Enable extending existing types to add custom methods

smnp/newast/node/extend.py

@@ -0,0 +1,69 @@
+from smnp.newast.node.block import BlockNode
+from smnp.newast.node.function import FunctionDefinitionNode
+from smnp.newast.node.identifier import IdentifierNode
+from smnp.newast.node.none import NoneNode
+from smnp.newast.node.statement import StatementNode
+from smnp.newast.node.type import TypeNode
+from smnp.newast.parser import Parser
+from smnp.token.type import TokenType
+
+
+class ExtendNode(StatementNode):
+    def __init__(self, pos):
+        super().__init__(pos)
+        self.children = [NoneNode(), NoneNode(), NoneNode()]
+
+    @property
+    def type(self):
+        return self[0]
+
+    @type.setter
+    def type(self, value):
+        self[0] = value
+
+    @property
+    def variable(self):
+        return self[1]
+
+    @variable.setter
+    def variable(self, value):
+        self[1] = value
+
+    @property
+    def methods(self):
+        return self[2]
+
+    @methods.setter
+    def methods(self, value):
+        self[2] = value
+
+    @classmethod
+    def _parse(cls, input):
+        def createNode(extend, type, variable, methods):
+            node = ExtendNode(extend.pos)
+            node.type = type
+            node.variable = variable
+            node.methods = methods
+            return node
+
+        return Parser.allOf(
+            Parser.terminalParser(TokenType.EXTEND),
+            TypeNode.parse,
+            IdentifierNode.identifierParser(),
+            cls._methodsDeclarationsParser(),
+            createNode=createNode
+        )(input)
+
+    @classmethod
+    def _methodsDeclarationsParser(cls):
+        def createNode(openBracket, items, closeBracket):
+            node = BlockNode(openBracket.pos)
+            node.children = items
+            return node
+
+        return Parser.loop(
+            Parser.terminalParser(TokenType.OPEN_BRACKET),
+            FunctionDefinitionNode.parse,
+            Parser.terminalParser(TokenType.CLOSE_BRACKET),
+            createNode=createNode
+        )