self-reporting perl code: how can it be done?

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Re: self-reporting perl code: how can it be done? by diotalevi (Canon) on Oct 29, 2004 at 16:06 UTC
Try `perl -MO=Xref your_script.pl` which produces this sort of output. ... skipping more output ... File GraphLotusScript.pl ... skipping some output ... Package main &class s158 &const s164 &function s152 &library s171 &main s41 &read_source s63 &subroutine s146 &unhandled s263 &usage s132 &variable s141 Subroutine (main) Package main $GRAPHVIZ 19 $OUT_FILE 22 $OUT_FMT 21 $SHOW_ALL 31 $SHOW_CLASSES 31 $SHOW_CODE 30, 31 $SHOW_CONSTANTS 31 $SHOW_FUNCTIONS 31 $SHOW_LIBRARIES 31 $SHOW_SUBS 31 $SHOW_VARIABLES 31 $VIEW 20 %SHAPES 23 &GetOptions &31 &main &41 @ARGV 41 Subroutine class Package (lexical) $name i200, 202 $self i202, 203 %$self 203, 204 %%$self 204, 206 %%%$self 206, 210 %%%%$self 210 Package main $ORDER 203 $_ 210, 210 %STASH 202 @_ 200 Subroutine const Package (lexical) $name i233, 235 $self i235, 236 %$self 236, 237 %%$self 237, 238 %%%$self 238 Package main $ORDER 236 %STASH 235 @_ 233 Subroutine function Package (lexical) $name i183, 185 $self i185, 186 %$self 186, 187 %%$self 187, 189 %%%$self 189, 193 %%%%$self 193 Package main $ORDER 186 $_ 193, 193 %STASH 185 @_ 183 Subroutine library Package (lexical) $name i243, 245 $self i245, 246 %$self 246, 247 %%$self 247, 248 %%%$self 248 Package main $ORDER 246 %STASH 245 @_ 243 Subroutine main Package (lexical) $file i64, 60, 60 $first_file i46, 47, 49, 49, 120, 120, 124 $match 105, 106 $object 77, 91 $shape i78, 81 $source i91, 93 $type i77, 78, 78 %$object 77, 81, 91, 105, 105 %%$object 105, 106 @files i45, 64 Package CORE::GLOBAL &glob &45 Package main $! 49, 60 $GRAPHVIZ 120 $OBJECT 55 $OUT_FILE 120, 124 $OUT_FMT 120 $VIEW 124 $_ 45, 45, 72, 86, 93, 93 %SHAPES 78 %STASH 55, 72, 77, 86, 91, 93, 105, 110 &read_source &63 DOT 51, 81, 84, 106, 116 SOURCE 60, 64 @_ 45 Subroutine read_source Package main $1 141, 146, 152, 158, 164, 171 $OBJECT 138 $SHOW_ALL 141, 146, 152, 158, 164, 171 $SHOW_CLASSES 158 $SHOW_CODE 146, 152, 158 $SHOW_CONSTANTS 164 $SHOW_FUNCTIONS 152 $SHOW_LIBRARIES 171 $SHOW_SUBS 146 $SHOW_VARIABLES 141 $_ 138, 141 %$OBJECT 138 &class &158 &const &164 &function &152 &library &171 &subroutine &146 &variable &141 Subroutine subroutine Package (lexical) $name i217, 219 $self i219, 220 %$self 220, 221 %%$self 221, 222 %%%$self 222, 227 %%%%$self 227 Package main $ORDER 220 $_ 227, 227 %STASH 219 @_ 217 Subroutine usage Package main $0 130 Subroutine variable Package (lexical) $name i253, 254 $self i254, 255 %$self 255, 256 %%$self 256, 257 %%%$self 257 Package main $ORDER 255 %STASH 254 @_ 253 ... skipping more output ... [download] Considered: radiantmatrix Serious need for trimming or readmore tags Unconsidered: ysth upon consultation with author - Keep/Edit/Delete: 6/21/0	[reply] [d/l] [select]
Re: self-reporting perl code: how can it be done? by Happy-the-monk (Canon) on Oct 29, 2004 at 14:49 UTC
write a module, so you don't have to report on the reporter-code. open the file itself - `open( 0 )` -, read, parse and report... Cheers, Sören Update: s/\$0/0/ ... I got it wrong, it's seldom used, sorry. Another update, now with code that's tested, as the first should have been. A simple Perl quine: `open ( 0 ) or die $!; while ( <0> ) { print };` [download]	[reply] [d/l]
Re: self-reporting perl code: how can it be done? by dragonchild (Archbishop) on Oct 29, 2004 at 14:54 UTC
Sounds like you want to parse Perl. For simple situations, you might want to consider using a source filter. For complex situations, especially regarding AUTOLOAD or modules like Class::MethodMaker, that's not going to work. For what you seem to be talking about, a source filter is probably the way to go. Start with Filter::Simple. Being right, does not endow the right to be rude; politeness costs nothing. Being unknowing, is not the same as being stupid. Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence. Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.	[reply]
Re: self-reporting perl code: how can it be done? by revdiablo (Prior) on Oct 29, 2004 at 16:36 UTC
How can one write a perl script in such a way that the code can report on itself? If you have a __DATA__ section at the end, you can seek on the DATA filehandle, and read the source of your current program. Note that without the __DATA__ section, it will not work. Here's a quick example: `#!/usr/bin/perl use strict; use warnings; my %chars; seek DATA, 0, 0; while (<DATA>) { chomp; $chars{$_}++ for split //; } for (sort keys %chars) { printf "%s => %2d\n", $_, $chars{$_}; } __DATA__` [download]	[reply] [d/l]

Try perl -MO=Xref your_script.pl which produces this sort of output.

... skipping more output ...
File GraphLotusScript.pl
    ... skipping some output ...
    Package main
      &class            s158
      &const            s164
      &function         s152
      &library          s171
      &main             s41
      &read_source      s63
      &subroutine       s146
      &unhandled        s263
      &usage            s132
      &variable         s141
  Subroutine (main)
    Package main
      $GRAPHVIZ         19
      $OUT_FILE         22
      $OUT_FMT          21
      $SHOW_ALL         31
      $SHOW_CLASSES     31
      $SHOW_CODE        30, 31
      $SHOW_CONSTANTS   31
      $SHOW_FUNCTIONS   31
      $SHOW_LIBRARIES   31
      $SHOW_SUBS        31
      $SHOW_VARIABLES   31
      $VIEW             20
      %SHAPES           23
      &GetOptions       &31
      &main             &41
      @ARGV             41
  Subroutine class
    Package (lexical)
      $name             i200, 202
      $self             i202, 203
      %$self            203, 204
      %%$self           204, 206
      %%%$self          206, 210
      %%%%$self         210
    Package main
      $ORDER            203
      $_                210, 210
      %STASH            202
      @_                200
  Subroutine const
    Package (lexical)
      $name             i233, 235
      $self             i235, 236
      %$self            236, 237
      %%$self           237, 238
      %%%$self          238
    Package main
      $ORDER            236
      %STASH            235
      @_                233
  Subroutine function
    Package (lexical)
      $name             i183, 185
      $self             i185, 186
      %$self            186, 187
      %%$self           187, 189
      %%%$self          189, 193
      %%%%$self         193
    Package main
      $ORDER            186
      $_                193, 193
      %STASH            185
      @_                183
  Subroutine library
    Package (lexical)
      $name             i243, 245
      $self             i245, 246
      %$self            246, 247
      %%$self           247, 248
      %%%$self          248
    Package main
      $ORDER            246
      %STASH            245
      @_                243
  Subroutine main
    Package (lexical)
      $file             i64, 60, 60
      $first_file       i46, 47, 49, 49, 120, 120, 124
      $match            105, 106
      $object           77, 91
      $shape            i78, 81
      $source           i91, 93
      $type             i77, 78, 78
      %$object          77, 81, 91, 105, 105
      %%$object         105, 106
      @files            i45, 64
    Package CORE::GLOBAL
      &glob             &45
    Package main
      $!                49, 60
      $GRAPHVIZ         120
      $OBJECT           55
      $OUT_FILE         120, 124
      $OUT_FMT          120
      $VIEW             124
      $_                45, 45, 72, 86, 93, 93
      %SHAPES           78
      %STASH            55, 72, 77, 86, 91, 93, 105, 110
      &read_source      &63
      *DOT              51, 81, 84, 106, 116
      *SOURCE           60, 64
      @_                45
  Subroutine read_source
    Package main
      $1                141, 146, 152, 158, 164, 171
      $OBJECT           138
      $SHOW_ALL         141, 146, 152, 158, 164, 171
      $SHOW_CLASSES     158
      $SHOW_CODE        146, 152, 158
      $SHOW_CONSTANTS   164
      $SHOW_FUNCTIONS   152
      $SHOW_LIBRARIES   171
      $SHOW_SUBS        146
      $SHOW_VARIABLES   141
      $_                138, 141
      %$OBJECT          138
      &class            &158
      &const            &164
      &function         &152
      &library          &171
      &subroutine       &146
      &variable         &141
  Subroutine subroutine
    Package (lexical)
      $name             i217, 219
      $self             i219, 220
      %$self            220, 221
      %%$self           221, 222
      %%%$self          222, 227
      %%%%$self         227
    Package main
      $ORDER            220
      $_                227, 227
      %STASH            219
      @_                217
  Subroutine usage
    Package main
      $0                130
  Subroutine variable
    Package (lexical)
      $name             i253, 254
      $self             i254, 255
      %$self            255, 256
      %%$self           256, 257
      %%%$self          257
    Package main
      $ORDER            255
      %STASH            254
      @_                253
... skipping more output ...
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Considered: radiantmatrix Serious need for trimming or readmore tags
Unconsidered: ysth upon consultation with author - Keep/Edit/Delete: 6/21/0

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write a module, so you don't have to report on the reporter-code.

open the file itself - open( 0 ) -, read, parse and report...

Cheers, Sören

Update: s/\$0/0/ ... I got it wrong, it's seldom used, sorry.

Another update, now with code that's tested, as the first should have been.
A simple Perl quine:

open ( 0 ) or die $!;
while ( <0> ) { print };
[download]

[reply]
[d/l]

Class::MethodMaker

For what you seem to be talking about, a source filter is probably the way to go. Start with Filter::Simple.

Being right, does not endow the right to be rude; politeness costs nothing.
Being unknowing, is not the same as being stupid.
Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence.
Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.

[reply]

How can one write a perl script in such a way that the code can report on itself?

If you have a __DATA__ section at the end, you can seek on the DATA filehandle, and read the source of your current program. Note that without the __DATA__ section, it will not work. Here's a quick example:

#!/usr/bin/perl
use strict;
use warnings;

my %chars;

seek DATA, 0, 0;
while (<DATA>) {
    chomp;
    $chars{$_}++ for split //;
}

for (sort keys %chars) {
    printf "%s => %2d\n", $_, $chars{$_};
}

__DATA__
[download]

[reply]
[d/l]