# regex operators - Thread: https://externals.io/message/4825 - Original archive: https://news-web.php.net/php.internals/4825 - Started by David Sklar on 2003-10-14T14:47:19+00:00 - Messages: 9 - Reply by email to internals@lists.php.net - More for agents: search with https://externals.io/search.md?q={query} · RFCs at https://externals.io/rfc.md · JSON API at https://externals.io/api · documentation at https://externals.io/llms.txt --- ## #4825 — David Sklar — 2003-10-14T14:47:19+00:00 URL: https://externals.io/message/4825#4825 I was thinking about adding one or two regex-related features to the engine: 1. "preg_case": this would behave just like case but instead of doing an equality comparison, would match against a regular expression, e.g. switch($data) { preg_case '/^\d{5}(-\d{4})?$/': print "US Postal Code"; break; preg_case '/^[a-z]\d[a-z] ?\d[a-z]\d$/i'; print "Canadian Postal Code"; break; default: print "something else!"; } Where should any captured subpatterns go? 2. A regex match operator that returns an array containing subpatterns. If there is no match against the regex, then an empty array (or just false?) would be returned. if ($data =~ '/^(\d{5})(-\d{4})?$/') { print "The whole postal code is $data[0]."; print "The first five digits is $data[1]."; if ($data[2]) { print "The ZIP+4 is $data[2].";} } Some issues with adding these features: - It creates an engine dependency on the PCRE library. - There would have to be some new opcodes and parser tokens - Ideally the code that implements these operators could share as much as possible with what's already been done in the PCRE extension -- is that possible? Comments? Thanks, David --- ## #4826 — Andrey Hristov — 2003-10-14T14:58:04+00:00 URL: https://externals.io/message/4825#4826 · In reply to: #4825 Hi David, 2 weeks ago Hartmut Holzgraefe had similar idea : switch ($data, "preg_match") { case '/foo.*?bar/i' : /* computation here */ break; } The second argument is a callback. Andrey David Sklar wrote: >I was thinking about adding one or two regex-related features to the engine: > >1. "preg_case": this would behave just like case but instead of doing an >equality comparison, would match against a regular expression, e.g. > >switch($data) { > preg_case '/^\d{5}(-\d{4})?$/': > print "US Postal Code"; > break; > preg_case '/^[a-z]\d[a-z] ?\d[a-z]\d$/i'; > print "Canadian Postal Code"; > break; > default: > print "something else!"; >} > >Where should any captured subpatterns go? > >2. A regex match operator that returns an array containing subpatterns. If >there is no match against the regex, then an empty array (or just false?) >would be returned. > >if ($data =~ '/^(\d{5})(-\d{4})?$/') { > print "The whole postal code is $data[0]."; > print "The first five digits is $data[1]."; > if ($data[2]) { print "The ZIP+4 is $data[2].";} >} > >Some issues with adding these features: > >- It creates an engine dependency on the PCRE library. >- There would have to be some new opcodes and parser tokens >- Ideally the code that implements these operators could share as much as >possible with what's already been done in the PCRE extension -- is that >possible? > >Comments? > >Thanks, >David --- ## #4827 — Hartmut Holzgraefe — 2003-10-14T15:04:03+00:00 URL: https://externals.io/message/4825#4827 · In reply to: #4825 David Sklar wrote: > I was thinking about adding one or two regex-related features to the engine: > > 1. "preg_case": this would behave just like case but instead of doing an > equality comparison, would match against a regular expression, e.g. > > switch($data) { > preg_case '/^\d{5}(-\d{4})?$/': > print "US Postal Code"; > break; > preg_case '/^[a-z]\d[a-z] ?\d[a-z]\d$/i'; > print "Canadian Postal Code"; > break; > default: > print "something else!"; > } > i've started to play with a more general way to handle this: switch(mixed data [, callback compare_function]) { ... "compare_function" would default to the functionality of the "==" operator to show the current behavior "compare_function" will be called with two parameters: the switch expression and the case value and should return true if both match, false otherwise as a special case "compare_function" should also accept "===" this way we do not have to add new keywords and are not limited to preg expresions here, possible uses not possible now would include: switch($foobar, "===") { case false: ... case 0: ... case '': ... switch($foobar, "preg_match") { case '/^\d{5}$/': ... case '/(foo)?bar/': ... switch($foobar, "fnmatch") { case '*.gif': ... case '*.jpg': ... switch($foober, "my_custom_function") { ... switch($foobar, array($this, "compare_function") { ... -- Hartmut Holzgraefe This should also be BC if you just pass one string. http://docs.php.net/en/function.preg-grep.html we already have that too. Derick -- "Interpreting what the GPL actually means is a job best left to those that read the future by examining animal entrails." ------------------------------------------------------------------------- Derick Rethans http://derickrethans.nl/ International PHP Magazine http://php-mag.net/ --- ## #4833 — Curt Zirzow — 2003-10-14T16:50:39+00:00 URL: https://externals.io/message/4825#4833 · In reply to: #4825 * Thus wrote David Sklar (sklar@sklar.com): > I was thinking about adding one or two regex-related features to the engine: > > 1. "preg_case": this would behave just like case but instead of doing an > equality comparison, would match against a regular expression, e.g. > > switch($data) { > preg_case '/^\d{5}(-\d{4})?$/': > print "US Postal Code"; > break; > preg_case '/^[a-z]\d[a-z] ?\d[a-z]\d$/i'; > print "Canadian Postal Code"; > break; > default: > print "something else!"; > } [...] > > Some issues with adding these features: > > - It creates an engine dependency on the PCRE library. > - There would have to be some new opcodes and parser tokens > - Ideally the code that implements these operators could share as much as > possible with what's already been done in the PCRE extension -- is that > possible? I'm thinking a more viable solution would be to do something like: mixed preg_match ( mixed pattern, string subject [, array matches [, int flags]]) if pattern is an array, preg_match will cycle through each one till a match is made; returns the index of the array passed (that matched) or false if not found. This should also be BC if you just pass one string. Curt -- "I used to think I was indecisive, but now I'm not so sure." --- ## #4842 — netcat — 2003-10-14T18:24:50+00:00 URL: https://externals.io/message/4825#4842 · In reply to: #4827 Hartmut Holzgraefe wrote: > David Sklar wrote: > > > […] > > i've started to play with a more general way to handle this: > > switch(mixed data [, callback compare_function]) seems the sanest thing up until now. slighly O.T.: would be and even better if lambda functions were available here > > { > ... > > "compare_function" would default to the functionality of the > "==" operator to show the current behavior > > "compare_function" will be called with two parameters: > the switch expression and the case value and should > return true if both match, false otherwise > > as a special case "compare_function" should also accept > "===" > > this way we do not have to add new keywords and are not > limited to preg expresions here, > possible uses not possible now would include: > > switch($foobar, "===") { > case false: ... > case 0: ... > case '': ... > > switch($foobar, "preg_match") { > case '/^\d{5}$/': ... > case '/(foo)?bar/': ... > > switch($foobar, "fnmatch") { > case '*.gif': ... > case '*.jpg': ... > > switch($foober, "my_custom_function") { > ... > > switch($foobar, array($this, "compare_function") { > ... > > > > -- NetCat -------------------------------------------------------- FREE 10MB email + Antivirus + AntiSpam + POP3 + more.... Get it at http://www.doal.co.il:81/free/?c=both --- ## #4854 — Hartmut Holzgraefe — 2003-10-15T08:12:48+00:00 URL: https://externals.io/message/4825#4854 · In reply to: #4842 netcat wrote: > > […] > > > seems the sanest thing up until now. > > slighly O.T.: would be and even better if lambda functions were > available here http://php.net/create-function -- Hartmut Holzgraefe netcat wrote: > > > […] > > > > http://php.net/create-function > Thanks for the link. It's just feels a little awkward to see something like: switch($x,create_function('$a,$b','return $a=="MY$b;"')) { } Again, it's a feeling, maybe it's just me. It doesn't feel right to me that inside definition of new function i have to escape quotes (that's because create_function is a function and not special construction on the other side if it would be a construct it can't return a value as in $x=create_function(...) ). Anyway, i have nothing better to suggest (yet) .... I hope one of you have some suggestion that will make create_function more usable. -- NetCat ------------------------------------------------------ SPAM-Free 10mb Free email + Antivirus + POP3 + more... Get it at http://www.doal.co.il:81/free/?c=all-spam --- ## #4860 — Kouber Saparev — 2003-10-15T12:35:16+00:00 URL: https://externals.io/message/4825#4860 · In reply to: #4833 "Curt Zirzow" wrote in message news:20031014165039.GP51024@bagend.shire... > * Thus wrote David Sklar (sklar@sklar.com): > > […] engine: > > […] > [...] > > […] as > > […] > > I'm thinking a more viable solution would be to do something like: > > mixed preg_match ( mixed pattern, string subject [, array matches [, int flags]]) > > if pattern is an array, preg_match will cycle through each one till > a match is made; returns the index of the array passed (that > matched) or false if not found. It's the same if you have the array with patterns and you make a simple foreach() cycle. I don't think that functions with internal loops should be created, when we have a clear solution without it. > > This should also be BC if you just pass one string. > > > Curt > -- > "I used to think I was indecisive, but now I'm not so sure."