From f112145814ed8243904d97c92a15bbdb7053d1a0 Mon Sep 17 00:00:00 2001 From: Nadrieril Date: Mon, 18 Mar 2019 00:21:41 +0100 Subject: Considerably simplify subst, shift and typechecking --- dhall/src/main.rs | 2 +- dhall/src/normalize.rs | 25 ++--- dhall/src/typecheck.rs | 297 +++++++++++++------------------------------------ 3 files changed, 87 insertions(+), 237 deletions(-) (limited to 'dhall/src') diff --git a/dhall/src/main.rs b/dhall/src/main.rs index 41953e3..810d789 100644 --- a/dhall/src/main.rs +++ b/dhall/src/main.rs @@ -90,5 +90,5 @@ fn main() { println!("{}", type_expr); println!(); - println!("{}", normalize::<_, X, _>(expr)); + println!("{}", normalize(expr)); } diff --git a/dhall/src/normalize.rs b/dhall/src/normalize.rs index af30e3b..8438670 100644 --- a/dhall/src/normalize.rs +++ b/dhall/src/normalize.rs @@ -163,10 +163,9 @@ where let just = Rc::clone(&args[3]); return normalize_whnf(&dhall_expr!(just x)); } - ( - OptionalFold, - [_, OptionalLit(_, None), _, _, _], - ) => return Rc::clone(&args[4]), + (OptionalFold, [_, OptionalLit(_, None), _, _, _]) => { + return Rc::clone(&args[4]) + } // // fold/build fusion // (OptionalFold, [_, App(box Builtin(OptionalBuild), [_, x, rest..]), rest..]) => { // normalize_whnf(&App(bx(x.clone()), rest.to_vec())) @@ -237,9 +236,7 @@ where NaturalLit(x * y) } // TODO: interpolation - (TextAppend, TextLit(x), TextLit(y)) => { - TextLit(x + y) - } + (TextAppend, TextLit(x), TextLit(y)) => TextLit(x + y), (ListAppend, ListLit(t1, xs), ListLit(t2, ys)) => { let t1: Option> = t1.as_ref().map(Rc::clone); let t2: Option> = t2.as_ref().map(Rc::clone); @@ -279,16 +276,10 @@ where /// However, `normalize` will not fail if the expression is ill-typed and will /// leave ill-typed sub-expressions unevaluated. /// -pub fn normalize(e: SubExpr) -> SubExpr +pub fn normalize(e: SubExpr) -> SubExpr where - S: Clone + fmt::Debug, - T: Clone + fmt::Debug, - A: Clone + fmt::Debug, + S: fmt::Debug, + A: fmt::Debug, { - rc(normalize_whnf(&e).map_shallow_rc( - |x| normalize(Rc::clone(x)), - |_| unreachable!(), - |x| x.clone(), - |x| x.clone(), - )) + map_subexpr_rc(&normalize_whnf(&e), |x| normalize(Rc::clone(x))) } diff --git a/dhall/src/typecheck.rs b/dhall/src/typecheck.rs index b507e52..15629a9 100644 --- a/dhall/src/typecheck.rs +++ b/dhall/src/typecheck.rs @@ -15,7 +15,7 @@ use dhall_generator::dhall_expr; use self::TypeMessage::*; -fn axiom(c: core::Const) -> Result> { +fn axiom(c: core::Const) -> Result> { match c { Type => Ok(Kind), Kind => Err(TypeError::new(&Context::new(), rc(Const(Kind)), Untyped)), @@ -49,8 +49,8 @@ fn match_vars(vl: &V, vr: &V, ctx: &[(Label, Label)]) -> bool { fn prop_equal(eL0: Rc>, eR0: Rc>) -> bool where - S: Clone + ::std::fmt::Debug, - T: Clone + ::std::fmt::Debug, + S: ::std::fmt::Debug, + T: ::std::fmt::Debug, { fn go( ctx: &mut Vec<(Label, Label)>, @@ -58,8 +58,8 @@ where er: Rc>, ) -> bool where - S: Clone + ::std::fmt::Debug, - T: Clone + ::std::fmt::Debug, + S: ::std::fmt::Debug, + T: ::std::fmt::Debug, { match (el.as_ref(), er.as_ref()) { (&Const(Type), &Const(Type)) | (&Const(Kind), &Const(Kind)) => true, @@ -153,7 +153,7 @@ fn op2_type( r: &Rc>, ) -> Result, TypeError> where - S: Clone + ::std::fmt::Debug, + S: ::std::fmt::Debug, EF: FnOnce(Rc>, Rc>) -> TypeMessage, { let tl = normalize(type_with(ctx, l.clone())?); @@ -182,17 +182,18 @@ pub fn type_with( e: Rc>, ) -> Result>, TypeError> where - S: Clone + ::std::fmt::Debug, + S: ::std::fmt::Debug, { use dhall_core::BinOp::*; use dhall_core::Expr; + let mkerr = |msg: TypeMessage<_>| TypeError::new(ctx, e.clone(), msg); match *e { Const(c) => axiom(c).map(Const), Var(V(ref x, n)) => { return ctx .lookup(x, n) .cloned() - .ok_or_else(|| TypeError::new(ctx, e.clone(), UnboundVariable)) + .ok_or_else(|| mkerr(UnboundVariable)) } Lam(ref x, ref tA, ref b) => { let ctx2 = ctx @@ -204,15 +205,11 @@ where return Ok(p); } Pi(ref x, ref tA, ref tB) => { - let tA2 = normalize::(type_with(ctx, tA.clone())?); + let tA2 = normalize(type_with(ctx, tA.clone())?); let kA = match tA2.as_ref() { Const(k) => k, _ => { - return Err(TypeError::new( - ctx, - e.clone(), - InvalidInputType(tA.clone()), - )); + return Err(mkerr(InvalidInputType(tA.clone()))); } }; @@ -232,29 +229,26 @@ where }; match rule(kA, kB) { - Err(()) => Err(TypeError::new( - ctx, - e.clone(), - NoDependentTypes(tA.clone(), tB), - )), + Err(()) => Err(mkerr(NoDependentTypes(tA.clone(), tB))), Ok(k) => Ok(Const(k)), } } App(ref f, ref args) => { - let (a, args) = match args.split_last() { + // Recurse on args + let (a, tf) = match args.split_last() { None => return type_with(ctx, f.clone()), - Some(x) => x, + Some((a, args)) => ( + a, + normalize(type_with( + ctx, + rc(App(f.clone(), args.to_vec())), + )?), + ), }; - let tf = - normalize(type_with(ctx, rc(App(f.clone(), args.to_vec())))?); let (x, tA, tB) = match tf.as_ref() { Pi(x, tA, tB) => (x, tA, tB), _ => { - return Err(TypeError::new( - ctx, - e.clone(), - NotAFunction(f.clone(), tf), - )); + return Err(mkerr(NotAFunction(f.clone(), tf))); } }; let tA2 = type_with(ctx, a.clone())?; @@ -267,62 +261,38 @@ where } else { let nf_A = normalize(tA.clone()); let nf_A2 = normalize(tA2); - Err(TypeError::new( - ctx, - e.clone(), - TypeMismatch(f.clone(), nf_A, a.clone(), nf_A2), - )) + Err(mkerr(TypeMismatch(f.clone(), nf_A, a.clone(), nf_A2))) } } Let(ref f, ref mt, ref r, ref b) => { let tR = type_with(ctx, r.clone())?; - let ttR = normalize::(type_with(ctx, tR.clone())?); + let ttR = normalize(type_with(ctx, tR.clone())?); let kR = match ttR.as_ref() { Const(k) => k, // Don't bother to provide a `let`-specific version of this error // message because this should never happen anyway - _ => { - return Err(TypeError::new( - ctx, - e.clone(), - InvalidInputType(tR), - )) - } + _ => return Err(mkerr(InvalidInputType(tR))), }; let ctx2 = ctx.insert(f.clone(), tR.clone()); let tB = type_with(&ctx2, b.clone())?; - let ttB = normalize::(type_with(ctx, tB.clone())?); + let ttB = normalize(type_with(ctx, tB.clone())?); let kB = match ttB.as_ref() { Const(k) => k, // Don't bother to provide a `let`-specific version of this error // message because this should never happen anyway - _ => { - return Err(TypeError::new( - ctx, - e.clone(), - InvalidOutputType(tB), - )) - } + _ => return Err(mkerr(InvalidOutputType(tB))), }; if let Err(()) = rule(kR, kB) { - return Err(TypeError::new( - ctx, - e.clone(), - NoDependentLet(tR, tB), - )); + return Err(mkerr(NoDependentLet(tR, tB))); } if let Some(ref t) = *mt { let nf_t = normalize(t.clone()); let nf_tR = normalize(tR); if !prop_equal(nf_tR.clone(), nf_t.clone()) { - return Err(TypeError::new( - ctx, - e.clone(), - AnnotMismatch(r.clone(), nf_t, nf_tR), - )); + return Err(mkerr(AnnotMismatch(r.clone(), nf_t, nf_tR))); } } @@ -338,11 +308,7 @@ where } else { let nf_t = normalize(t.clone()); let nf_t2 = normalize(t2); - Err(TypeError::new( - ctx, - e.clone(), - AnnotMismatch(x.clone(), nf_t, nf_t2), - )) + Err(mkerr(AnnotMismatch(x.clone(), nf_t, nf_t2))) } } BoolLit(_) => Ok(Builtin(Bool)), @@ -363,11 +329,7 @@ where match tx.as_ref() { Builtin(Bool) => {} _ => { - return Err(TypeError::new( - ctx, - e.clone(), - InvalidPredicate(x.clone(), tx), - )); + return Err(mkerr(InvalidPredicate(x.clone(), tx))); } } let ty = normalize(type_with(ctx, y.clone())?); @@ -375,11 +337,12 @@ where match tty.as_ref() { Const(Type) => {} _ => { - return Err(TypeError::new( - ctx, - e.clone(), - IfBranchMustBeTerm(true, y.clone(), ty, tty), - )); + return Err(mkerr(IfBranchMustBeTerm( + true, + y.clone(), + ty, + tty, + ))); } } @@ -388,20 +351,22 @@ where match ttz.as_ref() { Const(Type) => {} _ => { - return Err(TypeError::new( - ctx, - e.clone(), - IfBranchMustBeTerm(false, z.clone(), tz, ttz), - )); + return Err(mkerr(IfBranchMustBeTerm( + false, + z.clone(), + tz, + ttz, + ))); } } if !prop_equal(ty.clone(), tz.clone()) { - return Err(TypeError::new( - ctx, - e.clone(), - IfBranchMismatch(y.clone(), z.clone(), ty, tz), - )); + return Err(mkerr(IfBranchMismatch( + y.clone(), + z.clone(), + ty, + tz, + ))); } return Ok(ty); } @@ -451,27 +416,22 @@ where } }; - let s = normalize::<_, S, _>(type_with(ctx, t.clone())?); + let s = normalize(type_with(ctx, t.clone())?); match s.as_ref() { Const(Type) => {} - _ => { - return Err(TypeError::new( - ctx, - e.clone(), - InvalidListType(t), - )) - } + _ => return Err(mkerr(InvalidListType(t))), } for (i, x) in iter { let t2 = type_with(ctx, x.clone())?; if !prop_equal(t.clone(), t2.clone()) { let nf_t = normalize(t); let nf_t2 = normalize(t2); - return Err(TypeError::new( - ctx, - e.clone(), - InvalidListElement(i, nf_t, x.clone(), nf_t2), - )); + return Err(mkerr(InvalidListElement( + i, + nf_t, + x.clone(), + nf_t2, + ))); } } return Ok(dhall_expr!(List t)); @@ -524,15 +484,11 @@ where } }; - let s = normalize::<_, S, _>(type_with(ctx, t.clone())?); + let s = normalize(type_with(ctx, t.clone())?); match s.as_ref() { Const(Type) => {} _ => { - return Err(TypeError::new( - ctx, - e.clone(), - InvalidOptionalType(t), - )); + return Err(mkerr(InvalidOptionalType(t))); } } for x in iter { @@ -540,11 +496,11 @@ where if !prop_equal(t.clone(), t2.clone()) { let nf_t = normalize(t); let nf_t2 = normalize(t2); - return Err(TypeError::new( - ctx, - e.clone(), - InvalidOptionalElement(nf_t, x.clone(), nf_t2), - )); + return Err(mkerr(InvalidOptionalElement( + nf_t, + x.clone(), + nf_t2, + ))); } } return Ok(dhall_expr!(Optional t)); @@ -568,15 +524,14 @@ where | Builtin(Double) | Builtin(Text) => Ok(Const(Type)), Record(ref kts) => { for (k, t) in kts { - let s = normalize::(type_with(ctx, t.clone())?); + let s = normalize(type_with(ctx, t.clone())?); match s.as_ref() { Const(Type) => {} _ => { - return Err(TypeError::new( - ctx, - e.clone(), - InvalidFieldType(k.clone(), t.clone()), - )); + return Err(mkerr(InvalidFieldType( + k.clone(), + t.clone(), + ))); } } } @@ -587,15 +542,14 @@ where .iter() .map(|(k, v)| { let t = type_with(ctx, v.clone())?; - let s = normalize::(type_with(ctx, t.clone())?); + let s = normalize(type_with(ctx, t.clone())?); match s.as_ref() { Const(Type) => {} _ => { - return Err(TypeError::new( - ctx, - e.clone(), - InvalidField(k.clone(), v.clone()), - )); + return Err(mkerr(InvalidField( + k.clone(), + v.clone(), + ))); } } Ok((k.clone(), t)) @@ -603,112 +557,17 @@ where .collect::>()?; Ok(Record(kts)) } - /* - type_with ctx e@(Union kts ) = do - let process (k, t) = do - s <- fmap Dhall.Core.normalize (type_with ctx t) - case s of - Const Type -> return () - _ -> Left (TypeError ctx e (InvalidAlternativeType k t)) - mapM_ process (Data.Map.toList kts) - return (Const Type) - type_with ctx e@(UnionLit k v kts) = do - case Data.Map.lookup k kts of - Just _ -> Left (TypeError ctx e (DuplicateAlternative k)) - Nothing -> return () - t <- type_with ctx v - let union = Union (Data.Map.insert k t kts) - _ <- type_with ctx union - return union - type_with ctx e@(Combine kvsX kvsY) = do - tKvsX <- fmap Dhall.Core.normalize (type_with ctx kvsX) - ktsX <- case tKvsX of - Record kts -> return kts - _ -> Left (TypeError ctx e (MustCombineARecord kvsX tKvsX)) - - tKvsY <- fmap Dhall.Core.normalize (type_with ctx kvsY) - ktsY <- case tKvsY of - Record kts -> return kts - _ -> Left (TypeError ctx e (MustCombineARecord kvsY tKvsY)) - - let combineTypes ktsL ktsR = do - let ks = - Data.Set.union (Data.Map.keysSet ktsL) (Data.Map.keysSet ktsR) - kts <- forM (toList ks) (\k -> do - case (Data.Map.lookup k ktsL, Data.Map.lookup k ktsR) of - (Just (Record ktsL'), Just (Record ktsR')) -> do - t <- combineTypes ktsL' ktsR' - return (k, t) - (Nothing, Just t) -> do - return (k, t) - (Just t, Nothing) -> do - return (k, t) - _ -> do - Left (TypeError ctx e (FieldCollision k)) ) - return (Record (Data.Map.fromList kts)) - - combineTypes ktsX ktsY - type_with ctx e@(Merge kvsX kvsY t) = do - tKvsX <- fmap Dhall.Core.normalize (type_with ctx kvsX) - ktsX <- case tKvsX of - Record kts -> return kts - _ -> Left (TypeError ctx e (MustMergeARecord kvsX tKvsX)) - let ksX = Data.Map.keysSet ktsX - - tKvsY <- fmap Dhall.Core.normalize (type_with ctx kvsY) - ktsY <- case tKvsY of - Union kts -> return kts - _ -> Left (TypeError ctx e (MustMergeUnion kvsY tKvsY)) - let ksY = Data.Map.keysSet ktsY - - let diffX = Data.Set.difference ksX ksY - let diffY = Data.Set.difference ksY ksX - - if Data.Set.null diffX - then return () - else Left (TypeError ctx e (UnusedHandler diffX)) - - let process (kY, tY) = do - case Data.Map.lookup kY ktsX of - Nothing -> Left (TypeError ctx e (MissingHandler diffY)) - Just tX -> - case tX of - Pi _ tY' t' -> do - if prop_equal tY tY' - then return () - else Left (TypeError ctx e (HandlerInputTypeMismatch kY tY tY')) - if prop_equal t t' - then return () - else Left (TypeError ctx e (HandlerOutputTypeMismatch kY t t')) - _ -> Left (TypeError ctx e (HandlerNotAFunction kY tX)) - mapM_ process (Data.Map.toList ktsY) - return t - */ Field(ref r, ref x) => { let t = normalize(type_with(ctx, r.clone())?); match t.as_ref() { Record(ref kts) => { return kts.get(x).cloned().ok_or_else(|| { - TypeError::new( - ctx, - e.clone(), - MissingField(x.clone(), t.clone()), - ) + mkerr(MissingField(x.clone(), t.clone())) }) } - _ => Err(TypeError::new( - ctx, - e.clone(), - NotARecord(x.clone(), r.clone(), t.clone()), - )), + _ => Err(mkerr(NotARecord(x.clone(), r.clone(), t.clone()))), } } - /* - type_with ctx (Note s e' ) = case type_with ctx e' of - Left (TypeError ctx2 (Note s' e'') m) -> Left (TypeError ctx2 (Note s' e'') m) - Left (TypeError ctx2 e'' m) -> Left (TypeError ctx2 (Note s e'') m) - Right r -> Right r - */ Embed(p) => match p {}, _ => panic!("Unimplemented typecheck case: {:?}", e), } @@ -718,7 +577,7 @@ where /// `typeOf` is the same as `type_with` with an empty context, meaning that the /// expression must be closed (i.e. no free variables), otherwise type-checking /// will fail. -pub fn type_of( +pub fn type_of( e: Rc>, ) -> Result>, TypeError> { let ctx = Context::new(); @@ -788,7 +647,7 @@ pub struct TypeError { pub type_message: TypeMessage, } -impl TypeError { +impl TypeError { pub fn new( context: &Context>>, current: Rc>, -- cgit v1.2.3