Re: Change yield interpolation beha viour

  >Пятница, 8 октября 2021, 12:14 +03:00 от Kirill Nesmeyanov ><nesk@xakep.ru>: >  > >  >Hello Internals! > >At the moment, there is a feature/bug in the PHP that allows to use >interpolation of generators. > >``` >$code = <<<EXAMPLE >     Hello ${yield} >EXAMPLE; >``` > >I suspect that initially this functionality was not thought out, but it >partially works, which allows you to implement useful functionality. > >``` >[$query, $params] = sql(fn() => <<<SQL >     SELECT * FROM users WHERE id = ${yield 42} OR id = ${yield 0xDEADBEEF} >SQL); > >// Expected >// $query = "SELECT * FROM users WHERE id = ? OR id = ?" >// $params = [ 42, 0xDEADBEEF ] >``` > >When I say that the functionality was not thought out initially, I mean >the behavior of generators within strings. For example, the following >code, which should (seemingly) implement this functionality: > >``` >function sql(\Closure $expr) >{ >     [$generator, $params] = [$expr(), $params]; > >     while ($generator->valid()) { >        $params[] = $generator->current(); // Get the value from "yield" >        $generator->send('?'); // Insert placeholder >     } > >     return [$generator->getReturn(), $params]; >} >``` > >Causes an error: >``` >Warning: Undefined variable $? >``` > >That is, the expression "${yield 42}" expects back not the result of >this expression, but the name of the variable. Therefore, a complete and >workable implementation of such a functionality is as follows: >� >�ҧ��3�"�8[��https://gist.github.com/SerafimArts/2e7702620480fbce6c24bc87bfb9cb0e > > >I think it makes sense to do something about it. >I have two suggestions: >1) Forbid using "yield" inside strings >2) Expect not a variable name as a result of this expression, but a >substitution value. > >What do you think? >-- >Kirill Nesmeyanov   I apologize for the mail duplication. I did not see it receiving on the mailing list (https://news-web.php.net/php.internals) so I sent it again. However, the first came through.   -- Kirill Nesmeyanov