Req #54387 [NEW]: Add str_slice() function, simple & logical string slicing function

From: Operating system: agnostic PHP version: 5.3SVN-2011-03-26 (SVN) Package: Strings related Bug Type: Feature/Change Request Bug description:Add str_slice() function, simple & logical string slicing function Description: ------------ The current state of string slicing in PHP is very confusing and non-obvious. The substr() function attempted some nice string slicing features, but it just isn't a good interface for string slicing and due to legacy concerns it cannot be changed (I assume). substr() problems: - The interface is inconsistent and confusing. When length is positive, then the function effectively returns from [start, start+length). When length is negative, the function returns [start, str_len+length). str_slice() has a much simpler interface: It returns from [start, end), and start and end may be defined as positive numbers from the start of the string or negative numbers from the end of the string. - Returning FALSE when start + length parameters are invalid. This is annoying because when using this function you always have to deal with this FALSE case if you need a string. Here is an example where str_slice() produces a more logical output than substr: print var_dump(substr('', -1) == '0'); // TRUE print var_dump(str_slice('', -1) == '0'); // FALSE This patch effectively solves the following bug as well: http://bugs.php.net/bug.php?id=38437 (substr should return '' instead of FALSE) http://bugs.php.net/bug.php?id=50434 (add str_startswith and str_endswith functions, which are trivial with str_slice, even in corner cases) Test script: --------------- Test is attached in the patch. -- Edit bug report at http://bugs.php.net/bug.php?id=54387&edit=1 -- Try a snapshot (PHP 5.2): http://bugs.php.net/fix.php?id=54387&r=trysnapshot52 Try a snapshot (PHP 5.3): http://bugs.php.net/fix.php?id=54387&r=trysnapshot53 Try a snapshot (trunk): http://bugs.php.net/fix.php?id=54387&r=trysnapshottrunk Fixed in SVN: http://bugs.php.net/fix.php?id=54387&r=fixed Fixed in SVN and need be documented: http://bugs.php.net/fix.php?id=54387&r=needdocs Fixed in release: http://bugs.php.net/fix.php?id=54387&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=54387&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=54387&r=needscript Try newer version: http://bugs.php.net/fix.php?id=54387&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=54387&r=support Expected behavior: http://bugs.php.net/fix.php?id=54387&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=54387&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=54387&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=54387&r=globals PHP 4 support discontinued: http://bugs.php.net/fix.php?id=54387&r=php4 Daylight Savings: http://bugs.php.net/fix.php?id=54387&r=dst IIS Stability: http://bugs.php.net/fix.php?id=54387&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=54387&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=54387&r=float No Zend Extensions: http://bugs.php.net/fix.php?id=54387&r=nozend MySQL Configuration Error: http://bugs.php.net/fix.php?id=54387&r=mysqlcfg