====== Perlbrew at ÚFAL ======
[[http://perlbrew.pl/|Perlbrew]] is a great tool for switching different versions of perl.
I've created a new shared ÚFAL repository of Perl modules using Perlbrew as a substitute of the old [[internal:perl_repo|PERLREPO]].

Martin Popel

===== How to setup the Perlbrew environment =====
Add to your ''~/.bashrc'':

  source /net/work/projects/perlbrew/init
  eval "$(bash-complete setup)"


The second line is optional, but it enables [[https://metacpan.org/pod/Bash::Completion|Bash Completion]] for [[http://perlbrew.pl/|perlbrew]], [[https://metacpan.org/pod/App::cpanminus|cpanm]] and treex (if the respective ''Bash::Completion::Plugins::XY'' modules are installed).
Make sure you have deleted (commented out) the old setup_platform setup (''source /net/work/projects/perl_repo/admin/bin/setup_platform'') from your ''~/.bashrc''.

Also note that perlbrew (unlike ''setup_platform'') does not change your ''$PERL5LIB''. You probably add some local Perl modules to ''$PERL5LIB'' in your ''.bashrc'' (e.g. ''export PERL5LIB="/home/popel/tmt/treex/lib:$PERL5LIB"''). When you source ''.bashrc'' again, make sure you don't have duplicate paths in ''$PERL5LIB'' (e.g. ''"/home/popel/tmt/treex/lib:/home/popel/tmt/treex/lib"'') -- to prevent this add this line to the //beginning// of your ''.bashrc'':

  export PERL5LIB=""

To finish the Perlbrew environment setup, run (in a new bash session)

  perlbrew switch perl-5.18.2


===== How to use Perlbrew =====
  perlbrew list               # Which perl versions are installed?
  perlbrew use perl-5.18.2    # use one of these perls for the current shell
  perlbrew switch perl-5.18.2 # use this perl version permanently
  perlbrew off                # return to the system installation of perl

You can read [[https://metacpan.org/pod/distribution/App-perlbrew/bin/perlbrew|the full Perlbrew documentation]] (but it should not be needed).
Note that there is a separate Perlbrew environment for each architecture (32bit vs. 64bit machines) at ÚFAL, so if you switch to perl-5.18.2 on 32bit machines, you need to do it again on 64bit machines if you want to use perl-5.18.2 on both.

===== How to install missing modules from CPAN =====
If you see an error message such as ''Can't locate String/Diff.pm in @INC'', it means the module String::Diff is not installed.
You can install it into the ÚFAL perlbrew repository, so it will be available also for others.
If you are used to ''cpan'' tool, you can use it, but I recommend using ''cpanm'', which is faster.

  cpanm String::Diff

This installs String::Diff for the current architecture (32bit vs. 64bit) and the currently selected Perl version.
If you want to install it for all Perl versions and the current architecture, use this trick

  perlbrew exec cpanm String::Diff

If you did this on your machine (32bit), you still need to ssh to some 64bit machine (e.g. ''sol1'') and install it there, if you want the module to be available from the LRC cluster.

Useful switches for ''cpanm'' are ''-n'' (notest) and ''-v'' (verbose). See ''cpanm -h'' for more (e.g. installing from github, installing to your own local-lib).
You can install the modules also manually (''perl Build.PL && ./Build && ./Build test && ./Build install''). There is no need to set ''prefix'' nor ''install_base'', because you (everyone from the group ''ufal'') have write access to the shared ÚFAL perlbrew repository.

===== How to install new Perl version =====

  perlbrew available                    # list perl versions available for download
  perlbrew install perl-5.16.3          # install this older version
  perlbrew install -Dcc=gcc --thread --multi -j 4 perl-5.20.0 # on Ubuntu10.04 64bit, I had to use -Dcc=gcc
  
(Note that when trying to compile threaded perl on cluster machines I had to ignore [[http://www.nntp.perl.org/group/perl.perl5.porters/2014/05/msg214911.html|this]] error.)

Now, we probably want to install all modules from the current perl to the new perl:

  perlbrew list-modules > list.txt
  perlbrew switch perl-5.16.3
  #cpanm -n Tk # Tk tests are long and pop up many windows
  # but to get support for XFT anti-aliased fonts on newer Ubuntu, let's do:
  cpanm -n -v git://github.com/eserte/perl-tk.git
  cpanm -n PerlIO::Util # this module has (reported) errors
  cpanm < list.txt

==== Tricky modules ====

=== Tk ===

When compiled without XFT support, the fonts are ugly and some fonts (Cyrillic, Arabic,...) are completely unreadable.
First, you need some packages (which should be installed by default, so the following command is not needed)

  sudo apt-get install libx11-dev libfreetype6-dev libxft-dev libpng-dev libz-dev

However, new Debian and Ubuntu (14.04) changed location of some files (freetype.h, libXft.so,...) which is fixed only in the github repository of Tk (it is not on CPAN yet). Luckily, cpanm can install directly from github:

  cpanm -n -v git://github.com/eserte/perl-tk.git
  
Last time, I found some tests failing, so I add ''-n'' to skip tests (which pop up many windows for several minutes). To test Tk, run

  widget

and you should see a window with nice anti-aliased font.

=== Algorithm::SVM ===
In ''bindings.h'' after #include <assert.h> [[https://rt.cpan.org/Ticket/Display.html?id=43669|add these two lines]]:

  #include <cstdlib>
  #include <string.h>

=== Algorithm::FuzzyCmeans ===
[[https://rt.cpan.org/Ticket/Display.html?id=76248|Delete]] ''use_test_base;'' from ''Makefile.PL''.

=== ÚFAL modules unreleased on CPAN ===

  * ''Treex::External::NADA'': cd $TMT_ROOT/install/tool_installation/NADA && perl Makefile.PL && make && make install
  * ''Morce::English'': cd $TMT_ROOT/libs/packaged/Morce-English && perl Build.PL && ./Build && ./Build test && ./Build install
  * ''CzechMorpho'': cd $TMT_ROOT/libs/packaged/CzechMorpho && perl Build.PL && ./Build && ./Build test && ./Build install
  * ''Morce::Czech'': cd $TMT_ROOT/libs/packaged/Morce-Czech && perl Build.PL && ./Build && ./Build test && ./Build install
  * ''Featurama::Perc'': cd $TMT_ROOT/libs/packaged/Featurama && bash install.sh

===== How to install Perlbrew for a new architecture ===== 

  source /net/work/projects/perlbrew/init

(You probably have this in your ''~/.bashrc'', so you don't need to run it again.) This will issue some warnings because perlbrew is not installed, but it will set the variables PERLBREW_ROOT and PERLBREW_HOME, so the following installation goes to the shared directory (''/net/work/projects/perlbrew/$ARCHITECTURE''). We need to source it once again below, so ''$PERLBREW_ROOT/etc/bashrc'' is sourced after perlbrew is installed.

  wget -O - http://install.perlbrew.pl | bash
  source /net/work/projects/perlbrew/init
  perlbrew install-cpanm

That's all! Now, install some perl, as described [[perlbrew#how-to-install-new-perl-version|above]].

  perlbrew available
  perlbrew install -j 4 perl-5.18.2
  # If this fails as mentioned above, finish the installation with something like
  # cd /net/work/projects/perlbrew/Ubuntu/14.04/x86_64/build/perl-5.18.2; make install
  perlbrew switch perl-5.18.2