deriving Cmdliner is the easiest way to get a command line interface.
It is also a ppx_deriving plugin
that generates a Cmdliner Term for a
given type.
type params = {
username: string;
(** Your Github username *)
api_key: string;
(** Your Github API key *)
command: string; [@pos 0] [@docv "CMD"]
(** The Github API command to run *)
dry_run: bool;
(** Don't really run this command *)
time_to_wait: float; [@default 0.]
(** Just an example of another type *)
} [@@deriving cmdliner, show]
let main () =
let f p = show_params p |> print_endline in
let info = Cmdliner.Cmd.info Sys.argv.(0) in
let term = Cmdliner.Term.(const f $ params_cmdliner_term ()) in
let cmd = Cmdliner.Cmd.v info term in
exit (Cmdliner.Cmd.eval cmd)
let () = main ()Which gives you a CLI like the following:
NAME
awesome-cli
SYNOPSIS
awesome-cli [OPTION]... CMD
ARGUMENTS
CMD (required)
The Github API command to run
OPTIONS
--api-key=STRING (required)
Your Github API key
--dry-run
Don't really run this command
--help[=FMT] (default=auto)
Show this help in format FMT. The value FMT must be one of `auto',
`pager', `groff' or `plain'. With `auto', the format is `pager` or
`plain' whenever the TERM env var is `dumb' or undefined.
--time-to-wait=FLOAT (absent=0.)
Just an example of another type
--username=STRING (required)
Your Github username
Ppx_deriving_cmdliner supports arbitrary types via a cmdliner_converter
interface. For example, the below two methods work for supporting M.t (from
test/tests.ml)
module M = struct
type t = int * int
let fst (f,_) = f
let snd (_,s) = s
let of_string s =
try
let sepi = String.index s '|' in
let fst = String.sub s 0 sepi in
let snd = String.sub s (sepi+1) ((String.length s)-sepi-1) in
Result.Ok (int_of_string fst, int_of_string snd)
with _ -> Result.Error (`Msg (Printf.sprintf "Couldn't parse `%s`" s))
let to_string t =
Printf.sprintf "%d|%d" (fst t) (snd t)
let cmdliner_converter =
of_string,
(fun fmt t -> Format.fprintf fmt "%s" (to_string t))
end
type custom_types = {
foo: M.t; [@conv M.cmdliner_converter]
bar: M.t;
} [@@deriving cmdliner]In short, a value of type string -> ('a, [ `Msg of string ]) Result.result) * 'a printer must be provided (or will be looked for under the name
cmdliner_converter if the type is t, else type_name_cmdliner_converter)
for the given type.
- Docs:
[@doc "Overwrites the docstring"],[@docs "SECTION TWO"],[@docv "VAL"] - Environment variables:
[@env "ENVNAME"],[@env.doc "Docs for the variable"],[@env.docs "SECTION ENVS"] - Other:
[@list_sep '@'],[@default 123],[@enum [("a", Foo); ("b", Bar)]],[@aka ["b";"another-flag-name"]],[@conv cmdliner_converter](cf. required argument toconvin Cmdliner),[@opt_all]only ona' listfields,[@term cmdliner_term]for assiging an arbitraryCmdliner.Term.tto a field.
React
Typescript
Django
Laravel
Facebook
Microsoft
Google
Alibaba
D3
Tencent