And of course you can easily provide an example proving your polemic assertion...

Of course:

use enum qw[ CODE GRAPH START PATH SEEN ];
sub _pathsFrom {
    return $_[CODE]->( @{ $_[PATH] }, $_[START] )
        unless exists $_[GRAPH]->{ $_[START] };

    for ( @{ $_[GRAPH]->{ $_[START] } } ) {
        if( exists $_[SEEN]->{ $_[START] . "-$_" } ) {
            return $_[CODE]->( @{ $_[PATH] }, $_[START] );
        }
        else {
            _pathsFrom(
                @_[ CODE, GRAPH ], $_,
                [ @{ $_[PATH] }, $_[START] ], 
                { %{ $_[SEEN] }, $_[START] . "-$_", undef }
            );
        }
    }
}

sub pathsFrom(&@) { _pathsFrom( @_, [], {} ) }
[download]

Ah I see a trivial example already remotely requiring recursion

without sample data for your spontaneous example I can't test, but the following should do.

use enum qw[ CODE GRAPH START PATH SEEN ];
sub _pathsFrom {
 _PATHSFROM:
  {
    return $_[CODE]->( @{ $_[PATH] }, $_[START] )
      unless exists $_[GRAPH]->{ $_[START] };
 
    for ( @{ $_[GRAPH]->{ $_[START] } } ) {
      if ( exists $_[SEEN]->{ $_[START] . "-$_" } ) {
        return $_[CODE]->( @{ $_[PATH] }, $_[START] );
      } else {
        @_=(
            @_[ CODE, GRAPH ], $_,
            [ @{ $_[PATH] }, $_[START] ], 
            { %{ $_[SEEN] }, $_[START] . "-$_", undef }
           );
        redo _PATHSFROM;
      }
    }
  }
}
[download]

If not, enlighten us!

UPDATE(18:16 CEST): This thread is about implementating tail call recursions, thanks for trolling with a graph-search recursion which isn't tail code.

Cheers Rolf

This thread is about implementating tail call recursions, thanks for trolling with a graph-search recursion which isn't tail code.

Oh, sorry. I thought you'd know that every recursive algorithm can be made into a tail-recursive one(*).

So you see there is no trolling and no polemic; just an example, as you requested, that you don't know how to handle.

And, BTW, one disproves your flimsily expounded theory.

* All you need to do is implement the CPS transform.

---

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.