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Raku implementation of Mustache templates, [http://mustache.github.io/](http://mustache.github.io/).
Synopsis
========
```raku
use Template::Mustache;
# Call .render as a class method
Template::Mustache.render('Hello, {{planet}}!', { planet => 'world' }).say;
# Or instantiate an instance
my $stache = Template::Mustache.new: :from<./views>;
# Subroutines are called
say $stache.render('The time is {{time}}', {
time => { ~DateTime.new(now).local }
});
my @people =
{ :name('James T. Kirk'), :title<Captain> },
{ :name('Wesley'), :title('Dread Pirate'), :emcee },
{ :name('Dana Scully'), :title('Special Agent') },
;
# See this template in ./t/views/roster.mustache
$stache.render('roster', { :@people }).say;
my %context =
event => 'Masters of the Universe Convention',
:@people,
;
my %partials =
welcome =>
qq:b{Welcome to the {{event}}! We’re pleased to have you here.\n\n},
;
# See this result in ./t/50-readme.t
Template::Mustache.render(q:to/EOF/,
{{> welcome}}
{{> roster}}
Dinner at 7PM in the Grand Ballroom. Bring a chair!
EOF
%context,
:from([%partials, './views'])
).say;
```
Description
===========
Logging
-------
### Log levels
Messages are logged with varying severity levels (from most to least severe): `Fatal`, `Error`, `Warn`, `Info`, `Verbose`, `Audit`, `Debug`, `Trace`, `Trace2`
By default, only messages of `Error` or worse are logged. That default can be changed with the `TEMPLATE_MUSTACHE_LOGLEVEL` environment variable.
TEMPLATE_MUSTACHE_LOGLEVEL=Debug
The default is overridden with the `:log-level` option to `Template::Mustache.new`, or a `Template::Mustache::Logger` object can be passed via the `:logger` option.
```raku
my $stache = Template::Mustache.new: :log-level<Trace>;
my $logger = Template::Mustache::Logger.new: :level<Debug>;
my $stache = Template::Mustache.new: :$logger;
```
Either method can be used with the `.render` method, as well.
```raku
my %data = hello => 'world';
Template::Mustache.render: 'Hello, {{hello}}!', %data, :log-level<Trace>;
my $logger = Template::Mustache::Logger.new: :level<Debug>;
Template::Mustache.render: 'Hello, {{hello}}!', %data, :$logger;
```
### Log routine
By default, any messages at level `Warn` or worse are logged with the `warn` routine. A `CONTROL` block can handle such warnings if needed; see [Language/phasers](https://docs.raku.org/language/phasers#CONTROL) for details. Less severe messages (`Info` and up) are logged with the `note` routine.
The routine can be set per log level, in the `Template::Mustache::Logger.routines` hash.
```raku
# Use say instead of note for Info and up; the more severe
# levels (C<Warn> down to C<Fatal>) still use the warn routine
my $stache = Template::Mustache.new: :log-routine(&say);
# But even those can be set explicitly
$stache.logger.routines{$_} = &die for <Warn Error Fatal>;
$stache.render: '{{missing}}', {}; # dies
```
### method log
* `multi method log(Exception $exception, LogLevel :$level)`
* `multi method log(LogLevel :$level, *@msgs)`
Emit a message at `$level` (`Info` by default).
Extra features
==============
Template inheritence
--------------------
Support for `hogan.js`-style [template inheritence](https://github.com/groue/GRMustache/blob/master/Guides/template_inheritance.md) is available.
Pragma: KEEP-UNUSED-VARIABLES
-----------------------------
Specify `:pragma<KEEP-UNUSED-VARIABLES>` to either `Template::Mustache.new` or `.render`, and any variables which are not defined in the data context will be kept in the rendered text. See `t/13-pragmas.t` for examples.
More Examples and Tests
=======================
The Mustache spec provides a wealth of examples to demonstrate exactly how the format behaves.
[https://github.com/mustache/spec/tree/master/specs/](https://github.com/mustache/spec/tree/master/specs/)
All of the official Mustache spec tests pass. An updated copy of the tests is distributed in `t/specs`.
To check against the official specs repository, clone it into `../mustache-spec`:
git clone https://github.com/mustache/spec.git ../mustache-spec
prove -v -e 'raku -Ilib' t/
Extra Specifications
--------------------
The test file `t/specs/inheritable_partials.json` is taken from [groue/GRMustache](https:/github.com/groue/GRMustache).
Other Mustache Implementations
==============================
There are many, many Mustache implementations in various languages. Some of note are:
* The original Ruby version [https://github.com/defunkt/mustache](https://github.com/defunkt/mustache)
* Twitter's hogan.js [https://github.com/twitter/hogan.js](https://github.com/twitter/hogan.js)
* mustache.java [https://github.com/spullara/mustache.java](https://github.com/spullara/mustache.java)
* GRMustache (Objective C) [https://github.com/groue/GRMustache](https://github.com/groue/GRMustache)
* mustache.php [https://github.com/bobthecow/mustache.php](https://github.com/bobthecow/mustache.php)
TODO
====
* full object support (with method calls; currently the object is just stringified)
* global helpers (context items that float at the top of the stack)
* database loader
* pragmas (FILTERS?)
License
=======
[Artistic License 2.0](http://www.perlfoundation.org/artistic_license_2_0)