How do I automatically feed multiple yes'es into a subroutine that waits on reads from STDIN?

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

I have a subroutine that I cannot modify, that asks a number of yes-no style questions and waits for STDIN before continuing. I would like to invoke this subroutine and feed it yes to all the questions. How do I do this? (To clarify on what I am trying to do see the following exemplary pseudo-code. I know some of the syntax is not proper Perl. )

sub askQuestions()
{
 my $answer;

 my $isHumane;
 my $isStinky;

 print "Are you humane? ";
 $answer = getStringReadFromStdin(); # Will wait for input. 
 if ($anwser eq  "yes") {
  $isHumane = 1;
 } else {
  $isHumane = 0;
  # Should be ashamed of yourself
 }

 print "Do you smell? ";
 $answer = getStringReadFromStdin(); # Will wait for input. 
 if ($anwser eq  "yes") {
  $isStinky = 1;
  # Take a shower. 
 } else {
  $isStinky = 0;
 }
}

sub askQuestionWrapper()
{
 while (askQuestions() << print "yes") {
 }
}

askQuestionWrapper();
[download]

Comment on How do I automatically feed multiple yes'es into a subroutine that waits on reads from STDIN? Download Code

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Re: How do I automatically feed multiple yes'es into a subroutine that waits on reads from STDIN? by FunkyMonk (Bishop) on Aug 28, 2007 at 16:21 UTC
You could supply an alternative definition for `getStringReadFromStdin`. Eg `{ no warnings 'redefine'; local *{main::get_input} = sub { "yes" }; get_answers(); } sub get_answers { print "Is this right?"; return get_input(); } sub get_input { <> }` [download] The bare block at the top redefines `get_input` so that it returns 'yes', rather than input from STDIN. The redefinition is local to the block.	[reply] [d/l] [select]
Re: How do I automatically feed multiple yes'es into a subroutine that waits on reads from STDIN? by Anonymous Monk on Aug 28, 2007 at 16:12 UTC
You could redirect STDIN to a pipe from within the script. You could redirect STDIN to a pipe from outside the script. `perl wrapper.pl \| perl game.pl` [download] You could redirect STDIN to a buffer. `{ my $answers = "yes\nyes\n"; local *STDIN; open STDIN, '<', \$answers; # Requires Perl 5.8.0 askQuestions() }` [download] You could `tie` `STDIN`. - ikegami	[reply] [d/l] [select]