Remove the Typed module

[Halbaroth]

This PR removes the output AST of the legacy typechecker. This AST was still used by the compilation of match expressions in Expr.

[bclement-ocp]

Apologies, I thought I had already reviewed this one before my vacation but looks like I forgot to finish the review.

Overall looks good — I think the Expr module was a good boundary for the mk_match abstraction but I'm OK as is now that we have a single frontend.

[bclement-ocp]

Suggested change

	(* (* TO BE REMOVED *)
	let debug_compile_match e cases res =
	if Options.get_debug_adt () then begin
	Printer.print_dbg ~flushed:false ~module_name:"Expr"
	"compilation of: match %a with@ " print e;
	let p_list_vars fmt l =
	match l with
	[] -> ()
	| [e,_,_] -> Var.print fmt e
	| (e,_,_) :: l ->
	Format.fprintf fmt "(%a" Var.print e;
	List.iter (fun (e,_,_) -> Format.fprintf fmt ", %a" Var.print e) l;
	Format.fprintf fmt ")"
	in
	List.iter
	(fun (p, v) ->
	match p with
	| Typed.Constr {name; args} ->
	Printer.print_dbg ~flushed:false ~header:false
	"| %a %a -> %a@ "
	DE.Term.Const.print name
	p_list_vars args
	print v;
	| Typed.Var x ->
	Printer.print_dbg ~flushed:false ~header:false
	"| %a -> %a@ " Var.print x print v;
	)cases;
	Printer.print_dbg ~header:false
	"end@ result is: %a" print res;
	end *)

[bclement-ocp]

Nit: if using local modules for actual implementation work there is an abstraction boundary that should be ideally documented and at least typed.

Suggested change

	module Match = struct
	module Match : sig
	type pat
	val mk_pat : DE.term -> pat
	val make : Expr.t -> (pat * Expr.t) list -> Expr.t
	end = struct

[Halbaroth]

Overall looks good — I think the Expr module was a good boundary for the mk_match abstraction but I'm OK as is now that we have a single frontend.

I had the same concerns when I have done this modification. Expr is an internal AST of the library and Dolmen expressions will become the new input AST of the library. Moving this feature from Expr to Translate means we cannot use it directly on AE expressions as library developers, but we do not use it. Actually we could use it in models because it would be simpler to produce a match expression for model terms then compiles it. My opinion is that we do not need to focus on this detail now and we can move back a part of the code in Expr later if we want to produce match expressions from AE expressions. Keeping all the match compilation code in Translate now is just simpler in the current state of the code base.

[bclement-ocp]

I had the same concerns when I have done this modification. [..] My opinion is that we do not need to focus on this detail now and we can move back a part of the code in Expr later

This argument could have been made to avoid moving the code out of Expr in the first place ;)