Enable parsing negative integers

smnp/newast/node/integer.py

@@ -1,13 +1,31 @@
 from smnp.newast.node.access import AccessNode
-from smnp.newast.node.literal import LiteralNode
+from smnp.newast.parser import Parser
 from smnp.token.type import TokenType
 
 
-class IntegerLiteralNode(LiteralNode, AccessNode):
+class IntegerLiteralNode(AccessNode):
     def __init__(self, pos):
         super().__init__(pos)
         del self.children[1]
 
     @classmethod
-    def _getTokenType(cls):
-        return TokenType.INTEGER
+    def _literalParser(cls):
+        return Parser.oneOf(
+            cls._negativeIntegerParser(),
+            cls._positiveIntegerParser()
+        )
+
+    @classmethod
+    def _negativeIntegerParser(cls):
+        def createNode(minus, integer):
+            return IntegerLiteralNode.withValue(-integer.value, minus.pos)
+
+        return Parser.allOf(
+            Parser.terminalParser(TokenType.MINUS),
+            cls._positiveIntegerParser(),
+            createNode=createNode
+        )
+
+    @classmethod
+    def _positiveIntegerParser(cls):
+        return Parser.terminalParser(TokenType.INTEGER, lambda val, pos: IntegerLiteralNode.withValue(int(val), pos))