Add number, string and array arithmetic

Addition (+), subtraction (-), multiplication (*) and division (/) for numbers
follows the BIDMAS rules.

Strings and arrays can be concatenated with the addition operator

Strings can be concatenated with numbers with the addition operator

10 files changed, 164 insertions, 42 deletions

diff --git a/authors.txt b/authors.txt
index 1859942..e3652c8 100644
--- a/authors.txt
+++ b/authors.txt
@@ -8,3 +8,4 @@ The following people have submitted patches for the project
 Peter Koval
 Masashi Fujita
 Juhani Simola
+Robin McCorkell
diff --git a/interpreter.py b/interpreter.py
index e2a7b16..2b75fa8 100644
--- a/interpreter.py
+++ b/interpreter.py
@@ -1,4 +1,5 @@
 # Copyright 2012-2014 Jussi Pakkanen
+# Copyright 2014 Robin McCorkell
 
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -800,15 +801,19 @@ class Interpreter():
         elif isinstance(cur, mparser.ArrayNode):
             return self.evaluate_arraystatement(cur)
         elif isinstance(cur, mparser.NumberNode):
-            return cur
+            return cur.value
         elif isinstance(cur, mparser.AndNode):
             return self.evaluate_andstatement(cur)
         elif isinstance(cur, mparser.OrNode):
             return self.evaluate_orstatement(cur)
         elif isinstance(cur, mparser.NotNode):
             return self.evaluate_notstatement(cur)
+        elif isinstance(cur, mparser.ArithmeticNode):
+            return self.evaluate_arithmeticstatement(cur)
         elif isinstance(cur, mparser.ForeachClauseNode):
             return self.evaluate_foreach(cur)
+        elif self.is_elementary_type(cur):
+            return cur
         else:
             raise InvalidCode("Unknown statement.")
 
@@ -1393,37 +1398,17 @@ class Interpreter():
         self.set_variable(var_name, value)
         return value
 
-    def reduce_single(self, arg):
-        if isinstance(arg, mparser.IdNode):
-            return self.get_variable(arg.value)
-        elif isinstance(arg, str):
-            return arg
-        elif isinstance(arg, mparser.StringNode):
-            return arg.value
-        elif isinstance(arg, mparser.FunctionNode):
-            return self.function_call(arg)
-        elif isinstance(arg, mparser.MethodNode):
-            return self.method_call(arg)
-        elif isinstance(arg, mparser.BooleanNode):
-            return arg.value
-        elif isinstance(arg, mparser.ArrayNode):
-            return [self.reduce_single(curarg) for curarg in arg.args.arguments]
-        elif isinstance(arg, mparser.NumberNode):
-            return arg.value
-        else:
-            raise InvalidCode('Irreducible argument.')
-
     def reduce_arguments(self, args):
         assert(isinstance(args, mparser.ArgumentNode))
         if args.incorrect_order():
             raise InvalidArguments('All keyword arguments must be after positional arguments.')
-        reduced_pos = [self.reduce_single(arg) for arg in args.arguments]
+        reduced_pos = [self.evaluate_statement(arg) for arg in args.arguments]
         reduced_kw = {}
         for key in args.kwargs.keys():
             if not isinstance(key, str):
                 raise InvalidArguments('Keyword argument name is not a string.')
             a = args.kwargs[key]
-            reduced_kw[key] = self.reduce_single(a)
+            reduced_kw[key] = self.evaluate_statement(a)
         return (reduced_pos, reduced_kw)
 
     def string_method_call(self, obj, method_name, args):
@@ -1457,7 +1442,7 @@ class Interpreter():
         if isinstance(args, mparser.ArgumentNode):
             args = args.arguments
         for (i, arg) in enumerate(args):
-            arg = self.to_native(self.reduce_single(arg))
+            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))
@@ -1537,7 +1522,7 @@ class Interpreter():
             self.evaluate_codeblock(node.block)
 
     def is_elementary_type(self, v):
-        if isinstance(v, int) or isinstance(v, str) or isinstance(v, bool):
+        if isinstance(v, (int, float, str, bool, list)):
             return True
         return False
 
@@ -1552,9 +1537,6 @@ class Interpreter():
             val2 = v2
         else:
             val2 = v2.value
-        if type(val1) != type(val2):
-            raise InterpreterException('Comparison of different types %s and %s.' %
-                                       (str(type(val1)), str(type(val2))))
         if node.ctype == '==':
             return val1 == val2
         elif node.ctype == '!=':
@@ -1600,6 +1582,24 @@ class Interpreter():
             raise InterpreterException('Argument to "not" is not a boolean.')
         return not 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 isinstance(l, str) or isinstance(r, str):
+            l = str(l)
+            r = str(r)
+
+        if cur.operation == 'add':
+            return l + r
+        elif cur.operation == 'sub':
+            return l - r
+        elif cur.operation == 'mul':
+            return l * r
+        elif cur.operation == 'div':
+            return l // r
+        else:
+            raise InvalidCode('You broke me.')
+
     def evaluate_arraystatement(self, cur):
         (arguments, kwargs) = self.reduce_arguments(cur.args)
         if len(kwargs) > 0:
diff --git a/mparser.py b/mparser.py
index a0be378..1cdc953 100644
--- a/mparser.py
+++ b/mparser.py
@@ -1,6 +1,7 @@
 #!/usr/bin/python3
 
 # Copyright 2014 Jussi Pakkanen
+# Copyright 2014 Robin McCorkell
 
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -56,6 +57,10 @@ class Lexer:
             ('string', re.compile("'[^']*?'")),
             ('comma', re.compile(r',')),
             ('dot', re.compile(r'\.')),
+            ('plus', re.compile(r'\+')),
+            ('dash', re.compile(r'-')),
+            ('star', re.compile(r'\*')),
+            ('fslash', re.compile(r'/')),
             ('colon', re.compile(r':')),
             ('equal', re.compile(r'==')),
             ('nequal', re.compile(r'\!=')),
@@ -177,6 +182,14 @@ class ComparisonNode:
         self.right = right
         self.ctype = ctype
 
+class ArithmeticNode:
+    def __init__(self, lineno, colno, operation, left, right):
+        self.lineno = lineno
+        self.colno = colno
+        self.left = left
+        self.right = right
+        self.operation = operation
+
 class NotNode:
     def __init__(self, lineno, colno, value):
         self.lineno = lineno
@@ -277,12 +290,12 @@ class ArgumentNode():
 # 1 assignment
 # 2 or
 # 3 and
-# 4 equality
-# comparison, plus and multiplication would go here
-# 5 negation
-# 6 funcall, method call
-# 7 parentheses
-# 8 plain token
+# 4 comparison
+# 5 arithmetic
+# 6 negation
+# 7 funcall, method call
+# 8 parentheses
+# 9 plain token
 
 class Parser:
     def __init__(self, code):
@@ -345,12 +358,39 @@ class Parser:
         return left
 
     def e5(self):
-        if self.accept('not'):
-            return NotNode(self.current.lineno, self.current.colno, self.e6())
-        return self.e6()
+        return self.e5add()
+
+    def e5add(self):
+        left = self.e5sub()
+        if self.accept('plus'):
+            return ArithmeticNode(left.lineno, left.colno, 'add', left, self.e5add())
+        return left
+
+    def e5sub(self):
+        left = self.e5mul()
+        if self.accept('dash'):
+            return ArithmeticNode(left.lineno, left.colno, 'sub', left, self.e5sub())
+        return left
+
+    def e5mul(self):
+        left = self.e5div()
+        if self.accept('star'):
+            return ArithmeticNode(left.lineno, left.colno, 'mul', left, self.e5mul())
+        return left
+
+    def e5div(self):
+        left = self.e6()
+        if self.accept('fslash'):
+            return ArithmeticNode(left.lineno, left.colno, 'div', left, self.e5div())
+        return left
 
     def e6(self):
-        left = self.e7()
+        if self.accept('not'):
+            return NotNode(self.current.lineno, self.current.colno, self.e7())
+        return self.e7()
+
+    def e7(self):
+        left = self.e8()
         if self.accept('lparen'):
             args = self.args()
             self.expect('rparen')
@@ -362,7 +402,7 @@ class Parser:
             left = self.method_call(left)
         return left
 
-    def e7(self):
+    def e8(self):
         if self.accept('lparen'):
             e = self.statement()
             self.expect('rparen')
@@ -372,9 +412,9 @@ class Parser:
             self.expect('rbracket')
             return ArrayNode(args)
         else:
-            return self.e8()
+            return self.e9()
 
-    def e8(self):
+    def e9(self):
         t = self.current
         if self.accept('true'):
             return BooleanNode(t, True);
@@ -413,7 +453,7 @@ class Parser:
         return a
 
     def method_call(self, source_object):
-        methodname = self.e8()
+        methodname = self.e9()
         if not(isinstance(methodname, IdNode)):
             raise ParseException('Method name must be plain id',
                                  self.current.lineno, self.current.colno)
diff --git a/test cases/common/68 number arithmetic/meson.build b/test cases/common/68 number arithmetic/meson.build
new file mode 100644
index 0000000..894c065
--- /dev/null
+++ b/test cases/common/68 number arithmetic/meson.build
@@ -0,0 +1,22 @@
+project('number arithmetic', 'c')
+
+if 6 + 4 != 10
+  error('Number addition is broken')
+endif
+if 6 - 4 != 2
+  error('Number subtraction is broken')
+endif
+
+if 6 * 4 != 24
+  error('Number multiplication is broken')
+endif
+if 16 / 4 != 4
+  error('Number division is broken')
+endif
+
+#if (1 / 3) * 3 != 1
+#  error('Float interconversion broken')
+#endif
+if (5 / 3) * 3 != 3
+  error('Integer division is broken')
+endif
diff --git a/test cases/common/69 string arithmetic/meson.build b/test cases/common/69 string arithmetic/meson.build
new file mode 100644
index 0000000..f0e46e9
--- /dev/null
+++ b/test cases/common/69 string arithmetic/meson.build
@@ -0,0 +1,20 @@
+project('string arithmetic', 'c')
+
+if 'foo' + 'bar' != 'foobar'
+  error('String concatenation is broken')
+endif
+
+if 'foo' + 'bar' + 'baz' != 'foobarbaz'
+  error('Many-string concatenation is broken')
+endif
+
+if 'foobar' + 5 != 'foobar5' or 5 + 'foobar' != '5foobar'
+  error('String-number concatenation is broken')
+endif
+
+if (5 + 3) + 'foobar' != '8foobar'
+  error('String-number addition then concatenation broken')
+endif
+if 5 + (3 + 'foobar') != '53foobar'
+  error('String-number concatenation then addition broken')
+endif
diff --git a/test cases/common/70 array arithmetic/meson.build b/test cases/common/70 array arithmetic/meson.build
new file mode 100644
index 0000000..8b8785a
--- /dev/null
+++ b/test cases/common/70 array arithmetic/meson.build
@@ -0,0 +1,15 @@
+project('array arithmetic', 'c')
+
+array1 = ['foo', 'bar']
+array2 = ['qux', 'baz']
+
+if array1 + array2 != ['foo', 'bar', 'qux', 'baz']
+  error('Array concatenation is broken')
+endif
+if array2 + array1 != ['qux', 'baz', 'foo', 'bar']
+  error('Array concatenation is broken')
+endif
+
+if array1 + array1 + array1 != ['foo', 'bar', 'foo', 'bar', 'foo', 'bar']
+  error('Many-array concatenation is broken')
+endif
diff --git a/test cases/common/71 arithmetic bidmas/meson.build b/test cases/common/71 arithmetic bidmas/meson.build
new file mode 100644
index 0000000..2a530c8
--- /dev/null
+++ b/test cases/common/71 arithmetic bidmas/meson.build
@@ -0,0 +1,15 @@
+project('arithmetic bidmas', 'c')
+
+if 5 * 3 - 6 / 2 + 1 != 13
+  error('Arithemtic bidmas broken')
+endif
+if 5 * (3 - 6 / 2) + 1 != 1
+  error('Arithmetic bidmas with brackets broken')
+endif
+
+if 5 * 12 / 2 * 3 != 90
+  error('Sequential multiplication and division broken')
+endif
+if 5 * (12 / (2 * 3)) != 10
+  error('Sequential multiplication and division with brackets broken')
+endif
diff --git a/test cases/failing/11 object arithmetic/meson.build b/test cases/failing/11 object arithmetic/meson.build
new file mode 100644
index 0000000..34e3a7a
--- /dev/null
+++ b/test cases/failing/11 object arithmetic/meson.build
@@ -0,0 +1,3 @@
+project('object arithmetic')
+
+foo = '5' + meson
diff --git a/test cases/failing/12 string arithmetic/meson.build b/test cases/failing/12 string arithmetic/meson.build
new file mode 100644
index 0000000..753f62b
--- /dev/null
+++ b/test cases/failing/12 string arithmetic/meson.build
@@ -0,0 +1,3 @@
+project('string arithmetic')
+
+foo = 'a' / 'b'
diff --git a/test cases/failing/13 array arithmetic/meson.build b/test cases/failing/13 array arithmetic/meson.build
new file mode 100644
index 0000000..ceaa8bc
--- /dev/null
+++ b/test cases/failing/13 array arithmetic/meson.build
@@ -0,0 +1,3 @@
+project('array arithmetic')
+
+foo = ['a', 'b'] * ['6', '4']