code to get all var names hanging from a rasqal_expression

gistfile1.c

/* 
code to get all var names hanging from a rasqal_expression 
author: Manuel Salvadores (msalvadores@gmail.com)
*/

static void get_var_names(rasqal_expression *e,GList **list_vars) {
        GList *l = *list_vars;
        if (!e) return;
        if (e->literal != NULL) {
            rasqal_literal *lit  = e->literal;
            if (lit->type == RASQAL_LITERAL_VARIABLE) {
                l =  g_list_append(l,(gpointer)e->literal->value.variable->name); 
            }
        } else {
        if (e->arg1 != NULL)
            get_var_names(e->arg1,&l);
        if (e->arg2 != NULL)
            get_var_names(e->arg2,&l);
        if (e->arg3 != NULL)
            get_var_names(e->arg3,&l);
        }
}