Function par_substring

src/gpre/sqe.cpp:3118–3158

____________________________________________________________ Parse the SUBSTRING built-in function

//		Parse the SUBSTRING built-in function
//
static gpre_nod* par_substring(gpre_req* request)
{
	gpre_nod* node = MSC_node(nod_substring, 3);
	EXP_left_paren(0);
	node->nod_arg[0] = SQE_value(request, false, NULL, NULL);
	if (! MSC_match(KW_FROM))
		CPR_s_error("FROM");
	node->nod_arg[1] = EXP_literal();
	if (! node->nod_arg[1])
		CPR_s_error("numeric literal");

	const ref* reference = (ref*) node->nod_arg[1]->nod_arg[0];
	const TEXT* string = reference->ref_value;

	if (*string == '"' || *string == '\'')
		CPR_s_error("numeric literal");

	if (MSC_match(KW_FOR))
	{
		node->nod_arg[2] = EXP_literal();
		if (! node->nod_arg[2])
			CPR_s_error("numeric literal");
		reference = (ref*) node->nod_arg[2]->nod_arg[0];
		string = reference->ref_value;
		if ((*string == '"') || (*string == '\''))
			CPR_s_error("numeric literal");
	}
	else
	{
		// No FOR clause given, fake up a numeric literal of 32767 (the max length
		// of a VarChar) to force copying to end of string.
		ref* reference1 = (ref*) MSC_alloc(REF_LEN);
		node->nod_arg[2] = MSC_unary(nod_literal, (gpre_nod*) reference1);
		string = (TEXT*) MSC_alloc(6);
		MSC_copy("32767", 5, (char*) string);
		reference1->ref_value = string;
	}
	USHORT local_count = 1;
	par_terminating_parens(&local_count, &local_count);
	return node;
}

//____________________________________________________________
//