unless ($turn){...} evaluates $turn for what?

mhearse has asked for the wisdom of the Perl Monks concerning the following question:

In reading Learning More Perl, I need the following code explained:

unless ($turn) {
  print "on course.\n";
  return;
}
[download]

How (and for what) is turn being evaluated? I can't find much on the until statement, except that it evaluates for non-truth. _{janitored by ybiC: Retitle from "Until loop", add balanced <code> tags}

Comment on unless ($turn){...} evaluates $turn for what? Download Code

Replies are listed 'Best First'.
Re: unless ($turn){...} evaluates $turn for what? by valdez (Monsignor) on Sep 06, 2003 at 19:12 UTC
`unless ($turn)` can be read as `if (not($turn))`. What's the problem with `until`? Ciao, Valerio	[reply] [d/l] [select]
Re: unless ($turn){...} evaluates $turn for what? by LordWeber (Monk) on Sep 06, 2003 at 20:31 UTC
	[reply]
Re: unless ($turn){...} evaluates $turn for what? by bradcathey (Prior) on Sep 06, 2003 at 20:49 UTC
Not so sure I understand the question. Having said that, the `until` is just another great way Perl allows a "conditional loop". Don't read too much into it. Set up some examples with `do/hile/until` or `if/until` and see how each works and decide what's best for any given situation. It's more fun than just doing `if/else` every time.	[reply] [d/l] [select]
Re: unless ($turn){...} evaluates $turn for what? by bradcathey (Prior) on Sep 06, 2003 at 21:03 UTC
Just stumbled across this little thread on `until` in until loops. Check it out, especially the replies.	[reply] [d/l]
Re: unless ($turn){...} evaluates $turn for what? by mhearse (Chaplain) on Sep 06, 2003 at 20:37 UTC
Right, I meant unless in the title. It makes sense. $turn is being evaluated for truth.	[reply]