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MulleScion is a modern template engine for Objective C

(written in an oldfashioned way)

Release on github: Build Status

It's heavily (very heavily) inspired by

TWIG "The flexible, fast, and secure template engine for PHP"

MulleScion is fairly flexible, reasonably fast and can be made as secure as you wish.

  • Reasonably Fast : MulleScion can compile templates into a compressed archive format. Loading such an archive ought to be lots faster than parsing (but because the parse is so fast, maybe isn't). A compiled template is read-only, you can use it many times to render different output from different input.

  • Secure : MulleScion has hooks so your application can ensure that untrusted template code doesn't have access to all of the applications data.

  • Flexible : There is the possibility of extending KVC and writing your own "builtin" fuctions. A template can (if allowed) execute arbitrary ObjC code. MulleScion has a powerful define like preprocessing capability and macros to expand your template vocabulary.

Here is a simple example, where ObjC code is embedded in a template:

   <!-- rendered by {{ [[NSProcessInfo processInfo] processName] }} on
        {{ [NSDate date] }} -->
     {% for item in [NSTimeZone knownTimeZoneNames] %}
         {% if item#.isFirst %}
         {% endif %}
            <tr><td>{{ item }}</td></tr>
         {% if item#.isLast %}
         {% endif %}
      {% else %}
         Sorry, no timezone info available.
      {% endfor %}

Using the MulleScion.framework the creation of a string from your object using a template file is as easy as:

   NSString  *output;

   output = [MulleScionTemplate descriptionWithTemplateFile:@"test.scion"

This is the general architecture of MulleScion

MulleScion is happily used in a commercial project and has gone through enough iterations to pronounce it "ready for production".


There is a companion project MulleScionHTMLPreprocessor that uses HTML like tags, to make the template easier to reformat in HTML editors:

  <!-- rendered by {{ [[NSProcessInfo processInfo] processName] }} on
        {{ [NSDate date] }} -->
    <for item in [NSTimeZone knownTimeZoneNames]>
      <if item#.isFirst>
        <tr><td>{{ item }}</td></tr>
      <if item#.isLast>
      Sorry, no timezone info available.


There is an interactive editor available for OS X called MulleScionist, which allows you to edit a HTML scion template and preview the results at the same time.


Virtually all the documentation is contained in example .scion templates in the dox folder. For each command or feature there should be a separate template file that documents it. mulle-scion, the command line utility, contains a small quickly hacked together webserver that can present the documentation using MulleScion itself.

In Xcode just run Show Documentation in Webserver and it should setup the webserver and open your browser to the right address.

MulleScion is very similar to TWIG, so you can glean much of relevance from If you see a feature in TWIG but don't see it in the tests file, it's likely not there (but it's probably easily achieved some other way (using a define or a macro or an ObjC category on NSString).


Because you can execute arbitrary ObjC methods, and have access to Key Value Coding, MulleScion can pretty much do anything. MulleScion uses NSInvocation for method calls. That means there will be problems with variable arguments methods. Be wary of anything using structs and C-Arrays and C-strings, although MulleScion tries to be as helpful as possible.

MulleScion does not do arithmetic or bitwise logic, quite on purpose.

MulleScion && and || have no operator precedence, use parentheses.

MulleScion doesn't prevent you from trying stupid things.

The documentation is not very good, actually it is just more or less a collection of test cases with comments...


There is iOS Support :)


The main development site is Mulle kybernetiK.

releases are pushed to github


It might be nice to have delayed evaluation for render results. More tests.

INSTALLATION (mulle-scion command line tool only)

brew install mulle-kybernetik/software/mulle-scion

USAGE mulle-scion

   mulle-scion [options] <input> <datasource> [output] [arguments]

   -w       : start webserver for /usr/local/share/mulle-scion/dox
   -z       : write compressed archive to outputfile
   -Z       : write compressed keyed archive to outputfile (for IOS)

   -        : Read template from stdin
   template : a MulleScion template path or URL

   -        : Read data from stdin (only if input is not stdin already)
   args     : use arguments as datasource (see below)
   bundle   : a NSBundle. It's NSPrincipalClass will be used as the datasource
   plist    : a property list path or URL as datasource, see: plist(5)
   none     : empty datasource

   -        : Write result to stdout
   file     : Write result to file

   key=value: key/value pairs to be used as __ARGV__ contents
              (unless args as datasource was specified)

   echo '***{{ VALUE }}***' | mulle-scion - args - VALUE="VfL Bochum 1848"
   echo '***{{ __ARGV__[ 0]}}***' | mulle-scion - none - "VfL Bochum 1848"


Coded by Nat! 2013 Mulle kybernetiK

Mongoose Webserver by Sergey Lyubka

Hoedown Library by Natacha Porté Vicent Martí Xavier Mendez, Devin Torres and the Hoedown authors

Contributors: @hons82 (Hannes)