Module type Param.S

type +'a t

Command.Param is intended to be used with the [%map_open] syntax defined in ppx_let, like so:

let command =
  Command.basic ~summary:"..."
    [%map_open
      let count  = anon ("COUNT" %: int)
      and port   = flag "port" (optional int) ~doc:"N listen on this port"
      and person = person_param
      in
      (* ... Command-line validation code, if any, goes here ... *)
      fun () ->
        (* The body of the command *)
        do_stuff count port person
    ]

One can also use [%map_open] to define composite command line parameters, like person_param in the previous snippet:

type person = { name : string; age : int }

let person_param : person Command.Param.t =
  [%map_open
    let name = flag "name" (required string) ~doc:"X name of the person"
    and age  = flag "age"  (required int)    ~doc:"N how many years old"
    in
    {name; age}
  ]

The right-hand sides of [%map_open] definitions have Command.Param in scope.

Alternatively, you can say:

let open Foo.Let_syntax in
[%map_open
  let x ...
]

if Foo follows the same conventions as Command.Param.

See example/command/main.ml for more examples.

include Core_kernel__.Import.Applicative.S with type 'a t := 'a t
include Base__.Applicative_intf.For_let_syntax
type 'a t
val return : 'a -> 'a t
val map : 'a t -> f:('a -> 'b) -> 'b t
val both : 'a t -> 'b t -> ('a * 'b) t
include Base__.Applicative_intf.Applicative_infix with type 'a t := 'a t
type 'a t
val (<*>) : ('a -> 'b) t -> 'a t -> 'b t

same as apply

val (<*) : 'a t -> unit t -> 'a t
val (*>) : unit t -> 'a t -> 'a t
val (>>|) : 'a t -> ('a -> 'b) -> 'b t
val apply : ('a -> 'b) t -> 'a t -> 'b t
val map2 : 'a t -> 'b t -> f:('a -> 'b -> 'c) -> 'c t
val map3 : 'a t -> 'b t -> 'c t -> f:('a -> 'b -> 'c -> 'd) -> 'd t
val all : 'a t list -> 'a list t
val all_unit : unit t list -> unit t
val all_ignore : unit t list -> unit t

Various internal values

val help : Core_kernel__.Import.string Core_kernel.Lazy.t t

The help text for the command.

val path : Core_kernel__.Import.string Core_kernel__.Import.list t

The subcommand path of the command.

val args : Core_kernel__.Import.string Core_kernel__.Import.list t

The arguments passed to the command.

val flag : ?⁠aliases:Core_kernel__.Import.string Core_kernel__.Import.list -> ?⁠full_flag_required:Core_kernel__.Import.unit -> Core_kernel__.Import.string -> 'a Flag.t -> doc:Core_kernel__.Import.string -> 'a t

flag name spec ~doc specifies a command that, among other things, takes a flag named name on its command line. doc indicates the meaning of the flag.

All flags must have a dash at the beginning of the name. If name is not prefixed by "-", it will be normalized to "-" ^ name.

Unless full_flag_required is used, one doesn't have to pass name exactly on the command line, but only an unambiguous prefix of name (i.e., a prefix which is not a prefix of any other flag's name).

NOTE: the doc for a flag which takes an argument should be of the form arg_name ^ " " ^ description where arg_name describes the argument and description describes the meaning of the flag.

NOTE: flag names (including aliases) containing underscores will be rejected. Use dashes instead.

NOTE: "-" by itself is an invalid flag name and will be rejected.

val flag_optional_with_default_doc : ?⁠aliases:Core_kernel__.Import.string Core_kernel__.Import.list -> ?⁠full_flag_required:Core_kernel__.Import.unit -> Core_kernel__.Import.string -> 'a Arg_type.t -> ('a -> Core_kernel.Sexp.t) -> default:'a -> doc:Core_kernel__.Import.string -> 'a t

flag_optional_with_default_doc name arg_type sexp_of_default ~default ~doc is a shortcut for flag, where:

  1. The Flag.t is optional_with_default default arg_type
  2. The doc is passed through with an explanation of what the default value appended.
val anon : 'a Anons.t -> 'a t

anon spec specifies a command that, among other things, takes the anonymous arguments specified by spec.

val choose_one : 'a Core_kernel__.Import.option t Core_kernel__.Import.list -> if_nothing_chosen:[ `Default_to of 'a | `Raise ] -> 'a t

choose_one clauses ~if_nothing_chosen expresses a sum type. It raises if more than one of clauses is Some _. When if_nothing_chosen = `Raise, it also raises if none of clauses is Some _.