Perl and Perl++ (aka Perl6)

What Mo does isn't really golfing in the way it's typically known, but mostly minimization in the same style as many JS minifiers do it. Unless you have specific complaints, you have no reason to worry about it.

Also, it is done for the very specific reason that this way it can be dropped into software with copy&paste without even changing the line numbers.

Or in Moose/Moo:

has [qw/x y/] => ( is => 'rw' );

nice!

An upgrade to Mo::Inline appears to be behind this issue for YAML:

https://rt.cpan.org/Ticket/Display.html?id=90817

and I think a similar issue was behind this:

https://rt.cpan.org/Ticket/Display.html?id=76664

It's not the most pleasant code to be debugging either.

It's an interesting idea, but I'm treating it as a warning sign in code in future, particularly anything that so many other modules depend on.

> Is your issue about Mo or about non-core dependencies?

Neither - it's about modules which use Mo::Inline. Mo itself seems fine, if a module uses it and works, that's great. Non-core dependencies... the more the merrier. I have no objections to a module depending on Mo itself. My specific complaint (as Mithaldu was asking) is that debugging something which has been through the Mo::Inline process is a headache I'd rather avoid.

Granted, YAML is perhaps an extreme case, several things depend on it so breakage is very visible, and it's mildly disheartening to open the RT queue and see that there's >100 open tickets to check.

Also, please note that ingy has already released a new version of YAML which so far seems to resolve the problem -

At least Mo::Inline can update all your scripts with one command.

That's a nice feature.

My main issue is that these aren't my scripts/modules: if something breaks in a dependency it's usually worth taking a look at the source to see if it's an easy fix.

In this case... apparently there was a bug somewhere in here:

no warnings;my$M=__PACKAGE__.'::';*{$M.Object::new}=sub{my$c=shift;my$s=bless{@_},$c;my%n=%{$c.::.':E'};map{$s->{$_}=$n{$_}->()if!exists$s->{$_}}keys%n;$s};*{$M.import}=sub{import warnings;$^H|=1538;my($P,%e,%o)=caller.'::';shift;eval"no Mo::$_",&{$M.$_.::e}($P,\%e,\%o,\@_)for@_;return if$e{M};%e=(extends,sub{eval"no $_[0]()";@{$P.ISA}=$_[0]},has,sub{my$n=shift;my$m=sub{$#_?$_[0]{$n}=$_[1]:$_[0]{$n}};@_=(default,@_)if!($#_%2);$m=$o{$_}->($m,$n,@_)for sort keys%o;*{$P.$n}=$m},%e,);*{$P.$_}=$e{$_}for keys%e;@{$P.ISA}=$M.Object};*{$M.'builder::e'}=sub{my($P,$e,$o)=@_;$o->{builder}=sub{my($m,$n,%a)=@_;my$b=$a{builder}or return$m;my$i=exists$a{lazy}?$a{lazy}:!${$P.':N'};$i or ${$P.':E'}{$n}=\&{$P.$b}and return$m;sub{$#_?$m->(@_):!exists$_[0]{$n}?$_[0]{$n}=$_[0]->$b:$m->(@_)}}};*{$M.'default::e'}=sub{my($P,$e,$o)=@_;$o->{default}=sub{my($m,$n,%a)=@_;exists$a{default}or return$m;my($d,$r)=$a{default};my$g='HASH'eq($r=ref$d)?sub{+{%$d}}:'ARRAY'eq$r?sub{[@$d]}:'CODE'eq$r?$d:sub{$d};my$i=exists$a{lazy}?$a{lazy}:!${$P.':N'};$i or ${$P.':E'}{$n}=$g and return$m;sub{$#_?$m->(@_):!exists$_[0]{$n}?$_[0]{$n}=$g->(@_):$m->(@_)}}};my$i=\&import;*{$M.import}=sub{(@_==2 and not$_[1])?pop@_:@_==1?push@_,grep!/import/,@f:();goto&$i};@f=qw[builder default import];use strict;use warnings;

at which point I close the editor and look for other options...