Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!elroy.jpl.nasa.gov!jpl-devvax!lwall
From: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Newsgroups: comp.lang.perl
Subject: Re: Do be do be do.
Message-ID: <11295@jpl-devvax.JPL.NASA.GOV>
Date: 4 Feb 91 18:56:32 GMT
References: <1991Feb4.012916.7944@uvaarpa.Virginia.EDU> <1991Feb04.015138.28575@convex.com> <121266@uunet.UU.NET>
Reply-To: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 25

In article <121266@uunet.UU.NET> rbj@uunet.UU.NET (Root Boy Jim) writes:
: In article <1991Feb04.015138.28575@convex.com> tchrist@convex.COM (Tom Christiansen) writes:
: >It's in the section entitled ``Simple Statements'' in both the man page
: >and the Camel Book (see the top of page 94).  The essential text follows:
: >
: >    The loop conditional is evaluation before the expression, except when
: >    applied to a do-BLOCK or a do_SUBROUTINE command, in which case the
: >    block executes once before the conditional is evaluated.
: 
: Yeah, but it's not a "do SUBROUTINE", it's a "&SUBROUTINE".
: Oh. They're the same thing? I don't think they should be.

Neither do I.  This is something I've known about for several months
(my brother-in-law Mark Biggar pointed it out when he was writing the big*
packages), but I hadn't had a chance to fix it.  In 4.0,

	do foo() while $something;

will always execute at least once, and

	&foo() while $something

may execute 0 times.

Larry