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

It seems easy to use the "~" to make a format optional for write()...but it doesn't seem to work if I use formline()

I basically want to use a format to save in a string, not a filehandle and I would like to handle the case of text wrapping over... 

$^A = "";
formline(<<'OUTPUT_TABLE', $1, $2);
@<<<<<<<      @<<<<<<<<<<<<
~@<<<<<<<      @<<<<<<<<<<<<
OUTPUT_TABLE
  
$out .= $^A;

print $out...

[download]


thanks for any suggestions !

Replies are listed 'Best First'.
Re: format question
by jmcnamara (Monsignor) on Nov 08, 2001 at 14:23 UTC

    The code you posted works for me if $1 and $2 have been set.

    However, you have 4 placeholders and only 2 variables.

    --
    John.

[reply]
      the second "format" line, that starts with ~ is supposed to be optional if there is no more data from $1 or $2. It would work if I used "format =", but I am using formline(), and it doesn't seem to...

      thanks

      ps
      I posted this pretty late last night...is there a way to resubmit it now that there are more people logged on? I don't want to abuse this GREAT system.
[reply]

        Okay, I think I see the cause of the confusion. The tilde ~ does eliminate blank lines. However, setting $^A = "" does not reset the accumulator. You have to print it to do that.

        Consider the following example based on your code snippet: 

        #Something tells me we're not programming in Perl anymore Toto. ;-)

for (1..2) {

    print "Run: ", $_, "\n";

    $^A = "";
    formline(<<'OUTPUT_TABLE', 1, 2);
@<<<<<<<      @<<<<<<<<<<<<
@<<<<<<<      @<<<<<<<<<<<<~
OUTPUT_TABLE

    $out .= $^A;
    print $out;
}

for (3..4) {

    print "Run: ", $_, "\n";

    $^A = "";
    formline(<<'OUTPUT_TABLE', 1, 2);
@<<<<<<<      @<<<<<<<<<<<<
@<<<<<<<      @<<<<<<<<<<<<~
OUTPUT_TABLE

    print $^A;
}

        [download]
        This gives the following output. Note the additional line in Run 2. 

        Run: 1
1             2
Run: 2
1             2
1             2
Run: 3
1             2
Run: 4
1             2

        [download]
        Therefore, you will have to re-organise your code to make sure that you print $^A.

        --
        John.

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