Normalize symbol expressions

[fur] / parsing.py

diff --git a/parsing.py b/parsing.py
index 82c6528..b2a14a8 100644 (file)
--- a/parsing.py
+++ b/parsing.py
@@ -39,21 +39,21 @@ def _zero_or_more_parser(formatter, parser):
 FurIntegerLiteralExpression = collections.namedtuple(
     'FurIntegerLiteralExpression',
     [
-        'value',
+        'integer',
     ],
 )
 
 FurStringLiteralExpression = collections.namedtuple(
     'FurStringLiteralExpression',
     [
-        'value',
+        'string',
     ],
 )
 
 FurSymbolExpression = collections.namedtuple(
     'FurSymbolExpression',
     [
-        'value',
+        'symbol',
     ],
 )
 
@@ -82,17 +82,17 @@ def _integer_literal_expression_parser(index, tokens):
     value = int(tokens[index].match)
     index += 1
 
-    return True, index, FurIntegerLiteralExpression(value=value)
+    return True, index, FurIntegerLiteralExpression(integer=value)
 
 def _string_literal_expression_parser(index, tokens):
     if tokens[index].type == 'single_quoted_string_literal':
-        return (True, index + 1, FurStringLiteralExpression(value=tokens[index].match[1:-1]))
+        return (True, index + 1, FurStringLiteralExpression(string=tokens[index].match[1:-1]))
 
     return (False, index, None)
 
 def _symbol_expression_parser(index, tokens):
     if tokens[index].type == 'symbol':
-        return (True, index + 1, FurSymbolExpression(value=tokens[index].match))
+        return (True, index + 1, FurSymbolExpression(symbol=tokens[index].match))
 
     return (False, index, None)
 
@@ -327,18 +327,28 @@ def _expression_statement_parser(index, tokens):
 
     return (True, index, FurExpressionStatement(expression=expression))
 
+BUILTINS = {'print', 'pow'}
+
 def _assignment_statement_parser(index, tokens):
-    # TODO Use a FurSymbolExpression for the target? Maybe this is actually not a good idea
     failure = (False, index, None)
 
-    if tokens[index].type != 'symbol':
+    if tokens[index].type == 'symbol':
+        target = tokens[index].match
+        target_assignment_line = tokens[index].line
+
+        index += 1
+    else:
         return failure
-    target = tokens[index].match
-    index += 1
 
-    if tokens[index].type != 'assignment_operator':
+
+    if tokens[index].type == 'assignment_operator':
+        if target in BUILTINS:
+            raise Exception(
+                'Trying to assign to builtin "{}" on line {}'.format(target, target_assignment_line),
+            )
+        assignment_operator_index = index
+    else:
         return failure
-    assignment_operator_index = index
 
     success, index, expression = _expression_parser(index + 1, tokens)
 
@@ -405,7 +415,7 @@ def _function_definition_statement_parser(index, tokens):
 
     return True, index, FurFunctionDefinitionStatement(
         name=name,
-        argument_name_list=tuple(an.value for an in argument_name_list),
+    argument_name_list=tuple(an.symbol for an in argument_name_list),
         statement_list=statement_list,
     )
 
@@ -452,7 +462,7 @@ if __name__ == '__main__':
                 (
                     True,
                     1,
-                    FurStringLiteralExpression(value='Hello, world'),
+                    FurStringLiteralExpression(string='Hello, world'),
                 ),
             )
 
@@ -465,7 +475,7 @@ if __name__ == '__main__':
                     4,
                     FurFunctionCallExpression(
                         name='print',
-                        arguments=(FurStringLiteralExpression(value='Hello, world'),),
+                        arguments=(FurStringLiteralExpression(string='Hello, world'),),
                     ),
                 ),
             )