diff --git a/parser.y b/parser.y
index ea40c871..835486cc 100644
--- a/parser.y
+++ b/parser.y
@@ -65,7 +65,7 @@ int yylex (YYSTYPE *lvalp, YYLTYPE *llocp, struct parser_context *ctx) {
     if (isalpha (c))
     {
         size_t name_len = 1;
-        while(isalnum(ctx->input[ctx->pos+name_len]))
+        while(isalnum(ctx->input[ctx->pos+name_len]) || ctx->input[ctx->pos+name_len] == '_')
             name_len++;
         char *name=xstrndup(&ctx->input[ctx->pos], name_len);
         ctx->pos += name_len;