[% setvar title Retire chop(). %]

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Retire chop().


  Maintainer: Nathan Torkington <gnat@frii.com>
  Date: 5 Sep 2000
  Last Modified: 18 Sep 2000
  Mailing List: perl6-language@perl.org
  Number: 195
  Version: 3
  Status: Frozen
  Frozen since: v2


Remove chop() from the core. Its purpose is better served by chomp(), so its remaining applications are few and limited.


 * fixed perl526 translation. (v3)

 * Added mention of how per-filehandle autochomping would affect this
   RFC. (v2)


chop()'s original purpose was to remove trailing line terminators. However, chop() is dangerous: it always removes the last character, and it doesn't care whether the last character is a line terminator or not.

So chomp() was introduced. This only removes the value of $/, and if there's no $/ at the end of the string then it doesn't remove anything. This makes it safer: if you don't know whether your string is chomp()ed or not, you can chomp() it anyway. With chop() you had to have a separate explicit test. chop() also doesn't know about $/ and the different values it might have.

chop() is still occasionally used, but very rarely. Not enough, in my opinion, for chop() to stay in the core. Its functionality might be available in a library.

If filehandles gain the ability to automatically remove their record separators, then chomp() will still be needed.


The perl526 translator can simply use

  do { my ($foo) = s/(.)\z//s; $foo }

for a chop() action. If there were a chop() in a standard library then the conversion would simply be a matter of putting:

  use String::Chop;	# or whatever

at the top of any converted program that uses chop().

Implementation in perl6 is very straightforward: don't implement chop().


RFC 58: chomp() changes.

perlfunc manpage for discussion of chomp() and chop()