[RFC] Short-match

> Hey Larry, > > On Mon, Dec 14, 2020 at 6:34 PM Larry Garfield <larry@garfieldtech.com> > wrote: > > > I present to Internals this tiny RFC to follow up on the match() > > expression RFC from earlier in the year. There was solidly positive > > support for this shortcut previously but it was removed for simplicity at > > the time, with the intent to bring it back later. It's now later. > > > > https://wiki.php.net/rfc/short-match > > > > Overall back to the `switch (true)` case, which IMO is not a good idea in > first place :| > > Nothing wrong with using a set of conditional that are put in a sequence > through `if ()`, for these rare cases. > > Marco Pivetta > > http://twitter.com/Ocramius > > http://ocramius.github.com/ >

> I checked in my vendor directory for currently used switch(true) usages, > there were 96 matches. It is often used when handling an unknown value > and needing to display or convert it, as there the structure of a switch > is easier to scan compared to other comparisons like ifs (at least it is > for me). Compared to match these switch statements are a lot uglier, > which shows that there are use cases for it even when you are forced to > use switch. > > This is a good example in my estimation, from the Symfony Console Dumper > class (taken from Symfony 5.2), when a value is converted into a string > representation: > > ```php > $this->handler = function ($var): string { > switch (true) { > case null === $var: > return 'null'; > case true === $var: > return 'true'; > case false === $var: > return 'false'; > case \is_string($var): > return '"'.$var.'"'; > default: > return rtrim(print_r($var, true)); > } > }; > ``` > > With match this becomes much more concise: > > ```php > $this->handler = function ($var): string { > return match { > null === $var => 'null', > true === $var => 'true', > false === $var => 'false', > \is_string($var) => '"'.$var.'"', > default => rtrim(print_r($var, true)), > }; > }; > ``` > > The same with ifs: > > ```php > $this->handler = function ($var): string { > if (null === $var) { > return 'null'; > } > if (true === $var) { > return 'true'; > } > if (false === $var) { > return 'false'; > } > if (\is_string($var)) { > return '"'.$var.'"'; > } > > return rtrim(print_r($var, true)); > }; > ``` > > The implied return type for match and the reduced amount of code to scan > makes match {} much better in my opinion, with ifs you always have to > make sure there isn't additional logic somewhere, and it makes it easy > to add more complex code "by accident" compared to match. match (true) > would be possible now, but the true makes the code a bit confusing, > while without the (true) it reads more like natural language ("match the > first possible expression in this list and return a corresponding value"). > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: https://www.php.net/unsub.php

> With match this becomes much more concise: > > ```php > $this->handler = function ($var): string { > return match { > null === $var => 'null', > true === $var => 'true', > false === $var => 'false', > \is_string($var) => '"'.$var.'"', > default => rtrim(print_r($var, true)), > }; > }; > ```

> With match this becomes much more concise: > > ```php > $this->handler = function ($var): string { > return match { > null === $var => 'null', > true === $var => 'true', > false === $var => 'false', > \is_string($var) => '"'.$var.'"', > default => rtrim(print_r($var, true)), > }; > }; > ``` >

> On Mon, Dec 14, 2020 at 6:34 PM Larry Garfield <larry@garfieldtech.com> > wrote: > > > I present to Internals this tiny RFC to follow up on the match() > > expression RFC from earlier in the year. There was solidly positive > > support for this shortcut previously but it was removed for simplicity at > > the time, with the intent to bring it back later. It's now later. > > > > https://wiki.php.net/rfc/short-match > > > > -- > > Larry Garfield > > larry@garfieldtech.com > > > > Just like Sara, I'm not strongly opposed to this, but I'm also not sure > this is worthwhile. Writing "match (true) {" instead of "match {" is not > particularly tedious when compared to the size of the remaining structure. > Writing "match (true) {" has the advantage of being more explicit about > what this actually does, namely a "true ===" comparison. If it is omitted, > a reasonable person might think that > > match { > preg_match(...) => ... > } > > is going to do something sensible, like it would if placed inside an > "if()". But it does not, as preg_match() returns 1, not true, and as such > the match arm will never be taken. This is more obvious when the value that > is being compared against is explicitly given. > > Of course, with "match {" being a dedicated syntax, we could make it a > TypeError to use a non-bool match arm... > > Regards, > Nikita