Add support for subscripting array objects with [].

4 files changed, 40 insertions, 7 deletions

diff --git a/interpreter.py b/interpreter.py
index 91ec6aa..76964a6 100644
--- a/interpreter.py
+++ b/interpreter.py
@@ -1056,6 +1056,8 @@ class Interpreter():
             return self.evaluate_foreach(cur)
         elif isinstance(cur, mparser.PlusAssignmentNode):
             return self.evaluate_plusassign(cur)
+        elif isinstance(cur, mparser.IndexNode):
+            return self.evaluate_indexing(cur)
         elif self.is_elementary_type(cur):
             return cur
         else:
@@ -1903,6 +1905,18 @@ class Interpreter():
                 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):
         if isinstance(v, (int, float, str, bool, list)):
             return True
diff --git a/mparser.py b/mparser.py
index 83d9cca..455182a 100644
--- a/mparser.py
+++ b/mparser.py
@@ -210,6 +210,13 @@ class CodeBlockNode:
         self.colno = colno
         self.lines = []
 
+class IndexNode:
+    def __init__(self, iobject, index):
+        self.iobject = iobject
+        self.index = index
+        self.lineno = iobject.lineno
+        self.colno = iobject.colno
+
 class MethodNode:
     def __init__(self, lineno, colno, source_object, name, args):
         self.lineno = lineno
@@ -429,8 +436,15 @@ class Parser:
                 raise ParseException('Function call must be applied to plain id',
                                      left.lineno, left.colno)
             left = FunctionNode(left.lineno, left.colno, left.value, args)
-        while self.accept('dot'):
-            left = self.method_call(left)
+        go_again = True
+        while go_again:
+            go_again = False
+            if self.accept('dot'):
+                go_again = True
+                left = self.method_call(left)
+            if self.accept('lbracket'):
+                go_again = True
+                left = self.index_call(left)
         return left
 
     def e8(self):
@@ -492,6 +506,11 @@ class Parser:
             return self.method_call(method)
         return method
 
+    def index_call(self, source_object):
+        index_statement = self.statement()
+        self.expect('rbracket')
+        return IndexNode(source_object, index_statement)
+
     def foreachblock(self):
         t = self.current
         self.expect('id')
diff --git a/test cases/common/91 plusassign/meson.build b/test cases/common/91 plusassign/meson.build
index 0093d88..c1e47e0 100644
--- a/test cases/common/91 plusassign/meson.build
+++ b/test cases/common/91 plusassign/meson.build
@@ -8,7 +8,7 @@ if x.length() != 1
   error('Incorrect append')
 endif
 
-if x.get(0) != 'a'
+if x[0] != 'a'
   error('Incorrect append 2.')
 endif
 
@@ -20,7 +20,7 @@ if y.length() != 1
   error('Immutability broken.')
 endif
 
-if y.get(0) != 'a'
+if y[0] != 'a'
   error('Immutability broken 2.')
 endif
 
@@ -28,11 +28,11 @@ if x.length() != 2
   error('Incorrect append 3')
 endif
 
-if x.get(0) != 'a'
+if x[0] != 'a'
   error('Incorrect append 4.')
 endif
 
-if x.get(1) != 'b'
+if x[1] != 'b'
   error('Incorrect append 5.')
 endif
 
diff --git a/test cases/failing/10 out of bounds/meson.build b/test cases/failing/10 out of bounds/meson.build
index 5c7f267..f791675 100644
--- a/test cases/failing/10 out of bounds/meson.build
+++ b/test cases/failing/10 out of bounds/meson.build
@@ -1,4 +1,4 @@
 project('out of bounds', 'c')
 
 x = []
-y = x.get(0)
+y = x[0]