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From: Tom Christiansen <[e-mail]>
Subject: comp.lang.perl FAQ (part 1 of 2)
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Date: Mon, 30 Nov 1992 12:50:50 GMT
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Archive-name: perl-faq/part1
Version: $Id: perl-info,v 1.2 92/11/30 05:22:33 tchrist Exp Locker: tchrist $

This posting contains answers to general information questions,
mostly of a non-technical nature.  The following questions are
answered:

1.1) What is Perl?
1.2) Is Perl hard to learn?
1.3) Should I program everything in Perl?
1.4) Where can I get Perl over the Internet?
1.5) Where can I get Perl via Email?
1.6) How can I get Perl via UUCP?
1.7) Where can I get more information on Perl?
1.8) Can people who aren't on USENET receive comp.lang.perl as a digest?
1.9) Are archives of comp.lang.perl available?
1.10) How do I get Perl to run on machine FOO?
1.11) Where can I get (info|inter|ora|sql|syb)perl?
1.12) There's an a2p and an s2p; why isn't there a p2c (perl-to-C)?
1.13) Where can I get undump for my machine?
1.14) Where can I get a perl-mode for emacs?
1.15) How can I use Perl interactively?
1.16) Is there a Perl shell?
1.17) Is there a Perl profiler?
1.18) Is there a yacc for Perl?
1.19) How can I use curses with perl?
1.20) How can I use X with Perl?
1.21) What is perl4?  What is perl5?
1.22) How does Perl compare with languages like REXX or TCL?
1.23) Is it a Perl program or a Perl script?
1.24) What's the difference between "Perl" and "perl"?
1.25) What companies use or ship Perl?
1.26) Is there commercial, 3rd-party support for Perl?
1.27) Where can I get a list of the JAPH signature quotes?
1.28) Where can I get a list of Larry Wall witticisms?
1.29) Is there a pretty-printer for Perl?


1.1) What is Perl?

    A programming language, by Larry Wall <[e-mail]>.

    Here's the beginning of the description from the man page:

    Perl is an interpreted language optimized for scanning arbitrary text
    files, extracting information from those text files, and printing reports
    based on that information.  It's also a good language for many system
    management tasks.  The language is intended to be practical (easy to use,
    efficient, complete) rather than beautiful (tiny, elegant, minimal).  It
    combines (in the author's opinion, anyway) some of the best features of C,
    sed, awk, and sh, so people familiar with those languages should have
    little difficulty with it.  (Language historians will also note some
    vestiges of csh, Pascal, and even BASIC-PLUS.)  Expression syntax
    corresponds quite closely to C expression syntax.  Unlike most Unix
    utilities, Perl does not arbitrarily limit the size of your data--if
    you've got the memory, Perl can slurp in your whole file as a single
    string.  Recursion is of unlimited depth.  And the hash tables used by
    associative arrays grow as necessary to prevent degraded performance.
    Perl uses sophisticated pattern matching techniques to scan large amounts
    of data very quickly.  Although optimized for scanning text, Perl can also
    deal with binary data, and can make dbm files look like associative arrays
    (where dbm is available).  Setuid Perl scripts are safer than C programs
    through a dataflow tracing mechanism which prevents many stupid security
    holes.  If you have a problem that would ordinarily use sed or awk or sh,
    but it exceeds their capabilities or must run a little faster, and you
    don't want to write the silly thing in C, then Perl may be for you.  There
    are also translators to turn your sed and awk scripts into Perl scripts.


1.2) Is Perl hard to learn?

    No, Perl is easy to learn for two reasons.

    The first reason is that most of Perl is derived from existing tools
    and languages, ones that many people who turn to Perl already have
    some familiarity with.  These include the C programming language, the
    UNIX C library, the UNIX shell, sed, and awk.  If you already know
    these somewhat, Perl should be very easy for you.

    The second reason that Perl is easy to learn is that you don't have to
    know every thing there is to know about it in order to get good use
    out of it.  In fact, just a very small subset, mostly borrowed from C,
    the shell, and sed, will be enough for most tasks.  As you feel the
    need or desire to use more sophisticated features (such as C
    structures or networking), you can learn these as you go.  The
    learning curve for Perl is not a steep one, especially if you have
    the headstart of having a background in UNIX.  Rather, its learning
    curve is gentle and gradual, but it *is* admittedly rather long.

    If you don't know C or UNIX at all, it'll be a steeper learning curve,
    but what you then learn from Perl will carry over into other areas,
    like using the C library, UNIX system call, regular expressions, and
    associative arrays, just to name a few.  To know Perl is to know
    UNIX, and vice versa.


1.3) Should I program everything in Perl?

    Of course not.  You should choose the appropriate tool for the task at
    hand.  While it's true that the answer to the question "Can I do (some
    arbitrary task) in Perl?" is almost always "yes", that doesn't mean
    this is necessarily a good thing to do.  For many people, Perl serves
    as a great replacement for shell programming.  For a few people, it
    also serves as a replacement for most of what they'd do in C.  But
    for some things, Perl just isn't the optimal choice, such as tasks
    requiring very complex data structures.


1.4) Where can I get Perl over the Internet?

    From any comp.sources.misc archive.   Initial sources  were posted to
    Volume 18, Issues 19-54 at patchlevel 3.  The Patches 4-10 were posted
    to Volume 20, Issues 56-62.  You can use the archie server
    (see the alt.sources FAQ in news.answers) for ways to find these.

    These machines, at the very least, definitely have it available for
    anonymous FTP:

    ftp.uu.net                137.39.1.2
    archive.cis.ohio-state.edu      128.146.8.52
    jpl-devvax.jpl.nasa.gov         128.149.1.143
    ftp.netlabs.com         192.94.48.152
    prep.ai.mit.edu            18.71.0.38
    ftp.cs.ruu.nl            131.211.80.17  (Europe)




1.5) Where can I get Perl via Email?

    If you are in Europe, you might using the following site.  (I'm still
    looking for a domestic site.) This information thanks to "Henk P.
    Penning" <[e-mail]>:  One automated fashion is as follows:

    Email: Send a message to '[e-mail]' containing:
     begin
     path your_email_address
     send help
     send PERL/INDEX
     end
    The path-line may be omitted if your message contains a normal From:-line.
    You will receive a help-file and an index of the directory that contains
    the Perl stuff.

    If all else fails, mail to Larry usually suffices.


1.6) How can I get Perl via UUCP?

    You can get it from the site osu-cis; here is the appropriate info,
    thanks to J Greely <[e-mail]> or <osu-cis!jgreely>.

    E-mail contact:
        osu-cis!uucp
    Get these two files first:
        osu-cis!~/GNU.how-to-get.
        osu-cis!~/ls-lR.Z
    Current Perl distribution:
        osu-cis!~/perl/4.0/kits@10/perl.kitXX.Z (XX=01-37)
    How to reach osu-cis via uucp(L.sys/Systems file lines):
    #
    # Direct Trailblazer
    #
    osu-cis Any ACU 19200 1-614-292-5112 in:--in:--in: Uanon
    #
    # Direct V.32 (MNP 4)
    # dead, dead, dead...sigh.
    #
    #osu-cis Any ACU 9600 1-614-292-1153 in:--in:--in: Uanon
    #
    # Micom port selector, at 1200, 2400, or 9600 bps.
    # Replace ##'s below with 12, 24, or 96 (both speed and phone number).
    #
    osu-cis Any ACU ##00 1-614-292-31## "" \r\c Name? osu-cis nected \c GO \d\r\d\r\d\r in:--in:--in:
     Uanon

    Modify as appropriate for your site, of course, to deal with your
    local telephone system.  There are no limitations concerning the hours
    of the day you may call.

    Another possibility is to use UUNET, although they charge you
    for it.  You have been duly warned.  Here's the advert:

           Anonymous Access to UUNET's Source Archives

                 1-900-GOT-SRCS

     UUNET now provides access to its extensive collection of UNIX
    related sources to non- subscribers.  By  calling  1-900-468-7727
    and  using the login "uucp" with no password, anyone may uucp any
    of UUNET's on line source collection.  Callers will be charged 40
    cents  per  minute.   The charges will appear on their next tele-
    phone bill.

     The  file  uunet!/info/help  contains  instructions.   The  file
    uunet!/index//ls-lR.Z contains a complete list of the files available
    and is updated daily.  Files ending in Z need to be uncompressed
    before being used.   The file uunet!~/compress.tar is a tar
    archive containing the C sources for the uncompress program.

     This service provides a  cost  effective  way  of  obtaining
    current  releases  of sources without having to maintain accounts
    with UUNET or some other service.  All modems  connected  to  the
    900  number  are  Telebit T2500 modems.  These modems support all
    standard modem speeds including PEP, V.32 (9600), V.22bis (2400),
    Bell  212a  (1200), and Bell 103 (300).  Using PEP or V.32, a 1.5
    megabyte file such as the GNU C compiler would cost $10  in  con-
    nect  charges.   The  entire  55  megabyte X Window system V11 R4
    would cost only $370 in connect time.  These costs are less  than
    the  official  tape  distribution fees and they are available now
    via modem.

              UUNET Communications Services
           3110 Fairview Park Drive, Suite 570
             Falls Church, VA 22042
             [phone] (voice)
              [phone] (fax)
                [e-mail]



1.7) Where can I get more information on Perl?

    We'll cover five areas here: USENET (where you're probably reading
    this), publications, the reference guide, examples on the Internet,
    and Perl instructional courses.

    A.  USENET

    You should definitely read the USENET comp.lang.perl newsgroup or
    mailing list for all sorts of discussions regarding the language,
    bugs, features, history, humor, and trivia.  In this respect, it
    functions both as a comp.lang.* style newsgroup and also as a user
    group for the language; in fact, there's a mailing list called
    ``perl-users'' that is bidirectionally gatewayed to the newsgroup; see
    question #38 for details.  Larry Wall is a very frequent poster here,
    as well as many (if not most) of the other seasoned Perl programmers.
    It's the best place for the very latest information on Perl.

    B.  PUBLICATIONS

    If you've been dismayed by the ~80-page troffed Perl man page (or is
    that man treatise?) you should look to ``the Camel Book'', written by
    Larry and Randal L. Schwartz <[e-mail]>, published as a Nutshell
    Handbook by O'Reilly & Associates and entitled _Programming Perl_.
    Besides serving as a reference guide for Perl, it also contains
    tutorial material and is a great source of examples and cookbook
    procedures, as well as wit and wisdom, tricks and traps, pranks and
    pitfalls.  The code examples contained therein are available via
    anonymous FTP from ftp.uu.net in
    /published/oreilly/nutshell/perl/perl.tar.Z for your retrieval.
    Corrections and additions to the book can be found in the Perl man
    page right before the BUGS section under the heading ERRATA AND
    ADDENDA.

    If you can't find the book in your local technical bookstore, the book
    may be ordered directly from O'Reilly by calling 1-800-998-9938 if in
    North America and 1-707-829-0515.  The book's ISBN is 0-937175-64-1.

    Autographed copies are *NO LONGER* available from TECHbooks --
    you'll have to nab the authors in person if you want one.  Larry
    routinely carries around a camel stamp for just such an occasion.

    Reasonably substantiated rumor has it that there will be another Perl
    book out pretty soon, this one aimed more at beginners.  Look for it
    from ORA towards the beginning of 93.

    Larry Wall has published a 3-part article on perl in Unix World
    (August through October of 1991), and Rob Kolstad also had a 3-parter
    in Unix Review (May through July of 1990).  Tom Christiansen also has
    a brief overview article in the trade newsletter Unix Technology
    Advisor from November of 1989.  You might also investigate "The Wisdom
    of Perl" by Gordon Galligher from SunExpert magazine;  April 1991
    Volume 2 Number 4.  The newest (Dec 92) Computer Language magazine
    is also alleged to contain a cover article on Perl.

    The USENIX LISA (Large Installations Systems Administration) Conference
    have for several years now included many papers of tools written in
    Perl.  Old proceedings of these conferences are available; look in
    your current issue of ";login:" or send mail to [e-mail]
    for further information.

    C.  INTERNET

    For other examples of Perl scripts, look in the Perl source directory in
    the eg subdirectory.  You can also find a good deal of them on
    archive.cis.ohio-state.edu in the pub/perl/scripts/ subdirectory.

    Another source for examples, currently only for anonymous FTP, is on
    convex.com [130.168.1.1].  This contains, amongst other things,
    a copy of the newsgroup up through Aug 91, a text retrieval database
    for the newsgroup, a rather old and short troff version of Tom Christiansen's
    perl tutorial (this was the version presented at Washington DC USENIX),
    and quite a few of Tom's scripts.  You can look at the INDEX file
    in /pub/perl/INDEX for a list of what's in that directory.

    The Convex and Ohio State archives are mirrored on uunet
    in /languages/perl/scripts-{convex,osu}.

    D.  REFERENCE GUIDE

    A nice reference guide by Johan Vromans <[e-mail]> is also available;
    It is distributed in LaTeX (source) and PostScript (ready to
    print) forms. Obsolete versions may still be available in TeX and troff
    forms, although these don't print as nicely. The official kit
    includes both LaTeX and PostScript forms, and can be FTP'd from
    ftp.cs.ruu.nl [131.211.80.17], file /pub/DOC/perlref-4.035.tar.Z.
    The reference guide comes with the O'Reilly book in a nice, glossy
    card format.

    E.  PERL COURSES

    Various technical conferences, including USENIX, SUG, WCSAS, AUUG,
    FedUnix, and Europen have been sponsoring tutorials of varying lengths
    on Perl at their system administration and general conferences.  You
    might consider attending one of these.  These classes are typically
    taught by Tom Christiansen <[e-mail]>, although both Rob
    Kolstad <[e-mail]> and Randal Schwartz <[e-mail]> also
    teach Perl on occasion.  Special appearances by Tom, Rob, and/or
    Randal may also be negotiated.  Classes can run from one day up to a
    week ranging over a wide range of subject matter (most are two or
    three days), and can include lab time if you want; having lab time
    with exercises is generally of great benefit.  Send us mail if your
    organization is interested in having a Perl class taught at your site.


1.8) Can people who aren't on USENET receive comp.lang.perl as a digest?

    "Perl-Users" is the mailing list version of the comp.lang.perl
    newsgroup.  If you're not lucky enough to be on USENET you can post to
    comp.lang.perl by sending to one of the following addresses.  Which one
    will work best for you depends on which nets your site is hooked into.
    Ask your local network guru if you're not certain.

    Internet: [e-mail]
              [e-mail]

    BitNet: Perl@Virginia

    uucp: ...!uunet!virginia!perl-users

    The Perl-Users list is bidirectionally gatewayed with the USENET
    newsgroup comp.lang.perl.  This means that VIRGINIA functions as a
    reflector.  All traffic coming in from the non-USENET side is
    immediately posted to the newsgroup.  Postings from the USENET side are
    periodically digested and mailed out to the Perl-Users mailing list.  A
    digest is created and distributed at least once per day, more often if
    traffic warrants.

    All requests to be added to or deleted from this list, problems,
    questions, etc., should be sent to:

    Internet: [e-mail]
              [e-mail]

    BitNet: Perl-Req@Virginia

    uucp: ...!uunet!virginia!perl-users-request

    Coordinator: Marc Rouleau <[e-mail]>

1.9) Are archives of comp.lang.perl available?

    Yes, although they're poorly organized.  You can get them from
    the host ftp.cs.caltech.edu (131.215.128.204) in the directory
    /pub/comp.lang.perl.  The file is comp.lang.perl.tar.Z; this file
    was last modified on February 15, 1992, and is 8.9 megabytes long.

    These are currently stored in news- or MH-style format; there are
    subdirectories named things like "arrays", "programs", "taint", and
    "emacs".  Unfortunately, only the first ~1600 or so messages have been
    so categorized, and we're now up to almost 15000.  Furthermore, even
    this categorization was haphazardly done and contains errors.

    A more sophisticated query and retrieval mechanism is desirable.
    Preferably one that allows you to retrieve article using a fast-access
    indices, keyed on at least author, date, subject, thread (as in "trn")
    and probably keywords.  Right now, the MH pick command works for this,
    but it is very slow to select on 15000 articles.

    If you're serious about this, your best bet is probably to retrieve
    the compressed tarchive and play with what you get.  Any suggestions
    how to better sort this all out are extremely welcome.

    Currently the comp.lang.perl archives on convex.com are nearly a year
    behind.  That's because I no longer have room to store them there.  I
    do have them all on-line still, but they are not publicly accessible.
    If you have a special request for a query on the old newsgroup
    postings, and make nice noises in my direction, I can run the query
    and send them to you.  Algebraic queries are like "find me anything
    about this and that and the other thing but not this or whozits".  I
    hope to put this in the form of a mailserver.  Donated software would
    be fine. :-)

    The fast text-retrieval query system for this I'm currently using is
    Liam Quin's excellent lqtext system, available from ftp.cs.toronto.edu
    in /pub/lq-text* .

    Rumor has it that there are WAIS servers out there for comp.lang.perl
    these days, but I haven't used them.  Any information on these would
    be appreciated.


1.10) How do I get Perl to run on machine FOO?

    Perl comes with an elaborate auto-configuration script that allows Perl
    to be painlessly ported to a wide variety of platforms, including many
    non-UNIX ones.  Amiga and MS-DOS binaries are available on
    jpl-devvax.jpl.nasa.gov [128.149.1.143] for anonymous FTP.  Try to bring
    Perl up on your machine, and if you have problems, examine the README
    file carefully, and if all else fails, post to comp.lang.perl;
    probably someone out there has run into your problem and will be able
    to help you.

    In particular, since they're so often asked about, here's some information
    for the MacIntosh from Matthias Ulrich Neeracher <[e-mail]>:

    A port of Perl to the Apple Macintosh is available by anonymous
    ftp to wuarchive.wustl.edu [128.252.135.4] from the file
    /mirrors2/rascal.ics.utexas.edu/programming/Perl_402_MPW_CPT_bin .

    You can also get it from Host gatekeeper.dec.com [16.1.0.2]
    in /.9/plan/perl/macperl/Perl_402_MPW_CPT_bin .

    The file is 1.1M and must be transferred in BINARY mode. Please
    be considerate of the archive sites' users during CDT working hours.
    (And, no, there is no way to get it by email).

    For European users, the file should soon appear on lth.se.

    To make optimal use of all the features of this port, you
    should have MPW, ToolServer, and 5M of memory. There is also a
    standalone version included, but it's currently of very limited
    usefulness.

    This package contains all of the sources for compilation with
    MPW C 3.2

    Here's more, from Timothy Murphy <[e-mail] >


    I ported perl to the Mac, using Think C, a while ago.  I've
    used it quite a lot since without problems.

    It is available from ftp.maths.tcd.ie in pub/Mac/perl.hqx .
    The source (as diffs from the standard source) is in the
    subdirectory pub/Mac/perl-4.035 .

    A Mac version of patch is also available in pub/Mac/patch.hqx
    with source in pub/Mac/patch-2.0 .  Various other Mac ports of
    GNU programs can be found in the same place.

    They all use a small "ThinkCPosix" library containing various
    Unix-like functions, which again can be found in the same
    place.

    And here's some VMS information from Rao V. Akella
    <[e-mail]>:  (this appears to be an old port)

    You can pick up Perl for VMS (version 3.0.1.1 patchlevel 4) via
    anonymous ftp from ftp.pitt.edu [130.49.253.1] in the
    software/vms/perl subdirectory (there are two files there:
    perl-pl18.bck and perl-pl4.bck).

    There is also a v3.018 on info.rz.uni-ulm.de [134.60.1.125] or
    vms.huji.ac.il [128.139.4.3] in /pub/VMS/misc (information courtesy
    of Anders Rolff <[e-mail]>).

    And here is a recent version for MS-DOS from Budi Rahard
    <[e-mail]>, who says:

    I am collecting MS-DOS Perl(s) in ftp.ee.umanitoba.ca directory
    /pub/msdos/perl.  Currently I received three versions of Perl v4.019
    and one of 4.010.  (Tommy Thorn <[e-mail]> and Len Reed
    <holos0![e-mail]>)

    There is now a 4.035 for 386 [DOS], Hitoshi Doi <[e-mail]>
    port, is available ftp.ee.umanitoba.ca as /pub/msdos/perl/perl386.zoo .

    Please contact the porters directly in case of questions about
    these ports.


1.11) Where can I get (info|inter|ora|sql|syb)perl?

    Numerous database-oriented extensions to Perl have been written.
    These amount to using the usub mechanism (see the usub/ subdirectory
    in the distribution tree) to link in a database library, allowing
    embedded calls to Informix, Interbase, Oracle, Ingres, and Sybase.
    There is currently a project underway, organized by Buzz Moschetti
    <[e-mail]>, to create a higher level interface (DBperl) that
    will allow you to write your queries in a database-independent
    fashion.  If you're interested, send mail to
    <[e-mail]> about it.

    Meanwhile, here are the authors of the various extensions:

    What            Target DB       Who
    --------        -----------     ----------------------------------------
    Infoperl        Informix        Kurt Andersen ([e-mail])
    Interperl       Interbase       Buzz Moschetti ([e-mail])
    Oraperl         Oracle          Kevin Stock ([e-mail])
    Sqlperl         Ingres          Ted Lemon ([e-mail])
    Sybperl         Sybase          Michael Peppler ([e-mail])


1.12) There's an a2p and an s2p; why isn't there a p2c (perl-to-C)?

    Because the Pascal people would be upset that we stole their name. :-)

    The dynamic nature of Perl's do and eval operators (and remember that
    constructs like s/$mac_donald/$mac_gregor/eieio count as an eval) would
    make this very difficult.  To fully support them, you would have to put
    the whole Perl interpreter into each compiled version for those scripts
    using them.  This is what undump does right now, if your machine has it.
    If what you're doing will be faster in C than in Perl, maybe it should
    have been written in C in the first place.  For things that ought to be
    written in Perl, the interpreter will be just about as fast, because the
    pattern matching routines won't work any faster linked into a C program.
    Even in the case of simple Perl programs that don't do any fancy evals, the
    major gain would be in compiling the control flow tests, with the rest
    still being a maze of twisty, turny subroutine calls.  Since these are not
    usually the major bottleneck in the program, there's not as much to be
    gained via compilation as one might think.


1.13) Where can I get undump for my machine?

    The undump program comes from the TeX distribution.  If you have TeX, then
    you may have a working undump.  If you don't, and you can't get one,
    *AND* you have a GNU emacs working on your machine that can clone itself,
    then you might try taking its unexec() function and compiling Perl with
    -DUNEXEC, which will make Perl call unexec() instead of abort().  You'll
    have to add unexec.o to the objects line in the Makefile.  If you succeed,
    post to comp.lang.perl about your experience so others can benefit from it.


1.14) Where can I get a perl-mode for emacs?

    In the perl4.0 source directory, you'll find a directory called
    "emacs", which contains several files that should help you.


1.15) How can I use Perl interactively?

    The easiest way to do this is to run Perl under its debugger.
    If you have no program to debug, you can invoke the debugger
    on an `empty' program like this:

        perl -de 0

    (The more positive amongst us prefer "perl -de 1". :-)

    Now you can type in any legal Perl code, and it will be immediately
    evaluated.  You can also examine the symbol table, get stack
    backtraces, check variable Values, and if you want to, set
    breakpoints and do the other things you can do in a symbolic debugger.


1.16) Is there a Perl shell?

   Not really.  Perl is a programming language, not a command
   interpreter.  There is a very simple one called "perlsh"
   included in the Perl source distribution.  It just does this:

    $/ = '';        # set paragraph mode
    $SHlinesep = "\n";
    while ($SHcmd = <>) {
        $/ = $SHlinesep;
        eval $SHcmd; print $@ || "\n";
        $SHlinesep = $/; $/ = '';
    }

   Not very interesting, eh?

   Daniel Smith <[e-mail]> is working on an interactive Perl
   shell called SoftList.  It's currently at version 3.0beta.  SoftList
   3.0 has tcsh-like command line editing, can let you define a file of
   aliases so that you can run chunks of perl or UNIX commands, and so
   on.  You can send mail to him for further information and availability.


1.17) Is there a Perl profiler?

    While there isn't one included with the perl source distribution,
    various folks have written packages that allow you to do at least some
    sort of profiling.  The strategy usually includes modifying the perl
    debugger to handle profiling.  Authors of these packages include

    Wayne Thompson         <[e-mail]>
    Ray Lischner         <[e-mail]>
    Kresten Krab Thorup     <[e-mail]>

    The original articles by these folks containing their
    profilers are available on convex.com in
    /pub/perl/information/profiling.shar via anon ftp.


1.18) Is there a yacc for Perl?

    Yes!! It's a version of Berkeley yacc that outputs Perl code instead
    of C code!  You can get this from ftp.sterling.com [192.124.9.1] in
    /local/perl-byacc1.8.1.tar.Z, or send the author mail for details.


1.19) How can I use curses with perl?

    One way is to build a curseperl binary by linking in your C curses
    library as described in the usub subdirectory of the perl sources.
    This requires a modicum of work, but it will be reasonably fast
    since it's all in C (assuming you consider curses reasonably fast. :-)
    Programs written using this method require the modified curseperl,
    not vanilla perl, to run.  While this is something of a disadvantage,
    experience indicates that it's better to use curseperl than to
    try to roll your own using termcap directly.

    Another possibility is to use Henk Penning's cterm package, a curses
    emulation library written in perl.  cterm is actually a separate
    program with which you communicate via a pipe.  It is available from
    ftp.cs.ruu.nl [131.211.80.17] via anonymous ftp. in the directory
    pub/PERL.  You may also acquire the package via email in compressed,
    uuencoded form by sending a message to [e-mail]
    containing these lines:

    begin
    send PERL/cterm.shar.Z
    end

    See the question on retrieving perl via mail for more information on
    how to get retrieve other items of interest from the mail server
    there.


1.20) How can I use X with Perl?

    Right now, you have several choices.  You can wait for perl5, use
    the WAFE or STDWIN packages, or try to make your own usub bindings.

    Perl5 is anticipated to be released with bindings for X, called
    guiperl.  An exciting prototype for this, written by Jon Biggar
    <[e-mail]>, Larry's *other* brother-in-law and officemate,
    is already up and running inside of Netlabs.  This program addresses
    the same dynamic gui-building problem space as does tcl/tk.

    If you can't wait or don't think that guiperl will do what you want,
    a stab at Motif bindings was begun by Theodore C. Law
    <[e-mail]> area.  His article about this is
    on convex.com in /pub/perl/info/motif for anon ftp.

    STDWIN is a library written by Guido van Rossum <[e-mail]>
    (author of the Python programming language) that is portable
    between Mac, Dos and X11.  One could write a Perl agent to
    speak to this STDWIN server.

    WAFE is a package that implements a symbolic interface to the Athena
    widgets (X11R5). A typical Wafe application consists in our framework
    of two parts: the front-end (we call it Wafe for Widget[Athena]front
    end) and an application program running typically as separate process.
    The application program can be implemented in an arbitrary programming
    language and talks to the front-end via stdio.  Since Wafe (the
    front-end) was developed using the extensible TCL shell (cite John
    Ousterhout), an application program can dynamically submit requests to
    the front-end to build up the graphical user interface; the
    application can even down-load application specific procedures into
    the front-end.  The distribution contains sample application programs
    in Perl, GAWK, Prolog, TCL, and C talking to the same Wafe binary.
    Many of the demo applications are implemented in Perl.  Wafe 0.9 can
    be obtained via anonymous ftp from
    ftp.wu-wien.ac.at:pub/src/X11/wafe-0.9.tar.Z
    (for people without name server: the ip address is 137.208.3.5)


1.21) What is perl4?  What is perl5?

    The answer to what is perl4 is nearly anything you might otherwise
    program in shell or C.  The answer to what is perl5 is basically
    Perl: the Next Generation.  In fact, it's essentially a complete
    rewrite of perl from the bottom up, and back again.

    Larry gave a talk on perl5 at a Bay LISA meeting as well as at the
    most recent USENIX LISA conference in Long Beach in which he timorously
    admitted that perl5 might possibly be beta released in early 1993.
    He enumerated some of the following features.  Note that not only have
    not all these been implemented yet, the ones further down the list
    might well not get done at all.

    a faster, tighter, more flexible interpreter
    very easy GUI Perl applications using X bindings ("guiperl")
    embeddable Perl code in C code: cc prog.c -lperl
    multiple coresident perl interpreters:
        perhaps threading and/or coroutines
    named argument passing:
        some_func( OC => $red, TOF => "\f");
    recursive lists:
        [a, b, [c, d], e] has 4 elts, the 3rd being itself a list
    typed pointers and generalized indirection:
        like @{$aptr} or &{$fptr} or &{ $table[$index] . "func" }().
    merging of list operator and function calling syntax:
        split /pat/, $string;
    subroutines without &'s:   myfunc($arg);
    generalization of dbm binding for assoc arrays to handle
        any generic fetch/store/open/close/flush package.
        (thus allowing both dbm and gdbm at once)
    object oriented programming:
        STDOUT->flush(1);
        give dog $bone;
    lexical scoping
    dynamic loading of C libraries for systems that can
    byte-compiled code for speed and maybe security

    It's tempting to want this stuff soon, since the sooner it comes
    out the sooner we can all build really cool applications.  But the
    longer Larry works on it, the more items from this list will actually
    get done, and the more robust the release will be.  So let's not
    ask him about it too often.


1.22) How does Perl compare with languages like REXX or TCL?

    REXX is an interpreted programming language first seen on IBM systems,
    and TCL is John Ousterhout's embeddable command language.  TCL's most
    intriguing feature for many people is the tcl/tk toolset that allows
    for interpreted X-based tools.

    To avoid any flamage, if you really want to know the answer to this
    question, probably the best thing to do is try to write equivalent
    code to do a set of tasks.  All three have their own newsgroups in
    which you can learn about (but hopefully not argue about) these
    languages.

    To find out more about these or other languages, you might also check
    out David Muir Sharnoff <[e-mail]>'s posting on "Catalog of
    compilers, interpreters, and other language tools" which he posts to
    comp.lang.misc, comp.sources.d, comp.archives.admin, and the
    news.answers newsgroups.  It's a comprehensive treatment of many
    different languages.  (Caveat lector: he considers Perl's syntax
    "unappealing".)   This list is archived on convex.com in
    /pub/perl/info/lang-survey.shar .


1.23) Is it a Perl program or a Perl script?

    Certainly. :-)

    Current UNIX parlance holds that anything interpreted
    is a script, and anything compiled into native machine
    code is a program.  However, others hold that a program
    is a program is a program: after all, one seldom discusses
    scripts written in BASIC or LISP.  Larry considers it
    a program if it's set in stone and you can't change it,
    whereas if you go in and hack on it, then it's a script.

    But doesn't really matter.  The terms are generally
    interchangeable today.


1.24) What's the difference between "Perl" and "perl"?

     32 :-)  [  ord('p') - ord('P')  ]

     Larry now uses "Perl" to signify the language proper and "perl" the
     implementation of it, i.e. the current interpreter.  Hence my quip
     that "Nothing but perl can parse Perl."

     On the other hand, the aesthetic value of casewise parallelism
     in "awk", "sed", and "perl" as much require the lower-case
     version as "C", "Pascal", and "Perl" require the
     upper-case version.  It's also easier to type "Perl" in
     typeset print than to be constantly switching in Courier. :-)

     In other words, it doesn't matter much, especially if all
     you're doing is hearing someone talk about the language;
     case is hard to distingish aurally.


1.25) What companies use or ship Perl?

    At this time, the known list of companies that ship Perl includes at
    least the following:

    BSDI
    Comdisco Systems
    CONVEX Computer Corporation
    Dell
    Integraph
    Kubota Pacific (/usr/contrib)
    Netlabs

    Many other companies use Perl internally for purposes of tools
    development, systems administration, installation scripts, and test
    suites.  Rumor has it that the large workstation vendors (the TLA set)
    are seriously looking into shipping Perl with their standard systems
    "soon".

    People with support contracts with their vendors are actively
    encouraged to submit enhancement requests that Perl be shipped
    as part of their standard system.  It would, at the very least,
    reduce the FTP load on the Internet. :-)


1.26) Is there commercial, 3rd-party support for Perl?

    No.  Although perl is included in the GNU distribution, at last check,
    Cygnus does not offer support for it.  However, it's unclear whether
    they've ever been offered sufficient financial incentive to do so.

    On the other hand, you do have comp.lang.perl as a totally gratis
    support mechanism.  As long as you ask "interesting" questions,
    you'll probably get plenty of help. :-)

1.27) Where can I get a list of the JAPH signature quotes?

    These are the "just another perl hacker" signatures that
    some people sign their postings with.  About 100 of the
    of the earlier ones are on convex.com in /pub/perl/info/japh.

1.28) Where can I get a list of Larry Wall witticisms?

    Over a hundred quips by Larry, from postings of his or source code,
    can be found on convex.com in /pub/perl/info/lwall-quotes.

1.29) Is there a pretty-printer for Perl?

    That depends on what you mean.  If you want something
    that works like vgrind on Perl programs, then the answer
    is "yes, nearly".  Here's a vgrind entry for perl:

    PERL|perl|Perl:\
        :pb=(^\d?sub\d\p\d?|\{):\
        :bb={:be=}:cb=#:ce=$:sb=":se=\e":lb=':\
        :le=\e':tl:\
        :id=_:\
        :kw=\
        if for foreach unless until while continue else elsif \
        do eval require \
        die exit \
        defined delete reset \
        goto last redo next dump \
        local undef return  \
        write format  \
        sub package

    It doesn't actually do everything right; in particular,
    things like $#, $', s#/foo##, and $foo'bar all confuse it.

    If what you mean is whether there is a program that will
    reformat the program much as indent(1) will do for C, then
    the answer is no.  The complex feedback between the scanner
    and the parser (as in the things that confuse vgrind) make
    it challenging to write at best to write a stand-alone C parser.
--
    Tom Christiansen      [e-mail]      convex!tchrist

    California is a fine place to live -- if you happen to be an orange.
            -- Fred Allen
--
    Tom Christiansen      [e-mail]      convex!tchrist

    As far as we know, our computer has never had an undetected error.
            -- Weisert