Module Melange_compiler_libs.Signature_group

Iterate on signature by syntactic group of items

Classes, class types and private row types adds ghost components to the signature where they are defined.

When editing or printing a signature it is therefore important to identify those ghost components.

This module provides type grouping together ghost components with the corresponding core item (or recursive group) and the corresponding iterators.

type sig_item = {
  1. src : Types.signature_item;
    (*

    the syntactic item

    *)
  2. post_ghosts : Types.signature_item list;
    (*

    ghost classes types are post-declared

    *)
}

Classes and class types generate ghosts signature items, we group them together before printing

val flatten : sig_item -> Types.signature

flatten sig_item is x.src :: x.post_ghosts

type core_rec_group =
  1. | Not_rec of sig_item
  2. | Rec_group of sig_item list

A group of mutually recursive definition

val rec_items : core_rec_group -> sig_item list

rec_items group is the list of sig_items in the group

type rec_group = {
  1. pre_ghosts : Types.signature_item list;
  2. group : core_rec_group;
}

Private #row types are manifested as a sequence of definitions preceding a recursive group, we collect them and separate them from the syntactic recursive group.

val next : Types.signature -> (rec_group * Types.signature) option

The sequence seq signature iterates over signature rec_group by rec_group. The second element of the tuple in the full_seq case is the not-yet traversed part of the signature.

val seq : Types.signature -> rec_group Stdlib.Seq.t
val iter : (rec_group -> unit) -> Types.signature -> unit
val fold : ('acc -> rec_group -> 'acc) -> 'acc -> Types.signature -> 'acc
type in_place_patch = {
  1. ghosts : Types.signature;
    (*

    updated list of ghost items

    *)
  2. replace_by : Types.signature_item option;
    (*

    replacement for the selected item

    *)
}

Describe how to amend one element of a signature

val replace_in_place : (ghosts:Types.signature -> Types.signature_item -> ('a * in_place_patch) option) -> Types.signature -> ('a * Types.signature) option

!replace_in_place patch sg replaces the first element of the signature for which patch ~rec_group ~ghosts component returns Some (value,patch). The rec_group argument is the remaining part of the mutually recursive group of component. The ghosts list is the current prefix of ghost components associated to component