bedrock.lang.cpp.syntax.handler

(*
* Copyright (c) 2023-2024 BedRock Systems, Inc.
* This software is distributed under the terms of the BedRock Open-Source License.
* See the LICENSE-BedRock file in the repository root for details.
*)
Require Import bedrock.prelude.lens.
Require Import bedrock.lang.cpp.syntax.prelude.
Require Import bedrock.lang.cpp.syntax.core.
Import UPoly.

#[local] Set Primitive Projections.
#[local] Set Printing Implicit.

#[local] Set Universe Polymorphism.
#[local] Set Polymorphic Inductive Cumulativity.
#[local] Unset Auto Template Polymorphism.
#[local] Unset Universe Minimization ToSet.

Handlers for simple AST traversals

Types of "handlers" for interesting constructors of type, Expr.

These types support the generic traversals in mtraverse2.v. Clients of those dictate the sets of "interesting constructors".

The handler for a constructor receives the constructor's arguments as well as (delayed) traversal results.

Record type_handler'@{u} {lang} {N T E : Type@{u}} : Type@{u} := {

Dependent types

  handle_Tparam (_ : ident) : T;
  handle_Tresult_param (_ : ident) : T;
  handle_Tresult_global (_ : name' lang) (_ : unit -> N) : T;
  handle_Tresult_unop (_ : RUnOp) (_ : decltype' lang)
    (_ : unit -> T) : T;
  handle_Tresult_binop (_ : RBinOp) (_ _ : decltype' lang)
    (_ _ : unit -> T) : T;
  handle_Tresult_call (_ : name' lang) (_ : list (decltype' lang))
    (_ : unit -> N) (_ : unit -> list T) : T;
  handle_Tresult_member_call (_ : name' lang) (_ : decltype' lang) (_ : list (decltype' lang))
    (_ : unit -> N) (_ : unit -> T) (_ : unit -> list T) : T;
  handle_Tresult_parenlist (_ : decltype' lang) (_ : list (decltype' lang))
    (_ : unit -> T) (_ : unit -> list T) : T;
  handle_Tresult_member (_ : decltype' lang) (_ : name' lang) (_ : unit -> T) (_ : unit -> N) : T;

Alias expansion

handle_Tnamed (_ : name' lang) (_ : unit -> N) : T;

Reference collapsing

  handle_Tref (_ : type' lang) (_ : unit -> T) : T;
  handle_Trv_ref (_ : type' lang) (_ : unit -> T) : T;
  handle_Tqualified (_ : type_qualifiers) (_ : type' lang) (_ : unit -> T) : T;
}.
Arguments type_handler' : clear implicits.
Notation type_handler lang1 lang2 M := (
  type_handler' lang1
    (M (name' lang2%type))
    (M (decltype' lang2%type))
    (M (Expr' lang2%type))
).

Record expr_handler'@{u} {lang} {N T E : Set} {F : Set -> Type@{u}} : Type@{u} := {

Dependent terms

  handle_Eparam (_ : ident) : F E;
  handle_Eunresolved_global (_ : name' lang) (_ : unit -> F N) : F E;
  handle_Eunresolved_unop (_ : RUnOp) (_ : Expr' lang) (_ : unit -> F E) : F E;
  handle_Eunresolved_binop (_ : RBinOp) (_ _ : Expr' lang) (_ _ : unit -> F E) : F E;
  handle_Eunresolved_call (_ : name' lang) (_ : list (Expr' lang))
    (_ : unit -> F N) (_ : unit -> list (F E)) : F E;
  handle_Eunresolved_member_call (_ : name' lang) (_ : Expr' lang) (_ : list (Expr' lang))
    (_ : unit -> F N) (_ : unit -> F E) (_ : unit -> list (F E)) : F E;
  handle_Eunresolved_parenlist (_ : option (type' lang)) (_ : list (Expr' lang))
    (_ : unit -> option (F T)) (_ : unit -> list (F E)) : F E;
  handle_Eunresolved_member (_ : Expr' lang) (_ : name' lang) (_ : unit -> F E) (_ : unit -> F N) : F E;

Embedded expression types

handle_expr_type : F T -> F T;

casts

  handle_Eunresolved_cast (_ : type' lang) (_ : unit -> F T) (_ : Expr' lang) (_ : unit -> F E) : F E;

  handle_unresolved_init (_ : type' lang) (_ : unit -> F T) (_ : option (Expr' lang * (unit -> F E ))) : F (T * option E)%type
}.
Arguments expr_handler' : clear implicits.
Notation expr_handler lang1 lang2 M := (
  expr_handler' lang1
    (name' lang2%type)
    (type' lang2%type)
    (Expr' lang2%type) M
).

Handlers for derived traversal functions (e.g., for a traversal of type MMethod -> M SMethod) are a bit different from the preceding handlers as they aren't involved in the mutually recursive traversals on names, types, and expressions.

Record core_traversal@{u} {lang lang'} {F : Set -> Type@{u}} : Type@{u} :=
{

Traversal functions

  handle_traverseN (_ : name' lang) : F (name' lang');
  handle_traverseT (_ : type' lang) : F (type' lang');
  handle_traverseE (_ : Expr' lang) : F (Expr' lang');
  handle_traverseS (_ : Stmt' lang) : F (Stmt' lang');

Initializers

handle_classname (_ : classname' lang) : F (classname' lang');
handle_traverseE_init (_ : type' lang) (_ : option (Expr' lang)) : F (type' lang' * option (Expr' lang'))%type;
}.
Arguments core_traversal : clear implicits.

Basic handlers

Section handlers.
  Universe u.
  Context {F : Set -> Type@{u}} `{!FMap F, !MRet F, AP : !Ap F}.
  Context {lang1 lang2 : lang.t}.

Just traverse

Just traverse

  Definition handle_expr_traverse : expr_handler lang1 lang2 F := {|
    handle_Eparam X := mret $ Eparam X;
    handle_Eunresolved_global _ n := Eunresolved_global <$> n ();
    handle_Eunresolved_unop o _ e := Eunresolved_unop o <$> e ();
    handle_Eunresolved_binop o _ _ l r := Eunresolved_binop o <$> l () <*> r ();
    handle_Eunresolved_call _ _ n es := Eunresolved_call <$> n () <*> sequence@{eta list} (es ());
    handle_Eunresolved_member_call _ _ _ n e es := Eunresolved_member_call <$> n () <*> e () <*> sequence@{eta list} (es ());
    handle_Eunresolved_parenlist _ _ t es := Eunresolved_parenlist <$> sequence@{eta option} (t ()) <*> sequence@{eta list} (es ());
    handle_Eunresolved_member _ _ o f := Eunresolved_member <$> o () <*> f ();
    handle_expr_type := id;
    handle_Eunresolved_cast _ Mt _ Me := (fun t e => Ecast (Cdependent t) e) <$> Mt () <*> Me () ;
    handle_unresolved_init _ mt oe :=
      match oe with
      | None => (fun t => (t , None )) <$> mt ()
      | Some e => pair <$> mt () <*> (Some <$> e.2 ())
      end
  |}.
End handlers.

TODO: Adjust #[only(lens)] derive to support (primitive projections and) universe polymorphic records, then derive a full set of lenses for the handler types.