(jeffa) Re: Prompting via shell with default arguments

This (hopefully) has the same functionality as your code, with the execption of allowing the user of submitting nothing when there are no default arguments supplied by the programmer. (gotta love Carter's Compass! ok, ok, i just moved the return out of the loop)

sub query {
   my ($str,@argv) = @_;
   my $answer;

   while (1) {
      print "$str ", $argv[0] ? "[$argv[0]]: " : ": ";
      chomp($answer = <STDIN>);
      last unless @argv;
      last if grep $answer =~ /^\Q$_\E$/i, @argv;
   }
   return $answer;
}
[download]

I feel inclined to replace the regular expression used in that grep to

last if grep $answer eq $_, @argv;
[download]

... i see no need to use a regex if you have to match the entire string.

UPDATE:
Ahhh, i missed that you were allowing case insensitive answers via the regex. Here is another version that uses lc to match upper and lower cases. This code also fullfills the requirement of allowing the user to pick a default option. I missed that one the first time around ;)

sub query2 {
   my ($str,@argv) = @_;
   my $answer;

   while (1) {
      print "$str ", $argv[0] ? "[$argv[0]]: " : ": ";
      chomp($answer = <STDIN>);
      return $answer if !@argv or grep lc($answer) eq lc($_), @argv;
      return $argv[0] unless $answer;
   }
}
[download]

I also noticed you changed your original code. It looks much better now, but you should replace

$answer = $default if ($answer eq "");

# with this instead
$answer ||= $default;
[download]

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

Comment on (jeffa) Re: Prompting via shell with default arguments Select or Download Code

Replies are listed 'Best First'.
Re: (jeffa) Re: Prompting via shell with default arguments by Azhrarn (Friar) on Feb 02, 2003 at 02:18 UTC
Ahh, can't believe I didn't even think of using grep (although I did write this code a while ago). Also, that well-placed last does the trick of a null default argument nicely. But, as far as the regexp on the grep goes, I guess that's up to the behavior you want. I typically make it case insensitive, but if you didn't want that, the eq would work fine of course. The only other difference is the behavior on them using the default option I believe. In yours, it will treat the supplied default as one of the restricted arguments. I just wanted to be able to have a suggested argument that wasn't required (like a possible path to a file). Thanks for the reply. ;) ---------------- BP - DG - WB	[reply]
Re: (jeffa) Re: Prompting via shell with default arguments by Azhrarn (Friar) on Feb 02, 2003 at 20:24 UTC
If I were to use the following to check for a default answer: `$answer \|\|= $default;` That will likely not differentiate if the user were to enter an equivalent "false" value (like "0"). Which may not be desired behavior depending on what the question was. Also, is using the two lc()'s more efficient then the regexp? (Not that speed is a big factor in this situation) And don't forget if someone wants to do: `query("Make a decision!", "yes/no", @choices); #see snippet for @choices` Although that could be easily done in the prompt string. :D ---------------- BP - DG - WB	[reply] [d/l] [select]