[PHP-BUG] Req #70087 [NEW]: Better string interpolation

From:             mario dot dweller at seznam dot cz
Operating system: 
PHP version:      7.0.0beta1
Package:          PHP Language Specification
Bug Type:         Feature/Change Request
Bug description:Better string interpolation

Description:
------------
There is a support for variable interpolation in strings like
`$string = "$a/$b $c";`
or
`$string = "{$a}/{$b} {$c}";`

But it is not usable for functions.
`$string = "Length: {strlen($a)}";`

I guess that's why many programmers prefer using sprintf instead because
it is more readable than concatenation using dots. I personally use
sprintf almost everywhere because the code looks more consistent then.

Since there are many cool new features in PHP7, why not to add this
basic one?
I guess it would need a special syntax because of BC, or not?
But there are currently two ways to achieve the same thing:

`$string = "Hello {$a}";`
`$string = "Hello ${a}";`

The second one looks unnaturally, most prefer the first way. For example
it could be forbidden in favor of this:

`$string = "Length is ${strlen(a)}";`



-- 
Edit bug report at https://bugs.php.net/bug.php?id=70087&edit=1
-- 
Try a snapshot (PHP 5.4):   https://bugs.php.net/fix.php?id=70087&r=trysnapshot54
Try a snapshot (PHP 5.5):   https://bugs.php.net/fix.php?id=70087&r=trysnapshot55
Try a snapshot (trunk):     https://bugs.php.net/fix.php?id=70087&r=trysnapshottrunk
Fixed in SVN:               https://bugs.php.net/fix.php?id=70087&r=fixed
Fixed in release:           https://bugs.php.net/fix.php?id=70087&r=alreadyfixed
Need backtrace:             https://bugs.php.net/fix.php?id=70087&r=needtrace
Need Reproduce Script:      https://bugs.php.net/fix.php?id=70087&r=needscript
Try newer version:          https://bugs.php.net/fix.php?id=70087&r=oldversion
Not developer issue:        https://bugs.php.net/fix.php?id=70087&r=support
Expected behavior:          https://bugs.php.net/fix.php?id=70087&r=notwrong
Not enough info:            https://bugs.php.net/fix.php?id=70087&r=notenoughinfo
Submitted twice:            https://bugs.php.net/fix.php?id=70087&r=submittedtwice
register_globals:           https://bugs.php.net/fix.php?id=70087&r=globals
PHP 4 support discontinued: https://bugs.php.net/fix.php?id=70087&r=php4
Daylight Savings:           https://bugs.php.net/fix.php?id=70087&r=dst
IIS Stability:              https://bugs.php.net/fix.php?id=70087&r=isapi
Install GNU Sed:            https://bugs.php.net/fix.php?id=70087&r=gnused
Floating point limitations: https://bugs.php.net/fix.php?id=70087&r=float
No Zend Extensions:         https://bugs.php.net/fix.php?id=70087&r=nozend
MySQL Configuration Error:  https://bugs.php.net/fix.php?id=70087&r=mysqlcfg