to understand comma and lists better read http://www.crusoe.net/~jeffp/articles/pm/2000-02.html
for your 'and' and '&&' difference one has precedence higher than the other. see perldoc perlop search for nonassoc for a list of the hierarchy. > -----Original Message----- > From: bob ackerman [mailto:[EMAIL PROTECTED]] > Sent: Thursday, March 14, 2002 1:37 PM > To: [EMAIL PROTECTED] > Cc: [EMAIL PROTECTED] > Subject: Re: comma operator > > > now what? i tried 'and' instead '&&' and it worked - last > wasn't evaluated. > that seems tricky to get right. i still don't understand why > 'last' isn't > always evaluated. > > On Thursday, March 14, 2002, at 10:32 AM, bob ackerman wrote: > > > confusion i have with comma operator. > > docs seem to indicate it evaluates both sides, but i see > examples where > > it looks like if it evaluates to false on LHS it doesn't > evaluate RHS. i > > see this in examples of writing a case statement. > > $x='b'; > > { > > ($x eq 'a') && (print 'a'), last; > > print 'x'; > > } > > i see it work sortof sometimes - if $x isn't equal 'a', > 'last' isn't > > evaulated and it prints 'x'. > > shouldn't it also evaluate 'last', whether the LHS of that > line is true > > or not? > > in fact, i just tried it again and this time it didn't work - it > > evaluated 'last' and didn't print anything. > > > > > -- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > ---------------------------------------------------------------------------- -------------------- The views and opinions expressed in this email message are the sender's own, and do not necessarily represent the views and opinions of Summit Systems Inc. -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
