Introduction to mustach

mustach is a C implementation of mustache.

The main site for mustach is on gitlab.

The best way to use mustach is to copy the files mustach.h and mustach.c in your project and use it.

The current source files are:

• mustach.c core implementation of mustache in C
• mustach.h header file for core definitions
• mustach-json-c.c tiny json wrapper of mustach using json-c
• mustach-json-c.h header file for using the tiny json wrapper
• mustach-tool.c simple tool for applying template files to a json file

The file mustach-json-c.c is the main example of use of mustach core and it is also a practical implementation that can be used.

The tool mustach is build using Makefile. Its usage is:

mustach json template [template]...

and it prints the result of applying the templates files to the json file.

Extensions

By default, the current implementation provide the following extensions.

Explicit substitution

This is a core extension implemented in file mustach.c.

In somecases the name of the key used for substition begins with a character reserved for mustach: one of '#', '^', '/', '&', '{', '>' and '='. This extension introduces the special character ':' to explicitely tell mustach to just substitute the value. So ':' becomes a new special character!

Test of the value

This is a tool extension implmented in file mustach-json-c.c.

This extension allows to test the value of the selected key. It is allowed to write key=value (matching test) or key=!value (not matching test) in any query.

Removing extensions

When compiling mustach.c or mustach-json-c.c, extensions can be removed by defining macros using option -D.

The possible macros are:

• NO_COLON_EXTENSION_FOR_MUSTACH

This macro remove the ability to use colon (:) as explicit command for variable substituion. This extension allows to have name starting with one of the mustach character :#^/&{=<

• NO_EQUAL_VALUE_EXTENSION_FOR_MUSTACH

This macro allows the tool to check the whether the actual value is equal to an expected value. This is useful in {{#key=val}} or {{^key=val}} with the corresponding {{/key=val}}. It can also be used in {{key=val}} but this doesn't seem to be useful.

• NO_JSON_POINTER_EXTENSION_FOR_MUSTACH

This macro removes the possible use of JSON pointers. JSON pointers are defined by IETF RFC 6901. If not set, any key starting with / is a JSON pointer. This implies to use the colon to introduce keys. So NO_COLON_EXTENSION_FOR_MUSTACH implies NO_JSON_POINTER_EXTENSION_FOR_MUSTACH. A special escaping is used for = signs when values comparison is enabled: ~= leaves = in the key.

• NO_EXTENSION_FOR_MUSTACH

This macro disables any current or futur extension.