Create ast package

smnp/ast/parsers/list.py

@@ -0,0 +1,54 @@
+from smnp.ast.node.list import ListNode, ListItemNode, CloseListNode
+from smnp.ast.parsers.expression import parseExpression
+from smnp.ast.tools import rollup, assertToken
+from smnp.token.type import TokenType
+
+
+# list -> CLOSE_PAREN | expr listTail
+def parseList(input, parent):
+    if input.current().type == TokenType.OPEN_PAREN:
+        node = ListNode(parent, input.current().pos)
+        input.ahead()
+
+        # list -> CLOSE_PAREN (end of list)
+        if input.hasCurrent() and input.current().type == TokenType.CLOSE_PAREN:
+            close = CloseListNode(node, input.current().pos)
+            node.append(close)
+            input.ahead()
+            return node
+
+            # list -> expr listTail
+        if input.hasCurrent():
+            token = input.current()
+            expr = parseExpression(input, node)
+            item = ListItemNode(expr, node, token.pos)
+            expr.parent = item
+            node.append(item)
+            listTail = parseListTail(input, item)
+            item.append(listTail)
+            return node
+    return None
+
+
+# listTail -> COMMA expr listTail | CLOSE_PAREN
+def parseListTail(input, parent):
+    # listTail -> CLOSE_PAREN
+    if input.hasCurrent() and input.current().type == TokenType.CLOSE_PAREN:
+        close = CloseListNode(parent, input.current().pos)
+        input.ahead()
+        return close
+
+    # listTail -> COMMA expr listTail
+    if input.hasCurrent() and input.hasMore():
+        assertToken(TokenType.COMMA, input)
+        input.ahead()
+        expr = rollup(parseExpression)(input, parent)
+        if expr is not None:
+            item = ListItemNode(expr, parent, expr.pos)
+            expr.parent = item
+            listTail = parseListTail(input, item)
+            item.append(listTail)
+            listTail.parent = item
+            return item
+
+    return None