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Bernhard (4508)

https://www.xing ... hard_Schmalhofer

A freelance software engineer with experience in webapplications, databases and bioinformatics.

A contributor to Parrot and the person behind Pipp.

A physicist who worked with third sound in Helium-III and CCD X-ray detectors.

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Journal of Bernhard (4508)

Thursday January 01, 2009
11:57 AM

Closures for Pipp

[ #38198 ]

In the last days I have been working on supporting closures for Pipp. Yes, you've read correctly. The next version of PHP will support real closures. See a=drs-tp5008 for a nice writeup.

Closures are connected with lexical variables, so I had I had to rethink the way I handle variables in Pipp. Initially I had the variables outside functions as package variables. Since this doesn't play well with closures, and as there are problems with included files, I changed those to lexical variables. This was the major part of the work. Thanks to Patrich Michaud for advising me where I should define the lexicals.

After switching to lexicals everywhere I followed my usual approach and tried to do the same as Rakudo does. This worked without hassle for a simple case.


  function gen_indentor ( ) {
      $indention = '+';
      $indentor = function ($line) use ($indention) {
          echo $indention . $line . "\n";

      return $indentor;

  $sub_1 = gen_indentor();

  $sub_1('one plus');


correctly gives:

+one plus

But when I create a second closure I run into problems.


  function gen_indentor ($indention) {
      $indentor = function ($line) use ($indention) {
          echo $indention . $line . "\n";

      return $indentor;

  $sub_1 = gen_indentor('+');
  $sub_4 = gen_indentor('++++');

  $sub_1('one plus');
  $sub_2('four plusses');


incorrectly gives:

++++one plus
++++four plusses

Looks like I need to fiddle some more.

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