The Functoria DSL allows users to describe how to create portable and flexible applications. It allows to pass application parameters easily using command-line arguments either at configure-time or at runtime.

Users of the Functoria DSL composes their application by defining a list of module implementations, specify the command-line key that are required and combine all of them together using applicative operators.

The DSL expression is then compiled into an application builder, which will, once evaluated, produced the final portable and flexible application.


type 'a typ = 'a Type.t

The type for values representing module types.

val typ : 'a -> 'a typ

type t is a value representing the module type t.

val (@->) : 'a typ -> 'b typ -> ('a -> 'b) typ

Construct a functor type from a type and an existing functor type. This corresponds to prepending a parameter to the list of functor parameters. For example:

kv_ro @-> ip @-> kv_ro

This describes a functor type that accepts two arguments -- a kv_ro and an ip device -- and returns a kv_ro.

type 'a impl = 'a Impl.t

The type for values representing module implementations.

val ($) : ('a -> 'b) impl -> 'a impl -> 'b impl

m $ a applies the functor m to the module a.

type abstract_impl = Impl.abstract

Same as impl but with hidden type.

val dep : 'a impl -> abstract_impl

dep t is the (build-time) dependency towards t.

val abstract : 'a impl -> abstract_impl
  • deprecated Use Functoria.dep.


type 'a key = 'a Key.key

The type for command-line parameters.

type abstract_key = Key.t

The type for abstract keys.

type context = Key.context

The type for keys' parsing context. See Key.context.

type 'a value = 'a Key.value

The type for values parsed from the command-line. See Key.value.

val key : 'a key -> Key.t

key k is an untyped representation of k.

val if_impl : bool value -> 'a impl -> 'a impl -> 'a impl

if_impl v impl1 impl2 is impl1 if v is resolved to true and impl2 otherwise.

val match_impl : 'b value -> default:'a impl -> ('b * 'a impl) list -> 'a impl

match_impl v cases ~default chooses the implementation amongst cases by matching the v's value. default is chosen if no value matches.

Package dependencies

For specifying opam package dependencies, the type package is used. It consists of the opam package name, the ocamlfind names, and optional lower and upper bounds. The version constraints are merged with other modules.

type package = Package.t

The type for opam packages.

type scope = Package.scope

Installation scope of a package.

val package : ?scope:scope -> ?build:bool -> ?sublibs:string list -> ?libs:string list -> ?min:string -> ?max:string -> ?pin:string -> ?pin_version:string -> string -> package

Application Builder

Values of type impl are tied to concrete module implementation with the device and foreign construct. Module implementations of type job can then be registered into an application builder. The builder is in charge if parsing the command-line arguments and of generating code for the final application. See Functoria.Lib for details.

type info = Info.t

The type for build information.

val foreign : ?packages:package list -> ?packages_v:package list value -> ?keys:abstract_key list -> ?deps:abstract_impl list -> string -> 'a typ -> 'a impl

Alias for main, where ?extra_deps has been renamed to ?deps.

val main : ?packages:package list -> ?packages_v:package list value -> ?keys:abstract_key list -> ?extra_deps:abstract_impl list -> string -> 'a typ -> 'a impl

foreign name typ is the functor name, having the module type typ. The connect code will call <name>.start.

  • If packages or packages_v is set, then the given packages are installed before compiling the current application.
  • If keys is set, use the given keys to parse at configure and runtime the command-line arguments before calling <name>.connect.
  • If extra_deps is set, the given list of abstract implementations is added as data-dependencies: they will be initialized before calling <name>.connect.


type 'a device = ('a, abstract_impl) Device.t
val of_device : 'a device -> 'a impl

of_device t is the implementation device t.

val impl : ?packages:package list -> ?packages_v:package list Key.value -> ?install:(Info.t -> Install.t) -> ?install_v:(Info.t -> Install.t Key.value) -> ?keys:Key.t list -> ?extra_deps:abstract_impl list -> ?connect:(info -> string -> string list -> string) -> ?dune:(info -> Dune.stanza list) -> ?configure:(info -> unit Action.t) -> ?files:(info -> Fpath.t list) -> string -> 'a typ -> 'a impl

impl ... is of_device @@ Device.v ...


type job