package Blah; {
    sub foo {
        print "bar!\n";
    }
}

package main; {
    foo();
}
[download]

This code will define  foo() in the  Blah package; it will not be available in the  main package unless exported to it or invoked as a fully qualified subroutine (called without warnings or strictures):

c:\@Work\Perl\monks\R0b0t1>perl -le
"package Blah; {
     sub foo {
         print \"bar!\n\";
     }
 }
 package main; {
     foo();
 }
"
Undefined subroutine &main::foo called at -e line 1.

c:\@Work\Perl\monks\R0b0t1>perl -le
"package Blah; {
     sub foo {
         print \"bar!\n\";
     }
 }
 package main; {
     Blah::foo();
 }
"
bar!
[download]

On a tangential note, the package syntax

{ package Foo;
  my $x = ...;
  ...
  sub bar { ... }
  ...
  }
[download]

and from Perl version 5.14 onward

package Foo {
  my $x = ...;
  ...
  sub bar { ... }
  ...
  }
[download]

will cause the asserted package to be "turned off" at the end of the block, with reversion to the "original" package. E.g., (with full warnings and strictures):

c:\@Work\Perl\monks\R0b0t1>perl -wMstrict -le
"print 'perl version: ', $];
 ;;
 in_pkg('A');
 ;;
 package Foo {
   ::in_pkg('B');
   }
 ;;
 in_pkg('C');
 ;;
 sub in_pkg { print qq{$_[0]: in package }, scalar caller; }
"
perl version: 5.014004
A: in package main
B: in package Foo
C: in package main
[download]

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.