From 384de58d419db8373310acb7d9ee0954d0623ad6 Mon Sep 17 00:00:00 2001
From: Sasha Koshka <supergriffin64@gmail.com>
Date: Wed, 17 Aug 2022 12:39:26 -0400
Subject: [PATCH] Added previousToken method to parser

---
 parser/parser.go | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/parser/parser.go b/parser/parser.go
index 3907a53..ac183b6 100644
--- a/parser/parser.go
+++ b/parser/parser.go
@@ -111,3 +111,12 @@ func (parser *ParsingOperation) nextToken (allowed ...lexer.TokenKind) (err erro
 	err = parser.expect(allowed...)
 	return
 }
+
+// previousToken goes back one token. If the parser is already at the beginning,
+// this does nothing.
+func (parser *ParsingOperation) previousToken () {
+	parser.tokenIndex --
+	if parser.tokenIndex < 0 { parser.tokenIndex = 0 }
+	parser.token = parser.tokens[parser.tokenIndex]
+	return
+}