Introducing pragmas into PHP?

Hi, We have ongoing debates about the pull between BC behaviour and wanting to tidy up / optimize performance etc. And often BC for bizarre coding practices means that there is a performance penalty for everyone else. A common way of doing this in C etc. is the use of compiler pragmas, but such a change would in itself be not BC and INI parameters are too blunt an instrument here as these are set at runtime or globally as a PER_INI_USER etc. They can't impact the current source being compiled, and they can't be conveniently namespace-specific. I am suggestion the overload of constants of the form PHP_PRAGMA_XXX to define PHP / Zend compiler / executor behaviours. This approach would be BC to 5.3 unless, of course, the application already used PHP_PRAGMA_* constants, in which case we might also need an allow_php_pragmas INI parameter to globally enable/disable their interpretation. As a small example: namespace fred; echo \strlen("DDDD"); generates different .

   SEND_VAL                            'DDDD'
   DO_FCALL                 1  $0      'strlen'

and different (slower) opcode if you omit the \

   INIT_NS_FCALL_BY_NAME               'strlen'
   SEND_VAL                            'DDDD'
   DO_FCALL_BY_NAME         1  $0

Whilst most sane projects would have a simple programming standard which basically says "Don't override builtin functions", the odd one might for various reasons allow this. This practice can significantly complicate optimization for performance (see https://bugs.php.net/bug.php?id=64346). I've seen namespace-based project where all builtins have the explicit global \ prefix. IMO, yukkk. So my suggestion is that we allow the programmer to issue a pragma to inform compiler and runtime handling, so in this case for example, namespace fred; const PHP_PRAGMA_ALLOW_OVERRIDE_BUILTINS=false; echo strlen("DDDD"); would define the constant fred\PHP_PRAGMA_ALLOW_OVERRIDE_BUILTINS and also have the desired compile-time and runtime effect. Alternatively the corresponding global constant \PHP_PRAGMA_ALLOW_OVERRIDE_BUILTINS could be set to false and individual namespaces could set the corresponding namespace constant to true. Thoughts and comments? Terry Ellison