Functional Programming in Perl

Syntactic Difficulties

Another example: Perl has a built-in map operator:

        map { $_ * 2 + 1 } 1..10;

Suppose you want to write an analogous operator for an iterator

        sub imap {
          my ($f, $iterator) = @_;
          return sub {
            my $next = $iterator->();
            return defined($next) ? $f->($next) : undef;
          }
        }

So far, so good
But to call it, you must write

        imap(sub { $_[0] * 2 + 1 }, $iterator);

This kind of thing can be worked around through a variety of tricks
You can in fact squeeze out this syntax:

        imap { $_ * 2 + 1 } $iterator;