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diff --git a/doc/templating/templating-guide.tex b/doc/templating/templating-guide.tex new file mode 100644 index 00000000..4ddadde9 --- /dev/null +++ b/doc/templating/templating-guide.tex @@ -0,0 +1,241 @@ +% Copyright (C) 2007, The LedgerSMB core team. +% +% This program is free software; you can redistribute it and/or modify +% it under the terms of the GNU General Public License as published by +% the Free Software Foundation; version 2 of the License. +% +% This program is distributed in the hope that it will be useful, +% but WITHOUT ANY WARRANTY; without even the implied warranty of +% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +% GNU General Public License for more details. +% +% You should have received a copy of the GNU General Public License +% along with this program; if not, write to the Free Software +% Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + +\documentclass[english]{article} +\usepackage[utf8]{inputenc} +\hyphenation{LedgerSMB} +\newcommand{\pitag}[1]{\textless?lsmb #1 ?\textgreater} +\newcommand{\tg}{\textgreater} +\newcommand{\tl}{\textless} +\newcommand{\version}{1.3} +\newcommand{\lsmb}{LedgerSMB } +\newcommand{\lsmbn}{LedgerSMB} +\newcommand{\lsmbt}{LedgerSMB::Template} + +\title{Templating for LedgerSMB v. \version} +\author{The LedgerSMB Core Team} +\date{\today} + +\begin{document} +\maketitle +Copyright \copyright 2007 The LedgerSMB Core Team. Permission +is granted to copy, distribute and/or modify this document under the +terms of the GNU General Public License version 2. + +\tableofcontents{} +%\listoffigures +\clearpage + +\part{Template Syntax} + +As in \lsmb 1.2, templating directives in \version{ }are expressed with the base +form of \pitag{foo}. That, and basic variable substitution, is about the only +part of templating that has remained unchanged. Starting with 1.3, the primary +rendering engine is Template Toolkit, with START\_TAG changed to +``\textless?lsmb'' and END\_TAG changed to ``?\textgreater''. + +\section{Variable Substitution} +For simple output, the name of the variable is placed on its own, as in +\pitag{foo}. Hash elements are accessed using the form \pitag{hash.key}. +Arrays are treated as a form of hash where the key is the index of the element, +indexed from zero. In more complex cases, such as where the desired hash key +is the value of another variable, values can be extracted by prefixing the name +of the other variable with \$. This results in the form \pitag{row.\$column}. + +Through Template Toolkit, \lsmbt{ }has the concept of private variables. If +any component of the variable name starts with an underscore, it is private and +will not be output to the rendered document. + +Something to watch for when dealing with variable substitution for hashes is +that in some cases, the key name conflicts with one of TT's VMethods for the +type. When that occurs and the value is not defined, the VMethod is executed +instead of retrieving the value. An example of where this could happen is when +retreiving the value of form.sort. As it is often undefined and included in +``hidden'' HTML elements, it can cause application errors when a templater +attempts to retrieve it using form.sort instead of form.item('sort'). + +\section{Functions} + +\subsection{Internationalisation} +In addition to the regular Template Toolkit functions, \lsmb has the +additional functions text and gettext. Both of these functions are interfaces +to the underlying gettext infrastructure and both can handle simple gettext +substitutions. The difference between these functions is that text makes use +of the locale of the current user, while gettext must be passed a string that +identifies one of the gettext translations. + +These gettext lookups can take placeholders in the same syntax that the +underlying Perl does, ``[\_\emph{n}]''. The output of the i18n functions is +not escaped and the input values are not unescaped. + +\pitag{gettext('fr\_CA', 'Item \#[\_1]', value)} + +\subsection{Formatting} + +The only formatting function that is added is \emph{escape}. The escape +function escapes a value using the rules for the template format. + +\section{Control Structures} +The base +IF, ELSIF, ELSE +FOREACH + +\section{Debugging} +Two template-side tools that can help with debugging are the interface to +Data::Dumper and setting a debug message format. + +\subsection{Variable Dumping} +The Data::Dumper interface is loaded using \pitag{USE dumper()} and used with +either \pitag{dumper.dump(\emph{var})} or \pitag{dumper.dump\_html(\emph{var})}. +Both dumper.dump and dumper.dump\_html perform the same basic dumping, however +dump\_html also escapes the values and applies basic formatting. See +Template::Plugin::Dumper for details. + +\subsection{Line Specification} +Template Toolkit has a DEBUG directive that can cause line-based logging +messages to appear in the rendered output when the debug flag to \lsmbt{ }is +true. A sample tag to start a debugging region with \LaTeX{ }templates is +\pitag{DEBUG format '\% \$file:\$line \$text'}. The debugging messages will +start with the line that has the directive and a debugging region can be +optionally terminated with \pitag{DEBUG format ''}, which tells TT to use an +empty message. + +\part{The Templating API} +\section{\lsmbt} +A new templating API was added in \lsmb 1.3. This API is accessed through +\lsmbt, and has several support modules. Typical usage of this API is fairly +simple in that most places that use it instantiate a \lsmbt{ }object in +auto-output mode then use the resulting object's render method. The +constructor options are detailed in the POD for \lsmbt{ }with the most +interesting one for designing and testing user interface templates probably +being ``debug'', which enables the display of debugging messages. The render +method handles escaping the passed in template data for the selected output +format and the actual rendering with the appropriate support module. + +\subsection{Options} +\subsection{Input} +\subsection{Output} + +\section{\lsmbt{ }Support Modules} +\subsection{\lsmbt::LaTeX} +This module uses Template::Latex to generate DVI, PDF, or Postscript output. +It looks for template files that end in ``.tex'' and take marked-up \LaTeX. +Rendering of templates by these modules happens in two phases: the TT phase +and the \LaTeX phase. All templates that are directly called by \lsmbt{ }that +use these modules must be enclosed by the tag pair \pitag{FILTER latex} and +\pitag{END} for the second rendering phase to occur. The final output file +format is determined by the format\_option filetype. + +\subsection{\lsmbt::HTML} +This is the most frequently used \lsmbt{ }module as the migration of the user +interface to templates has started. It looks for template files that end in +``.html''. + +\subsection{\lsmbt::CSV} +A new form of output with \lsmb 1.3, this module is used by some reports to +give output in a standard form. It looks for template files that end in +``.csv''. + +\subsection{\lsmbt::ODS, \lsmbt::XLS} +This pair of module outputs spreadsheets. Their input is specially formatted +XML files that are processed by TT before the final conversion from XML to +their respective formats. Details about the XML format are available in the +documentation for Excel::Template. + +The templates used by these modules have the extensions ``.odst'' and +``.xlst''. + +\subsection{\lsmbt::TXT} +A format infrequently used by \lsmbn, this is used for Point Of Sale invoices. +It looks for templates that end in ``.txt''. + +\subsection{\lsmbt::TTI18N} +This module defines some internationalisation functions that can be called in +templates that use Template Toolkit. + +\subsection{\lsmbn::Mailer} +This module provides the functions used by \lsmbt{ }and the backup routines +in the administration module to email files and documents. + +\part{Appendix} +\appendix +\section{Quick Reference} +\begin{tabular}{|l|p{7cm}|} +\hline +\multicolumn{2}{|c|}{Variable Access}\\ +\hline +varname & The value of the scalar varname\\ +listname.\emph{i} & Element \emph{i} of the list, lists are indexed from 0\\ +hashname.key & The value of the hash with the key \emph{key}\\ +hashname.\$key & The value of the hash with the key whose name is stored in \$key\\ +\hline +\multicolumn{2}{|c|}{Flow Control}\\ +\hline +IF \emph{condition}; ELSIF; ELSE & A basic if/else block \\ +FOREACH \emph{var} IN \emph{list} & Iterate over the members of \emph{list}\\ +END & Conclude an open block \\ +\hline +\multicolumn{2}{|c|}{Special Variables}\\ +\hline +loop & Refers to the immediately containing loop\\ +\hline +\multicolumn{2}{|c|}{Built-in Methods}\\ +\hline +any.defined & Returns true if \emph{any} is defined\\ +scalar.split(delimiter) & Returns a list of elements from the split string\\ +list.size & Returns the number of elements in the list\\ +list.join(delimiter) & Returns the list's elements joined together\\ +list.defined(\emph{i}) & Returns true if the specified element is defined\\ +hash.item(name) & Returns the value of the element name from hash\\ +hash.keys & Returns a list containing the hash's keys\\ +hash.pairs & Returns a list of key/value pairs, sorted by key\\ +hash.size & Returns the number of key/value pairs in the hash\\ +loop.count & Returns the iteration number\\ +loop.last & Returns true if it is the final iteration\\ +loop.first & Returns true if it is the first iteration\\ +\hline +\multicolumn{2}{|c|}{Internationalisation}\\ +\hline +text(string, @args) & Returns the LSMB locale's gettext value for string\\ +gettext(locale, string, @args) & Returns the locale's gettext value for string\\ +\hline +\multicolumn{2}{|c|}{Debugging}\\ +\hline +DEBUG format '\$file:\$line' & Starts and specifies the format of a debug region\\ +DEBUG format '' & Ends a region of debug output\\ +USE dumper() & Load the dumper plugin\\ +dumper.dump\_html(var) & Dump variables\\ +\hline +\end{tabular} + +\section{Templating Changes Between Versions} +\subsection{\lsmb 1.3 to \lsmb 1.2} +\begin{itemize} +\item A new templating API was added to replace Form::parse\_template +\item The main rendering engine was changed to Template Toolkit +\item Migration of the user interface to using \lsmbt{ }was started +\item DVI, Excel, OpenDocument Spreadsheet, and CSV output support was added +\item The \lsmbn::Mailer API was changed and documented +\end{itemize} + +\subsection{\lsmb 1.2 to \lsmb 1.1} +\begin{itemize} +\item Tags were changed from the form \tl\% foo \%\tg to \pitag{foo} +\item The ability to compare two variables in templates was removed +\item \lsmbn::Mailer was rewritten to use MIME::Lite while retaining the old API +\item SMTP support was added to \lsmbn::Mailer +\end{itemize} + +\end{document} |