Text::NeatTemplate - a fast, middleweight template engine.

This describes version 0.08 of Text::NeatTemplate.

    use Text::NeatTemplate;

    my $tobj = Text::NeatTemplate->new();

    $result = $tobj->fill_in(data_hash=>\%data,
			     show_names=>\%names,
			     template=>$text);

This module provides a simple, middleweight but fast template engine, for when you need speed rather than complex features, yet need more features than simple variable substitution.

The markup format is as follows:

{$varname}

A variable; will display the value of the variable, or nothing if that value is empty.

{$varname:format}

A formatted variable; will apply the formatting directive(s) to the value before displaying it.

{?varname stuff [$varname] more stuff}

A conditional. If the value of 'varname' is not empty, this will display "stuff value-of-variable more stuff"; otherwise it displays nothing.

    {?var1 stuff [$var1] thing [$var2]}

This would use both the values of var1 and var2 if var1 is not empty.

{?varname stuff [$varname] more stuff!!other stuff}

A conditional with "else". If the value of 'varname' is not empty, this will display "stuff value-of-variable more stuff"; otherwise it displays "other stuff".

This version can likewise use multiple variables in its display parts.

    {?var1 stuff [$var1] thing [$var2]!![$var3]}

{&funcname(arg1,...,argN)}

Call a function with the given args; the return value of the function will be what is put in its place.

    {&MyPackage::myfunc(stuff,[$var1])}

This would call the function myfunc in the package MyPackage, with the arguments "stuff", and the value of var1.

Note, of course, that if you have a more complicated function and are processing much data, this will slow things down.

To make the parsing simpler (and therefore faster) there are certain restrictions in what this module can do:

• One cannot escape '{' '}' '[' or ']' characters. However, the substitution is clever enough so that you may be able to use them inside conditional constructs, provided the use does not resemble a variable.
  
  For example, to get a value surrounded by {}, the following will not work:
  
  
  
  
  
  However, this will:
  
  {?Var1 {[$Var1]}}
• One cannot have nested variables.
• Conditionals are limited to testing whether or not the variable has a value. If you want more elaborate tests, or tests on more than one value, you'll have to write a function to do it, and use the {&function()} construct.
• Function arguments (as given with the {&funcname(arg1,arg2...)} format) cannot have commas in them, since commas are used to separate the arguments.

When I was writing SQLite::Work, I originally tried using Text::Template (my favourite template engine) and also tried Text::FillIn. Both of them had some lovely, powerful features. Unfortunately, they were also relatively slow. In testing them with a 700-row table, using Text::Template took about 15 seconds to generate the report, and using Text::FillIn took 45 seconds! Rolling my own very simple template engine cut the time down to about 7 seconds.

The reasons for this aren't that surprising. Because Text::Template is basically an embedded Perl engine, it has to run the interpreter on each substitution. And Text::FillIn has a lot to do, what with being very generic and very recursive.

The trade-off for the speed-gain of Text::NeatTemplate is that it is quite simple. There is no nesting or recursion, there are no loops. But I do think I've managed to grab some of the nicer features of other template engines, such as limited conditionals, and formatting, and, the most powerful of all, calling external functions.

This is a middleweight engine rather than a lightweight one, because I needed more than just simple variable substitution, such as one has with Template::Trivial. I consider the trade-off worth it, and others might also, so I made this a separate module.

As well as simple substitution, this module can apply formatting to values before they are displayed.

For example:

{$Money:dollars}

will give the value of the Money variable formatted as a dollar value.

See convert_value for details of all the formatting directives.

my $tobj = Text::NeatTemplate->new();

Make a new template object.

Fill in the given values.

    $result = $tobj->fill_in(data_hash=>\%data,
			     show_names=>\%names,
			     template=>$text);

The 'data_hash' is a hash containing names and values.

The 'show_names' is a hash saying which of these "variable names" ought to be displayed, and which suppressed. This can be useful if you want to use a more generic template, and then dynamically suppress certain values at runtime.

The 'template' is the text of the template.

Replace the given value.

    $val = $tobj->do_replace(targ=>$targ,
			     data_hash=>$data_hashref,
			     show_names=>\%show_names);

Where 'targ' is the target value, which is either a variable target, or a conditional target.

The 'data_hash' is a hash containing names and values.

The 'show_names' is a hash saying which of these "variable names" ought to be displayed, and which suppressed.

This can do templating by using the exec ability of substitution, for example:

    $out =~ s/{([^}]+)}/$tobj->do_replace(data_hash=>$data_hash,targ=>$1)/eg;

$val = $tobj->get_value(val_id=>$val_id, data_hash=>$data_hashref, show_names=>\%show_names);

Get and format the given value.

    my $val = $tobj->convert_value(value=>$val,
				   format=>$format,
				   name=>$name);

Convert a value according to the given formatting directive.

Directives are:

upper

Convert to upper case.

lower

Convert to lower case.

int

Convert to integer

float

Convert to float.

string

Return the value with no change.

truncatenum

Truncate to num length.

dollars

Return as a dollar value (float of precision 2)

percent

Show as if the value is a percentage.

title

Put any trailing ",The" ",A" or ",An" at the front (as this is a title)

comma_front

Put anything after the last comma at the front (as with an author name) For example, "Smith,Sarah Jane" becomes "Sarah Jane Smith".

month

Convert the number value to a month name.

nth

Convert the number value to a N-th value. Numbers ending with 1 have 'st' appended, 2 have 'nd' appended, 3 have 'rd' appended, and everything else has 'th' appended.

url

Convert to a HTML href link.

email

Convert to a HTML mailto link.

hmail

Convert to a "humanized" version of the email, with the @ and '.' replaced with "at" and "dot". This is useful to prevent spambots harvesting email addresses.

html

Convert to simple HTML (simple formatting)

proper

Convert to a Proper Noun.

wordsnum

Give the first num words of the value.

alpha

Convert to a string containing only alphanumeric characters (useful for anchors or filenames)

namedalpha

Similar to 'alpha', but prepends the 'name' of the value. Assumes that the name is only alphanumeric.

$val = $tobj->simple_html($val);

Do a simple HTML conversion of the value. bold, italic, <br>

{&safe_backtick(myprog,arg1,arg2...argN)}

Return the results of a program, without risking evil shell calls. This requires that the program and the arguments to that program be given separately.

    Test::More

To install this module, run the following commands:

    perl Build.PL
    ./Build
    ./Build test
    ./Build install

Or, if you're on a platform (like DOS or Windows) that doesn't like the "./" notation, you can do this:

   perl Build.PL
   perl Build
   perl Build test
   perl Build install

In order to install somewhere other than the default, such as in a directory under your home directory, like "/home/fred/perl" go

   perl Build.PL --install_base /home/fred/perl

as the first step instead.

This will install the files underneath /home/fred/perl.

You will then need to make sure that you alter the PERL5LIB variable to find the module.

Therefore you will need to change the PERL5LIB variable to add /home/fred/perl/lib

	PERL5LIB=/home/fred/perl/lib:${PERL5LIB}

Text::Template Text::FillIn Text::QuickTemplate Template::Trivial Template::Toolkit HTML::Template

Please report any bugs or feature requests to the author.

    Kathryn Andersen (RUBYKAT)
    perlkat AT katspace dot com
    http://www.katspace.org/tools

Copyright (c) 2006 by Kathryn Andersen

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