 Summary: comp.lang.perl.tk Frequently Asked Questions.
 Archive-name: perl-faq/ptk-faq
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 Last-modified: Date: Sat May 31 16:48:37 1997
 URL: http://w4.lns.cornell.edu/~pvhp/ptk/ptkFAQ.html
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 Perl/Tk FAQ
 ***********
 
 
 
 The Perl/Tk extension to the Perl programming language is copyrighted by its
 author Nick Ing-Simmons <nik@tiuk.ti.com> whose Tk400.202/COPYING
 file reads as follows: 
 
 Copyright (c) 1995-1996 Nick Ing-Simmons. All rights reserved.
 This package is free software; you can redistribute it and/or
 modify it under the same terms as Perl itself, with the exception
 of the files in the pTk sub-directory which have separate terms
 derived from those of the orignal Tk4.0 sources and/or Tix.
 
 IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY
 FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 ARISING OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY
 DERIVATIVES THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED OF THE
 POSSIBILITY OF SUCH DAMAGE.
 
 THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT.  THIS SOFTWARE
 IS PROVIDED ON AN "AS IS" BASIS, AND THE AUTHORS AND DISTRIBUTORS HAVE
 NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR
 MODIFICATIONS.
 
 See pTk/license.terms for details of this Tk license, 
 and pTk/Tix.license for the Tix license.
 
 
 
 This compilation of Frequently Asked Questions & answers (FAQ) is
 intended to answer several of the first (and largely more basic) questions
 posted to the comp.lang.perl.tk newsgroup and the ptk mailing list. 
 
 This document concerns itself with the Perl/Tk programming language (or, if
 you prefer, the Tk extension to Perl). Please be aware that this is not the Perl
 FAQ, this is not the Tcl FAQ, nor is this the Tcl/Tk FAQ. Each of those
 other documents is a useful source of information for Perl/Tk programmers
 but they are completely different from this one. 
 
 This is a dynamic document and contributions, clarifications, and corrections
 are most welcome! Please send e-mail to <pvhp@lns62.lns.cornell.edu> or to 
 <pvhp@forte.com>. With your help this document will get better (-:
 
 perl/Tk FAQ
 
  1. What is perl/Tk? 
  2. What is the difference between perl/Tk and Tkperl? 
  3. Do I need Tcl/Tk in order to build Perl/Tk? 
  4. Where is it? 
  5. What/Where is CPAN? 
  6. How do I build it? 
  7. Where is the Documentation? 
  8. How do I write scripts in perl/Tk? 
  9. What widget types are available under perl/Tk? 
  10. How do I get widget X to do Y ? 
     1. How do I get a Button to call a Perl subroutine? 
     2. How do I get a Button to actively change under my mouse
       pointer? 
     3. How do I arrange the layout of my widgets? 
     4. How do I get a Popup to popup? 
     5. How do I bind keyboard keys? 
     6. How do I add bindings? 
     7. How do I bind the action of a slider (sic) to ... ? 
     8. How do I configure a Scrollbar to scroll multiple widgets? 
     9. How do I display a bitmap? 
     10. How do I display an image? 
     11. What Image types are available? 
     12. Is there any way to have more than one Listbox contain a
       selection? 
     13. How do I select a range of tags in a Text widget? 
     14. How do I group Radiobuttons together? 
     15. How do I specify fonts? 
     16. How do I get the entry in an Entry? 
     17. How do I hide a password Entry? 
     18. How do I limit an Entry's insertion width? 
     19. How do I obtain Menus that do not tear off? 
  11. How do I get a Canvas to ... ? 
     1. Display a bitmap? 
     2. Erase a display? 
     3. Display an Image? 
     4. What things can be created on a Canvas? 
     5. How do I redraw a line on a Canvas? 
     6. How do I use the Canvas as a geometry manager? 
     7. How do I get a Canvas to output PostScript(c)? 
     8. How do I get a PostScript(c) output of a Canvas w/ widgets? 
     9. How do I get the size of a Canvas? After a re-size? 
     10. How do I bind different actions to different areas of the same 
       Canvas? 
  12. Common Problems. 
     1. What do the ->, => and :: symbols mean? 
     2. What happened to the ampersands &? 
     3. What happened to the quotation marks? 
     4. Must I use "my" on all my variables? 
     5. Is there a way to find out what is in my perl/Tk "PATH"? 
     6. What is the difference between use and require? 
     7. How do I change the cursor/color? 
     8. How do I ring the bell? 
     9. How do I determine the version of perl/Tk that I am running? 
     10. How do I call perl from C? 
     11. How do I call Tcl code from perl/Tk? 
  13. What are some of the primary differences between Tcl/Tk and
    Perl/Tk? 
  14. How do I install new scripts | modules | extensions? 
  15. How do I write new modules? 
  16. Composite Widgets. 
     1. How do I get a Dialog box? 
     2. Is there a file selector? 
     3. Is there a color editor? 
     4. Is there a round Scale? 
     5. Is there something equivalent to tkerror? 
     6. Are there Tables? 
  17. Programming/development tools. 
     1. Is there a Tcl/Tk to perl/Tk translator? 
     2. Is there something equivalent to wish in perl/Tk? 
     3. Is there a debugger specifically for perl/Tk? 
     4. Is there a GUI builder in perl/Tk? 
  18. Processes & Inter-Process Communication under Perl/Tk. 
     1. How does one get Perl/Tk to act on events that are not coming
       from X? 
     2. Is there a send and do I need xauth? 
     3. How can I do animations using after? 
     4. How do I update widgets while waiting for other processes to
       complete? 
     5. How do you fork on System V (HP)? 
  19. How do I "clear the screen"? 
  20. Is there a way to have an X application draw inside a perl/Tk window? 
  21. Is there a version for Microsoft Windows(tm)? 
  22. Are there any international font packages for perl/Tk? 
  23. Are there any other ways to create event based interfaces from perl? 
  24. Where can I get more information on graphics (modules|scripts)? 
  25. Are there any major applications written in perl/Tk? 
  26. What is the history of pTk and perl/Tk? 
  27. What can we expect the future to hold? 
  28. How do I obtain the latest version of this FAQ? 
  29. Acknowledgements & maintainer. 
 
 ______________________________________________________________________
 
 
 1. What is perl/Tk? 
 
 Perl/Tk (also known as pTk or ptk) is a collection of modules and code that
 attempts to wed the easily configured Tk 4 widget toolkit to the powerful
 lexigraphic, dynamic memory, I/O, and object-oriented capabilities of Perl 5.
 In other words, it is an interpreted scripting language for making widgets and
 programs with Graphical User Interfaces (GUI). (Examples of widget
 programs [not necessarily written in perl/Tk] include xterm, xclock, most
 web-browsers, etc.. They are programs with "GUI" interfaces of one sort or
 another and are subject to the effects of your window manager.) 
 
 The current release of Perl/Tk is based on "Tk 4.0p3" the widget Toolkit
 originally associated with the Tcl (Tool command language) scripting
 language. However, Perl/Tk does not require any of the lexical
 features/idiosynchrocies of Tcl. Perl/Tk uses perl 5 syntax, grammar, and data
 structures. 
 
 The ``Tk400.202'' package is the production release of perl/Tk (corresponding
 to Tcl/Tk-4.0p3) and was written primarily by Nick Ing-Simmons 
 <Nick.Ing-Simmons@tiuk.ti.com> at Texas Instruments in Northampton,
 England, to work with the latest version of Larry Wall's ``perl''. Nick
 Ing-Simmons is currently busy converting the Tcl/Tk-4.1 code to perl
 callable code as well. An initial alpha release of the effort is available from
 CPAN as ``Tk402.000''. 
 
 The pTk code proper is an externally callable Tk toolkit (i.e. a re-write of the
 Tk 4.0 code that allows easier external linking & calling, especially by perl).
 Ptk can then be called from Perl 5 via the Tk.pm et al perl glue modules.
 Hence "ptk" does not necessarily refer to Perl Tk but could be taken to mean 
 portable Tk - given a glue package to another language. The stated goal of the
 pTk code is to have its library usable from perl, Tcl, LISP, C++, python, etc.. It
 just so happens that present work is concentrating on perl. 
 
 Historical note: "ptk" was known as "ntk" before about 11:30 EST 4 May 1995.
 
 The perl/Tk language is itself further extensible via the standard perl 5 module
 mechanism. A number of composite widget and special character extensions
 to the language have been written using perl modules. 
 
 ______________________________________________________________________
 
 
 
 2. What is the difference between perl/Tk and Tkperl? 
 
 TkPerl was originally the name of a (now unsupported) perl 4 package that
 Malcolm Beattie <mbeattie@sable.ox.ac.uk> at Oxford University gave to his
 code to wed the Tk X toolkit with Perl. (He has since referred to that package
 as a different "kettle of fish" from perl/Tk.) 
 
 Since that beginning Malcolm has also come up with a Tcl module for perl 5
 that has a Tcl::Tk module extension. That module allows the use of Tcl within
 a Perl script (i.e. you must know both languages to get your widgets to work.) If
 you are interested in that package instead, see the necessary kits for Malcolm
 Beattie's Tcl/Tk extensions to Perl, which have been distrubuted as 
 Tcl-b#.tar.gz and TclTk-b#.tar.gz files in the authors/id/MICB/
 directory at CPAN sites (locations given in a separate question in this FAQ). 
 
 The name "tkperl" is sometimes applied to the "perl/Tk" or "ptk" package that
 is the subject of this FAQ. Nick Ing-Simmons prefers "perl/Tk" as the name
 of the package, with "pTk" or "ptk" as contractions of that name as well as
 referring to something technically distinct: given the extensibility of the pTk
 code the "p" could also be taken to mean 'portable' or 'pure' (not to be
 confused with either the Helsinki University of Technology portTk, nor with
 Brian Warkentine's Rivet). In this document the code of interest is either
 referred to as "perl/Tk", "pTk", or "ptk" though the primary focus is on
 perl/Tk. 
 
 Warning: do not attempt to install both perl/Tk and Tcl/Tkperl in the same
 perl installation. The names in the respective modules overlap. In particular
 the Tcl::Tk module is declared in a Tk.pm file - so a statement like: 
 
     use Tk;
 
 will probably confuse your perl. If you cannot live without either module then
 install make & maintain separate perls for each and arrange your script
 writing accordingly (this will not be easy). 
 
 A more extensive comparison of the differences between the Tkperl and the
 perl/Tk code is given in the Tcl-perl.pod file that is distributed with
 perl/Tk (see the following questions for locations). 
 
 Lastly, it should be mentioned that if you build your perl/Tk statically rather
 than dynamically it will make a new perl interpreter called tkperl (confusing
 isn't it? :-). 
 
 ______________________________________________________________________
 
 
 
 3. Do I need Tcl/Tk in order to build Perl/Tk? 
 
 Short answer: No not at all. Perl/Tk is completely independent of Tcl/Tk. 
 
 Longer answer: In order to build Perl/Tk from source code you do need a
 recent version of perl, the perl/Tk source code kit, a graphical user interface
 library such as Xlib, a C or C++ compiler, and a make utility. In some rare
 cases Perl/Tk binaries are distributed for some platforms but that is more the
 exception than a general rule (see below). 
 
 If you will be attempting to port Perl/Tk to your platfrom then you might want
 to consult the document at: 
 
     http://w4.lns.cornell.edu/~pvhp/ptk/ptkPORT.html
 
 where each of these necessities is discussed in a bit more detail. 
 
 ______________________________________________________________________
 
 
 
 4. Where is it? 
 
 Source code
 -----------
 
 Tk400.202 & Tk402.00 the latest production and alpha releases are available
 from the modules/by-authors/Nick_Ing-Simmons/"> directory on the
 CPAN. You will need a made and installed perl (Perl 5.004 being an excellent
 choice), a recent MakeMaker and the Tk4* kit. To obtain all of these (as well
 as several other modules that sophisticated Tk programs now rely on) visit a 
 CPAN ftp site. CPAN (the Comprehensive Perl Archive Network) and what
 you need to get from it, is discussed in more detail in the next question. 
 
 (The rest of this question remains for historical reasons, as well as to point out
 some non CPAN resources.) 
 
 Tk-b8: The Tk-b8 kit remains on CPAN since it was compatible with the
 widely distributed and installed Perl (5.001m) 
 
 Binaries
 --------
 
 A pre-compiled binary distribution of Perl5.001m with Tk-b8 for Linux is
 available from: 
 
 Australia (please be patient and only try during off hours)
     ftp://syd.dit.csiro.au/pub/perl5/local/perl5.001m+Tk-b8-Linux-ELF.tar.gz
 
 It unpacks into /usr/local. You need to have ELF running and to have the
 ELF X11 libraries (please be patient and only try during off hours). 
 
 Binaries for the old Perl 5 & Tk-b6 are available for a number of UNIX
 platforms courtesy of Thomas Schlagel and Alan Stange of Brookhaven Lab
 at: 
 
 USA
     http://pubweb.bnl.gov/~ptk/
 
 Thomas and Alan have recently (winter 1995-1996) announced that they will
 update the Tk module version number of the many binaries they distribute. 
 
 Physical media (mostly source code)
 -----------------------------------
 
 With traffic jams on today's information superhighway more and more
 common it is often convenient to be able to snail mail a CD rather than suffer
 with .tar.gz files that are corrupted by network spottiness. Here is a very
 brief list of some folks who distribute perl (and hopefully Tk too!) on physical
 media. This list is not intended to be complete, nor an endorsement of any
 vendor (I personally do not have the time to check out any of these but have
 seen that some tend to be out of date by a few months with respect to CPAN
 so please be careful). See the hypertext version of this document for
 hyperlinks to the following vendors: 
 
 Walnut Creek Perl CD
    This CD specifies a release date. $39.95
 Cosmos Engineering Company
    Offers Linux plus perl for sale on a 1 Gigabyte IDE hard drive for
    PC-like computers. $279.00 (Fall 1996)
 Unix Review System Administration
    A CD that contains "Perl 5.0" (and much other stuff including Tcl/Tk
    and Expect) for $49.95. Telephone: (800) 444-4881. 
 InfoMagic Mother of Perl
    This 2 CD set contains perl 5.001 and sells for $35.00
 Ready to Run 
    Perl (unknown version) available for sale for many types of Unix and
    other operating systems.
 
 ______________________________________________________________________
 
 
 
 5. What/Where is CPAN? 
 
 "CPAN" = Comprehensive Perl Archive Network a worldwide collection of
 anonymous ftp sites for Perl et al (not to be confused with CTAN which is for
 TeX, nor CSPAN which rarely deals with computer software). The files of
 particular interest to a perl/Tk programmer would include: 
 
  o The latest Tk release should be in the 
    modules/by-authors/Nick_Ing-Simmons/ directory at any
    CPAN ftp site (listed below). 
  o The latest official Perl release should be in the src/ directory in a file
    called latest.tar.gz at any CPAN ftp site (listed below). 
  o If you need something older or newer than the "latest supported
    release" try the src/5.0/ directory at any CPAN ftp site (listed
    below). 
 
 There are a number of modules available for use with Tk. Among them: 
 
  o Alan Scheinine's SelFile.pm is in the 
    modules/by-authors/Alan_Scheinine/ directory at any CPAN
    ftp site (listed below). 
  o Guy Decoux's BLT_Table geometry manager is in the 
    modules/by-authors/id/GUYDX/ directory at any CPAN ftp site
    (listed below). 
  o Ilya Zakharevich's eText plug in replacement for the Text widget is in
    the modules/by-authors/id/ILYAZ/etext/ directory at any
    CPAN ftp site (listed below). 
  o Brent B. Powers' Tk-FileDialog and Tk-WaitBox are available from
    the modules/by-authors/id/BPOWERS/ directory at any CPAN
    ftp site (listed below). 
 
 Some of the fancier perl/Tk scripts (news readers and web browsers e.g.) make
 use of other perl modules/module-bundles. Among those that you ought to
 consider installing are: 
 
  o To run the ptknews script you will need Mail/Internet.pm from
    the Mailtools module kit, available from the 
    modules/by-authors/id/GBARR/ directory at any CPAN ftp/http
    site (listed below). While there pick up the latest libnet-* module
    bundle too. 
  o The build of recent versions of perl/Tk requests that you have the 
    URI::URL and HTML::Parse modules already installed. These
    modules are part of the libwww-perl-*.tar.gz kit, available from
    the modules/by-authors/id/GAAS/ at any CPAN ftp/http site
    (listed below). 
 
 Documentation is available from CPAN: 
 
  o Assorted documentation for perl is in the doc/ directory at any
    CPAN ftp site (listed below). 
  o Fairly up-to-date versions of some Perl/Tk external documentation
    (such as this FAQ) is in the modules/by-authors/id/PVHP/
    directory at any CPAN ftp/http site (listed below).
    (for Perl/Tk official documentation check the Tk/doc/*.htm files that
    are built with Nick's Tk kit on your computer.) 
 
 Bringing it all together one can look at: 
 
  o Most things perl/Tk (with certain exceptions) are also linked to a 
    modules/by-module/Tk/ directory at any CPAN ftp/http site
    (listed below). 
  o The long version of Tim Bunce and Andreas Koenig's module list
    helps you sort out things like "which kit is HTML::Parse a part of?". It
    is in modules/00modlist.long.html and is also posted
    periodically to newsgroups. 
 
 Here are the 52 CPAN sites/directories (with dotted quads [IP numbers] given
 on the right for those without name-servers): 
 
 Updated: Sun Dec 8 17:12:55 EST 1996 
 
 Africa
   South Africa    
     ftp://ftp.is.co.za/programming/perl/CPAN/           196.4.160.12
 Asia
   Hong Kong       
     ftp://ftp.hkstar.com/pub/CPAN/                      202.82.7.4
   Japan           
     ftp://ftp.jaist.ac.jp/pub/lang/perl/CPAN/           150.65.7.5
     ftp://ftp.lab.kdd.co.jp/lang/perl/CPAN/             192.26.91.6
   South Korea     
     ftp://ftp.nuri.net/pub/CPAN/                        203.255.112.6
   Taiwan          
     ftp://dongpo.math.ncu.edu.tw/perl/CPAN/             140.115.25.3
 Australasia
   Australia       
     ftp://coombs.anu.edu.au/pub/perl/CPAN/              150.203.76.2
     ftp://ftp.mame.mu.oz.au/pub/perl/CPAN/              128.250.209.2
   New Zealand     
     ftp://ftp.tekotago.ac.nz/pub/perl/CPAN/             202.49.6.24
 Europe
   Austria         
     ftp://ftp.tuwien.ac.at/pub/languages/perl/CPAN/     128.130.34.160
   Belgium         
     ftp://ftp.kulnet.kuleuven.ac.be/pub/mirror/CPAN/    134.58.127.2
   Czech Republic  
     ftp://sunsite.mff.cuni.cz/Languages/Perl/CPAN/      194.50.23.220
   Denmark         
     ftp://sunsite.auc.dk/pub/languages/perl/CPAN/       130.225.51.30
   Finland         
     ftp://ftp.funet.fi/pub/languages/perl/CPAN/         128.214.248.6
   France          
     ftp://ftp.pasteur.fr/pub/computing/unix/perl/CPAN/  157.99.64.12
   Germany         
     ftp://ftp.leo.org/pub/comp/programming/languages/perl/CPAN/  131.159.0.252
     ftp://ftp.rz.ruhr-uni-bochum.de/pub/CPAN/           134.147.32.42
     ftp://ftp.uni-hamburg.de/pub/soft/lang/perl/CPAN/   134.100.32.54
   Greece          
     ftp://ftp.ntua.gr/pub/lang/perl/                    
   Hungary         
     ftp://ftp.kfki.hu/pub/packages/perl/CPAN/           148.6.0.5
   Italy           
     ftp://cis.utovrm.it/CPAN/                           160.80.22.17
   the Netherlands 
     ftp://ftp.cs.ruu.nl/pub/PERL/CPAN/                  131.211.80.17
     ftp://ftp.EU.net/packages/cpan/                     134.222.91.7
   Norway          
     ftp://ftp.uit.no/pub/languages/perl/cpan/           129.242.4.34
   Poland          
     ftp://ftp.pk.edu.pl/pub/lang/perl/CPAN/             149.156.132.152
     ftp://sunsite.icm.edu.pl/pub/CPAN/                  148.81.209.3
   Portugal        
     ftp://ftp.ci.uminho.pt/pub/lang/perl/               193.136.16.247
     ftp://ftp.telepac.pt/pub/CPAN/                      194.65.5.98
   Russia          
     ftp://ftp.sai.msu.su/pub/lang/perl/CPAN/            158.250.29.1
   Slovenia        
     ftp://ftp.arnes.si/software/perl/CPAN/              193.2.1.72
   Spain           
     ftp://ftp.etse.urv.es/pub/mirror/perl/              193.144.20.6
     ftp://ftp.rediris.es/mirror/CPAN/                   130.206.1.2
   Sweden          
     ftp://ftp.sunet.se/pub/lang/perl/CPAN/              130.238.253.4
   Switzerland     
     ftp://sunsite.cnlab-switch.ch/mirror/CPAN/          193.5.24.1
   UK              
     ftp://ftp.demon.co.uk/pub/mirrors/perl/CPAN/        158.152.1.44
     ftp://sunsite.doc.ic.ac.uk/packages/CPAN/           193.63.255.1
     ftp://unix.hensa.ac.uk/mirrors/perl-CPAN/           129.12.200.129
 North America
   Ontario         
     ftp://ftp.utilis.com/public/CPAN/                   207.34.209.49
     ftp://enterprise.ic.gc.ca/pub/perl/CPAN/            192.197.182.100
   California      
     ftp://ftp.digital.com/pub/plan/perl/CPAN/           204.123.2.4
     ftp://ftp.cdrom.com/pub/perl/CPAN/                  165.113.58.253
   Colorado        
     ftp://ftp.cs.colorado.edu/pub/perl/CPAN/            128.138.243.20
   Florida         
     ftp://ftp.cis.ufl.edu/pub/perl/CPAN/                128.227.205.206
   Illinois        
     ftp://uiarchive.cso.uiuc.edu/pub/lang/perl/CPAN/    128.174.5.14
   Massachusetts   
     ftp://ftp.iguide.com/pub/mirrors/packages/perl/CPAN/  206.15.105.99
   New York        
     ftp://ftp.rge.com/pub/languages/perl/               157.225.178.12
   North Carolina  
     ftp://ftp.duke.edu/pub/perl/                        152.3.233.7
   Oklahoma        
     ftp://ftp.ou.edu/mirrors/CPAN/                      129.15.2.40
   Oregon          
     ftp://ftp.orst.edu/pub/packages/CPAN/               128.193.4.12
   Texas           
     ftp://ftp.sedl.org/pub/mirrors/CPAN/                198.213.9.194
     ftp://ftp.metronet.com/pub/perl/                    192.245.137.6
 South America
   Chile           
     ftp://sunsite.dcc.uchile.cl/pub/Lang/perl/CPAN/     146.83.5.204
 
 For those equipped with multi-protocol browsers you might pay a visit to Tom
 Christiansen's CPAN multiplexer whose relevant Tk URLs are (the second
 one is not active since it violates the HTML-2.0 spec according to nsgmls): 
 
     http://perl.com/cgi-bin/cpan_mod?module=Tk
     http://perl.com/cgi-bin/cpan_mod?module=Tk&readme=1
 
 According to Stephen P. Potter some of the CPAN sites have decompression
 on the fly for people who do not have programs like gunzip. For example, at
 the ufl site (Florida USA) type this into your ftp session to download a
 gunzipped version of Tk: 
 
     ftp> get Tk400.202.tar.gz Tk400.202.tar
 
 If you have the appropriate CPAN and FTP modules (yes there is a CPAN
 module for retreiving CPAN modules and its name is CPAN oddly enough)
 already installed you can retrieve a module from CPAN and carry out a
 complete installation with a perl one-liner like this: 
 
     perl -MCPAN -e 'install "Tk"'
 
 For more information on CPAN you can send e-mail to the CPAN
 administrators, <cpan-adm@ftp.funet.fi>. If you know of some Perl resources
 that seem not to be in the CPAN (you did check the contents listings in 
 indices/, didn't you?) please tell the CPAN administrators. If you have
 some modules/scripts/documentation yourself that you would like to
 contribute to CPAN, please read the file authors/00upload.howto and let
 the CPAN administrators know about it. 
 
 ______________________________________________________________________
 
 
 
 6. How do I build it? 
 
 In general, building perl/Tk requires: 
 
  1. A made & installed perl (requires a C language compiler). You may
    need different versions of perl depending on which version of Tk you
    wish to run. 
  2. A C language compiler for the Tk code itself. 
  3. A linkable Xlib (.o, .so, .a, etc.) for X-windows. 
 
 Perl/Tk has been successfully built using various vendors' cc compilers, as
 well as with the free GNU gcc compiler. A make utility of some sort (make/
 gmake) will be extremely helpful. 
 
 Step - by - step the commands to build the Tk extension to Perl are (for the
 dynamically linked version) roughly as follows: 
 
  1. make install # the appropriate version of perl. 
  2. uninstall # prior versions of the Tk extension to perl. 
  3. gunzip -c Tk400.202.tar.gz | tar xvf - (options to tar
    may vary esp. on SysV) 
  4. cd Tk400.200 
  5. read INSTALL 
  6. perl Makefile.PL 
  7. make 
  8. make test 
  9. make install 
 
 For the statically linked version you would `make tkperl` just after
 executing the `make` step and before the `make test` step. 
 
 Note carefully that this process leaves behind a large amount of
 documentation and examples in various sub-directories. You are strongly
 encouraged to look carefully through your build tree for docs, examples, etc.
 and keep those valuable files in a safe place. You might consider tar-ing them
 off and installing in a webserver directory tree. 
 
 A relatively easy way to determine if the perl on your system allows for
 dynamic linking was mentioned by Kenneth Albanowski
 <kjahds@kjahds.com>. If the following does not say "dl_none.xs" then you
 probably do have dynamically linked perl (or perhaps a very non-Unixy perl): 
 
     perl -e 'use Config; print $Config{dlsrc},"\n"'
 
 (thanks to Paul Lussier <plussier@isd.3com.com> for the correction!). 
 
 Here is a little more detailed discussion of each the steps just given: 
 
  o Install Perl Read the Tk files (Tk*/README, etc.) for info on which
    version of perl is required for the perl/Tk kit you obtained.) For code
    locations see a CPAN site (separate question in this FAQ), the actual
    installation instructions come bundled in the perl***.tar.gz
    distribution file. (Perl Configure & make troubles are beyond the
    scope of this FAQ - please see the Perl FAQ itself or the INSTALL file
    for more help with this critical step.)
    You can install perl almost anywhere you like by specifying the 
    -Dprefix=/path argument to sh Configure 
  o Unpack perl/Tk outside the Perl distribution
    (i.e. outside the perl build, perl install, or perl lib areas).
    gunzip Tk400.202.tar.gz
    tar -xvf Tk400.202.tar
    (Your tar program may not take -xvf. The resultant Tk400.202/
    area will be referred to as your ``Tk build'' directory throughout this
    document.)
  o Read INSTALL carefully
    cd Tk400.202
    pager INSTALL
    where pager is the program you use to scroll through text files more
    or less. Be sure to read it and don't just pound away on the spacebar. 
  o If necessary remove any previously installed version of perl/Tk
    If you had a previously working version of Tk installed, you may need
    to resurrect the Makefile for it and execute:
    make uninstall
    make realclean
    before you unpack the new version. (The uninstall target of
    MakeMaker is relatively new so please be careful here.)
  o Have perl generate a custom Makefile.
    perl Makefile.PL
    (see below for more on this step.)
  o Compile.
    make
    (if and only if building static: make tkperl
  o Test.
    make test
  o Install.
    make install 
  o Play with it.
    basic_demo
    (modify #! line if necessary, or specify /path/to/perl
    ./basic_demo)
    (warning if you build Tk-b9.01 with perl5.002gamma then change the
    line in basic_demo from
    use lib ./blib;
    to
    use lib qw(blib/arch blib/lib);) 
  o Save the documentation and examples in a safe accessible place.
    use tar, cp, mv, chmod or whatever you prefer to save the valuable
    ancillary files from your Tk build tree.
 
 On the perl Makefile.PL step it may be necessary to give explicit
 locations of the required X11 libraries and/or include headers. For example: 
 
     perl Makefile.PL X11=/usr/local/X11R5
 
 or perhaps different directory tree specification is necessary with your X
 installation: 
 
     perl Makefile.PL X11INC=/usr/local/share/X11R5/include \
                      X11LIB=/usr/local/arch/X11R5/lib
 
 There are system and site dependencies in all of the above steps. However, the
 largest single source of build trouble comes from not using the latest versions
 of the various utilities (C compiler, make, etc.). In particular ensure that
 when you say perl Makefile.PL that the perl that gets invoked is up to
 date - use which perl (or whence perl) and perl -v to determine this.
 If necessary specify the full path name to your perl5 interpreter/compiler.
 (Some people do not rm their older perl interpreters when upgrading to a more
 recent version - beware.) 
 
 If you still run into trouble take a look at the INSTALL, the README and the 
 README file for your specific system (e.g. README.AIX, README.OSF, etc.).
 You might also find your system mentioned in the ptk hyper-mail archive at: 
 
     http://www.rosat.mpe-garching.mpg.de/mailing-lists/ptk/
 or
     http://pubweb.bnl.gov/~ptk/
 or
     ftp://ftp.ccd.bnl.gov/pub/ptk/archives/
 
 or the Perl 5 Porters page at one of the following URLs: 
 
     http://www.rosat.mpe-garching.mpg.de/mailing-lists/Perl5-Porters/
     http://www.hut.fi/~jhi/perl5-porters.html
 
 If you wish to discuss your Tk build problems with others run and save the
 output from the myConfig script in the Tk build directory (the output may
 already be in the myConfig.out file from your perl/Tk build directory), as
 well as the myconfig script in your perl build directory (or the output of perl
 -V with a capitol V). It is often helpful to include the output of either (or both)
 of these scripts in your discussion. 
 
 Presented here are the beginnings of a list of problems associated with
 building perl/Tk on various platforms (for help building perl itself please refer
 to the Perl FAQ). This list is in no way complete nor authoritative (nor is it
 necessarily even up-to-date!) but simply lists problems people have reported.
 Keep in mind that your installation may differ (e.g. location differences such
 as /usr/bin/perl vs. /usr/local/bin/perl) even if its the same
 platform listed here: 
 
 A Sampling of Perl/Tk Platforms:
 ++++++++++++++++++++++++++++++++
 
 AIX:
    As of perl5.002b & Tk-b9.01 README.AIX says no patching is
    necessary. 
 
    For Tk-b8: modifying the perl.exp file may be necessary. There is a
    patch in Tk-b8/README.AIX. It may be necessary to make
    regen_headers after the patch. 
 FreeBSD:
    Nate Patwardhan <nvp@nfic.com> reports no trouble at all with
    Tk400.200 on FreeBSD-2.1.5 or FreeBSD-2.2.1. 
 HPUX:
    For Tk-b11: One person reports a need to add #define
    TIMEOFDAY_TZ to the tkConfig.h header file in order to compile on
    HPUX 9.05. 
 
    Previous versions: Most people seem to prefer the dynamic linking
    afforded by a recent version of the gcc compiler on this system. 
 Linux:
    John C. Wingenbach indicates that should you encounter an error
    message like Cannot find -lX11 anywhere at ./myConfig
    line 184 when running your perl Makefile.PL (under Slakware
    3.0) that you should be more specific about -l/path/to/libX11.a.
    Adam Wasserman <awasser@hermes.sgc.com> has graciously
    provided a compilation of Linux compilation trials & tribulations. It is
    an (as yet un-edited) document available at: 
    http://w4.lns.cornell.edu/~pvhp/ptk/hints/linux_compile.txt
 MachTen:
    Mark Pease <pease@act.sps.mot.com> mentions that:
    I was able to get Tk-b11.02 running under MachTen 2.2 perl5.002_01.
    I did need to make one change to get a round a MachTen problem. In
    pTk/tclUnix.h, pwd.h is included, but it is also included in pTk/tkPort.h
    (which is included in Lang.h, which is use by tclUnixUtil.c, whew!) 
 
    MachTen's pwd.h can't be included more that once or you get an
    error. 
 
    It looked to me like tclUnix.h was only used in tclUnixUtil.c, so I
    commented out the #include <pwd.h> in tclUnix.h. 
 NetBSD:
    Jesus M. Gonzalez <jgb@gsyc.inf.uc3m.es> mentions success with:
    Tk-b11.01 compiles, installs and runs just out of the box in
    NetBSD-1.1/i386. I just followed the INSTALL instructions. 
 NeXTSTEP:
    Gerd Knops recently posted a discussion of the steps to get perl
    running on several NeXTSTEPs to p5p.
 OS/2:
    Ilya Zakharevich <ilya@math.ohio-state.edu> has compiled a
    modified form of Tk-b11.02 to work with the Xfree86 client/server
    package, as well more advanced versions working with the Open32 PM
    package.
 OSF/1:
    As of perl5.002b & Tk-b9.01 you will probably be able to follow the
    usual instructions. John Stoffel <john@wpi.edu> reports that if you
    use gcc (rather than cc) you should use at least version 2.7.2 
 
    For Tk-b8: make is reputedly not up to the task on this system. 
    Tk-b8/README.OSF recommends gmake instead.
    Stephane Bortzmeyer <bortzmeyer@pasteur.fr> reports a successful
    build with Perl 5.001m, xsubpp 1.922, MakeMaker 4.23. He points
    out that it was necessary for him to upgrade the xsubpp and
    MakeMaker that he received with his copy of Perl5.001m. 
 SCO:
    For Tk-b8: Eric J. Bohm <bohm@cs.Buffalo.EDU> reported a need to
    comment out line(s) from myConfig and GNUMakefiles using GNU
    make 3.67. (See Tk-b8/README.SCO for specifics.) 
 SGI (Irix):
    For Tk-b11.02: Phillip Moore <wpm@morgan.com> reports a clean
    build on IRIX 5.3. 
 
    Matthew Black <black@csulb.edu> recently mentioned a need to apply
    "patchSG0000596" to get perl sockets to work. His message was
    copyrighted and is not included here. Send e-mail to him to find out
    where the get "patchSG0000596". 
 Suns:
    SunOS (BSD):
    For Tk-b10 on SunOS 4.1.3_U1
    using SparcWorks acc 3.0.1 Frederick L. Wagner <derf@ti.com>
    reports needing to use the perl malloc rather than the system malloc()
    when building perl.
    For Tk-b8: Tom Tignor <tpt2@BBN.COM> reports the following on
    SunOS (sun4m sparc): Tue, 28 Nov 1995 13:19:42
    In trying to make, I got a "write: argument mismatch" error for the file
    ptK/Lang.h. I looked at the file and found the offending function,
    Tcl_GetOpenFile, which has a third argument called "doWrite" (not
    "write") in tkGlue.c. I changed the argument from "write" to "doWrite"
    in Lang.h and it's compiling fine (for the moment. :) 
    Solaris (System V):
    For Tk-b8: There is trouble getting perl to use Socket routines (i.e.
    trouble with make perl itself not necessarily trouble with Tk-b8). See
    the perl FAQ for more info or the .shar file that Tom Christiansen
    occasionally posts to comp.lang.perl.misc. Further information on perl 
    inter process communication can be found in the perlipc* files at: 
    ftp://ftp.perl.com/perl/info/everything_to_know/. 
 SVR4:
    For Tk-b8: Martha G. Armour and Len Reed report on two separate
    hardware platforms running SVR4 - extensive details in 
    Tk-b8/README.SVR4. Interestingly, they report no trouble at all on
    Linux. 
 Ultrix:
    Peter Prymmer reports that with Tk-b11 it was necessary to change
    the line in Makefile.PL that reads:
    'LIBS' => ["$xlib -lX11 -lpt -lsocket -lnsl -lm"],
    to read:
    'LIBS' => ["$xlib -lX11 -lpt -lsocket -lnsl -lm
    -ldnet"],
    because of a newer X11 in /usr/local that needed the DECnet protocol
    linking. 
 
    John Stoffel reports a successful build of static Tk-b10 on Ultrix 4.5. 
 Windows NT:
    Nick Ing-Simmons reports success with the alpha Tk404.000 kit,
    perl5.004, and Visual C++. 
 
 non-Unix(ish)es:
 ++++++++++++++++
 
 Information on non-Unix(ish) perl platforms may be obtained from
 newsgroups and email lists as well as a few world wide web sites. For example,
 try the Perl 5 Porters (p5p) [page|archives] at one of: 
 
     http://www.rosat.mpe-garching.mpg.de/mailing-lists/Perl5-Porters/
     http://www.hut.fi/~jhi/perl5-porters.html
 
 In general your non-Unix platform must be able to support perl 5 and Xlib (a
 C compiler and a make utility are tremendously useful too). If you want to run
 perl/Tk on another computer and simply have the display show up on yours
 then all you need on your computer is an "X server" The long list of UNIX and
 non-unix perl 5 ports, Tcl/Tk ports, and Perl/Tk ports that used to appear in
 this FAQ has now moved to a separate web page at: 
 
     http://w4.lns.cornell.edu/~pvhp/ptk/ptkPORT.html
 
 ______________________________________________________________________
 
 
 
 7. Where is the Documentation? 
 
 A great deal of Perl/Tk documentation gets installed as part of the Tk
 extension building process. Hence, a great deal of documentation is probably
 residing on your computer already. 
 
 More documentation is "in the works": there are several books dealing with
 perl/Tk in progress, an ongoing magazine column and a growing FAQ (the
 document you are presently reading). 
 
 The additional material you may want to look at can be split into Perl/Tk, Perl,
 Tcl/Tk, and X documentation categories: 
 
 Perl/Tk Specific Documentation
 ++++++++++++++++++++++++++++++
 
 The man pages
 -------------
 
 With up to date Tk build kits the various perl/Tk pod documents are converted
 to your systems' helpfile format and installed as part of the perl/Tk "make
 install" process. If you have a recent verion of perl/Tk try something like 
 man 3 Tk::Tk if this does not work check with you system administrator for
 the proper MANPATH. 
 
 In your Tk build directory there should be a doc/ sub-directory in which
 there are a number of .htm files (after you make install). These files were
 originally Tcl/Tk man pages (from the man* sub-directories), but the *.htm
 files have been converted to Perl syntax and rendered in HTML format. You
 can use the Perl/Tk web browser to view them locally with a command like: 
 
     tkweb index.html
 
 or you may view them on the web itself by installing them in a web-server
 directory tree, or by pointing a browser at: 
 
     http://w4.lns.cornell.edu/~pvhp/ptk/doc/
 
 The newsgroup
 -------------
 
 The newsgroup name is comp.lang.perl.tk and this FAQ will be periodically
 posted to that group (as well as a few other newsgroups). The newsgroup
 and/or the ptk mailing list are the appropriate places to post questions - yes
 even simple ones! (Although answers may sometimes be long in coming ... :-( 
 
 The nTk/pTk mailing list
 ------------------------
 
 The mailing list is an excellent supplement and complement to the newsgroup 
 comp.lang.perl.tk. All messages mailed to the list are forwarded to the
 newsgroup. (But not all messages posted to the newsgroup are forwarded to
 the list.) Some Perl/Tk experts only have access to e-mail. 
 
 The nTk/pTk Mailing List Archive is a very useful source of information too,
 and is accesible at either 
 
     http://pubweb.bnl.gov/~ptk/
 
 or via ftp at 
 
     ftp://ftp.ccd.bnl.gov/pub/ptk/archives/
 
 (both in the USA). You may search the contents of another ptk mailing list
 hypertext archive thanks to a cgi-bin script written by Achim Bohnet in
 Germany at: 
 
     http://www.rosat.mpe-garching.mpg.de/mailing-lists/ptk/
 
 You must subscribe to the mailing list to receive e-mail from the list. To
 subscribe to the mailing list you can send mail to 
 majordomo@lists.stanford.edu (i.e. <majordomo@lists.stanford.edu>) with
 the following command in the body of your e-mail message: 
 
     subscribe ptk joe.user@somewhere (Joe D. User)
 
 To send a message to all recipients of the mailing list send e-mail to 
 <ptk@lists.stanford.edu>. 
 
 To remove yourself from the mailing list send e-mail to 
 majordomo@lists.stanford.edu (i.e. <majordomo@lists.stanford.edu>) with
 the following command in the body of your e-mail message: 
 
     unsubscribe ptk joe.user@somewhere (Joe D. User)
 
 Where instead of "joe.user@somewhere" you might very well like to
 substitute another string of characters. 
 
 (Please note: one does not send unsubscribe messages to the ptk list. One does
 send "unsubscribe ptk" messages to a special e-mail list administration
 program. In the case of the ptk list you send to majordomo@lists.stanford.edu.
 You must of course do this from the account and computer from which you
 initially subscribed. In particular if you are viewing the hypertext version of
 this FAQ you may not be able to unsubscribe from 
 majordomo@lists.stanford.edu by following the mailto: hyperlinks - if your
 web-browser account/computer is different from your subscribe to
 e-mail-lists account/computer (the details of this might depend on which
 browser you use though). Thank you for your cooperation on this.) 
 
 The demo programs
 -----------------
 
 Examine (and try running) the code in your Tk#/ build directory tree. You
 might also be interested in test-running the code that gets installed: 
 
  o or perl5/site_perl/Tk/demos/ or 
    perl5/site_perl/Tk/demos/widget_lib/ directories (recent
    Tk's). 
  o Tk#/ or perl5/Tk/demos/ or perl5/Tk/demos/widget_lib/
    directories (older versions e.g. Tk-b8). 
 
 In order to determine where on your system the perl5/ directory is located
 type the following one-line perl command (at your shell prompt - this is not a
 line from a perl script): 
 
     perl -e 'print join("\n",@INC,"");'
 
 If that command does not turn up a perl5/ directory then make sure that you
 are running perl 5 with the following: perl -v (this too can simply be
 entered at the shell prompt). 
 
 More on the pod & man documentation
 -----------------------------------
 
 [As previously mentioned a great number of Tcl/Tk man pages are converted
 from *roff format to html format and are to be found within your Tk build
 directory tree in the doc/ sub-directory. These documents form an
 authoritative and extensive reference set for Perl/Tk.] 
 
 The raw pod files that come with the Tk kit are examples of the perl "plain old
 documentation" format and are just about human readable as they are (e.g. you
 may more, cat, or less them; or send them to a printer). Many (not all) of
 the perl/Tk pod documents get are converted to *roff format and are installed
 in you perl man page area as part of the perl/Tk build process. 
 
 If you have a recent version of perl/Tk try something like man 3 Tk::Tk. If
 this does not work check your manual page path with 
 
     perl -MConfig -e 'print $Config{man1dir},"\n",$Config{man3dir},"\n"'
 
 And if you still cannot find the manual pages check with your system
 administrator for the proper MANPATH and/or Tk installation version. 
 
 "Raw" .pod (such as UserGuide.pod) can be viewed with the tkpod
 hypertext pod viewer. Raw .pod may also be run through any one or more of a
 large numbers of re-formatting perl filters. Such programs include pod2man, 
 pod2text, pod2html, pod2latex, etc. (these get installed when you install 
 perl). Other translators pod2texinfo, pod2fm, pod2pdf, etc., also exist.
 Check a CPAN site for these scripts if you do not already have them. 
 
 A command line like the following (but subject to local variations) should
 work for you: 
 
     tkpod site_perl/Tk/UserGuide.pod
 
 or if you like Unix manual page style: 
 
     pod2man perl5/Tk/UserGuide.pod | nroff -man | more
 
 (note that I am showing examples with almost full file path names - the
 alternative would be to cd into the appropriate directory then type: 
 
     pod2man UserGuide.pod | nroff -man | more
 
 There should even be a perl script to run that above command for you. It is
 executed as: 
 
     perldoc UserGuide
 
 Note that if there is pod like documentation in a perl module you may also
 execute tkpod (or perldoc) on it as in: 
 
     tkpod ColorEditor.pm
 
 (please note that unfortunately, not all .pm mod files have pod embedded.) 
 
 If you have misplaced your tkpod program but still want that GUI look and
 feel (like xman) make the appropriate changes to the following script: 
 
     #!/usr/bin/perl
     use Tk;
     use Tk::Pod;
     my $m = new MainWindow;
     $m -> Pod(-file => 'ColorEditor.pm');
     # or use command line path/filename:
     # $m -> Pod(-file => $ARGV[0]);
     MainLoop;
 
 A miscellany of internet perl/Tk resources includes:
 ----------------------------------------------------
 
 World Wide Web - perl/Tk man pages
     http://pubweb.bnl.gov/~ptk/doc/index.html
     http://w4.lns.cornell.edu/~pvhp/ptk/doc/
     http://w4.lns.cornell.edu/~pvhp/ptk/pod/
 The Perl/Tk Newsgroup
     comp.lang.perl.tk
 Perl Newsgroups
     comp.lang.perl.misc
     comp.lang.perl.anounce
     comp.lang.perl.modules
 Tcl Newsgroups
     comp.lang.tcl
     comp.lang.tcl.announce
 Miscellaneous Newsgroups
     comp.answers
     news.answers
 Perl/Tk FAQ-Archives (ftp sites) [Note: FAQ may be many separate files]
  (see also CPAN sites)
     ftp://rtfm.mit.edu/pub/usenet/comp.lang.perl.tk
     ftp://rtfm.mit.edu/pub/usenet-by-hierarchy/comp/lang/perl/tk
     ftp://ftp.uu.net/usenet/news.answers/perl-faq/ptk-faq
     ftp://ftp.ccd.bnl.gov/pub/ptk/                   130.199.54.188
     ftp://ftp.ccd.bnl.gov/pub/ptk/ptkFAQ.txt         130.199.54.188
     ftp://ftp.wpi.edu/perl5/pTk-FAQ                  130.215.24.209
     ftp://perl.com/pub/perl/doc/ptkFAQ.gz            199.45.129.30
     ftp://perl.com/pub/perl/doc/ptkFAQ.ps.gz         199.45.129.30
 WWW-FAQ for perl/Tk
     http://w4.lns.cornell.edu/~pvhp/ptk/ptkTOC.html
     http://w4.lns.cornell.edu/~pvhp/ptk/ptkFAQ.html
 World Wide Web - perl/Tk info sites
     http://pubweb.bnl.gov/~ptk/
     http://fxfx.com/kgr/compound/ (Perl Tk Compound Widget Page)
     http://w4.lns.cornell.edu/~pvhp/ptk/ptkIMG.html (FAQ image supplement)
     http://w4.lns.cornell.edu/~pvhp/ptk/etc/
     http://w4.lns.cornell.edu/~pvhp/ptk/misc/
     http://w4.lns.cornell.edu/~pvhp/ptk/PNMTYAK/
     http://www.mirai.com/wks/
 The Mailing list
     majordomo@lists.stanford.edu 
     ptk@lists.stanford.edu 
 
 Perl Specific Documentation
 +++++++++++++++++++++++++++
 
 There are a growing number Perl books available. A more complete
 Perl-bibliographic discussion than that given here is available in the Perl
 FAQ or at: 
 
     http://www.perl.com/perl/info/books.html
 
 For Perl 5 there is (as of September 1996) a "New Camel" by Larry Wall, Tom
 Christiansen, and Randal L. Schwartz, with Stephen Potter. 
 
  Programming Perl 2nd Edition
  Larry Wall, Tom Christiansen, & Randal L. Schwartz with Stephen
  Potter 
  (c) 1996 O'Reilly & Associates Inc.
  ISBN 1-56592-149-6 (English)
 
 A second edition of the Llama is due out soon too: 
 
  Learning Perl, 2ndEdition
  Randal L. Schwartz
  June 1997 (est.) O'Reilly & Associates Inc.
  ISBN 1-56592-284-0 (English)
 
 The two early Perl books by Schwartz and Wall are very helpful (even if they
 do pertain to perl 4 and not 5. Beware that perl/Tk makes extensive use of perl
 5 object-oriented features.): 
 
  Learning Perl (The Llama)
  Randal L. Schwartz
  Copyright (c) 1993 O'Reilly & Associates Inc.
  ISBN 1-56592-042-2 (English)
  ISBN 2-84177-005-2 (French)
  ISBN 3-930673-08-8 (German)
  ISBN 4-89502-678-1 (Japanese)
 
  Programming Perl (The Camel)
  Larry Wall and Randal L. Schwartz
  Copyright (c) 1991 O'Reilly & Associates Inc.
  ISBN 0-937175-64-1 (English)
  ISBN 3-446-17257-2 (German) (Programmieren in Perl, translator:
  Hanser Verlag)
  ISBN 4-89052-384-7 (Japanese)
 
 There is also some Perl5 (book material) information at: 
 
     http://www.metronet.com/1h/perlinfo/perl5/
 
 Jon Orwant (the organizer of the comp.lang.perl.tk newgroup) has a book on
 Perl 5 that has a chapter that discusses the Tk extension. (Please note that it is
 mostly about Perl 5, there is a some discussion of four simple Perl/Tk
 programs, but it is not a book wholly devoted to Perl/Tk.) It is nevertheless a
 good introduction to object-oriented Perl 5 programming. The relevant info: 
 
  Perl 5 Interactive Course
  Jon Orwant
  (c) 1996 The Waite Group Press
  A Division of SAMS Publishing, Corte Madera, CA USA
  ISBN: 1-57169-064-6
 
 The Perl 5 Quick Reference Guide (may require LaTeX for installation) can
 be obtained from any CPAN ftp site. Detailed location information is also
 available at the author's website: 
 
     http://www.xs4all.nl/~jvromans/perlref.html
 
 The quick reference guide has also been turned into a small Nutshell
 handbook: 
 
  Perl 5 Desktop Reference
  Johan Vromans
  Copyright (c) February 1996 O'Reilly & Associates Inc.
  ISBN: 1-56592-187-9; Order number: 1879
 
 Eric F. Johnson has a book that discusses many perl5 for Unix vs. perl5 for
 Windows NT issues. He includes a final chapter with extensive discussion of
 the Tk extension and the ->Text() widget in particular. The information on
 that book is: 
 
  Cross-Platform Perl
  (c) 1996 Eric F. Johnson
  MIS:Press/M&T Books
  ISBN: 1-55851-483-X
 
 Kamran Husain and Robert F. Breedlove have written a perl 5 book that
 includes a chapter on Tk with some discussion of Menu()s. That book is: 
 
  Perl 5 Unleashed
  Kamran Husain and Robert F. Breedlove
  (c) 1996 Sams Publishing, Indianapolis, IN
  ISBN: 0-672-30891-6
 
 There is also a "Perl 5 How-To" book available that contains a great deal of
 erroneous information about perl/Tk. Among other things that book wrongly
 mentions that it is necessary to have a complete Tcl/Tk library installed on
 one's system to compile the Tk extension to perl. (They are incorrect - it is
 only necessary to have the appropriate perl version, libc and Xlib, the Tk
 extension is otherwise "self-contained"). 
 
 There is also a book on perl web client. It features a a chapter on perl/Tk that
 was written by Nancy Walsh: 
 
  Web Client Programming with Perl
  Clinton Wong
  1st Edition March 1997
  O'Reilly & Associates Inc.
  ISBN: 1-56592-214-X; Order number: 214X
 
 Additional book information may be found at Tom Christiansen's perl & cgi
 books page, or at his Perl-related Book Reviews page. 
 
 The multi-part perl 5 manual pages are available (assuming they have been
 installed in your MANPATH, type man perl, man perlmod etc.). 
 
 The perl 5 man pages are also available on the web at a number of locations. In
 general the more recent the documentation the more helpful it is. 
 
 In addition to the CPAN ftp source sites, a miscellany of internet perl
 resources includes: 
 
 Newsgroups
     comp.lang.perl.misc
     comp.lang.perl.announce
     comp.lang.perl.modules
     comp.infosystems.www.authoring.cgi
     comp.answers
     news.answers
 Perl FAQ-Archives (ftp sites) [Note: FAQ may be many separate files]
 (as of 5.004 the FAQ ships in pod format with perl)
     (see also the CPAN sites)
   North America
     ftp://rtfm.mit.edu/pub/usenet/news.answers/perl-faq/
     ftp://ftp.uu.net/usenet/news.answers/perl-faq  192.48.96.9
     ftp://ftp.khoros.unm.edu/pub/perl/faq.gz       198.59.155.28
   Europe 
     ftp://ftp.cs.ruu.nl/pub/NEWS.ANSWERS/perl-faq/ 131.211.80.17
     ftp://src.doc.ic.ac.uk/packages/perl/FAQ       146.169.2.10
 Gopher Perl FAQ 
     gopher://gopher.metronet.com/11/perlinfo/faq
 WWW-FAQ for Perl
     http://www.perl.com/perl/faq/
     http://www.smartpages.com/bngfaqs/comp/lang/perl/top.html
     http://www.smartpages.com/bngfaqs/comp/lang/perl/misc/top.html
     http://www.smartpages.com/bngfaqs/comp/lang/perl/announce/top.html
     http://www.cis.ohio-state.edu/hypertext/faq/usenet/perl-faq/top.html
 Perl for Win32 FAQ  (discusses Win95)
     http://www.perl.org/CPAN/doc/FAQs/win32/Perl_for_Win32_FAQ.html
 
 Perl info sites
 Gopher (gopher:70) perl info sites
   USA
     gopher://gopher.metronet.com/11h/perlinfo
 World Wide Web (http:80) perl info sites
   USA
     http://www.yahoo.com/Computers_and_Internet/Languages/Perl/index.html
     http://www.perl.com/
     http://www.khoros.unm.edu/staff/neilb/perl/home.html
     http://www.khoros.unm.edu:80/staff/neilb/perl/metaFAQ/
     http://www.metronet.com/perlinfo/
     http://www.metronet.com/perlinfo/perl5.html (Perl 5)
     http://www.eecs.nwu.edu/perl/perl.html
     http://cesr39.lns.cornell.edu/public/perl/
     http://www.virtualschool.edu/mon/Perl.html
     http://www.hermetica.com/technologia/unexec/
     http://www.oac.uci.edu/indiv/ehood/perlWWW/
     http://web.sau.edu/~mkruse/www/scripts/
     http://orwant.www.media.mit.edu/the_perl_journal/
     http://www.perl.com/Architext/AT-allperl.html
     http://www.mispress.com/introcgi/
     http://www.walrus.com/~smithj/webcan/
     http://web.syr.edu/~chsiao05/cps600_project.html
     http://www.iftech.com/classes/webdev/webdev_perl.htm
     http://www.cc.iastate.edu/perlmenu/
     http://www.ora.com/www/item/cgi_prog.html
   UK
     http://pubweb.nexor.co.uk/public/perl/perl.html
     http://www.bio.cam.ac.uk/web/form.html
 Web references to Perl mailing lists
     http://www.perl.com/perl/info/mailing-lists.html
     http://www.nicoh.com/cgi-bin/lwgate/PERL5-PORTERS/
     http://www.hut.fi/~jhi/perl5-porters.html
     http://www.rosat.mpe-garching.mpg.de/mailing-lists/
 
 Tcl/Tk Specific Documentation
 +++++++++++++++++++++++++++++
 
 The two Tcl/Tk books by Ousterhout and Welch are very good starting points
 (you must however, translate the tcl-isms to perl in the sample scripts): 
 
  Tcl and the Tk Toolkit
  John K. Ousterhout
  Copyright (c) 1994 Addison-Wesley Publishing Company
  ISBN 0-201-63337-X (alk. paper)
  LOC QA76.73.T44097 1994; 005.13'3--dc20
 
  Practical Programming in Tcl and Tk
  Brent Welch
  Copyright (c) 1995 Prentice Hall
  ISBN 0-13-182007-9 
 
 Within the tclsh or wish shells your manpath includes the tcl/tk man pages
 (which may not be in your login MANPATH). Thus from the % prompt within
 either shell type commands like: 
 
     % man -k Tk
 
 The Tcl/Tk Reference Guide is also a source of useful information. Although
 it's Tcl specific most perl/Tk commands can be, more or less, easily derived
 from it. [Note that in perl/Tk the names of some functions and some
 configuration options have changed slightly from their Tcl/Tk counterparts.
 With recent versions of perl/Tk a great many functions start with an upper
 case letter and continue with all lower case letters (e.g. there is a perl/Tk 
 Entry widget but no entry widget), and many configuration options are all
 lower case (e.g. there is a perl/Tk highlightthickness option but no 
 highlightThickness option).] You may fetch the Tcl/Tk Reference Guide
 (may require LaTeX for installation) from: 
 
   ftp://ftp.slac.stanford.edu/software/TkMail/tkref-4.0.1.tar.gz 134.79.18.30
   ftp://ftp.aud.alcatel.com/tcl/docs/tkref-4.0.1.tar.gz          198.64.191.10
 
 There are a number of other Tcl/Tk resources on the internet including: 
 
 Newsgroups
     comp.lang.tcl
     comp.lang.tcl.announce
     comp.infosystems.www.authoring.cgi
     comp.answers
     news.answers
 FAQ-Archive (ftp) [Note: Tcl FAQ may be many files, Tk FAQ is one file]
     ftp://ftp.aud.alcatel.com/tcl/docs/                          198.64.191.10
     ftp://rtfm.mit.edu/pub/usenet/news.answers/tcl-faq
     ftp://rtfm.mit.edu/pub/usenet/news.answers/tcl-faq/tk
 WWW-FAQ for Tcl/Tk
     http://www.teraform.com/%7Elvirden/tcl-faq/
     http://www.smartpages.com/faqs/tcl-faq/top.html
     http://www.smartpages.com/bngfaqs/comp/lang/tcl/top.html
     http://www.cis.ohio-state.edu/hypertext/faq/usenet/tcl-faq/top.html
   http://www.cis.ohio-state.edu/hypertext/faq/bngusenet/comp/lang/tcl/top.html
     http://www.sco.com/Technology/tcl/Tcl.html
 World Wide Web - Tcl/Tk info sites
   Canada
     http://web.cs.ualberta.ca/~wade/Auto/Tcl.html
   UK
     http://http2.brunel.ac.uk:8080/~csstddm/TCL2/TCL2.html
     http://www.cis.rl.ac.uk/proj/TclTk/
   USA
     http://www.yahoo.com/Computers_and_Internet/Languages/Tcl_Tk/index.html
     http://www.sunlabs.com/research/tcl/docs.html
     http://www.sunlabs.com/research/tcl/4.0.html
     http://www.sco.com/Technology/tcl/Tcl.html
     http://www.neosoft.com/tcl/
     http://www.elf.org/tcltk-man-html/contents.html
 Tcl/Tk - miscellaneous extensions
     ftp://ftp.cme.nist.gov/pub/expect/
     http://www.cs.hut.fi/~kjk/porttk.html
     http://www.cis.upenn.edu/~ioi/tix/tix.html
     http://www.ece.cmu.edu/afs/ece/usr/svoboda/www/th/homepage.html
     http://www.tcltk.com/ [incr Tcl]
     http://www.neosoft.com/tcl/TclX.html
     http://www.eolas.com/eolas/webrouse/tcl.htm [WebWish]
     http://www.se.cuhk.hk/~hkng2/big5tk/big5tk.html
     http://www.cs.uoregon.edu/~jhobbs/work/ [BLT etc.]
 
 X Documentation
 +++++++++++++++
 
 Tk certainly makes the generation of GUI code a lot easier than hard coding
 things in traditional compiled languages such as C, C++, or Lisp. Nevertheless
 there is a very large body of X documentation out there that will assist all
 widget and GUI builders with issues of design, implementation, etc. Hence it is
 good practice to be informed of the general design goals of X itself as well as
 the other toolkits that have been built on top of X. 
 
 There are a number of X resources on the internet including: 
 
 Newsgroups
     comp.windows.x
     comp.windows.x.announce
     comp.windows.x.apps
 X FAQs:
     ftp://ftp.x.org/contrib/faqs/
 X FAQ on the World Wide Web:
     http://www.x.org/ftp/contrib/faqs/x-faq-multipart/x-faq-1
     http://www.x.org/ftp/contrib/faqs/x-faq-multipart/x-faq-2
     http://www.x.org/ftp/contrib/faqs/x-faq-multipart/x-faq-3
     http://www.x.org/ftp/contrib/faqs/x-faq-multipart/x-faq-4
     http://www.x.org/ftp/contrib/faqs/x-faq-multipart/x-faq-5
     http://www.x.org/ftp/contrib/faqs/x-faq-multipart/x-faq-6
     http://www.x.org/ftp/contrib/faqs/x-faq-multipart/x-faq-7
 X Window System book info on the Web:
     http://www.x.org/ftp/contrib/docs/Xbibliography.OReilly
     http://www.ora.com/catalog/v1/
     http://www.ora.com/catalog/v2/
     http://www.ora.com/catalog/v3/
     http://www.ora.com/catalog/v4/
     http://www.ora.com/catalog/v5/
     http://www.ora.com/catalog/v6a/
     http://www.ora.com/catalog/v6b/
     http://www.ora.com/catalog/v6c/
     http://www.ora.com/catalog/r6/noframes.html
     http://www.ora.com/oracom/prog/flanart.html
 World Wide Web - X Window System info sites
     http://www.x.org/
     http://www.x.org/consortium/GettingX.html
     http://www.x.org/consortium/x_info.html
     http://www.x.org/consortium/R6.1doc/man/X11/
     http://www.wolfram.com/~cwikla/widget/
     http://www.zeta.org.au/~rosko/pigui.htm
     http://www.rahul.net/kenton/xsites.html
     http://www.unx.com/DD/txaCurrent.shtml
 
 ______________________________________________________________________
 
 
 
 8. How do I write scripts in perl/Tk? 
 
 Start your script as you would any perl script (e.g. #!/usr/bin/perl, 
 #!/usr/local/bin/perl, #!/opt/bin/perl, [built static? then 
 #!/usr/bin/tkperl], whatever, see the perlrun(1) man page for more
 information).
 Throwing the -w warning switch is recommended.
 The use of the statement use strict; is recommended.
 Use of the statement use Tk; is required.
 
 A simple "Hello World!" widget script could be written as follows: 
 
     #!/usr/local/bin/perl -w
 
     use strict;
     use Tk;
 
     my $main = new MainWindow;
     $main->Label(-text => 'Hello World!'
                  )->pack;
     $main->Button(-text => 'Quit',
                   -command => sub{exit}
                   )->pack;
     MainLoop;
 
 The MainLoop; statement is the main widget event handler loop and is
 usually found in perl/Tk scripts (usually near the end of the main procedure
 after the widgets have been declared and packed). MainLoop; is actually a
 function call and you may see it written as MainLoop();, &Tk::MainLoop;, 
 &Tk::MainLoop();, etc. 
 
 Note the use of the -> infix dereference operator. Most things in calls to
 perl/Tk routines are passed by reference. 
 
 Note also the use of the => operator which is simply a synonym for the comma
 operator (well it is a bit more than that :-). In other words, the arguments that
 get passed to Label and Button in the above example are good old perl 
 associative arrays (perl 5 people prefer to call them "hashes" however).
 Indeed, we might have written the above as: 
 
     #!/usr/local/bin/perl -w
 
     use strict;
     use Tk;
 
     my $main = new MainWindow;
     $main->Label(-text , 'Hello World!'
                  )->pack;
     $main->Button(-text , 'Quit',
                   -command , sub{exit}
                   )->pack;
     MainLoop;
 
 Or even as: 
 
     #!/usr/local/bin/perl -w
     use strict;
     use Tk;
     my $main = new MainWindow;
 
     my %hello = ('-text','Hello World!');
     my %quit_com = ('-text' => 'Quit', '-command' => sub{exit});
 
     $main->Label(%hello)->pack;
     $main->Button(%quit_com)->pack;
     MainLoop;
 
 Note however, that the use of the => in the first method of writing this script
 makes it look more "Tcl-ish" :-). 
 
 Lastly, we note the extensive use of the my function in most perl/Tk programs.
 my is roughly equivalent to local in Perl 4 - but is purported to be "faster and
 safer" as well as much more strictly local in scope. See perlfunc(1)
 manpage for more information on my. 
 
 Other examples of code may be found in the perl5/Tk/demos/ directory
 and in perl5/Tk/demos/widget_lib/. 
 
 (A variant on this scipt called hello is available in the file 
 perl5/Tk/demos/hello in your own pTk distribution. Also, Source code
 for this and other examples from UserGuide.pod may be found at 
 http://w4.lns.cornell.edu/~pvhp/ptk/pod/. To load code from the web save as a
 local filename, edit the first line to point to your perl interpreter, then: chmod
 u+x filename, then execute: filename.) 
 
 ______________________________________________________________________
 
 
 
 9. What widget types are available under perl/Tk? 
 
 The following Tk widget primitives are available under perl/Tk: 
 
  o Button 
  o Canvas 
  o Checkbutton 
  o Entry 
  o Frame 
  o Label 
  o Listbox 
  o Menu 
  o Menubutton 
  o Message 
  o Radiobutton 
  o Scale 
  o Scrollbar 
  o Text 
  o Toplevel 
 
 The following are Tix widget primitives available under perl/Tk: 
 
  o HList 
  o InputOnly 
 
 There are (a lot of) other [compound|composite|constructs] available too. You
 can also synthesize new widgets out of these primitives using perl5's
 object-oriented multiple inheritance features. You can even build entirely new
 widget primitives from raw C (XS) code then use and re-use that. (Perl 5 is
 extremely configurable.) 
 
 A good introduction to the primitives and how they may be used in
 conjunction with each other may be found in the widget demo script. Note
 that all the widget demos have a "Show Code" button. To help figure out what
 is happening in the script you may, when the window appears, edit the text and
 instrument the code with print statements and then simply press "Rerun
 Demo". Another place to see examples of the primitives (on the web) is at the
 image supplement to this FAQ at the following URL: 
 
     http://w4.lns.cornell.edu/~pvhp/ptk/ptkIMG.html
 
 ______________________________________________________________________
 
 
 
 10. How do I get widget X to do Y ? 
 
 There are a number of tasks that can be accomplished with perl/Tk widgets,
 configurations, and bindings (a few that can't and a few that require specific
 tricks). Beginners are encouraged to work through the examples in 
 UserGuide.pod. Some examples from UserGuide.pod are addressed in
 this document among those that follow. 
 
 Basically a widget can be "created" by simply calling the sub of the same name:
 
     my $main = new MainWindow;
 
 will set aside the necessary system memory etc. for a new MainWindow widget
 (it does not appear until after the MainLoop; call). The object "created" is
 then callable via the variable $main. So, for example, if you wanted a Button
 in your MainWindow, then this: 
 
     $main->Button();
 
 would be a very basic example of a widget command. If you wanted to later call
 this button widget you would need a "widget tag or ID" to "get a handle on it".
 Instead of the above call try something like: 
 
     my $button = $main->Button();
 
 The variable $button is how you refer to the Button widget in subsequent
 calls, such as when we call the pack routine: 
 
     $button -> pack;
 
 A complete script that incorporates these ideas to make a very plain button
 would look like: 
 
     #!/usr/bin/perl -w
     use Tk;
     use strict;
     my $main = new MainWindow;
     my $button = $main -> Button();
     $button -> pack;
     MainLoop; 
 
 But who wants such a plain looking button? You can provide a number of
 different widget configurations via calls to the configure routine as in: 
 
     #!/usr/bin/perl -w
     use Tk;
     use strict;
     my $main = new MainWindow;
     my $button = $main->Button();
     $button -> configure(-text => 'Press me!');
     $button -> pack;
     MainLoop; 
 
 The Perl motto is "there is more than one way to do it." - perl/Tk remains
 quite true to this motto as well. Note that the above script could have been
 written quite succinctly without the use of either the $main or $button
 variables as: 
 
     #!/usr/bin/perl -w
     use Tk;
     use strict;
     new MainWindow -> Button(-text => 'Press me!') -> pack;
     MainLoop; 
 
 But if you want your widgets to actually do things then you must set up
 callback procedures as discussed later... 
 
 Do not overlook the - sign in front of some options (like -text in the above
 example) Another commonly overlooked problem is that elements in a hash
 are supposed to be strings hence a configuration option like -length +> 5,
 really ought to be specified as either '-length' +> 5, or "-length" +>
 5, etc., rather than perl's builtin length() function. 
 
 ______________________________________________________________________
 
 
 
 10.1. How do I get a Button to call a Perl subroutine? 
 
 You may specify the -command option in the call to create & pack the button
 as in: 
 
     $main->Button(-text => 'Print',
                    -command => sub{do_print($filename, $font)}
                    )->pack;
 
 Where sub do_print { } is a subroutine that handles two arguments and
 is declared elsewhere in the script. A full script example of the use of the
 above code is presented in the second example(s) in UserGuide.pod 
 
 (Full source code for this and other examples from UserGuide.pod may be
 found at http://w4.lns.cornell.edu/~pvhp/ptk/pod/. To load code from the web
 save as a local file say ex1.pl, edit the first line to point to your perl
 interpreter, then change permission: %chmod u+x ex1.pl, then execute the
 script: %ex1.pl.) 
 
 The above method is called the "anonymous subroutine (closure)" method.
 As discussed in Callback.pod one might have re-written that statement to
 use the "reference to a sub" method thusly: 
 
     $main->Button(-text => 'Print',
                    -command => [ \&do_print , $filename, $font ]
                    )->pack;
 
 Note the backslash in front of \&do_print. This causes perl to generate a
 reference to sub do_print rather than call it. (thanks Jim Stern :-) 
 
 ______________________________________________________________________
 
 
 
 10.2. How do I get a Button to actively change under my mouse pointer? 
 
 You should specify both an '-image' and an '-activeimage'
 configuration option either when calling the ->Button() method or in a
 later separate call to the ->configure() method. 
 
 Here is an example excerpted from the basic_demo script that comes with
 the Tk kit: 
 
     #!/usr/local/bin/perl -w
     
     use Tk;
     
     $main = MainWindow->new;
     
     $QPBFile  = "demos/images/QuitPB.xpm";
     $QPBaFile = "demos/images/QuitPBa.xpm";
     
     $QuitPB  = $main->Pixmap('-file' => Tk->findINC("$QPBFile"));
     $QuitPBa = $main->Pixmap('-file' => Tk->findINC("$QPBaFile"));
     
     my $but  = $main->Button('-image'       => $QuitPB,
                              '-activeimage' => $QuitPBa,
                              '-command'     => sub { $main->destroy }
                             ) -> pack;
     
     MainLoop;
     
     __END__
     
 
 ______________________________________________________________________
 
 
 
 10.3. How do I arrange the layout of my widgets? 
 
 To control the layout and appearance of widgets in a window one makes use of
 a geometry manager, as well as -padding, -fill, -expand, and -anchor options
 of individual widgets. 
 
 A geometry manager is any Tk procedure for controlling the arrangement of
 widgets in your application window. The predominant geometry manager used
 in both Tcl/Tk and perl/Tk is pack also known informally as the "packer"
 (other geometry managers are the "placer" and the canvas widget itself but
 are much less popular. There is also Nick Ing-Simmon's Table widget
 [discussed in a later question] and BLT_Table [which made it's way into
 perl/Tk thanks to Guy Decoux - but is also discussed in a later question]. So
 far tixForm is for Tcl/Tk only, but a perl/Tk version of Tix is in the works.
 You can invoke pack at the time of widget creation via calls like: 
 
     $widget->pack;
 
 where widget can be any of the perl/Tk widget primitives. Widget option lists
 are usually passed as an associative array (hash) in parentheses thusly: 
 
     $widget(-option0 => value0,-option1 => value1)->pack;
 
 pack is often used in conjunction with the frame container widget to arrange
 your widgets much like a hiearchically arranged set of window panes
 (ultimately in a rectangular "tiling" fashion of sorts). An example of this
 would be: 
 
     my $top2 = $main->Toplevel;
     my $frame = $top2->Frame;
     $frame->pack;
     $frame->Label(-text => 'Left2')->pack(-side => 'left');
     $frame->Label(-text => 'Right2')->pack(-side => 'right');
     $top2->Label(-text => 'Bottom2')->pack(-side => 'bottom');
     MainLoop;
 
 Note that pack itself is given parameters in this example. The default
 behavior for pack is equivalent to specifying -side => 'top' which can be
 overridden as in the above example. 
 
 (Full source code for this and other examples from UserGuide.pod may be
 found at http://w4.lns.cornell.edu/~pvhp/ptk/pod/. To load code from the web
 save as a local file say ex2.pl, edit the first line to point to your perl
 interpreter, change permission using: chmod u+x ex2.pl, then type the
 name of your script: ex2.pl.) 
 
 One of the more helpful options to pass to pack when trying to get a given
 widget layout "just right" is through padding: either -padx or -pady. The
 details of the use of pad depend on which specific widget you are trying to 
 pack. In fact you can often add the -pad in the call to create the widget rather
 than in the call to pack. 
 
 There is also the -anchor configuration option for widgets. A good
 introduction to the 9 possible -anchor (and -overanchor) values is given
 by the popup demo in your perl/Tk build directory. 
 
 When setting a widget within a frame next to another widget one may wish to
 make use of the -fill => 'style' (where style = none | x | y | both)
 options of either pack or the widget itself. A typical situation where this is
 used is in setting up the Scrollbar next to a Canvas or Text widget. 
 
 Another aspect to consider when laying out your widgets is their behavior
 under resize operations (grabbing a part of the window frame and making it
 bigger or smaller - details depend on your window manager). This may be
 controlled by the -expand option of either pack or the widget itself. 
 
 ______________________________________________________________________
 
 
 
 10.4. How do I get a Popup to popup? 
 
 For things like a simple "are you sure?" dialog box you might want to take a
 look at Dialog.pm which is discussed in a later question within this FAQ
 [16.1]. 
 
 If you don't wish to require Tk::Dialog, you need something more complicated,
 or you simply want to create your own independent window with widgets; you
 must first setup a Toplevel in perl/Tk. The fourth example in UserGuide.pod
 gives a simple example of how to call Toplevel. Quoting from that script: 
 
     my $main = new MainWindow;
     fill_window($main, 'Main');
     my $top1 = $main->Toplevel;
 
 Where sub fill_window is declared after the call to MainLoop;. When
 running that script take careful note of which window pops up first, which
 window has grabbed the active attention of your input device(s), and which
 widget within the active window has the keyboard/mouse focus when all three
 windows are open. 
 
 The use of Toplevels brings up the issue of grab - or which independent
 window is presently "active" and which are activatable. To make a Toplevel
 window active call grab thusly: 
 
     $Top_widget->grab(grab_option);
 
 where $Top_widget identifies the desired Toplevel (it would be either 
 $top1 or $top2 in the sample script referred to above). grab_option
 could be -global - but this is discouraged as a sign of "desparate
 programming style". To give a Toplevel "local grab" you may simply say: 
 
     $Top_widget->grab;
 
 That is, without an argument. 
 
 The use of Toplevels may also bring up the issue of focus - or which window
 - even which widget within a window - is presently "hot". You may call 
 focus on an entire Toplevel: 
 
     $Top_widget->focus;
 
 However, focus is most often used with individual widgets rather than a
 whole Toplevel. 
 
 To de-iconify a widget there is in fact a Popup function that may be called
 thusly: 
 
     $Top_widget->Popup();
 
 ______________________________________________________________________
 
 
 
 10.5. How do I bind keyboard keys? 
 
 There are many default key bindings built in to the widgets of perl/Tk. Making
 proper use of them often involves setting up the right callback. (You may wish
 to consult the examples in BindTable.pod for help with this subject.) 
 
 The basic idea is: 
 
     $widget -> bind('<keyname>' => action);
 
 Where $widget is the tag or ID of the widget for which the bindings are to
 hold (note for global bindings you have to bind to <All>, for semi-global
 bindings you need to bind to all the relevant widgets in your application), '<
 keyname>' can be things like: 
 
     <Key> or <KeyPress> or <Any-KeyPress>
     <KeyRelease>
     <Button> or <ButtonPress>
     <ButtonRelease>
     <Button-1> or <B1> 
     <Double-1>
     <Enter>
     <Leave>
     <Motion>
 
 To figure out what names perl/Tk uses for such <bindings> use the
 "binder-finder" on a widget's .pm file. For example, you could find bindings
 hidden inside of Button.pm by typing this at your shell prompt: 
 
     perl -ne 'print if s/.*(<[^>]*>).*/$1/g;' Button.pm
 
 while in the directory where Button.pm is located (and if you are not there
 then simply specify the /path/to/Button.pm). Note that due to
 inheritance (e.g.the type of script bindings that are being discussed here) what
 the binder-finder turns up may not be the last word on a given widget's
 behaviour. This may be especially true for a widget inside of a
 compound/composite widget. Note also that the binder-finder will turn up
 things like <FILEHANDLES> as well as honest <Bindings>. Discrimination
 in its use is called for (and while your at it you could have just as easily used an
 editor and actually examined the code directly now couldn't you?). 
 
 To get an idea of what the code is for a key that you are interested in try
 running the xlib_demo that comes in your perl/Tk build directory. Hold your
 mouse pointer over the window that appears and simply type the key that you
 are interested in. The code should appear in the window. If you do not have
 perl/Tk up and running yet try "xmodmap -pk" or look directly at the 
 /usr/include/X11/keysymdef.h file where keysym names are given with
 an XK_ pre-pended. Do not try things like the Tcl/Tk %k symbols in perl
 scripts. %Ks will be mis-interpreted as non-existant perl hashes. Instead look
 at the Xevent function. 
 
 Ali Corbin <corbin@adsw.fteil.ca.boeing.com> recently posted a great little
 script for determining keyboard key bindings on a MainWindow: 
 
     #!/usr/local/bin/perl -w
     use Tk;
     $top = MainWindow->new();
     $frame = $top->Frame( -height => '6c', -width => '6c',
                             -background => 'black', -cursor => 'gobbler' );
     $frame->pack;
     $top->bind( '<Any-KeyPress>' => sub
     {
         my($c) = @_;
         my $e = $c->XEvent;
         my( $x, $y, $W, $K, $A ) = ( $e->x, $e->y, $e->K, $e->W, $e->A );
 
         print "A key was pressed:\n";
         print "  x = $x\n";
         print "  y = $y\n";
         print "  W = $K\n";
         print "  K = $W\n";
         print "  A = $A\n";
     } );
     MainLoop();
 
 To bind the action of one widget to that of another try taking a look at the
 .pm file for the widget of interest - is there a binding function already
 defined? If so you may use it. An example would be the use of "Up" & "Down" 
 Buttons for a Listbox: one could bind the Buttons to call 
 Tk::Listbox::UpDown, however, Guy Decoux describes a much more
 clever way to use the <Up> and <Down> already defined in Listbox.pm (this
 does not work with Tk-b9.01): 
 
     #!/usr/local/bin/perl
     use Tk;
     $top = MainWindow->new;
     $lb = $top->Listbox(-height => 10);
     for($i=0; $i < 120; $i++) {
       $lb->insert('end', $i);
     }
     $f = $top->Frame;
     $up = $f->Button(
            -text => "Up",
            -command => [ $lb->bind(ref $lb, '<Up>'), $lb]
            );
     $down = $f->Button(
              -text => "Down",
              -command =>sub {&{$lb->bind(ref $lb, '<Down>')}($lb)}
              );
     $up->pack(-side => 'left');
     $down->pack;
     $f->pack;
     $lb->pack;
     MainLoop;
 
 ______________________________________________________________________
 
 
 
 10.6. How do I add bindings? 
 
 On Fri, 15 Sep 95 10:30:56 BST Nick Ing-Simmons
 <Nick.Ing-Simmons@tiuk.ti.com> writes: 
 
 
 Re: Multiple binds to a single widget?
 **************************************
 
 On Thu, 14 Sep 1995 14:57:54 -0400
 Alain St <astdenis@cmc.doe.CA> writes:
 !In the tcl/tk doc I have, they say that prepending the script 
 !with '+' appends the new binding to the current one.
 !
 !How do I do that in perlTk? 
 !
 
  You cannot do that that way (yet?) - one issue is what it would mean to
  prepend '+' to a perl/Tk callback : 
 
     $widget->bind('<A>','+',[\&subname,$arg]); 
     # did not look right to me
 
  Other issue is that I would need to manage a list-of-callbacks in glue
  code. 
 
  Bind your new command to a new tag: 
 
     $widget->bind('Extra',....);
 
  And add Extra to the widgets bindtags: 
 
     $widget->bindtags([ref($widget),$widget,'Extra',
                         $widget->toplevel,'all']);
 
 ______________________________________________________________________
 
 
 
 10.7. How do I bind the action of a slider (sic) to ... ? 
 
 Technically speaking they are called Scrollbars (not sliders) and one must 
 configure the action of the desired widget to call the Scrollbars (i.e. bind
 is not involved here) 
 
 A common task using Scrollbars is to configure things like Canvas, 
 Listbox, or a Text widgets to be updated (change appearance) when the
 slider of the acompanying Scrollbar is moved by the user. 
 
 As an example consider the code that sets up a twelve element Listbox and
 an accompanying vertical Scrollbar: 
 
     my $main = new MainWindow;
     my $box = $main->Listbox(-relief => 'sunken', 
                              -width => -1, # Shrink to fit
                              -height => 5,
                              -setgrid => 'yes');
     my @items = qw(One Two Three Four Five Six Seven
                    Eight Nine Ten Eleven Twelve);
     foreach (@items) {
        $box->insert('end', $_);
     }
     my $scroll = $main->Scrollbar(-command => ['yview', $box]);
 
 So far so good. But merely setting them up does not mean that the Listbox
 even knows that the Scrollbar is lying next to it. Note that the scalar
 variable $scroll is how we refer to the Scrollbar, thus, hooking the $box
 up to handle $scroll events is a matter of configuration: 
 
  
     $box->configure(-yscrollcommand => ['set', $scroll]);
 
 A complete script that makes use of this code (and adds the necessary calls to 
 pack and MainLoop;) is given as the fifth example in UserGuide.pod (and
 may be found at http://w4.lns.cornell.edu/~pvhp/ptk/pod/.) 
 
 There was an old Perl/Tk tendency to have a bunch of ScrlFoo widgets (such
 as ScrlListbox). The use of such widgets is now deprecated in favor of a
 new Scrolled class, as in: 
 
     $w = $patent->Scrolled('Text',...);
 
 The widgets that can be ->Scrolled() include: 
 
  o Canvas (::Axis) 
  o Entry 
  o Ghostview 
  o HList 
  o HTML (::Web) 
  o Listbox 
  o Pod 
  o Text (::ROText) (::TextUndo) 
  o Tiler 
 
 ______________________________________________________________________
 
 
 
 10.8. How do I configure a Scrollbar to scroll multiple widgets? 
 
 Note that the widget type that you wish to scroll can be important as a scroll
 "unit" on a Text or Listbox may be a character (several pixels - depending
 on font) whereas it would be an X "units" on a Canvas (could be pixel - but
 you may also specify other units). 
 
 A concrete answer for scrolling 3 Listboxes comes courtesy of Frederick L.
 Wagner <derf@ti.com>: 
 
  From a working example of multi-xscrolling: 
 
     sub multiscrollx
     {  # multiscrollx
      my ($sb,$wigs,@args) = @ARG;
      my $w;
      foreach $w (@$wigs)
      {
        $w->xview(@args);
      }
     }  # multiscrollx
  
     # %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
       $sh->configure( -command => [ \&multiscrollx, $sh,
                          [$scratchrule,$ruleheader,$ruletable]]);
       $ruletable->configure(  -xscrollcommand => [ 'set', $sh]);
       $ruleheader->configure( -xscrollcommand => [ 'set', $sh]);
       $scratchrule->configure(-xscrollcommand => [ 'set', $sh]);
 
  In this case,
  $sh is a horizontal Scrollbar,
  $ruletable and $scratchrule are Tables
  $ruleheader is an Entry
 
  However, this approach is good for any widget with X-scrolling
  capability, I think. So the Y counterpart should be: 
 
     sub multiscrolly
     {  # multiscrolly
      my ($sb,$wigs,@args) = @ARG;
      my $w;
      foreach $w (@$wigs)
      {
        $w->yview(@args);
      }
     }  # multiscrolly
  
     # %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
       $sv->configure( -command => [ \&multiscrolly, $sv,
                                     [$l1,$l2,$l3]]);
       $l1->configure( -yscrollcommand => [ 'set', $sv]);
       $l2->configure( -yscrollcommand => [ 'set', $sv]);
       $l3->configure( -yscrollcommand => [ 'set', $sv]);
 
  Hope that helps. 
 
 Greg VanSickle <vansickl@bnr.ca> points out that this little script snippet
 does not provide for the binding of '<Button-2<' that he is accustomed to.
 He wrote a package called DSListbox to address this binding issue. 
 
 Conversely, Jong Park asked how to setup multiple Scrollbars to scroll the
 same widget. Nick Ing-Simmon's reply makes use of an anonymous sub and
 can be summed up in a little script that scrolls a Text widget (to see the
 scrolling in action type more than 20 lines of text into the widget):
 
     #!/usr/local/bin/perl -w
     
     use Tk;
     my $mw = MainWindow->new();
     
     my $s1 = $mw->Scrollbar(-orient => 'vertical');
     my $s2 = $mw->Scrollbar(-orient => 'vertical');
     
     $s1->pack(-side => 'left', -fill => 'y');
     my $t = $mw->Text(
         -yscrollcommand =>  sub{$s1->set(@_), $s2->set(@_)},
         -wrap           => 'word',
         -width          => 70,
         -height         => 20, 
         -font           => $font,
         -setgrid        => 1,
     )->pack(-side => 'left');
     $s2->pack(-side => 'right', -fill => 'y');
     $s1->configure(-command => [$t => 'yview']);
     $s2->configure(-command => [$t => 'yview']);
     
     MainLoop;
     
     __END__
 
 ______________________________________________________________________
 
 
 
 10.9. How do I display a bitmap? 
 
 You can display X bitmaps on your widgets with the -bitmap configuration
 option. Typically -bitmaps are configured into Label, Frame, Button, etc.
 widgets (Canvas widgets are another story however see question [11.1] below).
 In order to emphasize the bitmap option itself let us assume we were
 specifying a bitmap for a Label with a call like: 
 
     $main->Label(-bitmap => 'bitmap-name')->pack;
 
 Where bitmap-name could be any of the built in Tk bitmaps: error, 
 gray25, gray50, hourglass, info, question, questhead, warning (see
 the widget demo for a full list). 
 
 In order to use some of the bitmaps in the perl5/Tk/demos/images/
 directory you would specify a fuller path name like: 
 
     $main->Label(-bitmap => "\@$tk_library/demos/images/face")->pack;
 
 Note the escaped "\@" on the directory specification (as well as the use of the 
 $tk_library variable imported by use Tk;). If you wanted to specify a file
 called foobar.xbm in the directory where you were running the script then
 either: 
 
     $main->Label(-bitmap => '@foobar.xbm')->pack;
 #or
     $main->Label(-bitmap => "\@foobar.xbm")->pack;
 
 should work just fine. In another directory however that would be a problem.
 So something like: 
 
     $main->Label(-bitmap => "\@$ENV{'HOME'}/img/foobar.xbm")->pack;
 
 will help someone who has an img/foobar.xbm file in their $HOME
 directory. If you don't mind the non-portability then hard-wiring in the full
 path name will help as well. (Or if you have write access then put your files in 
 Tk/demos/images/ e.g.) 
 
 ______________________________________________________________________
 
 
 
 10.10. How do I display an image? 
 
 You will want to get a "Photo" handle on the file as in the following example
 where 'imggif' is the Photo handle for a gif file that is distributed with
 perl/Tk: 
 
     #!/usr/bin/perl -w
     use strict;
     use Tk;
     my $main = new MainWindow;
 
     $main ->Label(-text => 'Main')->pack;
     $main -> Photo('imggif', 
                    -file => "$Tk::tk_library/demos/images/earth.gif");
     my $l = $main->Label('-image' => 'imggif')->pack;
 
     $main->Button(-text => 'close',
                   -command => sub{destroy $main}
                   )->pack(-side => 'left');
     $main->Button(-text => 'exit',
                   -command => [sub{exit}]
                   )->pack(-side => 'right');
     MainLoop;
 
 (Canvas widgets are another story however see question a later question
 within this FAQ). 
 
 ______________________________________________________________________
 
 
 
 10.11. What Image types are available? 
 
 In addition to the Tk builtin bitmaps there is support for reading images
 from files in formats such as: X11 Bitmaps (.xbm), X Pixmaps (.xpm), and
 Graphics Inline Format (.gif). See the CrtPhImgFmt man page for more info
 (if you have Tk 4.X installed). (In order to support other formats you might
 also consider running through a netpbm filter.) 
 
 For perl generation of images see the question (later in this FAQ) on graphics
 modules. 
 
 ______________________________________________________________________
 
 
 
 10.12. Is there any way to have more than one Listbox contain a selection? 
 
 To allow more than one Listbox to contain a "selection", (or at least a
 highlighted item - which need not be the actual selection) specify the
 configuration option: 
 
     -exportselection => 0
 
 which will dis-associate Listbox's selection from X selection (only one
 window can have X selection at a time). 
 
 Here is a rather simple script that illustrates what happens when only one 
 Listbox has -exportselection => 0 specified: 
 
     #!/usr/bin/perl -w
     
     use Tk;
     
     my $main = MainWindow->new;
     
     my @fruits = ('Apple','Banana','Cherry','Date','Elderberry','Fig');
     my @nuts   = qw(Almond Brazil Chestnut Doughnut Elmnut Filbert);
     
     my $fruit_list = $main->Listbox();
     for (@fruits) { $fruit_list -> insert('end',$_); }
     $fruit_list->pack();
     my $fruitprint_button = $main->Button(
                               -text => "print selection",
                               -command => sub{ printthem($fruit_list) }
                                           )->pack;
     
     my $nut_list = $main->Listbox(
                                   -selectmode => 'multiple',
                                   -exportselection => 0,
                                  )->pack;
     for (@nuts) { $nut_list -> insert('end',$_); }
     my $nutprint_button = $main->Button(
                               -text => "print selection(s)",
                               -command => sub{ printthem($nut_list) }
                                           )->pack;
     
     my $quit_button = $main->Button(-text => "quit program", 
          