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Value Pair Assignment

by ryan (Pilgrim)
on Apr 18, 2002 at 06:58 UTC ( #160122=perlquestion: print w/ replies, xml ) Need Help??
ryan has asked for the wisdom of the Perl Monks concerning the following question:

I am using HTML::Template with great success, but want to iterate through a huge number of template values as part of a form submission checker. Assigning the template variable values is lengthy and repetitive using the only method I know how. I have the template variables names and their required values in a hash, so wouldn't it be nice if I could just iterate through that and churn out the template variables?

So, is there a way to use a variable for all or part of the left hand side of the value pair assigmnent? Or another way to do the same thing?
# how I do it now $tmpl->param(flag_location => "foo $var bar"); # I have not used hashes here to make it easier # to see the two things I am trying to do. # how I want to do it my $param = 'flag_location'; $tmpl->param($param => "foo $var bar"); # or better still my $param = 'location'; $tmpl->param("flag_$param" => "foo $var bar");
Also, what is the correct name for the values either side of the '=>' so I can refer to these things correctly in the future?

Evidently I'm a little confused as to the exact usage of this type of assignment and it's limitations, and can't find any good explanations of it anywhere thus far.

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Re: Value Pair Assignment
by Biker (Priest) on Apr 18, 2002 at 07:29 UTC

    "what is the correct name for the values either side of the '=>' so I can refer to these things correctly in the future?"

    key => value


    Everything went worng, just as foreseen.

Re: Value Pair Assignment
by Fletch (Chancellor) on Apr 18, 2002 at 07:34 UTC

    => isn't an assignment. It's just a fancy comma that happens to quote its left hand side if its a bareword (unquoted string with no spaces).

      Thanks!
      $tmpl->param($param, "foo $var bar");
      Does it nicely.
Re: Value Pair Assignment
by Biker (Priest) on Apr 18, 2002 at 07:38 UTC

    This works:

    use strict; my %hash; my $foo='xxx'; my $bar='yyy'; $hash{$foo}='foo-value'; $hash{$bar}='bar-value'; my($k,$v); while(($k,$v)=each %hash) { print("$k => $v\n"); }


    Everything went worng, just as foreseen.

Re: Value Pair Assignment
by mce (Curate) on Apr 18, 2002 at 08:01 UTC
    Hi Ryan,

    Just call me stupid, but I don't see what the problem is :-).
    HTML::Template::param is a subroutine which takes two arguments, a key and a value. Of course you can loop over a hash and change the keys or values as arguments of the param sub.

    This has nothing to do with HTML::Template as such, but it works for every sub or command (like print, etc...).

    Perhaps post some actual code so I can understand your problem.


    ---------------------------
    Dr. Mark Ceulemans
    Senior Consultant
    IT Masters, Belgium

      I didn't realise HTML::Template::param took two arguments

      firstly) because I was not aware of the functionality of '=>' and that it was actually passing two parameters and not one. secondly) because every example I have ever seen that taught me to use it was of the form 'variable => value'.

      Simple problem, simple solution - All in a day's learning.

      param does not take two arguments. It takes a list of key/value pairs. Read the documentation next time.

      $tmp->param( foo => 'bar', baz => 'quux' ); # or $tmp->param(%pairs);

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