Add token kind matching lexer function

This function reads the next token, compares its kind to a parameter and
returns a boolean indicating whether it matched. If it did not match,
the token is pushed back into the lexer for later reuse.

2 files changed, 12 insertions, 0 deletions

diff --git a/include/lex.h b/include/lex.h
index 8b1fdf2..ba1596d 100644
--- a/include/lex.h
+++ b/include/lex.h
@@ -124,5 +124,6 @@ void lex_finish(struct lexer *lexer);
 
 enum lexical_token lex(struct lexer *lexer, struct token *out);
 void unlex(struct lexer *lexer, const struct token *in);
+bool match(struct lexer *lexer, enum lexical_token token);
 
 #endif
diff --git a/src/lex.c b/src/lex.c
index 80c1c5b..89d1fc6 100644
--- a/src/lex.c
+++ b/src/lex.c
@@ -392,3 +392,14 @@ unlex(struct lexer *lexer, const struct token *in)
 	assert(lexer->un.token == T_NONE);
 	lexer->un = *in;
 }
+
+bool
+match(struct lexer *lexer, enum lexical_token token)
+{
+	struct token tmp;
+	enum lexical_token kind = lex(lexer, &tmp);
+	if (kind != token) {
+		unlex(lexer, &tmp);
+	}
+	return kind == token;
+}