Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
En mar, 19 may 2020 08:53:46 +0200 Manuel Canga
escribió
>
> Hi, Internals,
>
>
>
> En dom, 17 may 2020 06:33:51 +0200 Peter Stalman
> escribió
> > A few thoughts:
> >
> >
> > 1. I agree with the sentiment that this syntactic sugar doesn't
> > actually save any verbosity, so it's not really syntactic sugar at
> > all.
> >
> >
> > 2. There appears to now be another RFC by Pavel Patapau, specifically
> > focused on a Guard statement as a new keyword
> > (https://wiki.php.net/rfc/guard_statement), which now has its separate
> > discussion.
> >
> >
> > 3. As Thomas Lamy mentioned, I too would prefer a single keyword.
> > Consider the following two examples:
> >
> > function foo($bar)
> > {
> > if ($bar === 1)
> > return;
> >
> > if ($bar === 666)
> > delete_everything();
> > }
> >
> >
> > Both would now be valid syntax, and IDEs would have a harder time
> > warning about the misplaced semicolon in the second example. Wouldn't
> > be very common, but still.
> >
> >
> > 4. However, this RFC is interesting to me because there be a way to
> > modify it to allow for less verbose refactoring, and kinda allowing
> > returns to bubble up like exceptions do. I think it would only make
> > sense if it's a "if not null then return" type of thing.
> >
> > Consider the following (a bit contrived, but I hope you get the point):
> >
> > function main_function()
> > {
> > $result = calculate($var);
> > if ($result !== null)
> > return $result;
> >
> > /* do other important stuff */
> > }
> >
> > function main_function()
> > {
> > ifnotnullreturn calculate($var);
> >
> > /* do other important stuff */
> > }
> >
> > Obviously not an ideal keyword, but this is the only thing I can think
> > of where this type of syntactic sugar makes sense and decreases
> > verbosity. Something similar can also be accomplished with exception
> > though.
> >
> >
> > 5. Finally, I think if we start putting several returns at the same
> > indentation then the cognitive load increases because we can no longer
> > tell if a return is actually a return at a glance.
> >
> >
> > Thanks,
> > Peter
> >
>
> I agree.
>
> ¿ Maybe something like...
>
>function main_function()
> {
> escape when( calculate($var) );
>
> /* do other important stuff */
> }
>
>
> `escape when( expr )` returns value of `expr` to caller function when
> `expr` evaluate to true otherwise next line.
>
>function main_function()
> {
> escape with $ a + 1 when( !calculate($var) );
>
> /* do other important stuff */
> }
>
>
> `escape with expr1 when( expr2 )` returns value of `expr1` to caller
> function when `expr2` evaluate to true otherwise next line.
>
>
Upgrade version.
Maybe is better:
`escape when( expr )` returns null to caller function when `expr` evaluate
to true otherwise next line.
`escape with expr1 when( expr2 )` returns value of `expr1` to caller function
when `expr2` evaluate to true otherwise next line.
Then these code are equals to:
> > function main_function()
> > {
> > $result = calculate($var);
> > if ($result !== null)
> > return $result;
> >
> > /* do other important stuff */
> > }
> >
function main_function()
{
escape with $result when( $result = calculate($var) );
/* do other important stuff */
}
> > function foo($bar)
> > {
> > if ($bar === 1)
> > return;
> >
> > if ($bar === 666)
> > delete_everything();
> > }
function foo($var) {
escape when( $bar === 1 || $bar !== 600 );
delete_everything();
}
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Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
Hi, Internals,
En dom, 17 may 2020 06:33:51 +0200 Peter Stalman
escribió
> A few thoughts:
>
>
> 1. I agree with the sentiment that this syntactic sugar doesn't
> actually save any verbosity, so it's not really syntactic sugar at
> all.
>
>
> 2. There appears to now be another RFC by Pavel Patapau, specifically
> focused on a Guard statement as a new keyword
> (https://wiki.php.net/rfc/guard_statement), which now has its separate
> discussion.
>
>
> 3. As Thomas Lamy mentioned, I too would prefer a single keyword.
> Consider the following two examples:
>
> function foo($bar)
> {
> if ($bar === 1)
> return;
>
> if ($bar === 666)
> delete_everything();
> }
>
> function foo($bar)
> {
> if ($bar === 1)
> return
>
> if ($bar === 666);
> delete_everything();
> }
>
> Both would now be valid syntax, and IDEs would have a harder time
> warning about the misplaced semicolon in the second example. Wouldn't
> be very common, but still.
>
>
> 4. However, this RFC is interesting to me because there be a way to
> modify it to allow for less verbose refactoring, and kinda allowing
> returns to bubble up like exceptions do. I think it would only make
> sense if it's a "if not null then return" type of thing.
>
> Consider the following (a bit contrived, but I hope you get the point):
>
> function main_function()
> {
> $result = calculate($var);
> if ($result !== null)
> return $result;
>
> /* do other important stuff */
> }
>
> function main_function()
> {
> ifnotnullreturn calculate($var);
>
> /* do other important stuff */
> }
>
> Obviously not an ideal keyword, but this is the only thing I can think
> of where this type of syntactic sugar makes sense and decreases
> verbosity. Something similar can also be accomplished with exception
> though.
>
>
> 5. Finally, I think if we start putting several returns at the same
> indentation then the cognitive load increases because we can no longer
> tell if a return is actually a return at a glance.
>
>
> Thanks,
> Peter
>
I agree.
¿ Maybe something like...
function main_function()
{
escape when( calculate($var) );
/* do other important stuff */
}
`escape when( expr )` returns value of `expr` to caller function when
`expr` evaluate to true otherwise next line.
function main_function()
{
escape with $ a + 1 when( !calculate($var) );
/* do other important stuff */
}
`escape with expr1 when( expr2 )` returns value of `expr1` to caller function
when `expr2` evaluate to true otherwise next line.
Regards
--
Manuel Canga
--
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Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
A few thoughts:
1. I agree with the sentiment that this syntactic sugar doesn't
actually save any verbosity, so it's not really syntactic sugar at
all.
2. There appears to now be another RFC by Pavel Patapau, specifically
focused on a Guard statement as a new keyword
(https://wiki.php.net/rfc/guard_statement), which now has its separate
discussion.
3. As Thomas Lamy mentioned, I too would prefer a single keyword.
Consider the following two examples:
function foo($bar)
{
if ($bar === 1)
return;
if ($bar === 666)
delete_everything();
}
function foo($bar)
{
if ($bar === 1)
return
if ($bar === 666);
delete_everything();
}
Both would now be valid syntax, and IDEs would have a harder time
warning about the misplaced semicolon in the second example. Wouldn't
be very common, but still.
4. However, this RFC is interesting to me because there be a way to
modify it to allow for less verbose refactoring, and kinda allowing
returns to bubble up like exceptions do. I think it would only make
sense if it's a "if not null then return" type of thing.
Consider the following (a bit contrived, but I hope you get the point):
function main_function()
{
$result = calculate($var);
if ($result !== null)
return $result;
/* do other important stuff */
}
function main_function()
{
ifnotnullreturn calculate($var);
/* do other important stuff */
}
Obviously not an ideal keyword, but this is the only thing I can think
of where this type of syntactic sugar makes sense and decreases
verbosity. Something similar can also be accomplished with exception
though.
5. Finally, I think if we start putting several returns at the same
indentation then the cognitive load increases because we can no longer
tell if a return is actually a return at a glance.
Thanks,
Peter
On Fri, May 15, 2020 at 11:58 AM Victor Bolshov wrote:
>
> Hi internals,
>
> I think it's just as good to write:
> if ($condition) return $retval;
> Yes, there are subtle semantic differences the new syntax would emphasize,
> but it doesn't feel like it justifies it. New syntax also means the need to
> support it, for IDEs and other tools, static analysis tools, code-style tools
> - and all that for a very tiny benefit, if any.
> Cheers,
> Victor
>
> Sent from Mailspring
> (https://link.getmailspring.com/link/85c8412b-b04a-4853-8c4c-e270fcb35...@getmailspring.com/0?redirect=https%3A%2F%2Fgetmailspring.com%2F=aW50ZXJuYWxzQGxpc3RzLnBocC5uZXQ%3D),
> the best free email app for work
> On May 10 2020, at 5:49 pm, Ralph Schindler wrote:
> > Hi! # Intro I am proposing what is a near completely syntactical addition
> > (only change is to language.y) to the language. The best terminology for
> > this syntax is are: `return if`, "return early", or "guard clauses". see:
> > https://en.wikipedia.org/wiki/Guard_(computer_science) Over the past few
> > years, I've seen a growing number of blog posts, conference talks, and even
> > tooling (for example code complexity scoring), that suggest writing guard
> > clauses is a good practice to utilize. I've also seen it more prevalent in
> > code, and even attempts at achieving this with Exceptions (in an HTTP
> > context) in a framework like Laravel. see abort_if/throw_if:
> > https://laravel.com/docs/7.x/helpers#method-abort-if It is also worth
> > mentioning that Ruby has similar features, and I believe they are heavily
> > utilized: see:
> > https://github.com/rubocop-hq/ruby-style-guide#no-nested-conditionals #
> > Proposal In an effort to make it a first class feature of the language, and
> > to make the control flow / guard clause
> s more visible when scanning code, I am proposing this in the syntax of
> adding `return if`. The chosen syntax is: return if ( if_expr ) [:
> optional_return_expression] ; As a contrived example: function
> divide($dividend, $divisor = null) { return if ($divisor === null || $divisor
> === 0); return $dividend / $divisor; } There is already a little discussion
> around the choice of order in the above statement, the main take-aways and
> (my) perceived benefits are: - it keeps the intent nearest the left rail of
> the code (in normal/common-ish coding standards) - it treats "return if" as a
> meta-keyword; if must follow return for the statement to be a guard clause.
> This also allows a person to more easily discern "returns" from "return ifs"
> more easily since there is not an arbitrary amount of code between them (for
> example if the return expression were after return but before if). - it has
> the quality that optional parts are towards the end - is also has the quality
> that the : return_expression;
> is very symmetrical to the way we demarcate the return type in method
> signatures "): return type {" for example. - has the quality of promoting
> single-line conditional
Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
Hi internals,
I think it's just as good to write:
if ($condition) return $retval;
Yes, there are subtle semantic differences the new syntax would emphasize, but
it doesn't feel like it justifies it. New syntax also means the need to support
it, for IDEs and other tools, static analysis tools, code-style tools - and all
that for a very tiny benefit, if any.
Cheers,
Victor
Sent from Mailspring
(https://link.getmailspring.com/link/85c8412b-b04a-4853-8c4c-e270fcb35...@getmailspring.com/0?redirect=https%3A%2F%2Fgetmailspring.com%2F=aW50ZXJuYWxzQGxpc3RzLnBocC5uZXQ%3D),
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On May 10 2020, at 5:49 pm, Ralph Schindler wrote:
> Hi! # Intro I am proposing what is a near completely syntactical addition
> (only change is to language.y) to the language. The best terminology for this
> syntax is are: `return if`, "return early", or "guard clauses". see:
> https://en.wikipedia.org/wiki/Guard_(computer_science) Over the past few
> years, I've seen a growing number of blog posts, conference talks, and even
> tooling (for example code complexity scoring), that suggest writing guard
> clauses is a good practice to utilize. I've also seen it more prevalent in
> code, and even attempts at achieving this with Exceptions (in an HTTP
> context) in a framework like Laravel. see abort_if/throw_if:
> https://laravel.com/docs/7.x/helpers#method-abort-if It is also worth
> mentioning that Ruby has similar features, and I believe they are heavily
> utilized: see:
> https://github.com/rubocop-hq/ruby-style-guide#no-nested-conditionals #
> Proposal In an effort to make it a first class feature of the language, and
> to make the control flow / guard clause
s more visible when scanning code, I am proposing this in the syntax of adding
`return if`. The chosen syntax is: return if ( if_expr ) [:
optional_return_expression] ; As a contrived example: function
divide($dividend, $divisor = null) { return if ($divisor === null || $divisor
=== 0); return $dividend / $divisor; } There is already a little discussion
around the choice of order in the above statement, the main take-aways and (my)
perceived benefits are: - it keeps the intent nearest the left rail of the code
(in normal/common-ish coding standards) - it treats "return if" as a
meta-keyword; if must follow return for the statement to be a guard clause.
This also allows a person to more easily discern "returns" from "return ifs"
more easily since there is not an arbitrary amount of code between them (for
example if the return expression were after return but before if). - it has the
quality that optional parts are towards the end - is also has the quality that
the : return_expression;
is very symmetrical to the way we demarcate the return type in method
signatures "): return type {" for example. - has the quality of promoting
single-line conditional returns # Finally One might say this is unnecessary
syntactic sugar, which is definitely arguable. But we do have multiple ways of
achieving this. Of course all of these things should be discussed, I think
sub-votes (should this PR make it that far) could be considered. The PR is
located here: https://github.com/php/php-src/pull/5552 As mentioned, some
discussion is happening there as well. Thanks! Ralph Schindler PS: since
implementing the ::class feature 8 years ago, the addition of the AST
abstraction made this kind of syntactical change proof-of-concept so much
easier, bravo! -- PHP Internals - PHP Runtime Development Mailing List To
unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
Hello, Not it's not and will likely never be so using `guard` is a really bad idea. Best regaeds, Benas Seliuginas
Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
Benas, > On May 15, 2020, at 04:33, Benas IML wrote: > > Hey, > > `guard` would be a keyword this means that all of the classes, interfaces and > traits named Guard would be illegal. Therefore Laravel's `Guard` interface > would be incompatible with PHP 8 which in turn means thousands of web > applications would be too. > > Best regards, > Benas Seliuginas If the parser were sufficiently smart, I don't think 'guard' would actually conflict with a class or function named 'guard'. If the syntax were: guard (EXPRESSION) else STATEMENT_OR_BLOCK then, 'guard' could not conflict with a class name, because there's no existing syntax that would fit the pattern of a type name followed by a parenthesis — you can't call a type name as if it were a function. Even if you could, it would still not conflict with a function call, because the 'else' keyword after the close parenthesis would not be valid syntax immediately following a function call. So the main question there is, is the parser sufficiently smart to be able to see 'guard' and look ahead for the 'else' to disambiguate a function call from a guard statement? -John -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
Hey, `guard` would be a keyword this means that all of the classes, interfaces and traits named Guard would be illegal. Therefore Laravel's `Guard` interface would be incompatible with PHP 8 which in turn means thousands of web applications would be too. Best regards, Benas Seliuginas
Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
Le Sun, 10 May 2020 10:49:15 -0500,
Ralph Schindler a écrit :
> The chosen syntax is:
>
>return if ( if_expr ) [: optional_return_expression] ;
>
> As a contrived example:
>
> function divide($dividend, $divisor = null) {
> return if ($divisor === null || $divisor === 0);
>
> return $dividend / $divisor;
> }
I do not understand the point, you are just reordering keywords, why is
that better than already correct code:
function divide($dividend, $divisor = null) {
if ($divisor === null || $divisor === 0) return;
return $dividend / $divisor;
}
I do not think an RFC and a special keyword are justified just to move
the word "return" from end to beginning of line.
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Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
I just think that this way is more compatible witth the reading. "Return X if Y" seems better than "return (if) X: (then) Y". Too the ":" could conflicts with return type. Em dom, 10 de mai de 2020 16:59, Ralph Schindler escreveu: > > > On 5/10/20 1:56 PM, David Rodrigues wrote: > > Suggestion: > > > > return if $x > 1; (to return "void") > > return $y if ($x > 1 && $x < 5); > > break if $x > 1; > > break 2 if $x > 1; > > throw new Exception if $x > 1; > > > > 100% that will/should be a votable alternative option should this get to > the voting phase. > > I have reasons for why I chose my initial path, but its worth mentioning > I favor the optional value at the end maybe 65% to 35% where the value > is after the initial keyword. > > Thanks for taking the time! > -ralph schindler >
Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
Hi Ralph, Like others, I think this feels too narrow in its scope, and doesn't add enough over existing syntax. You mention that Ruby has a similar feature, but there it's not a special syntax for guard clauses per se, but a "modifier" form of the if statement: https://docs.ruby-lang.org/en/2.7.0/syntax/control_expressions_rdoc.html#label-Modifier+if+and+unless Along with "unless" (an alias for "if not"), it's supposed to let you write more sentence-like code: print "Hat Trick!" if $goals == 3; throw new BadInputException unless is_valid($input); In fact, Ruby also has modifier forms of while and until; and Perl (where I think this all came from) also for and foreach. I'm not sure whether I'd welcome that syntax in PHP or not, but it would be one way to allow the throw, break, etc cases that other people have mentioned in addition to return, rather than having to invent special syntaxes for each. Regards, -- Rowan Tommins (né Collins) [IMSoP] -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
Benas,
> On May 10, 2020, at 15:19, Benas IML wrote:
>
> Hello,
>
> I think that we SHOULD not introduce a new keyword (e. g. guard) since that
> would be a "major major" backwards incompatibility. "Guard" is a really
> generic
> word and a great example of that is Laravel and their authentication guards.
>
> In general, I don't think that early returns require a seperate syntax and/or
> block statement since a simple `if (...) { return; }` is already sufficient
> enough.
>
> Best regards,
> Benas Seliuginas
I think there's three main reasons for guard, as opposed to if:
1) It further and clearly establishes intent: if you see guard, you have more
information about the programmer's intent and what the code will actually do.
2) It prevents having to negate the condition: guard (is valid) else, instead
of if (not valid) then; negations impose additional cognitive load when
attempting to understand code, especially if your condition already has a
negation.
3) The language provides a guarantee that if the guard condition is not met,
execution can not proceed past the else clause. This helps prevent accidental
fall-through, such as if you wrote: if(!$valid) { terminate(); } expecting it
to end execution (e.g. via a throw or exit), but for some reason it failed to
do so.
To take an idea from Ralph's original proposal, perhaps some syntax like "if
guard (condition) else ...". In this context, guard could not possibly be
confused with a function from the parser's point of view, instead serving as an
intent modifier to if.
-John
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Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
On 5/10/20 1:56 PM, David Rodrigues wrote: Suggestion: return if $x > 1; (to return "void") return $y if ($x > 1 && $x < 5); break if $x > 1; break 2 if $x > 1; throw new Exception if $x > 1; 100% that will/should be a votable alternative option should this get to the voting phase. I have reasons for why I chose my initial path, but its worth mentioning I favor the optional value at the end maybe 65% to 35% where the value is after the initial keyword. Thanks for taking the time! -ralph schindler -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
This proposal looks way too specific to me. I'm a big fan of returning early -- but also of throwing early, breaking early and continuing early. Supporting this just for returns seems odd / inconsistent to me. I agree with this sentiment, and I'll update the PR accordingly and this will be reflected when I make the RFC itself. (Throw feels different as its parameter is not optional and is always a complex type, and is in a different area of the parser... But I'll look more deeply at adding that soon.) That said, I don't think this syntax solves a real problem in the first place. If it solves a problem, it's mostly a problem of PHP coding styles being a bit overzealous when it comes to formatting requirements for early return/break/continue/throw. And that's not a problem that needs solving at the language level... I think we could say the same thing about most new additions: fn arrow functions, str_starts_with/str_ends_with, trailing comma in lists & function calls, str_contains(), flexible (indented) heredocs, list reference assignment, native de-structuring.. just to name a few that all fit into the same kind of quality of life category. Nearly all of those were achievable via some kind of syntax before their addition, but I think we can agree we're better off having them, than not- even if one chooses not to use them. Having been programming with PHP for 22+ years now, and making it a point to evolve my tastes/preferences with the changing language and whatever the prevalent practices are in the community (and other languages), my desire for including these quality of life improvements remains quite high as it keeps the language interesting and competitive. Put another way, as someone who's come to really appreciate the aesthetics and clarity of intent of code,.. and having seen this is some places in the wild already I feel are successful, I personally feel its a good thing to perhaps to run through the RFC process for inclusion in 8. Thanks! Ralph Schindler -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
Hello,
I think that we SHOULD not introduce a new keyword (e. g. guard) since that
would be a "major major" backwards incompatibility. "Guard" is a really
generic
word and a great example of that is Laravel and their authentication guards.
In general, I don't think that early returns require a seperate syntax
and/or
block statement since a simple `if (...) { return; }` is already sufficient
enough.
Best regards,
Benas Seliuginas
Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
Suggestion:
return if $x > 1; (to return "void")
return $y if ($x > 1 && $x < 5);
break if $x > 1;
break 2 if $x > 1;
throw new Exception if $x > 1;
Em dom, 10 de mai de 2020 15:48, Nikita Popov
escreveu:
> On Sun, May 10, 2020 at 5:49 PM Ralph Schindler
> wrote:
>
> > Hi!
> >
> >
> > # Intro
> >
> > I am proposing what is a near completely syntactical addition (only
> > change is to language.y) to the language. The best terminology for this
> > syntax is are: `return if`, "return early", or "guard clauses".
> >
> >see: https://en.wikipedia.org/wiki/Guard_(computer_science)
> >
> > Over the past few years, I've seen a growing number of blog posts,
> > conference talks, and even tooling (for example code complexity
> > scoring), that suggest writing guard clauses is a good practice to
> > utilize. I've also seen it more prevalent in code, and even attempts at
> > achieving this with Exceptions (in an HTTP context) in a framework like
> > Laravel.
> >
> >see abort_if/throw_if:
> > https://laravel.com/docs/7.x/helpers#method-abort-if
> >
> > It is also worth mentioning that Ruby has similar features, and I
> > believe they are heavily utilized:
> >
> >see:
> > https://github.com/rubocop-hq/ruby-style-guide#no-nested-conditionals
> >
> >
> > # Proposal
> >
> > In an effort to make it a first class feature of the language, and to
> > make the control flow / guard clauses more visible when scanning code, I
> > am proposing this in the syntax of adding `return if`.
> >
> > The chosen syntax is:
> >
> >return if ( if_expr ) [: optional_return_expression] ;
> >
> > As a contrived example:
> >
> > function divide($dividend, $divisor = null) {
> > return if ($divisor === null || $divisor === 0);
> >
> > return $dividend / $divisor;
> > }
> >
> > There is already a little discussion around the choice of order in the
> > above statement, the main take-aways and (my) perceived benefits are:
> >
> >- it keeps the intent nearest the left rail of the code (in
> > normal/common-ish coding standards)
> >
> >- it treats "return if" as a meta-keyword; if must follow return for
> > the statement to be a guard clause. This also allows a person to more
> > easily discern "returns" from "return ifs" more easily since there is
> > not an arbitrary amount of code between them (for example if the return
> > expression were after return but before if).
> >
> >- it has the quality that optional parts are towards the end
> >
> >- is also has the quality that the : return_expression; is very
> > symmetrical to the way we demarcate the return type in method signatures
> > "): return type {" for example.
> >
> >- has the quality of promoting single-line conditional returns
> >
> >
> > # Finally
> >
> > One might say this is unnecessary syntactic sugar, which is definitely
> > arguable. But we do have multiple ways of achieving this.
> >
> > Of course all of these things should be discussed, I think sub-votes
> > (should this PR make it that far) could be considered.
> >
> > The PR is located here:
> >
> >https://github.com/php/php-src/pull/5552
> >
> > As mentioned, some discussion is happening there as well.
> >
> >
> > Thanks!
> > Ralph Schindler
> >
> >
> > PS: since implementing the ::class feature 8 years ago, the addition of
> > the AST abstraction made this kind of syntactical change
> > proof-of-concept so much easier, bravo!
> >
>
> This proposal looks way too specific to me. I'm a big fan of returning
> early -- but also of throwing early, breaking early and continuing early.
> Supporting this just for returns seems odd / inconsistent to me.
>
> That said, I don't think this syntax solves a real problem in the first
> place. If it solves a problem, it's mostly a problem of PHP coding styles
> being a bit overzealous when it comes to formatting requirements for early
> return/break/continue/throw. And that's not a problem that needs solving at
> the language level...
>
> Regards,
> Nikita
>
Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
On Sun, May 10, 2020 at 5:49 PM Ralph Schindler
wrote:
> Hi!
>
>
> # Intro
>
> I am proposing what is a near completely syntactical addition (only
> change is to language.y) to the language. The best terminology for this
> syntax is are: `return if`, "return early", or "guard clauses".
>
>see: https://en.wikipedia.org/wiki/Guard_(computer_science)
>
> Over the past few years, I've seen a growing number of blog posts,
> conference talks, and even tooling (for example code complexity
> scoring), that suggest writing guard clauses is a good practice to
> utilize. I've also seen it more prevalent in code, and even attempts at
> achieving this with Exceptions (in an HTTP context) in a framework like
> Laravel.
>
>see abort_if/throw_if:
> https://laravel.com/docs/7.x/helpers#method-abort-if
>
> It is also worth mentioning that Ruby has similar features, and I
> believe they are heavily utilized:
>
>see:
> https://github.com/rubocop-hq/ruby-style-guide#no-nested-conditionals
>
>
> # Proposal
>
> In an effort to make it a first class feature of the language, and to
> make the control flow / guard clauses more visible when scanning code, I
> am proposing this in the syntax of adding `return if`.
>
> The chosen syntax is:
>
>return if ( if_expr ) [: optional_return_expression] ;
>
> As a contrived example:
>
> function divide($dividend, $divisor = null) {
> return if ($divisor === null || $divisor === 0);
>
> return $dividend / $divisor;
> }
>
> There is already a little discussion around the choice of order in the
> above statement, the main take-aways and (my) perceived benefits are:
>
>- it keeps the intent nearest the left rail of the code (in
> normal/common-ish coding standards)
>
>- it treats "return if" as a meta-keyword; if must follow return for
> the statement to be a guard clause. This also allows a person to more
> easily discern "returns" from "return ifs" more easily since there is
> not an arbitrary amount of code between them (for example if the return
> expression were after return but before if).
>
>- it has the quality that optional parts are towards the end
>
>- is also has the quality that the : return_expression; is very
> symmetrical to the way we demarcate the return type in method signatures
> "): return type {" for example.
>
>- has the quality of promoting single-line conditional returns
>
>
> # Finally
>
> One might say this is unnecessary syntactic sugar, which is definitely
> arguable. But we do have multiple ways of achieving this.
>
> Of course all of these things should be discussed, I think sub-votes
> (should this PR make it that far) could be considered.
>
> The PR is located here:
>
>https://github.com/php/php-src/pull/5552
>
> As mentioned, some discussion is happening there as well.
>
>
> Thanks!
> Ralph Schindler
>
>
> PS: since implementing the ::class feature 8 years ago, the addition of
> the AST abstraction made this kind of syntactical change
> proof-of-concept so much easier, bravo!
>
This proposal looks way too specific to me. I'm a big fan of returning
early -- but also of throwing early, breaking early and continuing early.
Supporting this just for returns seems odd / inconsistent to me.
That said, I don't think this syntax solves a real problem in the first
place. If it solves a problem, it's mostly a problem of PHP coding styles
being a bit overzealous when it comes to formatting requirements for early
return/break/continue/throw. And that's not a problem that needs solving at
the language level...
Regards,
Nikita
Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
Am 10.05.20 um 18:26 schrieb John Bafford:
Hi Ralph,
On May 10, 2020, at 11:49, Ralph Schindler wrote:
Hi!
# Intro
I am proposing what is a near completely syntactical addition (only change is to language.y) to the
language. The best terminology for this syntax is are: `return if`, "return early", or
"guard clauses".
see: https://en.wikipedia.org/wiki/Guard_(computer_science)
Over the past few years, I've seen a growing number of blog posts, conference
talks, and even tooling (for example code complexity scoring), that suggest
writing guard clauses is a good practice to utilize. I've also seen it more
prevalent in code, and even attempts at achieving this with Exceptions (in an
HTTP context) in a framework like Laravel.
see abort_if/throw_if: https://laravel.com/docs/7.x/helpers#method-abort-if
It is also worth mentioning that Ruby has similar features, and I believe they
are heavily utilized:
see: https://github.com/rubocop-hq/ruby-style-guide#no-nested-conditionals
# Proposal
In an effort to make it a first class feature of the language, and to make the
control flow / guard clauses more visible when scanning code, I am proposing
this in the syntax of adding `return if`.
The chosen syntax is:
return if ( if_expr ) [: optional_return_expression] ;
As a contrived example:
function divide($dividend, $divisor = null) {
return if ($divisor === null || $divisor === 0);
return $dividend / $divisor;
}
There is already a little discussion around the choice of order in the above
statement, the main take-aways and (my) perceived benefits are:
- it keeps the intent nearest the left rail of the code (in normal/common-ish
coding standards)
- it treats "return if" as a meta-keyword; if must follow return for the statement to be a guard
clause. This also allows a person to more easily discern "returns" from "return ifs"
more easily since there is not an arbitrary amount of code between them (for example if the return expression
were after return but before if).
- it has the quality that optional parts are towards the end
- is also has the quality that the : return_expression; is very symmetrical
to the way we demarcate the return type in method signatures
"): return type {" for example.
- has the quality of promoting single-line conditional returns
# Finally
One might say this is unnecessary syntactic sugar, which is definitely
arguable. But we do have multiple ways of achieving this.
Of course all of these things should be discussed, I think sub-votes (should
this PR make it that far) could be considered.
The PR is located here:
https://github.com/php/php-src/pull/5552
As mentioned, some discussion is happening there as well.
Thanks!
Ralph Schindler
PS: since implementing the ::class feature 8 years ago, the addition of the AST
abstraction made this kind of syntactical change proof-of-concept so much
easier, bravo!
I'm in favor of language features that encourage defensive coding, so, I think
the concept behind return-if is good, but your approach too limited.
I think a more general guard syntax would be better:
guard (some condition) else {
//code here must exit the parent block, or else an error is generated
(at compile-time if possible)
}
This would allow for more and broader use cases: the code in the else clause could do any
of return, continue, break, throw, exit, or maybe even goto, as appropriate to the
condition and its parent block, which could be any functional block — a function, loop,
if, else, try, or catch clause, or the "global" scope outside of a function or
class definition. And, if you did return (as opposed to something else), you'd retain
locality of 'return' and the return value, rather than separating it with the condition.
-John
Hi all,
In contrast, I really like Ralph's proposal for it's simplicity. I would
prefer a single keyword, though.
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Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
On Sun, 10 May 2020 at 17:49, Ralph Schindler
wrote:
> Hi!
>
>
> # Intro
>
> I am proposing what is a near completely syntactical addition (only
> change is to language.y) to the language. The best terminology for this
> syntax is are: `return if`, "return early", or "guard clauses".
>
>see: https://en.wikipedia.org/wiki/Guard_(computer_science)
>
> Over the past few years, I've seen a growing number of blog posts,
> conference talks, and even tooling (for example code complexity
> scoring), that suggest writing guard clauses is a good practice to
> utilize. I've also seen it more prevalent in code, and even attempts at
> achieving this with Exceptions (in an HTTP context) in a framework like
> Laravel.
>
>see abort_if/throw_if:
> https://laravel.com/docs/7.x/helpers#method-abort-if
>
> It is also worth mentioning that Ruby has similar features, and I
> believe they are heavily utilized:
>
>see:
> https://github.com/rubocop-hq/ruby-style-guide#no-nested-conditionals
>
>
> # Proposal
>
> In an effort to make it a first class feature of the language, and to
> make the control flow / guard clauses more visible when scanning code, I
> am proposing this in the syntax of adding `return if`.
>
> The chosen syntax is:
>
>return if ( if_expr ) [: optional_return_expression] ;
>
> As a contrived example:
>
> function divide($dividend, $divisor = null) {
> return if ($divisor === null || $divisor === 0);
>
> return $dividend / $divisor;
> }
>
> There is already a little discussion around the choice of order in the
> above statement, the main take-aways and (my) perceived benefits are:
>
>- it keeps the intent nearest the left rail of the code (in
> normal/common-ish coding standards)
>
>- it treats "return if" as a meta-keyword; if must follow return for
> the statement to be a guard clause. This also allows a person to more
> easily discern "returns" from "return ifs" more easily since there is
> not an arbitrary amount of code between them (for example if the return
> expression were after return but before if).
>
>- it has the quality that optional parts are towards the end
>
>- is also has the quality that the : return_expression; is very
> symmetrical to the way we demarcate the return type in method signatures
> "): return type {" for example.
>
>- has the quality of promoting single-line conditional returns
>
>
> # Finally
>
> One might say this is unnecessary syntactic sugar, which is definitely
> arguable. But we do have multiple ways of achieving this.
>
> Of course all of these things should be discussed, I think sub-votes
> (should this PR make it that far) could be considered.
>
> The PR is located here:
>
>https://github.com/php/php-src/pull/5552
>
> As mentioned, some discussion is happening there as well.
>
>
> Thanks!
> Ralph Schindler
>
>
> PS: since implementing the ::class feature 8 years ago, the addition of
> the AST abstraction made this kind of syntactical change
> proof-of-concept so much easier, bravo!
>
> --
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: http://www.php.net/unsub.php
Hello Ralph,
Have you written a formal RFC document? If not, you should do it for this
RFC: https://wiki.php.net/rfc/howto.
Re: [PHP-DEV] Proposal For Return-If / Early Return / Guard Clause Syntax
Hi Ralph,
> On May 10, 2020, at 11:49, Ralph Schindler wrote:
>
> Hi!
>
>
> # Intro
>
> I am proposing what is a near completely syntactical addition (only change is
> to language.y) to the language. The best terminology for this syntax is are:
> `return if`, "return early", or "guard clauses".
>
> see: https://en.wikipedia.org/wiki/Guard_(computer_science)
>
> Over the past few years, I've seen a growing number of blog posts, conference
> talks, and even tooling (for example code complexity scoring), that suggest
> writing guard clauses is a good practice to utilize. I've also seen it more
> prevalent in code, and even attempts at achieving this with Exceptions (in an
> HTTP context) in a framework like Laravel.
>
> see abort_if/throw_if: https://laravel.com/docs/7.x/helpers#method-abort-if
>
> It is also worth mentioning that Ruby has similar features, and I believe
> they are heavily utilized:
>
> see: https://github.com/rubocop-hq/ruby-style-guide#no-nested-conditionals
>
>
> # Proposal
>
> In an effort to make it a first class feature of the language, and to make
> the control flow / guard clauses more visible when scanning code, I am
> proposing this in the syntax of adding `return if`.
>
> The chosen syntax is:
>
> return if ( if_expr ) [: optional_return_expression] ;
>
> As a contrived example:
>
>function divide($dividend, $divisor = null) {
>return if ($divisor === null || $divisor === 0);
>
>return $dividend / $divisor;
>}
>
> There is already a little discussion around the choice of order in the above
> statement, the main take-aways and (my) perceived benefits are:
>
> - it keeps the intent nearest the left rail of the code (in
> normal/common-ish coding standards)
>
> - it treats "return if" as a meta-keyword; if must follow return for the
> statement to be a guard clause. This also allows a person to more easily
> discern "returns" from "return ifs" more easily since there is not an
> arbitrary amount of code between them (for example if the return expression
> were after return but before if).
>
> - it has the quality that optional parts are towards the end
>
> - is also has the quality that the : return_expression; is very symmetrical
> to the way we demarcate the return type in method signatures
> "): return type {" for example.
>
> - has the quality of promoting single-line conditional returns
>
>
> # Finally
>
> One might say this is unnecessary syntactic sugar, which is definitely
> arguable. But we do have multiple ways of achieving this.
>
> Of course all of these things should be discussed, I think sub-votes (should
> this PR make it that far) could be considered.
>
> The PR is located here:
>
> https://github.com/php/php-src/pull/5552
>
> As mentioned, some discussion is happening there as well.
>
>
> Thanks!
> Ralph Schindler
>
>
> PS: since implementing the ::class feature 8 years ago, the addition of the
> AST abstraction made this kind of syntactical change proof-of-concept so much
> easier, bravo!
I'm in favor of language features that encourage defensive coding, so, I think
the concept behind return-if is good, but your approach too limited.
I think a more general guard syntax would be better:
guard (some condition) else {
//code here must exit the parent block, or else an error is generated
(at compile-time if possible)
}
This would allow for more and broader use cases: the code in the else clause
could do any of return, continue, break, throw, exit, or maybe even goto, as
appropriate to the condition and its parent block, which could be any
functional block — a function, loop, if, else, try, or catch clause, or the
"global" scope outside of a function or class definition. And, if you did
return (as opposed to something else), you'd retain locality of 'return' and
the return value, rather than separating it with the condition.
-John
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