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refactor: simplify examples
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favonia committed Jan 20, 2024
1 parent e190580 commit 0f4ca03
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Showing 2 changed files with 29 additions and 34 deletions.
44 changes: 21 additions & 23 deletions examples/stlc/Checker.ml
Original file line number Diff line number Diff line change
Expand Up @@ -13,18 +13,18 @@ struct
let bind_var nm tp k =
Reader.scope (fun env -> Snoc(env, (nm, tp))) k

let lookup ?loc nm =
let lookup nm =
let ctx = Reader.read () in
match Bwd.find_opt (fun (nm', _) -> String.equal nm nm') ctx with
| Some (_, tp) -> tp
| None ->
Reporter.fatalf ?loc `UnboundVariable "variable '%s' is not in scope" nm
Reporter.fatalf UnboundVariable "variable '%s' is not in scope" nm

let expected_connective ?loc conn tp =
Reporter.fatalf ?loc `TypeError "expected a %s, but got %a" conn pp_tp tp
let expected_connective conn tp =
Reporter.fatalf TypeError "expected a %s, but got %a" conn pp_tp tp

let rec equate ?loc expected actual =
Reporter.tracef ?loc "when equating terms" @@ fun () ->
let rec equate expected actual =
Reporter.trace "when equating terms" @@ fun () ->
match expected, actual with
| Fun (a0, b0), Fun (a1, b1) ->
equate a0 a1;
Expand All @@ -35,7 +35,7 @@ struct
| Nat, Nat ->
()
| _, _ ->
Reporter.fatalf ?loc `TypeError "expected type %a, but got %a" pp_tp expected pp_tp actual
Reporter.fatalf TypeError "expected type %a, but got %a" pp_tp expected pp_tp actual

let rec chk (tm : tm) (tp : tp) : unit =
Reporter.tracef ?loc:tm.loc "when checking it against %a" Syntax.pp_tp tp @@ fun () ->
Expand All @@ -44,53 +44,53 @@ struct
bind_var nm a @@ fun () ->
chk body b
| Lam (_, _), _ ->
expected_connective ?loc:tm.loc "function type" tp
expected_connective "function type" tp
| Pair (l, r), Tuple (a, b) ->
chk l a;
chk r b;
| Pair (_, _), _ ->
expected_connective ?loc:tm.loc "pair type" tp
expected_connective "pair type" tp
| Lit _, Nat ->
()
| Lit _, _ ->
expected_connective ?loc:tm.loc "" tp
expected_connective "" tp
| Suc n, Nat ->
chk n Nat
| Suc _, _ ->
expected_connective ?loc:tm.loc "" tp
expected_connective "" tp
| _ ->
let actual_tp = syn tm in
equate ?loc:tm.loc tp actual_tp
equate tp actual_tp

and syn (tm : tm) : tp =
Reporter.tracef ?loc:tm.loc "when synthesizing its type" @@ fun () ->
Reporter.trace ?loc:tm.loc "when synthesizing its type" @@ fun () ->
match tm.value with
| Var nm ->
lookup ?loc:tm.loc nm
lookup nm
| Ap (fn, arg) ->
begin
match syn fn with
| Fun (a, b) ->
chk arg a;
b
| tp ->
expected_connective ?loc:tm.loc "function type" tp
expected_connective "function type" tp
end
| Fst tm ->
begin
match syn tm with
| Tuple (l, _) ->
l
| tp ->
expected_connective ?loc:tm.loc "pair type" tp
expected_connective "pair type" tp
end
| Snd tm ->
begin
match syn tm with
| Tuple (_, r) ->
r
| tp ->
expected_connective ?loc:tm.loc "pair type" tp
expected_connective "pair type" tp
end
| NatRec (z, s, scrut) ->
begin
Expand All @@ -100,7 +100,7 @@ struct
mot
end
| _ ->
Reporter.fatalf ?loc:tm.loc `TypeError "unable to infer its type"
Reporter.fatal ?loc:tm.loc TypeError "unable to infer its type"
end

module Driver =
Expand All @@ -111,12 +111,10 @@ struct
let (tm, tp) =
try Grammar.defn Lex.token lexbuf with
| Lex.SyntaxError tok ->
Reporter.fatalf ~loc:(Asai.Range.of_lexbuf lexbuf) `LexingError "unrecognized token %S" tok
Reporter.fatalf ~loc:(Asai.Range.of_lexbuf lexbuf) ParsingError "unrecognized token %S" tok
| Grammar.Error ->
Reporter.fatalf ~loc:(Asai.Range.of_lexbuf lexbuf) `LexingError "failed to parse"
in
Elab.Reader.run ~env:Emp @@ fun () ->
Elab.chk tm tp
Reporter.fatal ~loc:(Asai.Range.of_lexbuf lexbuf) ParsingError "failed to parse"
in Elab.Reader.run ~env:Emp @@ fun () -> Elab.chk tm tp

let load mode filepath =
let display : Reporter.Message.t Asai.Diagnostic.t -> unit =
Expand Down
19 changes: 8 additions & 11 deletions examples/stlc/Reporter.ml
Original file line number Diff line number Diff line change
@@ -1,22 +1,19 @@
module Message =
struct
type t =
[ `TypeError (* Type checking failed *)
| `UnboundVariable (* Unbound variable *)
| `RequiresAnnotation (* Unable to infer the type *)
| `LexingError (* The lexer encountered an error *)
| `ParsingError (* Parsing errors *)
]
| TypeError (* Type checking failed *)
| UnboundVariable (* Unbound variable *)
| RequiresAnnotation (* Unable to infer the type *)
| ParsingError (* Parsing errors *)

let default_severity _ = Asai.Diagnostic.Error

let short_code : t -> string =
function
| `TypeError -> "E001"
| `UnboundVariable -> "E002"
| `RequiresAnnotation -> "E003"
| `LexingError -> "E004"
| `ParsingError -> "E005"
| TypeError -> "E001"
| UnboundVariable -> "E002"
| RequiresAnnotation -> "E003"
| ParsingError -> "E004"
end

include Asai.Reporter.Make(Message)

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