=head1 NAME

Template::Tools::ttree - Process entire directory trees of templates

=head1 SYNOPSIS

    ttree [options] [files]

=head1 DESCRIPTION

The F<ttree> script is used to process entire directory trees containing
template files.  The resulting output from processing each file is then 
written to a corresponding file in a destination directory.  The script
compares the modification times of source and destination files (where
they already exist) and processes only those files that have been modified.
In other words, it is the equivalent of 'make' for the Template Toolkit.

It supports a number of options which can be used to configure
behaviour, define locations and set Template Toolkit options.  The
script first reads the F<.ttreerc> configuration file in the HOME
directory, or an alternative file specified in the TTREERC environment
variable.  Then, it processes any command line arguments, including
any additional configuration files specified via the C<-f> (file)
option.

=head2 The F<.ttreerc> Configuration File

When you run F<ttree> for the first time it will ask you if you want
it to create a F<.ttreerc> file for you.  This will be created in your
home directory.

    $ ttree
    Do you want me to create a sample '.ttreerc' file for you?
    (file: /home/abw/.ttreerc)   [y/n]: y
    /home/abw/.ttreerc created.  Please edit accordingly and re-run ttree

The purpose of this file is to set any I<global> configuration options
that you want applied I<every> time F<ttree> is run.  For example, you
can use the C<ignore> and C<copy> option to provide regular expressions
that specify which files should be ignored and which should be copied 
rather than being processed as templates.  You may also want to set 
flags like C<verbose> and C<recurse> according to your preference.

A minimal F<.ttreerc>:

    # ignore these files
    ignore = \b(CVS|RCS)\b
    ignore = ^#
    ignore = ~$

    # copy these files
    copy   = \.(gif|png|jpg|pdf)$ 

    # recurse into directories
    recurse

    # provide info about what's going on
    verbose

In most cases, you'll want to create a different F<ttree> configuration 
file for each project you're working on.  The C<cfg> option allows you
to specify a directory where F<ttree> can find further configuration 
files.

    cfg = /home/abw/.ttree

The C<-f> command line option can be used to specify which configuration
file should be used.  You can specify a filename using an absolute or 
relative path:

    $ ttree -f /home/abw/web/example/etc/ttree.cfg
    $ ttree -f ./etc/ttree.cfg
    $ ttree -f ../etc/ttree.cfg

If the configuration file does not begin with C</> or C<.> or something
that looks like a MS-DOS absolute path (e.g. C<C:\\etc\\ttree.cfg>) then
F<ttree> will look for it in the directory specified by the C<cfg> option.

    $ ttree -f test1          # /home/abw/.ttree/test1

The C<cfg> option can only be used in the F<.ttreerc> file.  All the
other options can be used in the F<.ttreerc> or any other F<ttree>
configuration file.  They can all also be specified as command line
options.

Remember that F<.ttreerc> is always processed I<before> any
configuration file specified with the C<-f> option.  Certain options
like C<lib> can be used any number of times and accumulate their values.

For example, consider the following configuration files:

F</home/abw/.ttreerc>:

    cfg = /home/abw/.ttree
    lib = /usr/local/tt2/templates

F</home/abw/.ttree/myconfig>:

    lib = /home/abw/web/example/templates/lib

When F<ttree> is invoked as follows:

    $ ttree -f myconfig

the C<lib> option will be set to the following directories:

    /usr/local/tt2/templates
    /home/abw/web/example/templates/lib

Any templates located under F</usr/local/tt2/templates> will be used
in preference to those located under
F</home/abw/web/example/templates/lib>.  This may be what you want,
but then again, it might not.  For this reason, it is good practice to
keep the F<.ttreerc> as simple as possible and use different
configuration files for each F<ttree> project.

=head2 Directory Options

The C<src> option is used to define the directory containing the
source templates to be processed.  It can be provided as a command
line option or in a configuration file as shown here:

    src = /home/abw/web/example/templates/src

Each template in this directory typically corresponds to a single
web page or other document. 

The C<dest> option is used to specify the destination directory for the
generated output.

    dest = /home/abw/web/example/html

The C<lib> option is used to define one or more directories containing
additional library templates.  These templates are not documents in
their own right and typically comprise of smaller, modular components
like headers, footers and menus that are incorporated into pages templates.

    lib = /home/abw/web/example/templates/lib
    lib = /usr/local/tt2/templates

The C<lib> option can be used repeatedly to add further directories to
the search path.

A list of templates can be passed to F<ttree> as command line arguments.

    $ ttree foo.html bar.html

It looks for these templates in the C<src> directory and processes them
through the Template Toolkit, using any additional template components
from the C<lib> directories.  The generated output is then written to 
the corresponding file in the C<dest> directory.

If F<ttree> is invoked without explicitly specifying any templates
to be processed then it will process every file in the C<src> directory.
If the C<-r> (recurse) option is set then it will additionally iterate
down through sub-directories and process and other template files it finds
therein.

    $ ttree -r

If a template has been processed previously, F<ttree> will compare the
modification times of the source and destination files.  If the source
template (or one it is dependant on) has not been modified more
recently than the generated output file then F<ttree> will not process
it.  The F<-a> (all) option can be used to force F<ttree> to process
all files regardless of modification time.

    $ tree -a

Any templates explicitly named as command line argument are always
processed and the modification time checking is bypassed.

=head2 File Options

The C<ignore>, C<copy> and C<accept> options are used to specify Perl
regexen to filter file names.  Files that match any of the C<ignore>
options will not be processed.  Remaining files that match any of the
C<copy> regexen will be copied to the destination directory.  Remaining
files that then match any of the C<accept> criteria are then processed
via the Template Toolkit.  If no C<accept> parameter is specified then 
all files will be accepted for processing if not already copied or
ignored.

    # ignore these files
    ignore = \b(CVS|RCS)\b
    ignore = ^#
    ignore = ~$

    # copy these files
    copy   = \.(gif|png|jpg|pdf)$ 

    # accept only .tt2 templates
    accept = \.tt2$

The C<suffix> option is used to define mappings between the file
extensions for source templates and the generated output files.  The
following example specifies that source templates with a C<.tt2>
suffix should be output as C<.html> files:

    suffix tt2=html

Or on the command line, 

    --suffix tt2=html

You can provide any number of different suffix mappings by repeating 
this option.

=head2 Template Dependencies

The C<depend> and C<depend_file> options allow you to specify
how any given template file depends on another file or group of files. 
The C<depend> option is used to express a single dependency.

  $ ttree --depend foo=bar,baz

This command line example shows the C<--depend> option being used to
specify that the F<foo> file is dependant on the F<bar> and F<baz>
templates.  This option can be used many time on the command line:

  $ ttree --depend foo=bar,baz --depend crash=bang,wallop

or in a configuration file:

  depend foo=bar,baz
  depend crash=bang,wallop

The file appearing on the left of the C<=> is specified relative to
the C<src> or C<lib> directories.  The file(s) appearing on the right
can be specified relative to any of these directories or as absolute
file paths.

For example:

  $ ttree --depend foo=bar,/tmp/baz

To define a dependency that applies to all files, use C<*> on the 
left of the C<=>.

  $ ttree --depend *=header,footer

or in a configuration file:

  depend *=header,footer

Any templates that are defined in the C<pre_process>, C<post_process>,
C<process> or C<wrapper> options will automatically be added to the
list of global dependencies that apply to all templates.

The C<depend_file> option can be used to specify a file that contains
dependency information.  

    $ ttree --depend_file=/home/abw/web/example/etc/ttree.dep

Here is an example of a dependency file:

   # This is a comment. It is ignored.
  
   index.html: header footer menubar 
  
   header: titlebar hotlinks
  
   menubar: menuitem
  
   # spanning multiple lines with the backslash
   another.html: header footer menubar \
   sidebar searchform

Lines beginning with the C<#> character are comments and are ignored.
Blank lines are also ignored.  All other lines should provide a
filename followed by a colon and then a list of dependant files
separated by whitespace, commas or both.  Whitespace around the colon
is also optional.  Lines ending in the C<\> character are continued
onto the following line.

Files that contain spaces can be quoted. That is only necessary
for files after the colon (':'). The file before the colon may be
quoted if it contains a colon. 

As with the command line options, the C<*> character can be used
as a wildcard to specify a dependency for all templates.

    * : config,header

=head2 Template Toolkit Options

F<ttree> also provides access to the usual range of Template Toolkit
options.  For example, the C<--pre_chomp> and C<--post_chomp> F<ttree>
options correspond to the C<PRE_CHOMP> and C<POST_CHOMP> options.

Run C<ttree -h> for a summary of the options available.

=head1 AUTHORS

Andy Wardley E<lt>abw@wardley.orgE<gt>

L<http://www.wardley.org>

With contributions from Dylan William Hardison (support for
dependencies), Bryce Harrington (C<absolute> and C<relative> options),
Mark Anderson (C<suffix> and C<debug> options), Harald Joerg and Leon
Brocard who gets everywhere, it seems.

=head1 COPYRIGHT

Copyright (C) 1996-2007 Andy Wardley.  All Rights Reserved.

This module is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.

=head1 SEE ALSO

L<Template::Tools::tpage|tpage>