jingoo

About jingoo

Jingoo is OCaml template engine almost compatible with Jinja2(python template engine).

Install

manual

make
sudo make install

opam

opam install jingoo

Difference between Jinja2 and Jingoo

1. i18n features are not supported yet.
2. Cause of language difference between ocaml and python, some of built-in filters are different from original one, especially orders of arguments and supported optional arguments etc.
3. Single line comment is not supported. Because single '#' is used very much especially in html.

Usage

Simple usage

open Jingoo

(* output from direct string template *)
let result = Jg_template.from_string "{{ msg }}" ~models:[("msg", Jg_types.Tstr "hello, world!")]

(* or output from file template *)
let result2 = Jg_template.from_file "hello.jingoo" ~models:[("msg", Jg_types.Tstr "hello, world!")]

(* or you can use functional model like this by using Jg_template2 module(ver >= 1.4.0) *)
let result3 = Jg_template2.from_string "{{ msg }}(random value = {{ randam_int }})" ~models:(function
 | "msg" -> Jg_types.Tstr "hello, world!"
 | "randam_int" -> Jg_types.Tint (Random.int 100)
 | _ -> Jg_types.Tnull
)

(* or you can use closure for models by using Jg_template2 module(ver >= 1.4.0) *)
let hash = Hashtbl.create 10 in
let () = Hashtbl.add hash "msg" (Jg_types.Tstr "hello, world!") in
let result4 = Jg_template2.from_string "{{ msg }}" ~models:(fun key ->
  try Hashtbl.find hash key with Not_found -> Tnull
)

More detailed example

template code

{# sample.jingoo #}
<h1>{{ title }}</h1>

<ul>
{% for user in users %}
  <li><a href="{{ user.url }}">{{ user.name }}(age = {{ user.age }})</a></li>
{% endfor %}
</ul>

{% if is_debug %}
<p>this is debug mode!</p>
{% endif %}

ocaml code

open Jingoo

let result = Jg_template.from_file "sample.jingoo" ~models:[
  ("title", Jg_types.Tstr "more detailed example");
  ("is_debug", Jg_types.Tbool true);
  ("users", Jg_types.Tlist [
    Jg_types.Tobj [
      ("name", Jg_types.Tstr "taro");
      ("url", Jg_types.Tstr "https://example.com");
      ("age", Jg_types.Tint 20);
    ];
    Jg_types.Tobj [
      ("name", Jg_types.Tstr "jiro");
      ("url", Jg_types.Tstr "https://example2.com");
      ("age", Jg_types.Tint 10);
    ];
  ])
]

Custom filter example

Set your custom filter to filters field of environment.

open Jingoo

let to_mail ?(kwargs=[]) ?(defaults=[]) value =
  let id = Jg_runtime.string_of_tvalue value in
  let domain = Jg_runtime.string_of_tvalue (Jg_runtime.jg_get_kvalue "domain" kwargs ~defaults) in
  Jg_types.Tstr (id ^ "@" ^ domain)

let () =
  let result = Jg_template.from_string "{{id | to_mail(domain='gmail.com')}}"
    (* set your extension to 'filters' field of environment *)
    ~env:{Jg_types.std_env with
      filters = [
        (* CAUTION!: if jingoo <= 1.2.21, use 'Jg_runtime.func_arg1' instead of 'Jg_types.func_arg1_kw' *)
        ("to_mail", Jg_types.func_arg1_kw (to_mail ~defaults:[
          ("domain", Jg_types.Tstr "gmail.com");
        ]));
      ]
    }
    ~models:[
      ("id", Jg_types.Tstr "foo")
    ] in
  (* should output 'foo@gmail.com' *)
  print_endline result

Dynlink filter example

1. Write your own filter(my_ext.ml for example) and add it by Jg_stub.add(namespace as my_ext and func_name as to_md5 for example).

open Jingoo

let to_md5 ?(kwargs=[]) ?(defaults=[]) value =
  let seed = Jg_runtime.jg_get_kvalue "seed" kwargs ~defaults in
  match value, seed with
  | Jg_types.Tstr str, Jg_types.Tstr seed ->
     Jg_types.Tstr (Digest.to_hex (Digest.string (str ^ seed)))
  | _ -> Jg_types.Tnull

let () =
  (* CAUTION!: if jingoo <= 1.2.21, use 'Jg_runtime.func_arg1' instead of 'Jg_types.func_arg1_kw' *)
  Jg_stub.add_func ~namespace:"my_ext" ~func_name:"to_md5" (Jg_types.func_arg1_kw (to_md5 ~defaults:[
    ("seed", Jg_types.Tstr "");
  ]))

2. Compile it to my_ext.cmxs by -shared option.

ocamlfind ocamlopt -shared -o my_ext.cmxs my_ext.ml

3. Set my_ext.cmxs to extensions field of environment, and you can use your custom filter my_ext.to_md5.

open Jingoo

let result = Jg_template.from_string "{{msg | my_ext.to_md5(seed='aaa')}}"
  (* set your extension to 'extensions' field *)
  ~env:{Jg_types.std_env with
    extensions = [
      "my_ext.cmxs";
    ]
  }
  ~models:[
    ("msg", Jg_types.Tstr "foo");
  ] in
(* should output '3cb988a734183289506ab7738261c827' *)
print_endline result

Cheatsheet

See samples directory.

*.jingoo is template example and *.expected is expected string.

Documentation

http://tategakibunko.github.io/jingoo/

Playground

https://sagotch.github.io/try-jingoo/

License

MIT License