From 0cefcd282b89420ec27f08fd2001e1e26556dc35 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bart=C5=82omiej=20Pluta?= <the.orleander@gmail.com>
Date: Fri, 12 Jul 2019 00:51:37 +0200
Subject: [PATCH] Improve minus operator

---
 smnp/ast/node/chain.py  | 24 ++++++++++++++++++++----
 smnp/ast/node/factor.py |  1 +
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/smnp/ast/node/chain.py b/smnp/ast/node/chain.py
index f3d9a8b..59ec56d 100644
--- a/smnp/ast/node/chain.py
+++ b/smnp/ast/node/chain.py
@@ -1,7 +1,7 @@
 from smnp.ast.node.atom import AtomParser
 from smnp.ast.node.list import ListParser
 from smnp.ast.node.map import MapParser
-from smnp.ast.node.operator import BinaryOperator
+from smnp.ast.node.operator import BinaryOperator, UnaryOperator, Operator
 from smnp.ast.node.valuable import Valuable
 from smnp.ast.parser import Parser
 from smnp.token.type import TokenType
@@ -11,17 +11,33 @@ class Chain(Valuable):
     pass
 
 
+class MinusOperator(UnaryOperator):
+    pass
+
+
 def ChainParser(input):
-    itemParser = Parser.oneOf(
+    chain1 = Parser.oneOf(
         ListParser,
         MapParser,
         AtomParser,
     )
 
+    minusOperator = Parser.allOf(
+        Parser.terminal(TokenType.MINUS, createNode=Operator.withValue),
+        chain1,
+        createNode=MinusOperator.withValues,
+        name="minus"
+    )
+
+    chain2 = Parser.oneOf(
+        minusOperator,
+        chain1
+    )
+
     return Parser.leftAssociativeOperatorParser(
-        itemParser,
+        chain2,
         [TokenType.DOT],
-        itemParser,
+        chain2,
         lambda left, op, right: Chain.withValue(BinaryOperator.withValues(left, op, right))
     )(input)
 
diff --git a/smnp/ast/node/factor.py b/smnp/ast/node/factor.py
index bbea8b0..25e231d 100644
--- a/smnp/ast/node/factor.py
+++ b/smnp/ast/node/factor.py
@@ -12,6 +12,7 @@ class Factor(Valuable):
 class NotOperator(UnaryOperator):
     pass
 
+
 class Loop(BinaryOperator):
     pass