380 lines
14 KiB
OCaml
380 lines
14 KiB
OCaml
(***********************************************************************)
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(* *)
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(* Caml Special Light *)
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(* *)
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(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
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(* *)
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(* Copyright 1995 Institut National de Recherche en Informatique et *)
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(* Automatique. Distributed only by permission. *)
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(* *)
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(***********************************************************************)
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(* $Id$ *)
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(* Type-checking of the module language *)
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open Misc
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open Longident
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open Path
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open Parsetree
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open Typedtree
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type error =
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Unbound_module of Longident.t
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| Unbound_modtype of Longident.t
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| Cannot_apply of module_type
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| Not_included of Includemod.error list
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| Cannot_eliminate_dependency of module_type
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| Signature_expected
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| Structure_expected of module_type
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| With_no_component of Longident.t
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| Repeated_name of string * string
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| Non_generalizable of type_expr
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exception Error of Location.t * error
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(* Extract a signature from a module type *)
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let extract_sig env loc mty =
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match Mtype.scrape env mty with
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Tmty_signature sg -> sg
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| _ -> raise(Error(loc, Signature_expected))
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let extract_sig_open env loc mty =
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match Mtype.scrape env mty with
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Tmty_signature sg -> sg
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| _ -> raise(Error(loc, Structure_expected mty))
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(* Lookup the type of a module path *)
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let type_module_path env loc lid =
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try
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Env.lookup_module lid env
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with Not_found ->
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raise(Error(loc, Unbound_module lid))
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(* Merge one "with" constraint in a signature *)
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let merge_constraint env loc sg lid constr =
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let rec merge sg namelist =
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match (sg, namelist, constr) with
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([], _, _) ->
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raise(Error(loc, With_no_component lid))
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| (Tsig_type(id, decl) :: rem, [s], Pwith_type sdecl)
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when Ident.name id = s ->
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let newdecl = Typedecl.transl_with_constraint env sdecl in
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Tsig_type(id, newdecl) :: rem
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| (Tsig_module(id, mty) :: rem, [s], Pwith_module lid)
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when Ident.name id = s ->
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let (path, mty') = type_module_path env loc lid in
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Tsig_module(id, Mtype.strengthen env mty' path) :: rem
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| (Tsig_module(id, mty) :: rem, s :: namelist, _) when Ident.name id = s ->
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let newsg = merge (extract_sig env loc mty) namelist in
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Tsig_module(id, Tmty_signature newsg) :: rem
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| (item :: rem, _, _) ->
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item :: merge rem namelist in
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merge sg (Longident.flatten lid)
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(* Check and translate a module type expression *)
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let rec transl_modtype env smty =
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match smty.pmty_desc with
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Pmty_ident lid ->
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begin try
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let (path, info) = Env.lookup_modtype lid env in
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Tmty_ident path
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with Not_found ->
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raise(Error(smty.pmty_loc, Unbound_modtype lid))
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end
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| Pmty_signature ssg ->
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Tmty_signature(transl_signature env ssg)
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| Pmty_functor(param, sarg, sres) ->
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let arg = transl_modtype env sarg in
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let (id, newenv) = Env.enter_module param arg env in
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let res = transl_modtype newenv sres in
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Tmty_functor(id, arg, res)
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| Pmty_with(sbody, constraints) ->
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let body = transl_modtype env sbody in
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let init_sg = extract_sig env sbody.pmty_loc body in
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let final_sg =
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List.fold_left
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(fun sg (lid, sdecl) ->
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merge_constraint env smty.pmty_loc sg lid sdecl)
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init_sg constraints in
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Tmty_signature final_sg
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and transl_signature env sg =
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match sg with
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[] -> []
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| {psig_desc = Psig_value(name, sdesc)} :: srem ->
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let desc = Typedecl.transl_value_decl env sdesc in
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let (id, newenv) = Env.enter_value name desc env in
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let rem = transl_signature newenv srem in
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Tsig_value(id, desc) :: rem
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| {psig_desc = Psig_type sdecls} :: srem ->
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let (decls, newenv) = Typedecl.transl_type_decl env sdecls in
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let rem = transl_signature newenv srem in
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map_end (fun (id, info) -> Tsig_type(id, info)) decls rem
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| {psig_desc = Psig_exception(name, sarg)} :: srem ->
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let arg = Typedecl.transl_exception env sarg in
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let (id, newenv) = Env.enter_exception name arg env in
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let rem = transl_signature newenv srem in
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Tsig_exception(id, arg) :: rem
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| {psig_desc = Psig_module(name, smty)} :: srem ->
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let mty = transl_modtype env smty in
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let (id, newenv) = Env.enter_module name mty env in
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let rem = transl_signature newenv srem in
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Tsig_module(id, mty) :: rem
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| {psig_desc = Psig_modtype(name, sinfo)} :: srem ->
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let info = transl_modtype_info env sinfo in
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let (id, newenv) = Env.enter_modtype name info env in
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let rem = transl_signature newenv srem in
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Tsig_modtype(id, info) :: rem
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| {psig_desc = Psig_open lid; psig_loc = loc} :: srem ->
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let (path, mty) = type_module_path env loc lid in
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let sg = extract_sig_open env loc mty in
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let newenv = Env.open_signature path sg env in
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transl_signature newenv srem
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| {psig_desc = Psig_include smty} :: srem ->
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let mty = transl_modtype env smty in
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let sg = extract_sig env smty.pmty_loc mty in
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let newenv = Env.add_signature sg env in
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let rem = transl_signature newenv srem in
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sg @ rem
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and transl_modtype_info env sinfo =
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match sinfo with
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Pmodtype_abstract ->
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Tmodtype_abstract
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| Pmodtype_manifest smty ->
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Tmodtype_manifest(transl_modtype env smty)
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(* Try to convert a module expression to a module path. *)
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exception Not_a_path
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let rec path_of_module mexp =
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match mexp.mod_desc with
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Tmod_ident p -> p
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| Tmod_apply(funct, arg, coercion) ->
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Papply(path_of_module funct, path_of_module arg)
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| _ -> raise Not_a_path
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(* Check that all type and module identifiers in a structure have
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distinct names (so that access by named paths is unambiguous). *)
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module StringSet = Set.Make(struct type t = string let compare = compare end)
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let check_unique_names sg =
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let type_names = ref StringSet.empty
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and module_names = ref StringSet.empty
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and modtype_names = ref StringSet.empty in
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let check class loc set_ref name =
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if StringSet.mem name !set_ref
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then raise(Error(loc, Repeated_name(class, name)))
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else set_ref := StringSet.add name !set_ref in
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let check_item item =
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match item.pstr_desc with
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Pstr_eval exp -> ()
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| Pstr_value(rec_flag, exps) -> ()
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| Pstr_primitive(name, desc) -> ()
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| Pstr_type name_decl_list ->
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List.iter
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(fun (name, decl) -> check "type" item.pstr_loc type_names name)
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name_decl_list
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| Pstr_exception(name, decl) -> ()
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| Pstr_module(name, smod) ->
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check "module" item.pstr_loc module_names name
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| Pstr_modtype(name, decl) ->
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check "module type" item.pstr_loc modtype_names name
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| Pstr_open lid -> () in
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List.iter check_item sg
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(* Check that all core type schemes in a structure are closed *)
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let check_nongen_schemes str =
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List.iter
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(function
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Tstr_value(rec_flag, pat_exp_list) ->
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List.iter
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(fun (pat, exp) ->
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if not (Ctype.closed_schema exp.exp_type) then
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raise(Error(exp.exp_loc, Non_generalizable exp.exp_type)))
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pat_exp_list
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| _ -> ()) (* Sub-structures have been checked before *)
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str
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(* Type a module value expression *)
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let rec type_module env smod =
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match smod.pmod_desc with
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Pmod_ident lid ->
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let (path, mty) = type_module_path env smod.pmod_loc lid in
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{ mod_desc = Tmod_ident path;
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mod_type = Mtype.strengthen env mty path;
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mod_loc = smod.pmod_loc }
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| Pmod_structure sstr ->
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let (str, sg, _) = type_structure env sstr in
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check_nongen_schemes str;
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{ mod_desc = Tmod_structure str;
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mod_type = Tmty_signature sg;
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mod_loc = smod.pmod_loc }
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| Pmod_functor(name, smty, sbody) ->
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let mty = transl_modtype env smty in
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let (id, newenv) = Env.enter_module name mty env in
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let body = type_module newenv sbody in
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{ mod_desc = Tmod_functor(id, mty, body);
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mod_type = Tmty_functor(id, mty, body.mod_type);
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mod_loc = smod.pmod_loc }
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| Pmod_apply(sfunct, sarg) ->
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let funct = type_module env sfunct in
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let arg = type_module env sarg in
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begin match Mtype.scrape env funct.mod_type with
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Tmty_functor(param, mty_param, mty_res) as mty_functor ->
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let coercion =
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try
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Includemod.modtypes env arg.mod_type mty_param
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with Includemod.Error msg ->
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raise(Error(sarg.pmod_loc, Not_included msg)) in
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let mty_appl =
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try
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let path = path_of_module arg in
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Subst.modtype (Subst.add_module param path Subst.identity)
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mty_res
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with Not_a_path ->
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try
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Mtype.nondep_supertype
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(Env.add_module param arg.mod_type env) param mty_res
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with Not_found ->
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raise(Error(smod.pmod_loc,
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Cannot_eliminate_dependency mty_functor)) in
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{ mod_desc = Tmod_apply(funct, arg, coercion);
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mod_type = mty_appl;
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mod_loc = smod.pmod_loc }
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| _ ->
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raise(Error(sfunct.pmod_loc, Cannot_apply funct.mod_type))
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end
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| Pmod_constraint(sarg, smty) ->
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let arg = type_module env sarg in
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let mty = transl_modtype env smty in
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let coercion =
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try
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Includemod.modtypes env arg.mod_type mty
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with Includemod.Error msg ->
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raise(Error(sarg.pmod_loc, Not_included msg)) in
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{ mod_desc = Tmod_constraint(arg, mty, coercion);
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mod_type = mty;
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mod_loc = smod.pmod_loc }
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and type_structure env sstr =
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check_unique_names sstr;
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type_struct env sstr
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and type_struct env = function
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[] ->
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([], [], env)
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| {pstr_desc = Pstr_eval sexpr} :: srem ->
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let expr = Typecore.type_expression env sexpr in
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let (str_rem, sig_rem, final_env) = type_struct env srem in
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(Tstr_eval expr :: str_rem, sig_rem, final_env)
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| {pstr_desc = Pstr_value(rec_flag, sdefs)} :: srem ->
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let (defs, newenv) =
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Typecore.type_binding env rec_flag sdefs in
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let (str_rem, sig_rem, final_env) = type_struct newenv srem in
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let bound_idents = List.rev(let_bound_idents defs) in
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let make_sig_value id =
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Tsig_value(id, Env.find_value (Pident id) newenv) in
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(Tstr_value(rec_flag, defs) :: str_rem,
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map_end make_sig_value bound_idents sig_rem,
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final_env)
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| {pstr_desc = Pstr_primitive(name, sdesc)} :: srem ->
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let desc = Typedecl.transl_value_decl env sdesc in
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let (id, newenv) = Env.enter_value name desc env in
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let (str_rem, sig_rem, final_env) = type_struct newenv srem in
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(Tstr_primitive(id, desc) :: str_rem,
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Tsig_value(id, desc) :: sig_rem,
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final_env)
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| {pstr_desc = Pstr_type sdecls} :: srem ->
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let (decls, newenv) = Typedecl.transl_type_decl env sdecls in
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let (str_rem, sig_rem, final_env) = type_struct newenv srem in
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(Tstr_type decls :: str_rem,
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map_end (fun (id, info) -> Tsig_type(id, info)) decls sig_rem,
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final_env)
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| {pstr_desc = Pstr_exception(name, sarg)} :: srem ->
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let arg = Typedecl.transl_exception env sarg in
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let (id, newenv) = Env.enter_exception name arg env in
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let (str_rem, sig_rem, final_env) = type_struct newenv srem in
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(Tstr_exception(id, arg) :: str_rem,
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Tsig_exception(id, arg) :: sig_rem,
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final_env)
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| {pstr_desc = Pstr_module(name, smodl)} :: srem ->
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let modl = type_module env smodl in
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let (id, newenv) = Env.enter_module name modl.mod_type env in
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let (str_rem, sig_rem, final_env) = type_struct newenv srem in
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(Tstr_module(id, modl) :: str_rem,
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Tsig_module(id, modl.mod_type) :: sig_rem,
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final_env)
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| {pstr_desc = Pstr_modtype(name, smty)} :: srem ->
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let mty = transl_modtype env smty in
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let (id, newenv) = Env.enter_modtype name (Tmodtype_manifest mty) env in
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let (str_rem, sig_rem, final_env) = type_struct newenv srem in
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(Tstr_modtype(id, mty) :: str_rem,
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Tsig_modtype(id, Tmodtype_manifest mty) :: sig_rem,
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final_env)
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| {pstr_desc = Pstr_open lid; pstr_loc = loc} :: srem ->
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let (path, mty) = type_module_path env loc lid in
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let sg = extract_sig_open env loc mty in
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type_struct (Env.open_signature path sg env) srem
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(* Error report *)
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open Format
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open Printtyp
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let report_error = function
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Unbound_module lid ->
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print_string "Unbound module "; longident lid
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| Unbound_modtype lid ->
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print_string "Unbound module type "; longident lid
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| Cannot_apply mty ->
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open_hovbox 0;
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print_string "This module is not a functor; it has type";
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print_space(); modtype mty;
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close_box()
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| Not_included errs ->
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open_vbox 0;
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print_string "Signature mismatch:"; print_space();
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Includemod.report_error errs;
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close_box()
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| Cannot_eliminate_dependency mty ->
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open_hovbox 0;
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print_string "This functor has type";
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print_space(); modtype mty; print_space();
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print_string "The parameter cannot be eliminated in the result type.";
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print_space();
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print_string "Please bind the argument to a module identifier.";
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close_box()
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| Signature_expected ->
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print_string "This module type is not a signature"
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| Structure_expected mty ->
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open_hovbox 0;
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print_string "This module is not a structure; it has type";
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print_space(); modtype mty;
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close_box()
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| With_no_component lid ->
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print_string "The signature constrained by `with' has no component named";
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print_space(); longident lid
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| Repeated_name(kind, name) ->
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open_hovbox 0;
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print_string "Multiple definition of the "; print_string kind;
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print_string " name "; print_string name; print_string ".";
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print_space();
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print_string "Names must be unique in a given structure.";
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close_box()
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| Non_generalizable typ ->
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open_hovbox 0;
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print_string "The type of this expression,"; print_space();
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type_scheme typ; print_string ","; print_space();
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print_string "contains type variables that cannot be generalized"
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