Implement comma separating expressions

Author: ShivamSarodia

shivyc/parser/declaration.py

@@ -5,7 +5,7 @@
 import shivyc.parser.utils as p
 import shivyc.token_kinds as token_kinds
 import shivyc.tree.nodes as nodes
-from shivyc.parser.expression import parse_expression
+from shivyc.parser.expression import parse_assignment
 from shivyc.parser.utils import (add_range, ParserError, match_token, token_is,
                                  raise_error)
 
@@ -36,7 +36,7 @@ def parse_declaration(index):
         if token_is(index, token_kinds.equals):
             # Parse initializer expression
             # Currently, only simple initializers are supported
-            expr, index = parse_expression(index + 1)
+            expr, index = parse_assignment(index + 1)
             inits.append(expr)
         else:
             inits.append(None)

shivyc/parser/expression.py

@@ -10,8 +10,9 @@
 @add_range
 def parse_expression(index):
     """Parse expression."""
-    # TODO: Support expressions separated by commas
-    return parse_assignment(index)
+    return parse_series(
+        index, parse_assignment,
+        {token_kinds.comma: expr_nodes.MultiExpr})
 
 
 @add_range
@@ -153,7 +154,7 @@ def parse_postfix(index):
                 return expr_nodes.FuncCall(cur, args, tok), index + 1
 
             while True:
-                arg, index = parse_expression(index)
+                arg, index = parse_assignment(index)
                 args.append(arg)
 
                 if token_is(index, token_kinds.comma):

shivyc/tree/expr_nodes.py

@@ -99,6 +99,21 @@ def make_il(self, il_code, symbol_table, c):
             return lvalue.val(il_code)
 
 
+class MultiExpr(_RExprNode):
+    """Expression that is two expressions joined by comma."""
+
+    def __init__(self, left, right, op):
+        """Initialize node."""
+        self.left = left
+        self.right = right
+        self.op = op
+
+    def make_il(self, il_code, symbol_table, c):
+        """Make code for this node."""
+        self.left.make_il(il_code, symbol_table, c)
+        return self.right.make_il(il_code, symbol_table, c)
+
+
 class Number(_RExprNode):
     """Expression that is just a single number."""
 

tests/feature_tests/expr_comma.c

@@ -0,0 +1,7 @@
+int main() {
+  int a = (3, 5);
+  int *p = (10, &a);
+
+  if(a != 5) return 1;
+  if(p != &a) return 2;
+}