Bug #79044 [Com]: Curly Braces Throw T_LNUMBER Error

From: Date: Mon, 30 Dec 2019 00:04:54 +0000
Subject: Bug #79044 [Com]: Curly Braces Throw T_LNUMBER Error
References: 1  Groups: php.bugs 
Request: Send a blank email to php-bugs+get-224603@lists.php.net to get a copy of this message
Edit report at https://bugs.php.net/bug.php?id=79044&edit=1

 ID:                 79044
 Comment by:         bugreports at gmail dot com
 Reported by:        thebluewalrus at gmail dot com
 Summary:            Curly Braces Throw T_LNUMBER Error
 Status:             Not a bug
 Type:               Bug
 Package:            *General Issues
 Operating System:   Mac OSX 10.12.4
 PHP Version:        7.4.1
 Block user comment: N
 Private report:     N

 New Comment:

> Unless, of course, you have a compelling reason why 
> PHP should suddenly break functionality that has 
> been allowed since basically forever?

well, nobody right in his mind would write "$1test" instead "\$1test" and call
that simply *udenfeined* hehavior given that yiu are supposed to escape $ within double quotes and
undefined behavior by it's definition can change at whatever point in time


Previous Comments:
------------------------------------------------------------------------
[2019-12-29 23:42:48] requinix@php.net

> irrelevant
By all means, please invent a time machine and go back a couple decades to tell the people
developing PHP that they should have done this differently. That way people in the other timeline
won't have to deal with such utterly ridiculous behavior. I know that for me, personally, if I
were to fork PHP, prohibiting writing "$1" is at the top of my list of things to change.

Meanwhile for those of us in this timeline, that's how it is. Unless, of course, you have a
compelling reason why PHP should suddenly break functionality that has been allowed since basically
forever?
If you actually do despite my sarcasm, go ahead and start working on an RFC for it. I'm sure
everyone will love it.

------------------------------------------------------------------------
[2019-12-29 23:10:49] bugreports at gmail dot com

irrelevant, the second one should throw the same error than the first and that can even throw at
compile time

php > echo $1test;
Parse error: syntax error, unexpected '1' (T_LNUMBER), expecting variable (T_VARIABLE) or
'{' or '$' in php shell code on line 1

php > echo "$1test";
$1test

------------------------------------------------------------------------
[2019-12-29 22:44:18] requinix@php.net

Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to
report
a bug at http://bugs.php.net/how-to-report.php

https://www.php.net/manual/en/language.types.string.php#language.types.string.parsing

When PHP reads the simple syntax it sees the '$' and takes
> as many tokens as possible to form a valid variable name

No tokens means no variable and PHP ignores it.

Complex syntax works differently as it
> allows for the use of complex expressions

With complex syntax PHP sees '{$' and everything up to the closing '}' is used.
In other words, PHP looks for a valid expression - the kind you use in your regular code, but with
the obvious limitation that it has to start with a dollar sign.

"$1" is not a valid expression, and PHP raises the same syntax error that it would as if
you wrote that outside of a string.

------------------------------------------------------------------------
[2019-12-29 21:21:15] thebluewalrus at gmail dot com

Yes, I agree I would expect '"$1"' and '"{$1}"' to behave
the same but they don't. I think one or the other is functioning incorrectly. Simplifying the
"correct" example it still executes:

preg_replace('/(a)/', "$1", 'a');

------------------------------------------------------------------------
[2019-12-29 16:23:30] bugreports at gmail dot com

you can't have variables starting with a number in PHP

-----------------------

Correct behavior:
preg_replace('/(a)/', "$1test", 'a');

i would say this is not correct behavior and should trhow the same error becasue you can't have
a variable $1test nor can you have $1

-----------------------

php > $1test = 'test';

Parse error: syntax error, unexpected '1' (T_LNUMBER), expecting variable (T_VARIABLE) or
'{' or '$' in php shell code on line 1

------------------------------------------------------------------------


The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at

    https://bugs.php.net/bug.php?id=79044


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Edit this bug report at https://bugs.php.net/bug.php?id=79044&edit=1


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