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Perl Bit #1: Streaming to a String

In-memory files can be opened very easily with the module IO::String. Just like this.

  use IO::String;
  my $s = <<SQL;
    SELECT a, b, c FROM T 
    WHERE k = ?
  SQL
  my $io = new IO::String($s);
  while (<$io>) {
    print;
  }

This can be done also with IO::Scalar. None of these methods are part of Perl standard distribution. But since 5.8, you have in-memory files for free with PerlIO support. No module needed, you just use a scalar variable as you would use a handle with the three-arguments open.

  open my $io, "<", $s
    or die "can't open in-memory file: $!\n";

Why would you like this? Strings are just as easy to handle in Perl as io handles. But even so, they are treated differently. Turning a scalar into an io handle, you avoid the need for two versions of the same code.

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