Velocity Reviews - Computer Hardware Reviews

Velocity Reviews > Newsgroups > Programming > Perl > Perl Misc > FAQ 7.19 What's the difference between deep and shallow binding?

Thread Tools

FAQ 7.19 What's the difference between deep and shallow binding?

PerlFAQ Server
Posts: n/a
This is an excerpt from the latest version perlfaq7.pod, which
comes with the standard Perl distribution. These postings aim to
reduce the number of repeated questions as well as allow the community
to review and update the answers. The latest version of the complete
perlfaq is at .


7.19: What's the difference between deep and shallow binding?

In deep binding, lexical variables mentioned in anonymous subroutines
are the same ones that were in scope when the subroutine was created. In
shallow binding, they are whichever variables with the same names happen
to be in scope when the subroutine is called. Perl always uses deep
binding of lexical variables (i.e., those created with my()). However,
dynamic variables (aka global, local, or package variables) are
effectively shallowly bound. Consider this just one more reason not to
use them. See the answer to "What's a closure?".


The perlfaq-workers, a group of volunteers, maintain the perlfaq. They
are not necessarily experts in every domain where Perl might show up,
so please include as much information as possible and relevant in any
corrections. The perlfaq-workers also don't have access to every
operating system or platform, so please include relevant details for
corrections to examples that do not work on particular platforms.
Working code is greatly appreciated.

If you'd like to help maintain the perlfaq, see the details in
Reply With Quote

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
FAQ 7.19 What's the difference between deep and shallow binding? PerlFAQ Server Perl Misc 0 04-13-2011 10:00 AM
Deep and shallow copies C++ 5 10-22-2006 11:00 PM
what is Deep Copy, shallow copy and bitwises copy.? C++ 26 09-01-2006 09:37 PM
How to overload operator= to have both deep copy and shallow copy semantics C++ 1 06-24-2005 05:28 PM
deep and shallow copy Tony Johansson C++ 5 05-19-2005 04:13 PM