Function defGetString

src/backend/commands/define.c:48–79

* Extract a string value (otherwise uninterpreted) from a DefElem. */

 * Extract a string value (otherwise uninterpreted) from a DefElem.
 */
char *
defGetString(DefElem *def)
{
	if (def->arg == NULL)
		ereport(ERROR,
				(errcode(ERRCODE_SYNTAX_ERROR),
				 errmsg("%s requires a parameter",
						def->defname)));
	switch (nodeTag(def->arg))
	{
		case T_Integer:
			return psprintf("%ld", (long) intVal(def->arg));
		case T_Float:

			/*
			 * T_Float values are kept in string form, so this type cheat
			 * works (and doesn't risk losing precision)
			 */
			return strVal(def->arg);
		case T_String:
			return strVal(def->arg);
		case T_TypeName:
			return TypeNameToString((TypeName *) def->arg);
		case T_List:
			return NameListToString((List *) def->arg);
		case T_A_Star:
			return pstrdup("*");
		default:
			elog(ERROR, "unrecognized node type: %d", (int) nodeTag(def->arg));
	}
	return NULL;				/* keep compiler quiet */
}

/*
 * Extract a numeric value (actually double) from a DefElem.