camelCase to snake_case

Here is a TextMate command that will convert all of the selected text from camelCase to snake_case. This command is specifically designed for PHP. Thanks to PHP not having namespaces (until recently) many developers use PEAR naming conventions resulting in code that has class names like BP_Common::fancy_function(). This command will not convert the BP_Common.

Here is the code that you can paste in to the TextMate Bundle Editor as your new command for converting cameleCase variable to snake_case.

#!/usr/bin/env php 
<?php
$input = file_get_contents('php://stdin');
$pattern = '/([a-z])([A-Z])/e';
$replace = "'${1}_' . strtolower('${2}')";
echo preg_replace($pattern, $replace, $input);

#!/usr/bin/env php

<?php

$input = file_get_contents('php://stdin');

$pattern = '/([a-z])([A-Z])/e';

$replace = "'${1}_' . strtolower('${2}')";

echo preg_replace($pattern, $replace, $input);

One thought on “camelCase to snake_case”

Tom Payne says:

May 26, 2014 at 8:29 pm

Thanks for this, it was very helpful. However PREG_REPLACE_EVAL is now deprecated so I have used preg_replace_callback instead. Here’s the code I now use.

function camel_to_snake ( $input )
{
 if ( preg_match ( '/[A-Z]/', $input ) === 0 ) { return $input; }
 $pattern = '/([a-z])([A-Z])/';
 $r = strtolower ( preg_replace_callback ( $pattern, function ($a) {
  return $a[1] . "_" . strtolower ( $a[2] ); 
 }, $input ) );
 return $r;
}

function camel_to_snake ( $input )

{

if ( preg_match ( '/[A-Z]/', $input ) === 0 ) { return $input; }

$pattern = '/([a-z])([A-Z])/';

$r = strtolower ( preg_replace_callback ( $pattern, function ($a) {

return $a[1] . "_" . strtolower ( $a[2] );

}, $input ) );

return $r;

}

Thanks!

Tom.

One thought on “camelCase to snake_case”

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