IO-stringy(3)
NAME
IO-stringy - I/O on in-core objects like strings and arrays
SYNOPSIS
IO::
::AtomicFile adpO Write a file which is updated atomically ERYQ
::Lines bdpO I/O handle to read/write to array of lines ERYQ
::Scalar RdpO I/O handle to read/write to a string ERYQ
::ScalarArray RdpO I/O handle to read/write to array of scalars ERYQ
::Wrap RdpO Wrap old-style FHs in standard OO interface ERYQ
::WrapTie adpO Tie your handles & retain full OO interface ERYQ
DESCRIPTION
This toolkit primarily provides modules for performing both traditional
and object-oriented i/o) on things other than normal filehandles; in
particular, IO::Scalar, IO::ScalarArray, and IO::Lines.
In the more-traditional IO::Handle front, we have IO::AtomicFile which
may be used to painlessly create files which are updated atomically.
And in the "this-may-prove-useful" corner, we have IO::Wrap, whose
exported wraphandle() function will clothe anything that's not a
blessed object in an IO::Handle-like wrapper... so you can just use OO
syntax and stop worrying about whether your function's caller handed
you a string, a globref, or a FileHandle.
WARNINGS
Perl's TIEHANDLE spec was incomplete prior to 5.005_57; it was missing
support for "seek()", "tell()", and "eof()". Attempting to use these
functions with an IO::Scalar, IO::ScalarArray, IO::Lines, etc. will not
work prior to 5.005_57. None of the relevant methods will be invoked
by Perl; and even worse, this kind of bug can lie dormant for a while.
If you turn warnings on (via $^W or "perl -w"), and you see something
like this...
seek() on unopened file
...then you are probably trying to use one of these functions on one of
our IO:: classes with an old Perl. The remedy is to simply use the OO
version; e.g.:
$SH->seek(0,0); ### GOOD: will work on any 5.005
seek($SH,0,0); ### WARNING: will only work on 5.005_57 and beyond
INSTALLATION
Requirements
As of version 2.x, this toolkit requires Perl 5.005 for the IO::Handle
subclasses, and 5.005_57 or better is strongly recommended. See "WARN-
INGS" for details.
Directions
Most of you already know the drill...
perl Makefile.PL
make
make test
make install
For everyone else out there... if you've never installed Perl code
before, or you're trying to use this in an environment where your
sysadmin or ISP won't let you do interesting things, relax: since this
module contains no binary extensions, you can cheat. That means copy-
ing the directory tree under my "./lib" directory into someplace where
your script can "see" it. For example, under Linux:
cp -r IO-stringy-1.234/lib/* /path/to/my/perl/
Now, in your Perl code, do this:
use lib "/path/to/my/perl";
use IO::Scalar; ### or whatever
Ok, now you've been told. At this point, anyone who whines about not
being given enough information gets an unflattering haiku written about
them in the next change log. I'll do it. Don't think I won't.
VERSION
$Id: Stringy.pm,v 2.109 2003/12/21 18:51:45 eryq Exp $
TO DO
(2000/08/02) Finalize $/ support
Graham Barr submitted this patch half a year ago; Like a moron, I
lost his message under a ton of others, and only now have the
experimental implementation done.
Will the sudden sensitivity to $/ hose anyone out there? I'm wor-
ried, so you have to enable it explicitly in 1.x. It will be on by
default in 2.x, though only IO::Scalar has been implemented.
(2000/09/28) Separate read/write cursors?
Binkley sent me a very interesting variant of IO::Scalar which
maintains two separate cursors on the data, one for reading and one
for writing. Quoth he:
Isn't it the case that real operating system file descriptors
maintain an independent read and write file position (and
seek(2) resets them both)?
(My answer: perhaps, but stdio's fseek/ftell manpages seem to imply
a single file position indicator, and I'm trying to be IO::-ish.)
Binkley also pointed out some issues with his implementation:
For example, what does eof or tell return? The read position or
the write position? (I assumed read position was more important).
Your opinions on this are most welcome. (Me, I'm just squeamish
that this will break some code which depends on the existing behav-
ior, and that attempts to maintain backwards-compatibility will
slow down the code.)
(2001/08/08) Remove IO::WrapTie from new IO:: classes
It's not needed. Backwards compatibility could be maintained by
having new_tie() be identical to new(). Heck, I'll bet that
IO::WrapTie should be reimplemented so the returned object is just
like an IO::Scalar in its use of globrefs.
CHANGE LOG
Version 2.109 (2003/12/21)
IO::Scalar::getline now works with ref to int. Thanks to Dominique
Quatravaux for this patch.
Version 2.108 (2001/08/20)
The terms-of-use have been placed in the distribution file "COPY-
ING". Also, small documentation tweaks were made.
Version 2.105 (2001/08/09)
Added support for various seek() whences to IO::ScalarArray.
Added support for consulting $/ in IO::Scalar and IO::ScalarArray.
The old "use_RS()" is not even an option. Unsupported record sepa-
rators will cause a croak().
Added a lot of regression tests to supoprt the above.
Better on-line docs (hyperlinks to individual functions).
Version 2.103 (2001/08/08)
After sober consideration I have reimplemented IO::Scalar::print()
so that it once again always seeks to the end of the string.
Benchmarks show the new implementation to be just as fast as Juer-
gen's contributed patch; until someone can convince me otherwise,
the current, safer implementation stays.
I thought more about giving IO::Scalar two separate handles, one
for reading and one for writing, as suggested by Binkley. His
points about what tell() and eof() return are, I think, show-stop-
pers for this feature. Even the manpages for stdio's fseek() seem
to imply a single file position indicator, not two. So I think I
will take this off the TO DO list. Remedy: you can always have two
handles open on the same scalar, one which you only write to, and
one which you only read from. That should give the same effect.
Version 2.101 (2001/08/07)
Alpha release. This is the initial release of the "IO::Scalar and
friends are now subclasses of IO::Handle". I'm flinging it against
the wall. Please tell me if the banana sticks. When it does, the
banana will be called 2.2x.
First off, many many thanks to Doug Wilson, who has provided an
invaluable service by patching IO::Scalar and friends so that they
(1) inherit from IO::Handle, (2) automatically tie themselves so
that the "new()" objects can be used in native i/o constructs, and
(3) doing it so that the whole damn thing passes its regression
tests. As Doug knows, my globref Kung-Fu was not up to the task;
he graciously provided the patches. This has earned him a seat at
the Co-Authors table, and the right to have me address him as sen-
sei.
Performance of IO::Scalar::print() has been improved by as much as
2x for lots of little prints, with the cost of forcing those who
print-then-seek-then-print to explicitly seek to end-of-string
before printing again. Thanks to Juergen Zeller for this patch.
Added the COPYING file, which had been missing from prior versions.
Thanks to Albert Chin-A-Young for pointing this out.
IO::Scalar consults $/ by default (1.x ignored it by default).
Yes, I still need to support IO::ScalarArray.
Version 1.221 (2001/08/07)
I threatened in "INSTALLATION" to write an unflattering haiku about
anyone who whined that I gave them insufficient information... but
it turns out that I left out a crucial direction. D'OH! Thanks to
David Beroff for the "patch" and the haiku...
Enough info there?
Here's unflattering haiku:
Forgot the line, "make"! ;-)
Version 1.220 (2001/04/03)
Added untested SEEK, TELL, and EOF methods to IO::Scalar and
IO::ScalarArray to support corresponding functions for tied file-
handles: untested, because I'm still running 5.00556 and Perl is
complaining about "tell() on unopened file". Thanks to Graham Barr
for the suggestion.
Removed not-fully-blank lines from modules; these were causing lots
of POD-related warnings. Thanks to Nicolas Joly for the sugges-
tion.
Version 1.219 (2001/02/23)
IO::Scalar objects can now be made sensitive to $/ . Pains were
taken to keep the fast code fast while adding this feature. Cheers
to Graham Barr for submitting his patch; jeers to me for losing his
email for 6 months.
Version 1.218 (2001/02/23)
IO::Scalar has a new sysseek() method. Thanks again to Richard
Jones.
New "TO DO" section, because people who submit patches/ideas should
at least know that they're in the system... and that I won't lose
their stuff. Please read it.
New entries in "AUTHOR". Please read those too.
Version 1.216 (2000/09/28)
IO::Scalar and IO::ScalarArray now inherit from IO::Handle. I
thought I'd remembered a problem with this ages ago, related to the
fact that these IO:: modules don't have "real" filehandles, but the
problem apparently isn't surfacing now. If you suddenly encounter
Perl warnings during global destruction (especially if you're using
tied filehandles), then please let me know! Thanks to B. K. Oxley
(binkley) for this.
Nasty bug fixed in IIOO::::SSccaallaarr::::wwrriittee(()). Apparently, the offset and
the number-of-bytes arguments were, for all practical purposes,
reversed. You were okay if you did all your writing with print(),
but boy was this a stupid bug! Thanks to Richard Jones for finding
this one. For you, Rich, a double-length haiku:
Newspaper headline
typeset by dyslexic man
loses urgency
BABY EATS FISH is
simply not equivalent
to FISH EATS BABY
New sysread and syswrite methods for IO::Scalar. Thanks again to
Richard Jones for this.
Version 1.215 (2000/09/05)
Added 'bool' overload to '""' overload, so object always evaluates
to true. (Whew. Glad I caught this before it went to CPAN.)
Version 1.214 (2000/09/03)
Evaluating an IO::Scalar in a string context now yields the under-
lying string. Thanks to B. K. Oxley (binkley) for this.
Version 1.213 (2000/08/16)
Minor documentation fixes.
Version 1.212 (2000/06/02)
Fixed IO::InnerFile incompatibility with Perl5.004. Thanks to many
folks for reporting this.
Version 1.210 (2000/04/17)
Added flush() and other no-op methods. Thanks to Doru Petrescu for
suggesting this.
Version 1.209 (2000/03/17)
Small bug fixes.
Version 1.208 (2000/03/14)
Incorporated a number of contributed patches and extensions, mostly
related to speed hacks, support for "offset", and WRITE/CLOSE meth-
ods. Thanks to Richard Jones, Doru Petrescu, and many others.
Version 1.206 (1999/04/18)
Added creation of ./testout when Makefile.PL is run.
Version 1.205 (1999/01/15)
Verified for Perl5.005.
Version 1.202 (1998/04/18)
New IO::WrapTie and IO::AtomicFile added.
Version 1.110
Added IO::WrapTie.
Version 1.107
Added IO::Lines, and made some bug fixes to IO::ScalarArray. Also,
added getc().
Version 1.105
No real changes; just upgraded IO::Wrap to have a $VERSION string.
AUTHOR
Primary Maintainer
Eryq (eryq@zeegee.com). President, ZeeGee Software Inc
(http://www.zeegee.com).
Co-Authors
For all their bug reports and patch submissions, the following are
officially recognized:
Richard Jones
B. K. Oxley (binkley)
Doru Petrescu
Doug Wilson (for picking up the ball I dropped, and doing tie() right)
Go to http://www.zeegee.com for the latest downloads and on-line docu-
mentation for this module.
Enjoy. Yell if it breaks.
perl v5.8.6 2001-08-09 IO::Stringy(3)
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