While not directly answering your question (I really don't see any recursion in the example). Recursion is possible with Inline::C. $self can look like almost anything, it depends on how you set up your code. Here's a very contrived example borrowing from K&R's "Self-referential Structures" paragraph (chapter 6.5 from K&R 1). First is a simplistic pure-perl approach (not that I recommend doing trees this way in perl). 

#!/usr/bin/perl -w

package Tnode;

sub new {
   my( $class, $word, $count ) = @_;
   my $self = {};
   $self->{word}  = $word;
   $self->{count} = $count;
   $self->{left}  = undef;
   $self->{right} = undef;

   return bless $self, $class;
}

package main;

die unless @ARGV;

my $root = undef;

while(<>) {
   chomp;
   $word = $_;
   $root = tree( $root, $word );
}

treeprint( $root );

sub tree {
   my( $node, $word ) = @_;

   if( ! $node ) {
      $node = Tnode->new( $word, 1 );
      $node->{left} = undef;
      $node->{right} = undef;
   } elsif( $node->{word} eq $word ) {
      $node->{count}++;
   } elsif( $word lt $node->{word} ) {
      $node->{left} = tree( $node->{left}, $word );
   } else {
      $node->{right} = tree( $node->{right}, $word );
   }

   return $node;
}

sub treeprint {
   my( $root ) = shift;

   if( $root ) {
      treeprint( $root->{left} );
      printf( "%4d %s\n", $root->{count}, $root->{word} );
      treeprint( $root->{right} );
   }
}

[download]

given a file with a list of words, this script will output the ascii ordered words with their counts.

Now here's the sample example with the treeprint function done via inline. Now a couple notes about this example, my brain could not make the hv_fetch function work correctly, so this example rather ineffeciently uses a for loop to walk the hash entries. And speaking of hashes, we just assume the reference is a hash and blithely cast it as such (not good coding but the attempt here is to show recursion). 

#!/usr/bin/perl -w

use Inline C;

package Tnode;

sub new {
   my( $class, $word, $count ) = @_;
   my $self = {};
   $self->{word}  = $word;
   $self->{count} = $count;
   $self->{left}  = undef;
   $self->{right} = undef;

   return bless $self, $class;
}

package main;

die unless @ARGV;

my $root = undef;

while(<>) {
   chomp;
   $word = $_;
   $root = tree( $root, $word );
}

treeprint( $root );

sub tree {
   my( $node, $word ) = @_;

   if( ! $node ) {
      $node = Tnode->new( $word, 1 );
      $node->{left} = undef;
      $node->{right} = undef;
   } elsif( $node->{word} eq $word ) {
      $node->{count}++;
   } elsif( $word lt $node->{word} ) {
      $node->{left} = tree( $node->{left}, $word );
   } else {
      $node->{right} = tree( $node->{right}, $word );
   }

   return $node;
}
__END__
__C__

void treeprint( SV *root ) {

   HV* hash;
   HE* hash_entry;
   SV* node;
   SV* word;
   SV* count;

   if( !SvROK(root) )
      return;

   hash = (HV*)SvRV(root);

   node = get_child( hash, "left" );
   if( node != NULL ) {
      treeprint( node );
   }

   output( hash );

   node = get_child( hash, "right" );
   if( node != NULL ) {
      treeprint( node );
   }
}

SV *get_child( HV *hash, char *key ) {
   int num_keys, i;
   HE *hash_entry;
   SV *sv_key;
   SV *sv_val;

   num_keys = hv_iterinit(hash);
   for (i = 0; i < num_keys; i++) {
      hash_entry = hv_iternext(hash);
      sv_key = hv_iterkeysv(hash_entry);
      sv_val = hv_iterval(hash, hash_entry);
      if( strcmp( SvPV( sv_key, PL_na), key ) == 0 ) {
         return( sv_val );
      }
   }

   sv_val = NULL;
   return sv_val;
}

void output( HV *hash ) {
   int num_keys, i;
   HE *hash_entry;
   SV *sv_key;
   SV *sv_val;
   int count;
   char *word = NULL;

   num_keys = hv_iterinit(hash);
   for(i = 0; i < num_keys; i++) {
      hash_entry = hv_iternext(hash);
      sv_key = hv_iterkeysv(hash_entry);
      sv_val = hv_iterval(hash, hash_entry);
      if( strcmp( SvPV( sv_key, PL_na), "word" ) == 0 ) {
         word = SvPV( sv_val, PL_na);
      }
      if( strcmp( SvPV( sv_key, PL_na), "count" ) == 0 ) {
         count = SvIV( sv_val );
      }
   }

   if( word ) {
      printf( "%4d %s\n", count, word );
   }
}

[download]

Now that all being said, a benchmark of the two approaches shows very little difference 

Benchmark: timing 50000 iterations of inline, perl...
   inline: 13 wallclock secs (12.42 usr +  0.00 sys = 12.42 CPU) @ 
      4025.76/s (n=50000)
   perl: 12 wallclock secs (12.27 usr +  0.00 sys = 12.27 CPU) @ 
      4074.98/s (n=50000)

[download]

but maybe if I could get hv_fetch to work properly, there would be a noticeable diff.

-derby

In reply to Re: inline perl and recursion by derby
in thread inline perl and recursion by abitkin

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.