1 files changed, 79 insertions, 0 deletions
diff --git a/mesonbuild/interpreterbase/baseobjects.py b/mesonbuild/interpreterbase/baseobjects.py
new file mode 100644
index 0000000..f48ab9b
--- /dev/null
+++ b/mesonbuild/interpreterbase/baseobjects.py
@@ -0,0 +1,79 @@
+# Copyright 2013-2021 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 .exceptions import InvalidCode
+from .helpers import flatten
+
+import typing as T
+
+TV_fw_var = T.Union[str, int, float, bool, list, dict, 'InterpreterObject', 'ObjectHolder']
+TV_fw_args = T.List[T.Union[mparser.BaseNode, TV_fw_var]]
+TV_fw_kwargs = T.Dict[str, T.Union[mparser.BaseNode, TV_fw_var]]
+
+TV_func = T.TypeVar('TV_func', bound=T.Callable[..., T.Any])
+
+TYPE_elementary = T.Union[str, int, float, bool]
+TYPE_var = T.Union[TYPE_elementary, T.List[T.Any], T.Dict[str, T.Any], 'InterpreterObject', 'ObjectHolder']
+TYPE_nvar = T.Union[TYPE_var, mparser.BaseNode]
+TYPE_nkwargs = T.Dict[str, TYPE_nvar]
+TYPE_key_resolver = T.Callable[[mparser.BaseNode], str]
+
+class InterpreterObject:
+    def __init__(self) -> None:
+        self.methods = {}  # type: T.Dict[str, T.Callable[[T.List[TYPE_nvar], TYPE_nkwargs], TYPE_var]]
+        # Current node set during a method call. This can be used as location
+        # when printing a warning message during a method call.
+        self.current_node = None  # type: mparser.BaseNode
+
+    def method_call(
+                self,
+                method_name: str,
+                args: TV_fw_args,
+                kwargs: TV_fw_kwargs
+            ) -> TYPE_var:
+        if method_name in self.methods:
+            method = self.methods[method_name]
+            if not getattr(method, 'no-args-flattening', False):
+                args = flatten(args)
+            return method(args, kwargs)
+        raise InvalidCode('Unknown method "%s" in object.' % method_name)
+
+class MutableInterpreterObject(InterpreterObject):
+    def __init__(self) -> None:
+        super().__init__()
+
+TV_InterpreterObject = T.TypeVar('TV_InterpreterObject')
+
+class ObjectHolder(T.Generic[TV_InterpreterObject]):
+    def __init__(self, obj: TV_InterpreterObject, subproject: str = '') -> None:
+        self.held_object = obj
+        self.subproject = subproject
+
+    def __repr__(self) -> str:
+        return f'<Holder: {self.held_object!r}>'
+
+class RangeHolder(InterpreterObject):
+    def __init__(self, start: int, stop: int, step: int) -> None:
+        super().__init__()
+        self.range = range(start, stop, step)
+
+    def __iter__(self) -> T.Iterator[int]:
+        return iter(self.range)
+
+    def __getitem__(self, key: int) -> int:
+        return self.range[key]
+
+    def __len__(self) -> int:
+        return len(self.range)