Create ast package

smnp/ast/tools.py

@@ -0,0 +1,30 @@
+from smnp.ast.node.model import Node
+from smnp.error.syntax import SyntaxException
+
+
+def rollup(parser):
+    def _rollup(input, parent):
+        node = Node(None, (-1, -1))
+        elem = parser(input, node)
+        while elem is not None:
+            node.append(elem)
+            elem = parser(input, node)
+        return node.children[0] if len(node.children) > 0 else None
+    return _rollup
+
+
+def assertToken(expected, input):    
+    if not input.hasCurrent():
+        raise SyntaxException(None, f"Expected '{expected}'")    
+    if expected != input.current().type:
+        raise SyntaxException(input.current().pos, f"Expected '{expected}', found '{input.current().value}'")
+
+
+def combineParsers(parsers):
+    def combinedParser(input, parent):
+        for parser in parsers:
+            value = parser(input, parent)
+            if value is not None:
+                return value
+        return None
+    return combinedParser