in reply to Dynamically constructed function calls

From perldoc perlop
Otherwise, the right side is a method name or a simple scalar variable containing either the method name or a subroutine reference, and the left side must be either an object (a blessed reference) or a class name (that is, a package name). See perlobj.

This means that you can't have a string or an expression as a method name. It has to be a simple scalar. So if you do the following, everything should work fine: 

my $method = "prefix_$key";
$f->$method($atr);

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Re^2: Dynamically constructed function calls
by dpuu (Chaplain) on Nov 04, 2004 at 01:07 UTC
    It has to be a scalar, but it doesn't need to be a variable. You can say 
      $f->${\("prefix_$key")}($atr);

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    However, using a variable is probably clearer.

    Update: added the missing '$' pointed out by ikegami

    --Dave
    Opinions my own; statements of fact may be in error.

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[d/l]
      I've toyed with the idea of making $object->do {expression-yielding-method-name} work. Right now it gives a syntax error.

      Of course, you can do something pretty close by just having a do method: 

      sub foo { print "in foo" }
sub do {
   my $self = shift;
   my $meth = shift;
   $self->$meth(@_)
}

$object->do("foo", @args);

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[d/l]
        It would have to be something that has scalar context applied to it. That would yield some neat obfu. 
        package Foo;

sub new { bless {}, shift }

*$_ = sub { my ($self, $arg) = @_; print "I am $_ $arg.\n" } for 1 .. 
+5;

package main;

my $foo = Foo->new;

$foo->do { @ARGV }( 'world' );

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        Blammo! :-)

        Being right, does not endow the right to be rude; politeness costs nothing.
        Being unknowing, is not the same as being stupid.
        Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence.
        Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.

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[d/l]

      You're missing a $. It should be $f->${\("prefix_$key")}($atr);

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[d/l]
[select]
      Nice trick, I had never thought about that! :-)
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