This produces a deprecation warning in recent versions of Perl thanks to ?/?. You can use '/' or "/" instead to avoid the deprecation warning. Perl is smart enough to know you meant a regexp rather than a string if it follows =~.

bigrat is in core, so I don't consider it cheating. Now, if you wrote chkrat.pm, and uploaded it to CPAN specifically to help your golf score, that would be cheating.

However, I'm disappointed by the lack of a line break.

Here's my reinterpretation of your implementation. I've added a line break at the cost of three keystrokes, but managed to save six keystrokes elsewhere...

use bigrat;print((shift()*10**1000/shift)=~"/"?N:Y,$/)

[download]

These are also quite cute, though very slightly longer...

use bigrat;print[Y,N]->[(shift()*10**1000/shift)=~"/"],$/

[download]
use bigrat;$_=shift()*10**1000/shift;print[Y,N]->[m"/"],$/

[download]
perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'

In reply to Re^2: Determining if a rational number terminates by tobyink
in thread Determining if a rational number terminates by blackle

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