🐐 Negation

centvrion/ast_nodes.py

@@ -330,6 +330,18 @@ class BinOp(Node):
         raise Exception(self.op)
 
 
+class UnaryMinus(Node):
+  def __init__(self, expr):
+    self.expr = expr
+
+  def __repr__(self):
+    return f"UnaryMinus({self.expr!r})"
+
+  def _eval(self, vtable):
+    vtable, val = self.expr.eval(vtable)
+    return vtable, ValInt(-val.value())
+
+
 class SiStatement(Node):
   def __init__(self, test, statements, else_part) -> None:
     self.test = test