Re: style for returning errors from subroutines

How about to return CODE-refs e.g.

sub makeclosure {
 my @x=(@_);
 return sub {
  return @x
 }
}
sub yoursubhere{
#do stuff
return makeclosure(val1,val2);
#on error
return bless sub {undef or die},"errormessage";
[download]

yoursubhere is called without checking like &yoursubhere($a->(),$s->())->() or with check like

if(ref($return=&yoursubhere($a->(),$s->())ne"CODE"){
#error
}
&nextsub($return->())
[download]

Comment on Re: style for returning errors from subroutines Select or Download Code

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Re: Re: style for returning errors from subroutines by Boldra (Curate) on Jun 15, 2001 at 13:54 UTC
This looks really interesting. I wish I could understand more of it! You lost me just after the closure (which I have read about in The Panther Book, but have never used). Am I right in thinking that the closure creates a place to store return values, and that if a closure is not returned, an error is? Or is the error in the closure? Where exactly? Or is that left up to me? Boldra	[reply]
Re: Re: Re: style for returning errors from subroutines by Anonymous Monk on Jun 15, 2001 at 18:08 UTC
The closure is a holder for a value. You can instead return an error. That is a subref (legally the same as a closure, but not holding a value) that on deref gives a default (including a possibility to leave the program for dead) but is blessed to contain the error and at the same time providing an easy test to distinguish from a closure.	[reply]