Allow identifier in expressions to contain an underliner

Makefile

@@ -727,6 +727,7 @@ test_mxqd_control: mx_util.o
 test_mxqd_control: mx_mysql.o
 test_mxqd_control: mxq_group.o
 test_mxqd_control: keywordset.o
+test_mxqd_control: parser.tab.o
 test_mxqd_control: LDLIBS += $(LDLIBS_MYSQL)
 
 clean: CLEAN += test_mxqd_control

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;

test_parser.c

@@ -62,6 +62,10 @@ int main() {
     test_expression(tags, "(true | false) & false ", 0, 0);
     test_expression(tags, "(true | false) & ( false || false ) & true & x", 1, 0);
 
+    keywordset_add(tags, "test test_1");
+    test_expression(tags, "test", 0, 1);
+    test_expression(tags, "test_1", 0, 1);
+
     keywordset_free(tags);
 
     static char text[8001];