : self.func_library,
                      'jar' : self.func_jar,
                      'build_target': self.func_build_target,
                      'custom_target' : self.func_custom_target,
                      'run_target' : self.func_run_target,
                      'generator' : self.func_generator,
                      'test' : self.func_test,
                      'benchmark' : self.func_benchmark,
                      'install_headers' : self.func_install_headers,
                      'install_man' : self.func_install_man,
                      'subdir' : self.func_subdir,
                      'install_data' : self.func_install_data,
                      'install_subdir' : self.func_install_subdir,
                      'configure_file' : self.func_configure_file,
                      'include_directories' : self.func_include_directories,
                      'add_global_arguments' : self.func_add_global_arguments,
                      'add_project_arguments' : self.func_add_project_arguments,
                      'add_global_link_arguments' : self.func_add_global_link_arguments,
                      'add_project_link_arguments' : self.func_add_project_link_arguments,
                      'add_languages' : self.func_add_languages,
                      'find_program' : self.func_find_program,
                      'find_library' : self.func_find_library,
                      'configuration_data' : self.func_configuration_data,
                      'run_command' : self.func_run_command,
                      'gettext' : self.func_gettext,
                      'option' : self.func_option,
                      'get_option' : self.func_get_option,
                      'subproject' : self.func_subproject,
                      'vcs_tag' : self.func_vcs_tag,
                      'set_variable' : self.func_set_variable,
                      'is_variable' : self.func_is_variable,
                      'get_variable' : self.func_get_variable,
                      'import' : self.func_import,
                      'files' : self.func_files,
                      'declare_dependency': self.func_declare_dependency,
                      'assert': self.func_assert,
                      'environment' : self.func_environment,
                      'join_paths' : self.func_join_paths,
                     })

    def module_method_callback(self, invalues):
        unwrap_single = False
        if invalues is None:
            return
        if not isinstance(invalues, list):
            unwrap_single = True
            invalues = [invalues]
        outvalues = []
        for v in invalues:
            if isinstance(v, build.CustomTarget):
                self.add_target(v.name, v)
                outvalues.append(CustomTargetHolder(v, self))
            elif isinstance(v, (int, str)):
                outvalues.append(v)
            elif isinstance(v, build.Executable):
                self.add_target(v.name, v)
                outvalues.append(ExecutableHolder(v))
            elif isinstance(v, list):
                outvalues.append(self.module_method_callback(v))
            elif isinstance(v, build.GeneratedList):
                outvalues.append(GeneratedListHolder(v))
            elif isinstance(v, build.RunTarget):
                self.add_target(v.name, v)
            elif isinstance(v, build.InstallScript):
                self.build.install_scripts.append(v)
            elif isinstance(v, build.Data):
                self.build.data.append(v)
            elif isinstance(v, dependencies.InternalDependency):
                # FIXME: This is special cased and not ideal:
                # The first source is our new VapiTarget, the rest are deps
                self.module_method_callback(v.sources[0])
                outvalues.append(InternalDependencyHolder(v))
            else:
                print(v)
                raise InterpreterException('Module returned a value of unknown type.')
        if len(outvalues) == 1 and unwrap_single:
            return outvalues[0]
        return outvalues

    def get_build_def_files(self):
        return self.build_def_files

    def get_variables(self):
        return self.variables

    def check_cross_stdlibs(self):
        if self.build.environment.is_cross_build():
            cross_info = self.build.environment.cross_info
            for c in self.build.cross_compilers:
                l = c.language
                try:
                    di = mesonlib.stringlistify(cross_info.get_stdlib(l))
                    if len(di) != 2:
                        raise InterpreterException('Stdlib definition for %s should have exactly two elements.' \
                                                   % l)
                    projname, depname = di
                    subproj = self.do_subproject(projname, {})
                    self.build.cross_stdlibs[l] = subproj.get_variable_method([depname], {})
                except KeyError as e:
                    pass

    def func_set_variable(self, node, args, kwargs):
        if len(args) != 2:
            raise InvalidCode('Set_variable takes two arguments.')
        varname = args[0]
        value = self.to_native(args[1])
        self.set_variable(varname, value)

    @noKwargs
    def func_get_variable(self, node, args, kwargs):
        if len(args)<1 or len(args)>2:
            raise InvalidCode('Get_variable takes one or two arguments.')
        varname = args[0]
        if not isinstance(varname, str):
            raise InterpreterException('First argument must be a string.')
        try:
            return self.variables[varname]
        except KeyError:
            pass
        if len(args) == 2:
            return args[1]
        raise InterpreterException('Tried to get unknown variable "%s".' % varname)

    @stringArgs
    @noKwargs
    def func_is_variable(self, node, args, kwargs):
        if len(args) != 1:
            raise InvalidCode('Is_variable takes two arguments.')
        varname = args[0]
        return varname in self.variables

    @stringArgs
    @noKwargs
    def func_import(self, node, args, kwargs):
        if len(args) != 1:
            raise InvalidCode('Import takes one argument.')
        modname = args[0]
        if not modname in self.environment.coredata.modules:
            module = importlib.import_module('mesonbuild.modules.' + modname).initialize()
            self.environment.coredata.modules[modname] = module
        return ModuleHolder(modname, self.environment.coredata.modules[modname], self)

    @stringArgs
    @noKwargs
    def func_files(self, node, args, kwargs):
        return [mesonlib.File.from_source_file(self.environment.source_dir, self.subdir, fname) for fname in args]

    @noPosargs
    def func_declare_dependency(self, node, args, kwargs):
        version = kwargs.get('version', self.project_version)
        if not isinstance(version, str):
            raise InterpreterException('Version must be a string.')
        incs = kwargs.get('include_directories', [])
        if not isinstance(incs, list):
            incs = [incs]
        libs = kwargs.get('link_with', [])
        if not isinstance(libs, list):
            libs = [libs]
        sources = kwargs.get('sources', [])
        if not isinstance(sources, list):
            sources = [sources]
        sources = self.source_strings_to_files(self.flatten(sources))
        deps = kwargs.get('dependencies', [])
        if not isinstance(deps, list):
            deps = [deps]
        compile_args = mesonlib.stringlistify(kwargs.get('compile_args', []))
        link_args = mesonlib.stringlistify(kwargs.get('link_args', []))
        final_deps = []
        for d in deps:
            try:
                d = d.held_object
            except Exception:
                pass
            if not isinstance(d, (dependencies.Dependency, dependencies.ExternalLibrary, dependencies.InternalDependency)):
                raise InterpreterException('Dependencies must be external deps')
            final_deps.append(d)
        dep = dependencies.InternalDependency(version, incs, compile_args, link_args, libs, sources, final_deps)
        return DependencyHolder(dep)

    @noKwargs
    def func_assert(self, node, args, kwargs):
        if len(args) != 2:
            raise InterpreterException('Assert takes exactly two arguments')
        value, message = args
        if not isinstance(value, bool):
            raise InterpreterException('Assert value not bool.')
        if not isinstance(message, str):
            raise InterpreterException('Assert message not a string.')
        if not value:
            raise InterpreterException('Assert failed: ' + message)

    def validate_arguments(self, args, argcount, arg_types):
        if argcount is not None:
            if argcount != len(args):
                raise InvalidArguments('Expected %d arguments, got %d.' %
                                       (argcount, len(args)))
        for i in range(min(len(args), len(arg_types))):
            wanted = arg_types[i]
            actual = args[i]
            if wanted != None:
                if not isinstance(actual, wanted):
                    raise InvalidArguments('Incorrect argument type.')

    def func_run_command(self, node, args, kwargs):
        if len(args) < 1:
            raise InterpreterException('Not enough arguments')
        cmd = args[0]
        cargs = args[1:]
        if isinstance(cmd, ExternalProgramHolder):
            cmd = cmd.get_command()
        elif isinstance(cmd, str):
            cmd = [cmd]
        else:
            raise InterpreterException('First argument is of incorrect type.')
        expanded_args = []
        for a in mesonlib.flatten(cargs):
            if isinstance(a, str):
                expanded_args.append(a)
            elif isinstance(a, mesonlib.File):
                if a.is_built:
                    raise InterpreterException('Can not use generated files in run_command.')
                expanded_args.append(os.path.join(self.environment.get_source_dir(), str(a)))
            else:
                raise InterpreterException('Run_command arguments must be strings or the output of files().')
        args = cmd + expanded_args
        in_builddir = kwargs.get('in_builddir', False)
        if not isinstance(in_builddir, bool):
            raise InterpreterException('in_builddir must be boolean.')
        return RunProcess(args, self.environment.source_dir, self.environment.build_dir,
                          self.subdir, in_builddir)

    @stringArgs
    def func_gettext(self, nodes, args, kwargs):
        raise InterpreterException('Gettext() function has been moved to module i18n. Import it and use i18n.gettext() instead')

    def func_option(self, nodes, args, kwargs):
        raise InterpreterException('Tried to call option() in build description file. All options must be in the option file.')

    @stringArgs
    def func_subproject(self, nodes, args, kwargs):
        if len(args) != 1:
            raise InterpreterException('Subproject takes exactly one argument')
        dirname = args[0]
        return self.do_subproject(dirname, kwargs)

    def do_subproject(self, dirname, kwargs):
        if dirname in self.subproject_stack:
            fullstack = self.subproject_stack + [dirname]
            incpath = ' => '.join(fullstack)
            raise InvalidCode('Recursive include of subprojects: %s.' % incpath)
        if dirname in self.subprojects:
            return self.subprojects[dirname]
        r = wrap.Resolver(os.path.join(self.build.environment.get_source_dir(), self.subproject_dir))
        resolved = r.resolve(dirname)
        if resolved is None:
            msg = 'Subproject directory {!r} does not exist and cannot be downloaded.'
            raise InterpreterException(msg.format(os.path.join(self.subproject_dir, dirname)))
        subdir = os.path.join(self.subproject_dir, resolved)
        os.makedirs(os.path.join(self.build.environment.get_build_dir(), subdir), exist_ok=True)
        self.args_frozen = True
        mlog.log('\nExecuting subproject ', mlog.bold(dirname), '.\n', sep='')
        subi = Interpreter(self.build, self.backend, dirname, subdir, self.subproject_dir)
        subi.subprojects = self.subprojects

        subi.subproject_stack = self.subproject_stack + [dirname]
        current_active = self.active_projectname
        subi.run()
        if 'version' in kwargs:
            pv = subi.project_version
            wanted = kwargs['version']
            if pv == 'undefined' or not mesonlib.version_compare(pv, wanted):
                raise InterpreterException('Subproject %s version is %s but %s required.' % (dirname, pv, wanted))
        self.active_projectname = current_active
        mlog.log('\nSubproject', mlog.bold(dirname), 'finished.')
        self.build.subprojects[dirname] = True
        self.subprojects.update(subi.subprojects)
        self.subprojects[dirname] = SubprojectHolder(subi)
        self.build_def_files += subi.build_def_files
        return self.subprojects[dirname]

    @stringArgs
    @noKwargs
    def func_get_option(self, nodes, args, kwargs):
        if len(args) != 1:
            raise InterpreterException('Argument required for get_option.')
        optname = args[0]
        try:
            return self.environment.get_coredata().get_builtin_option(optname)
        except RuntimeError:
            pass
        try:
            return self.environment.coredata.compiler_options[optname].value
        except KeyError:
            pass
        if not coredata.is_builtin_option(optname) and self.is_subproject():
            optname = self.subproject + ':' + optname
        try:
            return self.environment.coredata.user_options[optname].value
        except KeyError:
            pass
        if optname.endswith('_link_args'):
            try:
                lang = optname[:-10]
                return self.coredata.external_link_args[lang]
            except KeyError:
                pass
        if optname.endswith('_args'):
            try:
                lang = optname[:-5]
                return self.coredata.external_args[lang]
            except KeyError:
                pass
        raise InterpreterException('Tried to access unknown option "%s".' % optname)

    @noKwargs
    def func_configuration_data(self, node, args, kwargs):
        if len(args) != 0:
            raise InterpreterException('configuration_data takes no arguments')
        return ConfigurationDataHolder()

    def parse_default_options(self, default_options):
        if not isinstance(default_options, list):
            default_options = [default_options]
        for option in default_options:
            if not isinstance(option, str):
                mlog.debug(option)
                raise InterpreterException('Default options must be strings')
            if '=' not in option:
                raise InterpreterException('All default options must be of type key=value.')
            key, value = option.split('=', 1)
            if coredata.is_builtin_option(key):
                if not self.environment.had_argument_for(key):
                    self.coredata.set_builtin_option(key, value)
                # If this was set on the command line, do not override.
            else:
                newoptions = [option] + self.environment.cmd_line_options.projectoptions
                self.environment.cmd_line_options.projectoptions = newoptions

    @stringArgs
    def func_project(self, node, args, kwargs):
        if not self.is_subproject():
            self.build.project_name = args[0]
            if self.environment.first_invocation and 'default_options' in kwargs:
                self.parse_default_options(kwargs['default_options'])
        if len(args) < 2:
            raise InvalidArguments('Not enough arguments to project(). Needs at least the project name and one language')
        self.active_projectname = args[0]
        self.project_version = kwargs.get('version', 'undefined')
        proj_license = mesonlib.stringlistify(kwargs.get('license', 'unknown'))
        self.build.dep_manifest[args[0]] = {'version': self.project_version,
                                            'license': proj_license}
        if self.subproject in self.build.projects:
            raise InvalidCode('Second call to project().')
        if not self.is_subproject() and 'subproject_dir' in kwargs:
            self.subproject_dir = kwargs['subproject_dir']

        if 'meson_version' in kwargs:
            cv = coredata.version
            pv = kwargs['meson_version']
            if not mesonlib.version_compare(cv, pv):
                raise InterpreterException('Meson version is %s but project requires %s.' % (cv, pv))
        self.build.projects[self.subproject] = args[0]
        mlog.log('Project name: ', mlog.bold(args[0]), sep='')
        self.add_languages(args[1:], True)
        langs = self.coredata.compilers.keys()
        if 'vala' in langs:
            if not 'c' in langs:
                raise InterpreterException('Compiling Vala requires C. Add C to your project languages and rerun Meson.')
        if not self.is_subproject():
            self.check_cross_stdlibs()

    @stringArgs
    def func_add_languages(self, node, args, kwargs):
        return self.add_languages(args, kwargs.get('required', True))

    @noKwargs
    def func_message(self, node, args, kwargs):
        # reduce arguments again to avoid flattening posargs
        (posargs, _) = self.reduce_arguments(node.args)
        if len(posargs) != 1:
            raise InvalidArguments('Expected 1 argument, got %d' % len(posargs))

        arg = posargs[0]
        if isinstance(arg, list):
            argstr = stringifyUserArguments(arg)
        elif isinstance(arg, str):
            argstr = arg
        elif isinstance(arg, int):
            argstr = str(arg)
        else:
            raise InvalidArguments('Function accepts only strings, integers, lists and lists thereof.')

        mlog.log(mlog.bold('Message:'), argstr)

    @noKwargs
    def func_error(self, node, args, kwargs):
        self.validate_arguments(args, 1, [str])
        raise InterpreterException('Error encountered: ' + args[0])

    def detect_compilers(self, lang, need_cross_compiler):
        cross_comp = None
        if lang == 'c':
            comp = self.environment.detect_c_compiler(False)
            if need_cross_compiler:
                cross_comp = self.environment.detect_c_compiler(True)
        elif lang == 'cpp':
            comp = self.environment.detect_cpp_compiler(False)
            if need_cross_compiler:
                cross_comp = self.environment.detect_cpp_compiler(True)
        elif lang == 'objc':
            comp = self.environment.detect_objc_compiler(False)
            if need_cross_compiler:
                cross_comp = self.environment.detect_objc_compiler(True)
        elif lang == 'objcpp':
            comp = self.environment.detect_objcpp_compiler(False)
            if need_cross_compiler:
                cross_comp = self.environment.detect_objcpp_compiler(True)
        elif lang == 'java':
            comp = self.environment.detect_java_compiler()
            if need_cross_compiler:
                cross_comp = comp  # Java is platform independent.
        elif lang == 'cs':
            comp = self.environment.detect_cs_compiler()
            if need_cross_compiler:
                cross_comp = comp  # C# is platform independent.
        elif lang == 'vala':
            comp = self.environment.detect_vala_compiler()
            if need_cross_compiler:
                        cross_comp = comp  # Vala is too (I think).
        elif lang == 'd':
            comp = self.environment.detect_d_compiler()
            if need_cross_compiler:
                cross_comp = comp  # D as well (AFAIK).
        elif lang == 'rust':
            comp = self.environment.detect_rust_compiler()
            if need_cross_compiler:
                cross_comp = comp  # FIXME, probably not correct.
        elif lang == 'fortran':
            comp = self.environment.detect_fortran_compiler(False)
            if need_cross_compiler:
                cross_comp = self.environment.detect_fortran_compiler(True)
        elif lang == 'swift':
            comp = self.environment.detect_swift_compiler()
            if need_cross_compiler:
                raise InterpreterException('Cross compilation with Swift is not working yet.')
                # cross_comp = self.environment.detect_fortran_compiler(True)
        else:
            raise InvalidCode('Tried to use unknown language "%s".' % lang)
        comp.sanity_check(self.environment.get_scratch_dir(), self.environment)
        self.coredata.compilers[lang] = comp
        if cross_comp is not None:
            cross_comp.sanity_check(self.environment.get_scratch_dir(), self.environment)
            self.coredata.cross_compilers[lang] = cross_comp
            new_options = cross_comp.get_options()
        else:
            new_options = comp.get_options()
        optprefix = lang + '_'
        for i in new_options:
            if not i.startswith(optprefix):
                raise InterpreterException('Internal error, %s has incorrect prefix.' % i)
            cmd_prefix = i + '='
            for cmd_arg in self.environment.cmd_line_options.projectoptions:
                if cmd_arg.startswith(cmd_prefix):
                    value = cmd_arg.split('=', 1)[1]
                    new_options[i].set_value(value)
        new_options.update(self.coredata.compiler_options)
        self.coredata.compiler_options = new_options
        return (comp, cross_comp)

    def add_languages(self, args, required):
        success = True
        need_cross_compiler = self.environment.is_cross_build() and self.environment.cross_info.need_cross_compiler()
        for lang in args:
            lang = lang.lower()
            if lang in self.coredata.compilers:
                comp = self.coredata.compilers[lang]
                cross_comp = self.coredata.cross_compilers.get(lang, None)
            else:
                try:
                    (comp, cross_comp) = self.detect_compilers(lang, need_cross_compiler)
                except Exception:
                    if not required:
                        mlog.log('Compiler for language', mlog.bold(lang), 'not found.')
                        success = False
                        continue
                    else:
                        raise
            mlog.log('Native %s compiler: ' % lang, mlog.bold(' '.join(comp.get_exelist())), ' (%s %s)' % (comp.id, comp.version), sep='')
            if not comp.get_language() in self.coredata.external_args:
                (ext_compile_args, ext_link_args) = environment.get_args_from_envvars(comp)
                self.coredata.external_args[comp.get_language()] = ext_compile_args
                self.coredata.external_link_args[comp.get_language()] = ext_link_args
            self.build.add_compiler(comp)
            if need_cross_compiler:
                mlog.log('Cross %s compiler: ' % lang, mlog.bold(' '.join(cross_comp.get_exelist())), ' (%s %s)' % (cross_comp.id, cross_comp.version), sep='')
                self.build.add_cross_compiler(cross_comp)
            if self.environment.is_cross_build() and not need_cross_compiler:
                self.build.add_cross_compiler(comp)
            self.add_base_options(comp)
        return success

    def add_base_options(self, compiler):
        proj_opt = self.environment.cmd_line_options.projectoptions
        for optname in compiler.base_options:
            if optname in self.coredata.base_options:
                continue
            oobj = compilers.base_options[optname]
            for po in proj_opt:
                if po.startswith(optname + '='):
                    oobj.set_value(po.split('=', 1)[1])
                    break
            self.coredata.base_options[optname] = oobj

    def func_find_program(self, node, args, kwargs):
        self.validate_arguments(args, 1, [str])
        required = kwargs.get('required', True)
        if not isinstance(required, bool):
            raise InvalidArguments('"required" argument must be a boolean.')
        exename = args[0]
        # Search for scripts relative to current subdir.
        # Do not cache found programs because find_program('foobar')
        # might give different results when run from different source dirs.
        search_dir = os.path.join(self.environment.get_source_dir(), self.subdir)
        extprog = dependencies.ExternalProgram(exename, search_dir=search_dir)
        progobj = ExternalProgramHolder(extprog)
        if required and not progobj.found():
            raise InvalidArguments('Program "%s" not found.' % exename)
        return progobj

    def func_find_library(self, node, args, kwargs):
        mlog.log(mlog.red('DEPRECATION:'), 'find_library() is removed, use the corresponding method in compiler object instead.')

    def func_dependency(self, node, args, kwargs):
        self.validate_arguments(args, 1, [str])
        name = args[0]
        if '<' in name or '>' in name or '=' in name:
            raise InvalidArguments('''Characters <, > and = are forbidden in target names. To specify version
requirements use the version keyword argument instead.''')
        identifier = dependencies.get_dep_identifier(name, kwargs)
        # Check if we've already searched for and found this dep
        cached_dep = None
        if identifier in self.coredata.deps:
            cached_dep = self.coredata.deps[identifier]
            if 'version' in kwargs:
                wanted = kwargs['version']
                found = cached_dep.get_version()
                if not cached_dep.found() or not mesonlib.version_compare(found, wanted):
                    # Cached dep has the wrong version. Check if an external
                    # dependency or a fallback dependency provides it.
                    cached_dep = None
            # Don't re-use cached dep if it wasn't required but this one is,
            # so we properly go into fallback/error code paths
            if kwargs.get('required', True) and not getattr(cached_dep, 'required', False):
                cached_dep = None

        if cached_dep:
            dep = cached_dep
        else:
            # We need to actually search for this dep
            exception = None
            dep = None
            # If the fallback has already been configured (possibly by a higher level project)
            # try to use it before using the native version
            if 'fallback' in kwargs:
                dirname, varname = self.get_subproject_infos(kwargs)
                if dirname in self.subprojects:
                    try:
                        dep = self.subprojects[dirname].get_variable_method([varname], {})
                        dep = dep.held_object
                    except KeyError:
                        pass

            if not dep:
                try:
                    dep = dependencies.find_external_dependency(name, self.environment, kwargs)
                except dependencies.DependencyException as e:
                    exception = e
                    pass

            if not dep or not dep.found():
                if 'fallback' in kwargs:
                    fallback_dep = self.dependency_fallback(name, kwargs)
                    if fallback_dep:
                        return fallback_dep

                if not dep:
                    raise exception

        self.coredata.deps[identifier] = dep
        return DependencyHolder(dep)

    def get_subproject_infos(self, kwargs):
        fbinfo = kwargs['fallback']
        check_stringlist(fbinfo)
        if len(fbinfo) != 2:
            raise InterpreterException('Fallback info must have exactly two items.')
        return fbinfo

    def dependency_fallback(self, name, kwargs):
        dirname, varname = self.get_subproject_infos(kwargs)
        # Try to execute the subproject
        try:
            self.do_subproject(dirname, {})
        # Invalid code is always an error
        except InvalidCode:
            raise
        # If the subproject execution failed in a non-fatal way, don't raise an
        # exception; let the caller handle things.
        except:
            mlog.log('Also couldn\'t find a fallback subproject in',
                    mlog.bold(os.path.join(self.subproject_dir, dirname)),
                    'for the dependency', mlog.bold(name))
            return None
        try:
            dep = self.subprojects[dirname].get_variable_method([varname], {})
        except KeyError:
            raise InvalidCode('Fallback variable {!r} in the subproject '
                              '{!r} does not exist'.format(varname, dirname))
        if not isinstance(dep, DependencyHolder):
            raise InvalidCode('Fallback variable {!r} in the subproject {!r} is '
                              'not a dependency object.'.format(varname, dirname))
            return None
        # Check if the version of the declared dependency matches what we want
        if 'version' in kwargs:
            wanted = kwargs['version']
            found = dep.version_method([], {})
            if found == 'undefined' or not mesonlib.version_compare(found, wanted):
                mlog.log('Subproject', mlog.bold(dirname), 'dependency',
                        mlog.bold(varname), 'version is', mlog.bold(found),
                        'but', mlog.bold(wanted), 'is required.')
                return None
        mlog.log('Found a', mlog.green('fallback'), 'subproject',
                 mlog.bold(os.path.join(self.subproject_dir, dirname)), 'for',
                 mlog.bold(name))
        return dep

    def func_executable(self, node, args, kwargs):
        return self.build_target(node, args, kwargs, ExecutableHolder)

    def func_static_lib(self, node, args, kwargs):
        return self.build_target(node, args, kwargs, StaticLibraryHolder)

    def func_shared_lib(self, node, args, kwargs):
        return self.build_target(node, args, kwargs, SharedLibraryHolder)

    def func_library(self, node, args, kwargs):
        if self.coredata.get_builtin_option('default_library') == 'shared':
            return self.func_shared_lib(node, args, kwargs)
        return self.func_static_lib(node, args, kwargs)

    def func_jar(self, node, args, kwargs):
        return self.build_target(node, args, kwargs, JarHolder)

    def func_build_target(self, node, args, kwargs):
        if 'target_type' not in kwargs:
            raise InterpreterException('Missing target_type keyword argument')
        target_type = kwargs.pop('target_type')
        if target_type == 'executable':
            return self.func_executable(node, args, kwargs)
        elif target_type == 'shared_library':
            return self.func_shared_lib(node, args, kwargs)
        elif target_type == 'static_library':
            return self.func_static_lib(node, args, kwargs)
        elif target_type == 'library':
            return self.func_library(node, args, kwargs)
        elif target_type == 'jar':
            return self.func_jar(node, args, kwargs)
        else:
            raise InterpreterException('Unknown target_type.')

    def func_vcs_tag(self, node, args, kwargs):
        fallback = kwargs.pop('fallback', None)
        if not isinstance(fallback, str):
            raise InterpreterException('Keyword argument fallback must exist and be a string.')
        replace_string = kwargs.pop('replace_string', '@VCS_TAG@')
        regex_selector = '(.*)' # default regex selector for custom command: use complete output
        vcs_cmd = kwargs.get('command', None)
        if vcs_cmd and not isinstance(vcs_cmd, list):
            vcs_cmd = [vcs_cmd]
        source_dir = os.path.normpath(os.path.join(self.environment.get_source_dir(), self.subdir))
        if vcs_cmd:
            # Is the command an executable in path or maybe a script in the source tree?
            vcs_cmd[0] = shutil.which(vcs_cmd[0]) or os.path.join(source_dir, vcs_cmd[0])
        else:
            vcs = mesonlib.detect_vcs(source_dir)
            if vcs:
                mlog.log('Found %s repository at %s' % (vcs['name'], vcs['wc_dir']))
                vcs_cmd = vcs['get_rev'].split()
                regex_selector = vcs['rev_regex']
            else:
                vcs_cmd = [' '] # executing this cmd will fail in vcstagger.py and force to use the fallback string
        # vcstagger.py parameters: infile, outfile, fallback, source_dir, replace_string, regex_selector, command...
        kwargs['command'] = [sys.executable,
                             self.environment.get_build_command(),
                             '--internal',
                             'vcstagger',
                             '@INPUT0@',
                             '@OUTPUT0@',
                             fallback,
                             source_dir,
                             replace_string,
                             regex_selector] + vcs_cmd
        kwargs.setdefault('build_always', True)
        return self.func_custom_target(node, [kwargs['output']], kwargs)

    @stringArgs
    def func_custom_target(self, node, args, kwargs):
        if len(args) != 1:
            raise InterpreterException('custom_target: Only one positional argument is allowed, and it must be a string name')
        name = args[0]
        tg = CustomTargetHolder(build.CustomTarget(name, self.subdir, kwargs), self)
        self.add_target(name, tg.held_object)
        return tg

    def func_run_target(self, node, args, kwargs):
        global run_depr_printed
        if len(args) > 1:
            if not run_depr_printed:
                mlog.log(mlog.red('DEPRECATION'), 'positional version of run_target is deprecated, use the keyword version instead.')
                run_depr_printed = True
            if 'command' in kwargs:
                raise InterpreterException('Can not have command both in positional and keyword arguments.')
            all_args = args[1:]
            deps = []
        elif len(args) == 1:
            if not 'command' in kwargs:
                raise InterpreterException('Missing "command" keyword argument')
            all_args = kwargs['command']
            if not isinstance(all_args, list):
                all_args = [all_args]
            deps = kwargs.get('depends', [])
            if not isinstance(deps, list):
                deps = [deps]
        else:
            raise InterpreterException('Run_target needs at least one positional argument.')

        cleaned_args = []
        for i in mesonlib.flatten(all_args):
            try:
                i = i.held_object
            except AttributeError:
                pass
            if not isinstance(i, (str, build.BuildTarget, build.CustomTarget, dependencies.ExternalProgram, mesonlib.File)):
                mlog.debug('Wrong type:', str(i))
                raise InterpreterException('Invalid argument to run_target.')
            cleaned_args.append(i)
        name = args[0]
        if not isinstance(name, str):
            raise InterpreterException('First argument must be a string.')
        cleaned_deps = []
        for d in deps:
            try:
                d = d.held_object
            except AttributeError:
                pass
            if not isinstance(d, (build.BuildTarget, build.CustomTarget)):
                raise InterpreterException('Depends items must be build targets.')
            cleaned_deps.append(d)
        command = cleaned_args[0]
        cmd_args = cleaned_args[1:]
        tg = RunTargetHolder(name, command, cmd_args, cleaned_deps, self.subdir)
        self.add_target(name, tg.held_object)
        return tg

    def func_generator(self, node, args, kwargs):
        gen = GeneratorHolder(self, args, kwargs)
        self.generators.append(gen)
        return gen

    def func_benchmark(self, node, args, kwargs):
        self.add_test(node, args, kwargs, False)

    def func_test(self, node, args, kwargs):
        self.add_test(node, args, kwargs, True)

    def add_test(self, node, args, kwargs, is_base_test):
        if len(args) != 2:
            raise InterpreterException('Incorrect number of arguments')
        if not isinstance(args[0], str):
            raise InterpreterException('First argument of test must be a string.')
        if not isinstance(args[1], (ExecutableHolder, JarHolder, ExternalProgramHolder)):
            raise InterpreterException('Second argument must be executable.')
        par = kwargs.get('is_parallel', True)
        if not isinstance(par, bool):
            raise InterpreterException('Keyword argument is_parallel must be a boolean.')
        cmd_args = kwargs.get('args', [])
        if not isinstance(cmd_args, list):
            cmd_args = [cmd_args]
        for i in cmd_args:
            if not isinstance(i, (str, mesonlib.File)):
                raise InterpreterException('Command line arguments must be strings')
        envlist = kwargs.get('env', [])
        if isinstance(envlist, EnvironmentVariablesHolder):
            env = envlist.held_object
        else:
            if not isinstance(envlist, list):
                envlist = [envlist]
            env = {}
            for e in envlist:
                if '=' not in e:
                    raise InterpreterException('Env var definition must be of type key=val.')
                (k, val) = e.split('=', 1)
                k = k.strip()
                val = val.strip()
                if ' ' in k:
                    raise InterpreterException('Env var key must not have spaces in it.')
                env[k] = val
        valgrind_args = kwargs.get('valgrind_args', [])
        if not isinstance(valgrind_args, list):
            valgrind_args = [valgrind_args]
        for a in valgrind_args:
            if not isinstance(a, str):
                raise InterpreterException('Valgrind_arg not a string.')
        should_fail = kwargs.get('should_fail', False)
        if not isinstance(should_fail, bool):
            raise InterpreterException('Keyword argument should_fail must be a boolean.')
        timeout = kwargs.get('timeout', 30)
        if 'workdir' in kwargs:
            workdir = kwargs['workdir']
            if not isinstance(workdir, str):
                raise InterpreterException('Workdir keyword argument must be a string.')
            if not os.path.isabs(workdir):
                raise InterpreterException('Workdir keyword argument must be an absolute path.')
        else:
            workdir = None
        if not isinstance(timeout, int):
            raise InterpreterException('Timeout must be an integer.')
        suite = mesonlib.stringlistify(kwargs.get('suite', ''))
        if self.is_subproject():
            newsuite = []
            for s in suite:
                if len(s) > 0:
                    s = '.' + s
                newsuite.append(self.subproject.replace(' ', '_').replace('.', '_') + s)
            suite = newsuite
        t = Test(args[0], suite, args[1].held_object, par, cmd_args, env, should_fail, valgrind_args, timeout, workdir)
        if is_base_test:
            self.build.tests.append(t)
            mlog.debug('Adding test "', mlog.bold(args[0]), '".', sep='')
        else:
            self.build.benchmarks.append(t)
            mlog.debug('Adding benchmark "', mlog.bold(args[0]), '".', sep='')

    @stringArgs
    def func_install_headers(self, node, args, kwargs):
        h = Headers(self.subdir, args, kwargs)
        self.build.headers.append(h)
        return h

    @stringArgs
    def func_install_man(self, node, args, kwargs):
        m = Man(self.subdir, args, kwargs)
        self.build.man.append(m)
        return m

    @noKwargs
    def func_subdir(self, node, args, kwargs):
        self.validate_arguments(args, 1, [str])
        if '..' in args[0]:
            raise InvalidArguments('Subdir contains ..')
        if self.subdir == '' and args[0] == self.subproject_dir:
            raise InvalidArguments('Must not go into subprojects dir with subdir(), use subproject() instead.')
        prev_subdir = self.subdir
        subdir = os.path.join(prev_subdir, args[0])
        if subdir in self.visited_subdirs:
            raise InvalidArguments('Tried to enter directory "%s", which has already been visited.'\
                                   % subdir)
        self.visited_subdirs[subdir] = True
        self.subdir = subdir
        os.makedirs(os.path.join(self.environment.build_dir, subdir), exist_ok=True)
        buildfilename = os.path.join(self.subdir, environment.build_filename)
        self.build_def_files.append(buildfilename)
        absname = os.path.join(self.environment.get_source_dir(), buildfilename)
        if not os.path.isfile(absname):
            self.subdir = prev_subdir
            raise InterpreterException('Nonexistant build def file %s.' % buildfilename)
        with open(absname, encoding='utf8') as f:
            code = f.read()
        assert(isinstance(code, str))
        try:
            codeblock = mparser.Parser(code).parse()
        except mesonlib.MesonException as me:
            me.file = buildfilename
            raise me
        self.evaluate_codeblock(codeblock)
        self.subdir = prev_subdir

    def func_install_data(self, node, args, kwargs):
        kwsource = mesonlib.stringlistify(kwargs.get('sources', []))
        raw_sources = args + kwsource
        sources = []
        source_strings = []
        for s in raw_sources:
            if isinstance(s, mesonlib.File):
                sources.append(s)
            else:
                source_strings.append(s)
        sources += self.source_strings_to_files(source_strings)
        install_dir = kwargs.get('install_dir', None)
        data = DataHolder(sources, install_dir)
        self.build.data.append(data.held_object)
        return data

    @stringArgs
    def func_install_subdir(self, node, args, kwargs):
        if len(args) != 1:
            raise InvalidArguments('Install_subdir requires exactly one argument.')
        if not 'install_dir' in kwargs:
            raise InvalidArguments('Missing keyword argument install_dir')
        install_dir = kwargs['install_dir']
        if not isinstance(install_dir, str):
            raise InvalidArguments('Keyword argument install_dir not a string.')
        idir = InstallDir(self.subdir, args[0], install_dir)
        self.build.install_dirs.append(idir)
        return idir

    def func_configure_file(self, node, args, kwargs):
        if len(args) > 0:
            raise InterpreterException("configure_file takes only keyword arguments.")
        if not 'output' in kwargs:
            raise InterpreterException('Required keyword argument "output" not defined.')
        inputfile = kwargs.get('input', None)
        output = kwargs['output']
        if not isinstance(inputfile, (str, type(None))):
            raise InterpreterException('Input must be a string.')
        if not isinstance(output, str):
            raise InterpreterException('Output must be a string.')
        if os.path.split(output)[0] != '':
            raise InterpreterException('Output file name must not contain a subdirectory.')
        (ofile_path, ofile_fname) = os.path.split(os.path.join(self.subdir, output))
        ofile_abs = os.path.join(self.environment.build_dir, ofile_path, ofile_fname)
        if 'configuration' in kwargs:
            conf = kwargs['configuration']
            if not isinstance(conf, ConfigurationDataHolder):
                raise InterpreterException('Argument "configuration" is not of type configuration_data')
            if inputfile is not None:
                # Normalize the path of the conffile to avoid duplicates
                # This is especially important to convert '/' to '\' on Windows
                conffile = os.path.normpath(os.path.join(self.subdir, inputfile))
                if conffile not in self.build_def_files:
                    self.build_def_files.append(conffile)
                os.makedirs(os.path.join(self.environment.build_dir, self.subdir), exist_ok=True)
                ifile_abs = os.path.join(self.environment.source_dir, self.subdir, inputfile)
                mesonlib.do_conf_file(ifile_abs, ofile_abs, conf.held_object)
            else:
                mesonlib.dump_conf_header(ofile_abs, conf.held_object)
            conf.mark_used()
        elif 'command' in kwargs:
            if 'input' not in kwargs:
                raise InterpreterException('Required keyword input missing.')
            res = self.func_run_command(node, kwargs['command'], {})
            if res.returncode != 0:
                raise InterpreterException('Running configure command failed.\n%s\n%s' %
                                           (res.stdout, res.stderr))
        else:
            raise InterpreterException('Configure_file must have either "configuration" or "command".')
        idir = kwargs.get('install_dir', None)
        if isinstance(idir, str):
            cfile = mesonlib.File.from_built_file(ofile_path, ofile_fname)
            self.build.data.append(DataHolder([cfile], idir).held_object)
        return mesonlib.File.from_built_file(self.subdir, output)

    @stringArgs
    def func_include_directories(self, node, args, kwargs):
        absbase = os.path.join(self.environment.get_source_dir(), self.subdir)
        for a in args:
            absdir = os.path.join(absbase, a)
            if not os.path.isdir(absdir):
                raise InvalidArguments('Include dir %s does not exist.' % a)
        is_system = kwargs.get('is_system', False)
        if not isinstance(is_system, bool):
            raise InvalidArguments('Is_system must be boolean.')
        i = IncludeDirsHolder(build.IncludeDirs(self.subdir, args, is_system))
        return i

    @stringArgs
    def func_add_global_arguments(self, node, args, kwargs):
        if self.subproject != '':
            msg = 'Global arguments can not be set in subprojects because ' \
                  'there is no way to make that reliable.\nPlease only call ' \
                  'this if is_subproject() returns false. Alternatively, ' \
                  'define a variable that\ncontains your language-specific ' \
                  'arguments and add it to the appropriate *_args kwarg ' \
                  'in each target.'
            raise InvalidCode(msg)
        if self.args_frozen:
            msg = 'Tried to set global arguments after a build target has ' \
                  'been declared.\nThis is not permitted. Please declare all ' \
                  'global arguments before your targets.'
            raise InvalidCode(msg)
        if not 'language' in kwargs:
            raise InvalidCode('Missing language definition in add_global_arguments')
        lang = kwargs['language'].lower()
        if lang in self.build.global_args:
            self.build.global_args[lang] += args
        else:
            self.build.global_args[lang] = args

    @stringArgs
    def func_add_global_link_arguments(self, node, args, kwargs):
        if self.subproject != '':
            msg = 'Global link arguments can not be set in subprojects because ' \
                  'there is no way to make that reliable.\nPlease only call ' \
                  'this if is_subproject() returns false. Alternatively, ' \
                  'define a variable that\ncontains your language-specific ' \
                  'arguments and add it to the appropriate *_args kwarg ' \
                  'in each target.'
            raise InvalidCode(msg)
        if self.args_frozen:
            msg = 'Tried to set global link arguments after a build target has ' \
                  'been declared.\nThis is not permitted. Please declare all ' \
                  'global arguments before your targets.'
            raise InvalidCode(msg)
        if not 'language' in kwargs:
            raise InvalidCode('Missing language definition in add_global_link_arguments')
        lang = kwargs['language'].lower()
        if lang in self.build.global_link_args:
            self.build.global_link_args[lang] += args
        else:
            self.build.global_link_args[lang] = args

    @stringArgs
    def func_add_project_link_arguments(self, node, args, kwargs):
        if self.args_frozen:
            msg = 'Tried to set project link arguments after a build target has ' \
                  'been declared.\nThis is not permitted. Please declare all ' \
                  'project link arguments before your targets.'
            raise InvalidCode(msg)
        if not 'language' in kwargs:
            raise InvalidCode('Missing language definition in add_project_link_arguments')
        lang = kwargs['language'].lower()
        if self.subproject not in self.build.projects_link_args:
            self.build.projects_link_args[self.subproject] = {}

        args = self.build.projects_link_args[self.subproject].get(lang, []) + args
        self.build.projects_link_args[self.subproject][lang] = args

    @stringArgs
    def func_add_project_arguments(self, node, args, kwargs):
        if self.args_frozen:
            msg = 'Tried to set project arguments after a build target has ' \
                  'been declared.\nThis is not permitted. Please declare all ' \
                  'project arguments before your targets.'
            raise InvalidCode(msg)

        if not 'language' in kwargs:
            raise InvalidCode('Missing language definition in add_project_arguments')

        if self.subproject not in self.build.projects_args:
            self.build.projects_args[self.subproject] = {}

        lang = kwargs['language'].lower()
        args = self.build.projects_args[self.subproject].get(lang, []) + args
        self.build.projects_args[self.subproject][lang] = args

    def func_environment(self, node, args, kwargs):
        return EnvironmentVariablesHolder()

    @stringArgs
    @noKwargs
    def func_join_paths(self, node, args, kwargs):
        if isinstance(args, str):
            st = (args,)
        else:
            st = tuple(args)
        return os.path.join(*args).replace('\\', '/')

    def run(self):
        super().run()
        mlog.log('Build targets in project:', mlog.bold(str(len(self.build.targets))))

    def source_strings_to_files(self, sources):
        results = []
        for s in sources:
            if isinstance(s, (mesonlib.File, GeneratedListHolder,
                              CustomTargetHolder)):
                pass
            elif isinstance(s, str):
                s = mesonlib.File.from_source_file(self.environment.source_dir, self.subdir, s)
            else:
                raise InterpreterException("Source item is not string or File-type object.")
            results.append(s)
        return results

    def add_target(self, name, tobj):
        if name == '':
            raise InterpreterException('Target name must not be empty.')
        if name in coredata.forbidden_target_names:
            raise InvalidArguments('Target name "%s" is reserved for Meson\'s internal use. Please rename.'\
                                   % name)
        # To permit an executable and a shared library to have the
        # same name, such as "foo.exe" and "libfoo.a".
        idname = tobj.get_id()
        if idname in self.build.targets:
            raise InvalidCode('Tried to create target "%s", but a target of that name already exists.' % name)
        self.build.targets[idname] = tobj
        if idname not in self.coredata.target_guids:
            self.coredata.target_guids[idname] = str(uuid.uuid4()).upper()

    def build_target(self, node, args, kwargs, targetholder):
        if len(args) == 0:
            raise InterpreterException('Target does not have a name.')
        name = args[0]
        sources = args[1:]
        if self.environment.is_cross_build():
            if kwargs.get('native', False):
                is_cross = False
            else:
                is_cross = True
        else:
            is_cross = False
        try:
            kw_src = self.flatten(kwargs['sources'])
            if not isinstance(kw_src, list):
                kw_src = [kw_src]
        except KeyError:
            kw_src = []
        sources += kw_src
        sources = self.source_strings_to_files(sources)
        objs = self.flatten(kwargs.get('objects', []))
        kwargs['dependencies'] = self.flatten(kwargs.get('dependencies', []))
        if not isinstance(objs, list):
            objs = [objs]
        self.check_sources_exist(os.path.join(self.source_root, self.subdir), sources)
        if targetholder is ExecutableHolder:
            targetclass = build.Executable
        elif targetholder is SharedLibraryHolder:
            targetclass = build.SharedLibrary
        elif targetholder is StaticLibraryHolder:
            targetclass = build.StaticLibrary
        elif targetholder is JarHolder:
            targetclass = build.Jar
        else:
            mlog.debug('Unknown target type:', str(targetholder))
            raise RuntimeError('Unreachable code')
        target = targetclass(name, self.subdir, self.subproject, is_cross, sources, objs, self.environment, kwargs)
        if is_cross:
            self.add_cross_stdlib_info(target)
        l = targetholder(target, self)
        self.add_target(name, l.held_object)
        self.args_frozen = True
        return l

    def get_used_languages(self, target):
        result = {}
        for i in target.sources:
            for c in self.build.compilers:
                if c.can_compile(i):
                    result[c.language] = True
                    break
        return result

    def add_cross_stdlib_info(self, target):
        for l in self.get_used_languages(target):
            if self.environment.cross_info.has_stdlib(l) and \
                self.subproject != self.environment.cross_info.get_stdlib(l)[0]:
                target.add_deps(self.build.cross_stdlibs[l])

    def check_sources_exist(self, subdir, sources):
        for s in sources:
            if not isinstance(s, str):
                continue # This means a generated source and they always exist.
            fname = os.path.join(subdir, s)
            if not os.path.isfile(fname):
                raise InterpreterException('Tried to add non-existing source file %s.' % s)

    def bool_method_call(self, obj, method_name, args):
        obj = self.to_native(obj)
        (posargs, _) = self.reduce_arguments(args)
        if method_name == 'to_string':
            if len(posargs) == 0:
                if obj == True:
                    return 'true'
                else:
                    return 'false'
            elif len(posargs) == 2 and isinstance(posargs[0], str) and isinstance(posargs[1], str):
                if obj == True:
                    return posargs[0]
                else:
                    return posargs[1]
            else:
                raise InterpreterException('bool.to_string() must have either no arguments or exactly two string arguments that signify what values to return for true and false.')
        elif method_name == 'to_int':
            if obj == True:
                return 1
            else:
                return 0
        else:
            raise InterpreterException('Unknown method "%s" for a boolean.' % method_name)

    def int_method_call(self, obj, method_name, args):
        obj = self.to_native(obj)
        (posargs, _) = self.reduce_arguments(args)
        if method_name == 'is_even':
            if len(posargs) == 0:
                return obj % 2 == 0
            else:
                raise InterpreterException('int.is_even() must have no arguments.')
        elif method_name == 'is_odd':
            if len(posargs) == 0:
                return obj % 2 != 0
            else:
                raise InterpreterException('int.is_odd() must have no arguments.')
        else:
            raise InterpreterException('Unknown method "%s" for an integer.' % method_name)

    def string_method_call(self, obj, method_name, args):
        obj = self.to_native(obj)
        (posargs, _) = self.reduce_arguments(args)
        if method_name == 'strip':
            return obj.strip()
        elif method_name == 'format':
            return self.format_string(obj, args)
        elif method_name == 'to_upper':
            return obj.upper()
        elif method_name == 'to_lower':
            return obj.lower()
        elif method_name == 'underscorify':
            return re.sub(r'[^a-zA-Z0-9]', '_', obj)
        elif method_name == 'split':
            if len(posargs) > 1:
                raise InterpreterException('Split() must have at most one argument.')
            elif len(posargs) == 1:
                s = posargs[0]
                if not isinstance(s, str):
                    raise InterpreterException('Split() argument must be a string')
                return obj.split(s)
            else:
                return obj.split()
        elif method_name == 'startswith' or method_name == 'contains' or method_name == 'endswith':
            s = posargs[0]
            if not isinstance(s, str):
                raise InterpreterException('Argument must be a string.')
            if method_name == 'startswith':
                return obj.startswith(s)
            elif method_name == 'contains':
                return obj.find(s) >= 0
            return obj.endswith(s)
        elif method_name == 'to_int':
            try:
                return int(obj)
            except Exception:
                raise InterpreterException('String {!r} cannot be converted to int'.format(obj))
        elif method_name == 'join':
            if len(posargs) != 1:
                raise InterpreterException('Join() takes exactly one argument.')
            strlist = posargs[0]
            check_stringlist(strlist)
            return obj.join(strlist)
        elif method_name == 'version_compare':
            if len(posargs) != 1:
                raise InterpreterException('Version_compare() takes exactly one argument.')
            cmpr = posargs[0]
            if not isinstance(cmpr, str):
                raise InterpreterException('Version_compare() argument must be a string.')
            return mesonlib.version_compare(obj, cmpr)
        raise InterpreterException('Unknown method "%s" for a string.' % method_name)

    def format_string(self, templ, args):
        templ = self.to_native(templ)
        if isinstance(args, mparser.ArgumentNode):
            args = args.arguments
        for (i, arg) in enumerate(args):
            arg = self.to_native(self.evaluate_statement(arg))
            if isinstance(arg, bool): # Python boolean is upper case.
                arg = str(arg).lower()
            templ = templ.replace('@{}@'.format(i), str(arg))
        return templ

    def method_call(self, node):
        invokable = node.source_object
        if isinstance(invokable, mparser.IdNode):
            object_name = invokable.value
            obj = self.get_variable(object_name)
        else:
            obj = self.evaluate_statement(invokable)
        method_name = node.name
        args = node.args
        if isinstance(obj, mparser.StringNode):
            obj = obj.get_value()
        if isinstance(obj, str):
            return self.string_method_call(obj, method_name, args)
        if isinstance(obj, bool):
            return self.bool_method_call(obj, method_name, args)
        if isinstance(obj, int):
            return self.int_method_call(obj, method_name, args)
        if isinstance(obj, list):
            return self.array_method_call(obj, method_name, self.reduce_arguments(args)[0])
        if not isinstance(obj, InterpreterObject):
            raise InvalidArguments('Variable "%s" is not callable.' % object_name)
        (args, kwargs) = self.reduce_arguments(args)
        if method_name == 'extract_objects':
            self.validate_extraction(obj.held_object)
        return obj.method_call(method_name, self.flatten(args), kwargs)

    # Only permit object extraction from the same subproject
    def validate_extraction(self, buildtarget):
        if not self.subdir.startswith(self.subproject_dir):
            if buildtarget.subdir.startswith(self.subproject_dir):
                raise InterpreterException('Tried to extract objects from a subproject target.')
        else:
            if not buildtarget.subdir.startswith(self.subproject_dir):
                raise InterpreterException('Tried to extract objects from the main project from a subproject.')
            if self.subdir.split('/')[1] != buildtarget.subdir.split('/')[1]:
                raise InterpreterException('Tried to extract objects from a different subproject.')

    def array_method_call(self, obj, method_name, args):
        if method_name == 'contains':
            return self.check_contains(obj, args)
        elif method_name == 'length':
            return len(obj)
        elif method_name == 'get':
            index = args[0]
            if not isinstance(index, int):
                raise InvalidArguments('Array index must be a number.')
            if index < -len(obj) or index >= len(obj):
                raise InvalidArguments('Array index %s is out of bounds for array of size %d.' % (index, len(obj)))
            return obj[index]
        raise InterpreterException('Arrays do not have a method called "%s".' % method_name)

    def check_contains(self, obj, args):
        if len(args) != 1:
            raise InterpreterException('Contains method takes exactly one argument.')
        item = args[0]
        for element in obj:
            if isinstance(element, list):
                found = self.check_contains(element, args)
                if found:
                    return True
            try:
                if element == item:
                    return True
            except Exception:
                pass
        return False

    def evaluate_if(self, node):
        assert(isinstance(node, mparser.IfClauseNode))
        for i in node.ifs:
            result = self.evaluate_statement(i.condition)
            if not(isinstance(result, bool)):
                raise InvalidCode('If clause {!r} does not evaluate to true or false.'.format(result))
            if result:
                self.evaluate_codeblock(i.block)
                return
        if not isinstance(node.elseblock, mparser.EmptyNode):
            self.evaluate_codeblock(node.elseblock)

    def evaluate_ternary(self, node):
        assert(isinstance(node, mparser.TernaryNode))
        result = self.evaluate_statement(node.condition)
        if not isinstance(result, bool):
            raise InterpreterException('Ternary condition is not boolean.')
        if result:
            return self.evaluate_statement(node.trueblock)
        else:
            return self.evaluate_statement(node.falseblock)

    def evaluate_foreach(self, node):
        assert(isinstance(node, mparser.ForeachClauseNode))
        varname = node.varname.value
        items = self.evaluate_statement(node.items)
        if not isinstance(items, list):
            raise InvalidArguments('Items of foreach loop is not an array')
        for item in items:
            self.set_variable(varname, item)
            self.evaluate_codeblock(node.block)

    def evaluate_plusassign(self, node):
        assert(isinstance(node, mparser.PlusAssignmentNode))
        varname = node.var_name
        addition = self.evaluate_statement(node.value)
        # Remember that all variables are immutable. We must always create a
        # full new variable and then assign it.
        old_variable = self.get_variable(varname)
        if isinstance(old_variable, str):
          if not isinstance(addition, str):
            raise InvalidArguments('The += operator requires a string on the right hand side if the variable on the left is a string')
          new_value = old_variable + addition
        elif isinstance(old_variable, int):
          if not isinstance(addition, int):
            raise InvalidArguments('The += operator requires an int on the right hand side if the variable on the left is an int')
          new_value = old_variable + addition
        elif not isinstance(old_variable, list):
            raise InvalidArguments('The += operator currently only works with arrays, strings or ints ')
        # Add other data types here.
        else:
            if isinstance(addition, list):
                new_value = old_variable + addition
            else:
                new_value = old_variable + [addition]
        self.set_variable(varname, new_value)

    def evaluate_indexing(self, node):
        assert(isinstance(node, mparser.IndexNode))
        iobject = self.evaluate_statement(node.iobject)
        if not isinstance(iobject, list):
            raise InterpreterException('Tried to index a non-array object.')
        index = self.evaluate_statement(node.index)
        if not isinstance(index, int):
            raise InterpreterException('Index value is not an integer.')
        if index < -len(iobject) or index >= len(iobject):
            raise InterpreterException('Index %d out of bounds of array of size %d.' % (index, len(iobject)))
        return iobject[index]

    def is_elementary_type(self, v):
        return isinstance(v, (int, float, str, bool, list))

    def evaluate_comparison(self, node):
        v1 = self.evaluate_statement(node.left)
        v2 = self.evaluate_statement(node.right)
        if self.is_elementary_type(v1):
            val1 = v1
        else:
            val1 = v1.value
        if self.is_elementary_type(v2):
            val2 = v2
        else:
            val2 = v2.value
        if node.ctype == '==':
            return val1 == val2
        elif node.ctype == '!=':
            return val1 != val2
        elif node.ctype == '<':
            return val1 < val2
        elif node.ctype == '<=':
            return val1 <= val2
        elif node.ctype == '>':
            return val1 > val2
        elif node.ctype == '>=':
            return val1 >= val2
        else:
            raise InvalidCode('You broke my compare eval.')

    def evaluate_andstatement(self, cur):
        l = self.evaluate_statement(cur.left)
        if isinstance(l, mparser.BooleanNode):
            l = l.value
        if not isinstance(l, bool):
            raise InterpreterException('First argument to "and" is not a boolean.')
        if not l:
            return False
        r = self.evaluate_statement(cur.right)
        if isinstance(r, mparser.BooleanNode):
            r = r.value
        if not isinstance(r, bool):
            raise InterpreterException('Second argument to "and" is not a boolean.')
        return r

    def evaluate_orstatement(self, cur):
        l = self.evaluate_statement(cur.left)
        if isinstance(l, mparser.BooleanNode):
            l = l.get_value()
        if not isinstance(l, bool):
            raise InterpreterException('First argument to "or" is not a boolean.')
        if l:
            return True
        r = self.evaluate_statement(cur.right)
        if isinstance(r, mparser.BooleanNode):
            r = r.get_value()
        if not isinstance(r, bool):
            raise InterpreterException('Second argument to "or" is not a boolean.')
        return r

    def evaluate_notstatement(self, cur):
        v = self.evaluate_statement(cur.value)
        if isinstance(v, mparser.BooleanNode):
            v = v.value
        if not isinstance(v, bool):
            raise InterpreterException('Argument to "not" is not a boolean.')
        return not v

    def evaluate_uminusstatement(self, cur):
        v = self.evaluate_statement(cur.value)
        if isinstance(v, mparser.NumberNode):
            v = v.value
        if not isinstance(v, int):
            raise InterpreterException('Argument to negation is not an integer.')
        return -v

    def evaluate_arithmeticstatement(self, cur):
        l = self.to_native(self.evaluate_statement(cur.left))
        r = self.to_native(self.evaluate_statement(cur.right))

        if cur.operation == 'add':
            try:
                return l + r
            except Exception as e:
                raise InvalidCode('Invalid use of addition: ' + str(e))
        elif cur.operation == 'sub':
            if not isinstance(l, int) or not isinstance(r, int):
                raise InvalidCode('Subtraction works only with integers.')
            return l - r
        elif cur.operation == 'mul':
            if not isinstance(l, int) or not isinstance(r, int):
                raise InvalidCode('Multiplication works only with integers.')
            return l * r
        elif cur.operation == 'div':
            if not isinstance(l, int) or not isinstance(r, int):
                raise InvalidCode('Division works only with integers.')
            return l // r
        elif cur.operation == 'mod':
            if not isinstance(l, int) or not isinstance(r, int):
                raise InvalidCode('Modulo works only with integers.')
            return l % r
        else:
            raise InvalidCode('You broke me.')

    def is_subproject(self):
        return self.subproject != ''