Walrus - Mustache-like Templating

Walrus is 50% Mustache and 50% large flippered marine mammal.

Lexing is done with Leex and parsing is done with Yecc, both of which are included in newer versions of Erlang.

Most Mustache constructs work, such as variables, unescaped variables, blocks, and inverse blocks. However, The Walrus is an opinionated animal, and partials will never be supported. Also, functions passed into the context are simply evaluated and are not passed the raw template.

You can skip lexing and parsing templates every time you want to render them by using compile/1, which returns a renderer you can then pass a context that renders the template.

Examples

Simple Render

1> Tmpl = "Hello {{{name}}}.
1> 
1> Drinks:
1> 
1> {{#drinks}}
1>     - {{name}}, {{tastiness}}
1> {{/drinks}}".
"Hello {{{name}}}.\n\nDrinks:\n\n{{#drinks}}\n    - {{name}}, {{tastiness}}\n{{/drinks}}"
2> 
2> Ctx = [{name, "Devin & Jane"},
2>        {drinks, [[{name, "Beer"},
2>                   {tastiness, 5}],
2>                  [{name, "Juice"},
2>                   {tastiness, 8}]]}].
[{name,"Devin & Jane"},
 {drinks,[[{name,"Beer"},{tastiness,5}],
          [{name,"Juice"},{tastiness,8}]]}]
3> 
3> walrus:render(Tmpl, Ctx).
<<"Hello Devin & Jane.\n\nDrinks:\n\n\n    - Beer, 5\n\n    - Juice, 8\n">>

Compiled Renderer

1> Renderer = walrus:compile("Hello {{{name}}}.\n\nDrinks:\n\n{{#drinks}}\n    - {{name}}, {{tastiness}}\n{{/drinks}}").
#Fun<walrus.0.90102984>
2> Ctx = [{name, "Devin & Jane"},
2>        {drinks, [[{name, "Beer"},
2>                   {tastiness, 5}],
2>                  [{name, "Juice"},
2>                   {tastiness, 8}]]}].
[{name,"Devin & Jane"},
 {drinks,[[{name,"Beer"},{tastiness,5}],
          [{name,"Juice"},{tastiness,8}]]}]
3> 
3> Renderer(Ctx).
<<"Hello Devin & Jane.\n\nDrinks:\n\n\n    - Beer, 5\n\n    - Juice, 8\n">>

Acknowledgments

Robert Virding helped me tremendously when I struggled to understand Leex. He's also responsible for ([^{}]|({[^{])|(}[^}]))+.

License

All code released into the public domain (see UNLICENSE) except for the file walrus_mochinum.erl, which has it's own license (see LICENSE).

joewilliams / walrus