+
+/*----------------------------------.
+| Whether S is a valid identifier. |
+`----------------------------------*/
+
+static bool
+is_identifier (uniqstr s)
+{
+ static char const alphanum[26 + 26 + 1 + 10] =
+ "abcdefghijklmnopqrstuvwxyz"
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+ "_"
+ "0123456789";
+ if (!s || ! memchr (alphanum, *s, sizeof alphanum - 10))
+ return false;
+ for (++s; *s; ++s)
+ if (! memchr (alphanum, *s, sizeof alphanum))
+ return false;
+ return true;
+}
+
+
+/*-----------------------------------------------.
+| Get the identifier associated to this symbol. |
+`-----------------------------------------------*/
+uniqstr
+symbol_id_get (symbol const *sym)
+{
+ aver (sym->user_token_number != USER_NUMBER_HAS_STRING_ALIAS);
+ if (sym->alias)
+ sym = sym->alias;
+ return is_identifier (sym->tag) ? sym->tag : 0;
+}
+
+