> On May 16, 2020, at 5:13 AM, Pavel Patapau <algerd....@gmail.com> wrote:
>
> Hello everyone,
>
> I want to propose new syntax addition - guard statement, that executes code
> only if expression equals false and must contain control-flow changing code,
> and written a respective RFC:
>
> https://wiki.php.net/rfc/guard_statement
> <https://wiki.php.net/rfc/unbundle_xmlprc>
>
> Implementation in progress.
>
> I started work before this proposal https://externals.io/message/110107 and
> respected some moments in the RFC.
>
>
> Thanks for consideration,
> Pavel
Many others have already made comments that I agree with so won't echo as they
have already been said.
Two points:
1. That adding a `guard` would make it a reserved word is of significant
concern to me, and looking at your examples I would ask why not simply ask that
the if statement be able to omit the "true" block which could accomplish the
same w/o needing to add another reserved word? e.g.
if (condition) else {
//this code executed only if condition equals false
return|throw|goto;
//or
continue | break(in loop context only);
}
// in loop context - valid code
while (condition){
if (condition) else {
break; //valid
}
}
Alternately, why not simply use what we already have, and what I do often,
invert the condition?
if ( ! condition) {
//this code executed only if condition equals false
return|throw|goto;
//or
continue | break(in loop context only);
}
// in loop context - valid code
while (condition){
if ( ! condition ) {
break; //valid
}
}
Secondly, you reference this essay[1] which mentions why multiple returns are a
bad idea, yet your proposal seems to want to encourage people to write more
early returns, not fewer.
Regarding the multiple returns, consider the following, using an
if(condition)else{} syntax AND assuming that we could add support for try{}
without being required to use a catch():
function example() {
try {
$value = null;
if (condition1) else {
break;
}
if (condition2) else {
break;
}
if (condition3) else {
break;
}
$value = do_work();
}
return $value;
}
-Mike
[1]
https://medium.com/@scadge/if-statements-design-guard-clauses-might-be-all-you-need-67219a1a981a
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