frappy.lib.mathparser: add relational operators

frappy/lib/mathparser.py

@@ -37,6 +37,13 @@ class MathParser:
         ast.Div:  op.truediv,
         ast.Pow:  op.pow,
         ast.FloorDiv: op.floordiv,
+        ast.Lt: op.lt,
+        ast.Gt: op.gt,
+        ast.LtE: op.le,
+        ast.GtE: op.ge,
+        ast.Eq: op.eq,
+        ast.NotEq: op.ne,
+        ast.Not: op.not_,
         ast.USub: op.neg,
         ast.UAdd: lambda a:a}
 
@@ -74,6 +81,15 @@ class MathParser:
         if isinstance(node, ast.BinOp):    # evaluate binary operations
             method = self._operators2method[type(node.op)]
             return method( self.eval_(node.left), self.eval_(node.right))
+        if isinstance(node, ast.Compare):    # evaluate binary operations
+            left = self.eval_(node.left)
+            for oper, value in zip(node.ops, node.comparators):
+                method = self._operators2method[type(oper)]
+                right = self.eval_(value)
+                if not method(left, right):
+                    return False
+                left = right
+            return True
         if isinstance(node, ast.UnaryOp):    # handle operators
             method = self._operators2method[type(node.op)]
             return method( self.eval_(node.operand) )