/* Test whether bracket collation elements work with backslashes. */

#include "suite.h"

int main(void)
{
	flags = 0;

	// Control test that collation elements are implemented.
	match("[[.a.]]", "a");
	reject("[[.a.]]", "#");

	reject("[\\[.a.]]", "\\");
	reject("[\\[.a.]]", "a");
	reject("[\\[.a.]]", "b");
	reject("[\\[.a.]]", ".");
	reject("[\\[.a.]]", "[");
	reject("[\\[.a.]]", "]");
	match("[\\[.a.]]", "a]");
	reject("[\\[.a.]]", "b]");
	match("[\\[.a.]]", ".]");
	match("[\\[.a.]]", "[]");
	reject("[\\[.a.]]", "]]");

	// Okay we are in wild territory like bracket-charclass-escape-mid.c:
	//
	// I don't think anybody ever considered this case and it works on no
	// existing operating system. However POSIX.1-2024 2.14.1 is quite clear:
	//
	// "In a pattern, or part of one, where a shell-quoting <backslash> can be
	//  used, a <backslash> character shall escape the following character as
	//  described in 2.2.1 Escape Character (Backslash), regardless of whether
	//  or not the <backslash> is inside a bracket expression. "
	//
	// POSIX expressly clarifies patterns like [\x] [\]] do escape in its
	// examples. There are no special exemptions defined for the [[:foo:]],
	// [[=x=]] and [[.x.]] syntaxes with regards to backslashes. fnmatch is
	// supposed to implement shell escaping throughout the whole string, where
	// \x means a literal x for all characters x.
	//
	// The backslash escaping needs to be supported, otherwise there is no way
	// to use the backslash collation element in the shell pattern language.
	//
	// My conclusion is that [[.\x.]] must be equivalent to [[.x.]].
	//
	// We may need an official POSIX resolution here.
	match("[[.\\a.]]", "a");
	reject("[[.\\a.]]", "#");

	match("[[.\\..]]", ".");
	reject("[[.\\..]]", "#");

	match("[[.\\a.]]", "a");
	reject("[[.\\a.]]", "#");

	match("[[.\\\\.]]", "\\");
	reject("[[.\\\\.]]", ".");
	reject("[[.\\\\.]]", "[");
	reject("[[.\\\\.]]", "]");
	reject("[[.\\\\.]]", "a");

	match("[[.\\].]]", "]");
	reject("[[.\\].]]", "#");
	reject("[[.\\].]]", ".");

	match("[[.\\[.]]", "[");
	reject("[[.\\[.]]", "#");
	reject("[[.\\[.]]", ".");

	return 0;
}