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Thread-Topic: [PHP-DEV] RFC: Add `println(string $data = ''): int`
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Date: Sun, 14 Mar 2021 15:52:59 +0000
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Subject: Re: [PHP-DEV] RFC: Add `println(string $data = ''): int`
From: tysonandre775@hotmail.com (tyson andre)

Hi Rowan,=0A=
=0A=
> Hi Tyson,=0A=
> =0A=
> I'm on the fence on this one: I've certainly had occasions when it would =
=0A=
> be useful, but mostly in quick prototypes and demo code, and just as =0A=
> often in HTML context (where I'd want it to add '<br>') as plain text =0A=
> context.=0A=
> =0A=
> I am not keen, however, on the proposed implementation details, and =0A=
> would prefer it to much more closely match either print or echo.=0A=
> =0A=
> =0A=
> - Until reading this RFC, I would not have guessed that printf() =0A=
> returned the number of bytes written; I guess it's useful in C, where =0A=
> you're managing string buffers, but in PHP it feels very arbitrary. I =0A=
> would also not particularly associate this new function with printf() so =
=0A=
> my immediate guess would be the same return value as print (even though =
=0A=
> that return value, int(1), is equally arbitrary).=0A=
=0A=
There's also the alias fputs of https://www.php.net/manual/en/function.fwri=
te.php=0A=
which also returns the byte count.=0A=
=0A=
I'd considered just returning void, but then you'd have a mix of standard l=
ibrary=0A=
functions that did/didn't return void and users would need to remember whic=
h did what.=0A=
If someone actually had a need to use the result of println, it would likel=
y be to count bytes,=0A=
rather than to get a hardcoded constant such as 1/null.=0A=
(or expression chaining, but `println('Starting') or die(2); // somehow fai=
led to output` also has a use case)=0A=
=0A=
> - You explicitly state that this function would depend on strict_types =
=0A=
> mode, but echo and print do not. I can't see any particular advantage to =
=0A=
> doing so, and 'println((string)$foo)' would be longer than 'print =0A=
> $foo,"\n"' rather defeating the purpose.=0A=
=0A=
I could change it to accept `mixed` and convert it to a string inside of th=
e function.=0A=
(or `object|string|float|int|bool|null` and throw or return false if an obj=
ect could not be converted to a string).=0A=
Throwing/warning for bool/null in strict mode may be worth it but may be mo=
re convenient to detect with external static analyzers)=0A=
It initially seemed consistent with the behavior of https://www.php.net/fwr=
ite to only accept a string=0A=
and forcing callers to do so would catch unexpected edge cases with bool/nu=
ll (''/'1'),=0A=
floats, etc. in strict mode.=0A=
=0A=
Surprisingly, some output functions in PHP do accept `mixed`.=0A=
https://www.php.net/file_put_contents accepts `mixed` and casts non-resourc=
es =0A=
and non-arrays to strings (php-src/ext/standard/file.c)=0A=
(handling of arrays/resources is different)=0A=
=0A=
```=0A=
		case IS_NULL:=0A=
		case IS_LONG:=0A=
		case IS_DOUBLE:=0A=
		case IS_FALSE:=0A=
		case IS_TRUE:=0A=
			convert_to_string(data);=0A=
=0A=
		case IS_STRING:=0A=
```=0A=
=0A=
Annoyingly, any decision I make would be inconsistent with something,=0A=
e.g. file_put_contents currently doesn't even emit a notice for a failure t=
o convert to string.=0A=
=0A=
```=0A=
php > var_dump(file_put_contents('test.txt', new stdClass()));=0A=
bool(false)=0A=
```=0A=
=0A=
It definitely would be longer to use `println((string)$foo)`,=0A=
but there may be cases where that would be done,=0A=
e.g. if you are writing a script that would be reviewed/modified/used by =
=0A=
programmers that are more familiar with languages that aren't PHP.=0A=
(It'd be more readable using 1 output method than 3)=0A=
=0A=
There's also `println("$foo");`=0A=
=0A=
> - Most importantly, I accept your points about a function being more =0A=
> forward- and backward-compatible, but worry that not making it a keyword =
=0A=
> will lead to further confusion about how parentheses interact with echo =
=0A=
> and print. There is a common misconception that they have some kind of =
=0A=
> "optional parentheses", because they are usually used with a single =0A=
> expression, so wrapping it in parentheses usually doesn't change the =0A=
> outcome; but this is not the case, and it does sometimes matter.=0A=
> =0A=
> =0A=
> As currently proposed, I can see people getting nasty surprises from =0A=
> these inconsistencies. For instance:=0A=
> =0A=
> print (1+2)*3; // prints "9"=0A=
> println (1+2)*3; // prints "3\n"; unless strict_types=3D1 is in effect, i=
n =0A=
> which case TypeError=0A=
> print ($foo ?? 'Foo') . ($bar ?? 'Bar'); // prints "FooBar" if both vars =
=0A=
> are null=0A=
> println ($foo ?? 'Foo') . ($bar ?? 'Bar'); // never prints $bar or =0A=
> "Bar", because they are not passed to println()=0A=
=0A=
Static analyzers for PHP such as Phan warn about the unused result of multi=
plication=0A=
to catch cases like this, and other analyzers can easily add this check if =
they don't already check for it.=0A=
https://github.com/phan/phan/wiki/Issue-Types-Caught-by-Phan#phannoopbinary=
operator=0A=
=0A=
> if ( something() && println($foo) && somethingElse() )=A0 // does what it=
 =0A=
> looks like, if println is a normal function=0A=
> if ( something() && print($foo) && somethingElse() )=A0 // does not print=
 =0A=
> $foo, because the expression passed is actually ($foo)&&somethingElse()=
=0A=
=0A=
The fact that `print` doesn't require parenthesis is something that surpris=
ed me initially,=0A=
though changing it to force it to use function syntax would be a much large=
r bc break=0A=
more suitable for a major version, that I don't expect to pass.=0A=
It may be possible to start deprecating `print` if the expression didn't co=
ntain a parenthesis=0A=
(like the change in precedence of `+` and `-` did), but I'm not planning to=
 work on that.=0A=
(Python converted `print` from a statement in Python 2 to a call in Python =
3)=0A=
=0A=
Regards,=0A=
Tyson=0A=