Add functions that work with suffixes and prefixes

[carlos-granados]

Adds 6 new functions which can be used to work with string suffixes and prefixes:

function str_prefix_ensure(string $prefix, string $subject): string
function str_suffix_ensure(string $suffix, string $subject): string

Add a prefix or suffix to a string only if the string does not yet have it

function str_prefix_remove(string $prefix, string $subject): string
function str_suffix_remove(string $suffix, string $subject): string

Remove a prefix or suffix from a string if the string has it

function str_prefix_replace(string $prefix, string $replace, string $subject): string
function str_suffix_replace(string $suffix, string $replace, string $subject): string

Replace a prefix or suffix in a string if the string has it

[iluuu1994]

Hi @carlos-granados. Thanks for your proposal. I think the addition of new string functions is controversial enough to warrant an RFC. See https://wiki.php.net/rfc/howto. I'm foreseeing some disagreements on naming / namespacing, among other things. The add_{suffix,prefix} functions are also pretty much pointless, unless you're working with higher order functions I guess.

[carlos-granados]

Hi @carlos-granados. Thanks for your proposal. I think the addition of new string functions is controversial enough to warrant an RFC. See https://wiki.php.net/rfc/howto. I'm foreseeing some disagreements on naming / namespacing, among other things. The add_{suffix,prefix} functions are also pretty much pointless, unless you're working with higher order functions I guess.

Thank @iluuu1994 yes, I was planning to create an RFC and in fact I did not intend to create this PR. I wanted to first create it in my fork but it seems that somehow I made a mistake and created it here. Now that it is created I'll leave it here.

[blar]

The parameter order should be (in my opinion) ($subject, $prefix) and ($subject, $suffix) to maintain consistency with the existing str_* family:

• str_starts_with(string $haystack, string $needle)
• str_ends_with(string $haystack, string $needle)
• str_contains(string $haystack, string $needle)

Arguments for $subject first:

1. Consistency: All three existing str_* functions from PHP 8.0 use this order
2. Readability: Reads naturally as "string X ensure prefix Y" vs. "prefix Y ensure on string X"
3. Potential future extensions (wish str_starts_with accepted string|array $needle #11267): str_starts_with($string, ["foo", "bar"]) is far clearer than str_starts_with(["foo", "bar"], $string). Same applies here: str_prefix_ensure($path, ["/", "\\"]) vs. the confusing str_prefix_ensure(["/", "\\"], $path)
4. Method chaining: Future OOP string methods would use $string->ensurePrefix($prefix), not $prefix->ensureOn($string)
5. Named parameters: str_prefix_ensure(subject: $path, prefix: '/') is clearer than str_prefix_ensure(prefix: '/', subject: $path)
6. Future options parameter: This PR's test cases already hint at potential extensions (e.g., handling multiple occurrences). The typical pattern would be $haystack, $needle, $options - not $needle, $haystack, $options