Ugly alert: false !== strpos( $which_one_was_needle, $this_one )

[nbachiyski]

In WordPress strpos() is used hundreds of times. Very large percentage of those calls are trying to accomplish one of these 3 goals:

• Check if a string starts with another string
• Check if a string contains another string
• Check if a string ends with another string

The code for doing these 3 things is not very readable, ugly, and error-prone:

0 === strpos( $one_string, $other_string )
false !== strpos( $one_string, $other_string )
strpos( $one_string, $other_string ) == ( strlen( $one_string ) - strlen( $other_string )

I propose we introduce functions to hide the ugliness and the complexity behind these three common operations:

• wp_startswith( $haystack, $needle )
• wp_in( $needle, $haystack )
• wp_endswith( $haystack, $needle )

The logic of the arguments order is consistent and easy to remember:

first argument verb second argument.

• everything starts with a beginning translates to wp_startswith( "everything", "a beginning" )
• goat is in distress translates to wp_in( "goat", "distress" )
• movie ends with happy end translates to wp_endswith( "movie", "happy end" )

These three functions are happily used in GlotPress and WordPress.com.

The implementations are attached.

[nacin]

Remembering haystack/needle order is a pain and something that all still venture to php.net for on a regular basis.

However, wp_in() still ends up being reversed from startswith() and endswith(). Sure, it's natural with the whole verb thing, but it requires one to switch contexts and think about it a little more than "oh, the haystack is always going to be first." So I don't know how much I like this. I feel like adding new functions on top of this will only end up making it more difficult to follow code, not less.

[merty]

What about renaming wp_in() to wp_has(), so we can both use the word in the function and not cause any confusions?

/**
 * Checks if $haystack has $needle
 * 
 * @param string $haystack
 * @param string $needle
 * @return bool
 */
function wp_has( $haystack, $needle ) {
	return false !== strpos( $haystack, $needle );
}

[johnbillion]

Replying to nacin:

Remembering haystack/needle order is a pain and something that all still venture to php.net for on a regular basis.

For array functions and string functions, ​there is actually consistency. Once you've successfully recalled the correct function name, that is.

However, wp_in() still ends up being reversed from startswith() and endswith().

These are all string functions so they should accept $haystack, $needle. merty's suggestion of wp_has() works, as does wp_contains().

[daniloercoli]

strpos( $one_string, $other_string ) == ( strlen( $one_string ) - strlen( $other_string )

The code above doesn't work if there are multiple occurrences of '$other_string' in '$one_string'. I think the best way to test the 'EndWith' condition is using something like the code below:

strpos(  strrev( $one_string  ), strrev( $other_string  )  ) ===  0 

[merty]

These are all string functions so they should accept $haystack, $needle. merty's suggestion of wp_has() works, as does wp_contains().

Yes, "contains" is so much better. "has" sounds like it's an array-related thing.

[mitchoyoshitaka]

+1 to all of this. wp_contains and standardizing on $haystack, $needle makes sense to me.

[hd-J]

+1 to this. And I'd personnally vote for wp_contains instead of wp_has.

[nbachiyski]

For me wp_in was good enough, because consistent narrative naming has a lot higher priority in my brain compared to consistent argument. And it is much shorter.

But I can see your point and I agree wp_contains() is good.

[nacin]

I don't actually see the true usefulness in these wrappers. Before committing there should be a patch against core instances of strpos(), to evaluate it.

[nbachiyski]

Replying to nacin:

I don't actually see the true usefulness in these wrappers. Before committing there should be a patch against core instances of strpos(), to evaluate it.

Nacin, if you commit it, I will make sure to patch everything :-)

[nbachiyski]

And I'd like to propose another a last-minute change. In the spirit of the WordPress naming scheme, I think the best names would be:

• wp_starts_with()
• wp_ends_with()
• wp_contains()

The arguments and their order should be obvious.

[wonderboymusic]

I think we are good without this, correct me if I am wrong

[johnbillion]

Agreed