From 655f67fb29ca847f86c3e19338757e7b031d4f50 Mon Sep 17 00:00:00 2001 From: Nadrieril Date: Thu, 30 Jan 2020 11:09:39 +0000 Subject: Move builtins-related code to its own module --- dhall/src/semantics/builtins.rs | 511 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 511 insertions(+) create mode 100644 dhall/src/semantics/builtins.rs (limited to 'dhall/src/semantics/builtins.rs') diff --git a/dhall/src/semantics/builtins.rs b/dhall/src/semantics/builtins.rs new file mode 100644 index 0000000..58cf0d6 --- /dev/null +++ b/dhall/src/semantics/builtins.rs @@ -0,0 +1,511 @@ +use crate::semantics::phase::Normalized; +use crate::semantics::{type_with, NzEnv, Value, ValueKind}; +use crate::syntax::Const::Type; +use crate::syntax::{ + self, Builtin, Const, Expr, ExprKind, InterpolatedText, + InterpolatedTextContents, Label, NaiveDouble, Span, UnspannedExpr, V, +}; +use std::collections::HashMap; +use std::convert::TryInto; + +pub(crate) fn rc(x: UnspannedExpr) -> Expr { + Expr::new(x, Span::Artificial) +} + +// Ad-hoc macro to help construct the types of builtins +macro_rules! make_type { + (Type) => { rc(ExprKind::Const(Const::Type)) }; + (Bool) => { rc(ExprKind::Builtin(Builtin::Bool)) }; + (Natural) => { rc(ExprKind::Builtin(Builtin::Natural)) }; + (Integer) => { rc(ExprKind::Builtin(Builtin::Integer)) }; + (Double) => { rc(ExprKind::Builtin(Builtin::Double)) }; + (Text) => { rc(ExprKind::Builtin(Builtin::Text)) }; + ($var:ident) => { + rc(ExprKind::Var(V(stringify!($var).into(), 0))) + }; + (Optional $ty:ident) => { + rc(ExprKind::App( + rc(ExprKind::Builtin(Builtin::Optional)), + make_type!($ty) + )) + }; + (List $($rest:tt)*) => { + rc(ExprKind::App( + rc(ExprKind::Builtin(Builtin::List)), + make_type!($($rest)*) + )) + }; + ({ $($label:ident : $ty:ident),* }) => {{ + let mut kts = syntax::map::DupTreeMap::new(); + $( + kts.insert( + Label::from(stringify!($label)), + make_type!($ty), + ); + )* + rc(ExprKind::RecordType(kts)) + }}; + ($ty:ident -> $($rest:tt)*) => { + rc(ExprKind::Pi( + "_".into(), + make_type!($ty), + make_type!($($rest)*) + )) + }; + (($($arg:tt)*) -> $($rest:tt)*) => { + rc(ExprKind::Pi( + "_".into(), + make_type!($($arg)*), + make_type!($($rest)*) + )) + }; + (forall ($var:ident : $($ty:tt)*) -> $($rest:tt)*) => { + rc(ExprKind::Pi( + stringify!($var).into(), + make_type!($($ty)*), + make_type!($($rest)*) + )) + }; +} + +pub(crate) fn type_of_builtin(b: Builtin) -> Expr { + use Builtin::*; + match b { + Bool | Natural | Integer | Double | Text => make_type!(Type), + List | Optional => make_type!( + Type -> Type + ), + + NaturalFold => make_type!( + Natural -> + forall (natural: Type) -> + forall (succ: natural -> natural) -> + forall (zero: natural) -> + natural + ), + NaturalBuild => make_type!( + (forall (natural: Type) -> + forall (succ: natural -> natural) -> + forall (zero: natural) -> + natural) -> + Natural + ), + NaturalIsZero | NaturalEven | NaturalOdd => make_type!( + Natural -> Bool + ), + NaturalToInteger => make_type!(Natural -> Integer), + NaturalShow => make_type!(Natural -> Text), + NaturalSubtract => make_type!(Natural -> Natural -> Natural), + + IntegerToDouble => make_type!(Integer -> Double), + IntegerShow => make_type!(Integer -> Text), + IntegerNegate => make_type!(Integer -> Integer), + IntegerClamp => make_type!(Integer -> Natural), + + DoubleShow => make_type!(Double -> Text), + TextShow => make_type!(Text -> Text), + + ListBuild => make_type!( + forall (a: Type) -> + (forall (list: Type) -> + forall (cons: a -> list -> list) -> + forall (nil: list) -> + list) -> + List a + ), + ListFold => make_type!( + forall (a: Type) -> + (List a) -> + forall (list: Type) -> + forall (cons: a -> list -> list) -> + forall (nil: list) -> + list + ), + ListLength => make_type!(forall (a: Type) -> (List a) -> Natural), + ListHead | ListLast => { + make_type!(forall (a: Type) -> (List a) -> Optional a) + } + ListIndexed => make_type!( + forall (a: Type) -> + (List a) -> + List { index: Natural, value: a } + ), + ListReverse => make_type!( + forall (a: Type) -> (List a) -> List a + ), + + OptionalBuild => make_type!( + forall (a: Type) -> + (forall (optional: Type) -> + forall (just: a -> optional) -> + forall (nothing: optional) -> + optional) -> + Optional a + ), + OptionalFold => make_type!( + forall (a: Type) -> + (Optional a) -> + forall (optional: Type) -> + forall (just: a -> optional) -> + forall (nothing: optional) -> + optional + ), + OptionalNone => make_type!( + forall (A: Type) -> Optional A + ), + } +} + +// Ad-hoc macro to help construct closures +macro_rules! make_closure { + (var($var:ident)) => {{ + rc(ExprKind::Var(syntax::V( + Label::from(stringify!($var)).into(), + 0 + ))) + }}; + (λ($var:tt : $($ty:tt)*) -> $($body:tt)*) => {{ + let var = Label::from(stringify!($var)); + let ty = make_closure!($($ty)*); + let body = make_closure!($($body)*); + rc(ExprKind::Lam(var, ty, body)) + }}; + (Type) => { + rc(ExprKind::Const(Type)) + }; + (Natural) => { + rc(ExprKind::Builtin(Builtin::Natural)) + }; + (List $($ty:tt)*) => {{ + let ty = make_closure!($($ty)*); + rc(ExprKind::App( + rc(ExprKind::Builtin(Builtin::List)), + ty + )) + }}; + (Some($($v:tt)*)) => { + rc(ExprKind::SomeLit( + make_closure!($($v)*) + )) + }; + (1 + $($v:tt)*) => { + rc(ExprKind::BinOp( + syntax::BinOp::NaturalPlus, + make_closure!($($v)*), + rc(ExprKind::NaturalLit(1)) + )) + }; + ([ $($head:tt)* ] # $($tail:tt)*) => {{ + let head = make_closure!($($head)*); + let tail = make_closure!($($tail)*); + rc(ExprKind::BinOp( + syntax::BinOp::ListAppend, + rc(ExprKind::NEListLit(vec![head])), + tail, + )) + }}; +} + +#[allow(clippy::cognitive_complexity)] +pub(crate) fn apply_builtin( + b: Builtin, + args: Vec, + ty: &Value, + types: Vec, + env: NzEnv, +) -> ValueKind { + use syntax::Builtin::*; + use ValueKind::*; + + // Small helper enum + enum Ret<'a> { + ValueKind(ValueKind), + Value(Value), + // For applications that can return a function, it's important to keep the remaining + // arguments to apply them to the resulting function. + ValueWithRemainingArgs(&'a [Value], Value), + DoneAsIs, + } + let make_closure = |e| { + type_with(&env.to_alpha_tyenv(), &e) + .unwrap() + .normalize_whnf(&env) + }; + + let ret = match (b, args.as_slice()) { + (OptionalNone, [t]) => Ret::ValueKind(EmptyOptionalLit(t.clone())), + (NaturalIsZero, [n]) => match &*n.as_whnf() { + NaturalLit(n) => Ret::ValueKind(BoolLit(*n == 0)), + _ => Ret::DoneAsIs, + }, + (NaturalEven, [n]) => match &*n.as_whnf() { + NaturalLit(n) => Ret::ValueKind(BoolLit(*n % 2 == 0)), + _ => Ret::DoneAsIs, + }, + (NaturalOdd, [n]) => match &*n.as_whnf() { + NaturalLit(n) => Ret::ValueKind(BoolLit(*n % 2 != 0)), + _ => Ret::DoneAsIs, + }, + (NaturalToInteger, [n]) => match &*n.as_whnf() { + NaturalLit(n) => Ret::ValueKind(IntegerLit(*n as isize)), + _ => Ret::DoneAsIs, + }, + (NaturalShow, [n]) => { + match &*n.as_whnf() { + NaturalLit(n) => Ret::ValueKind(TextLit(vec![ + InterpolatedTextContents::Text(n.to_string()), + ])), + _ => Ret::DoneAsIs, + } + } + (NaturalSubtract, [a, b]) => match (&*a.as_whnf(), &*b.as_whnf()) { + (NaturalLit(a), NaturalLit(b)) => { + Ret::ValueKind(NaturalLit(if b > a { b - a } else { 0 })) + } + (NaturalLit(0), _) => Ret::Value(b.clone()), + (_, NaturalLit(0)) => Ret::ValueKind(NaturalLit(0)), + _ if a == b => Ret::ValueKind(NaturalLit(0)), + _ => Ret::DoneAsIs, + }, + (IntegerShow, [n]) => match &*n.as_whnf() { + IntegerLit(n) => { + let s = if *n < 0 { + n.to_string() + } else { + format!("+{}", n) + }; + Ret::ValueKind(TextLit(vec![InterpolatedTextContents::Text(s)])) + } + _ => Ret::DoneAsIs, + }, + (IntegerToDouble, [n]) => match &*n.as_whnf() { + IntegerLit(n) => { + Ret::ValueKind(DoubleLit(NaiveDouble::from(*n as f64))) + } + _ => Ret::DoneAsIs, + }, + (IntegerNegate, [n]) => match &*n.as_whnf() { + IntegerLit(n) => Ret::ValueKind(IntegerLit(-n)), + _ => Ret::DoneAsIs, + }, + (IntegerClamp, [n]) => match &*n.as_whnf() { + IntegerLit(n) => { + Ret::ValueKind(NaturalLit((*n).try_into().unwrap_or(0))) + } + _ => Ret::DoneAsIs, + }, + (DoubleShow, [n]) => { + match &*n.as_whnf() { + DoubleLit(n) => Ret::ValueKind(TextLit(vec![ + InterpolatedTextContents::Text(n.to_string()), + ])), + _ => Ret::DoneAsIs, + } + } + (TextShow, [v]) => match &*v.as_whnf() { + TextLit(elts) => { + match elts.as_slice() { + // Empty string literal. + [] => { + // Printing InterpolatedText takes care of all the escaping + let txt: InterpolatedText = + std::iter::empty().collect(); + let s = txt.to_string(); + Ret::ValueKind(TextLit(vec![ + InterpolatedTextContents::Text(s), + ])) + } + // If there are no interpolations (invariants ensure that when there are no + // interpolations, there is a single Text item) in the literal. + [InterpolatedTextContents::Text(s)] => { + // Printing InterpolatedText takes care of all the escaping + let txt: InterpolatedText = + std::iter::once(InterpolatedTextContents::Text( + s.clone(), + )) + .collect(); + let s = txt.to_string(); + Ret::ValueKind(TextLit(vec![ + InterpolatedTextContents::Text(s), + ])) + } + _ => Ret::DoneAsIs, + } + } + _ => Ret::DoneAsIs, + }, + (ListLength, [_, l]) => match &*l.as_whnf() { + EmptyListLit(_) => Ret::ValueKind(NaturalLit(0)), + NEListLit(xs) => Ret::ValueKind(NaturalLit(xs.len())), + _ => Ret::DoneAsIs, + }, + (ListHead, [_, l]) => match &*l.as_whnf() { + EmptyListLit(n) => Ret::ValueKind(EmptyOptionalLit(n.clone())), + NEListLit(xs) => { + Ret::ValueKind(NEOptionalLit(xs.iter().next().unwrap().clone())) + } + _ => Ret::DoneAsIs, + }, + (ListLast, [_, l]) => match &*l.as_whnf() { + EmptyListLit(n) => Ret::ValueKind(EmptyOptionalLit(n.clone())), + NEListLit(xs) => Ret::ValueKind(NEOptionalLit( + xs.iter().rev().next().unwrap().clone(), + )), + _ => Ret::DoneAsIs, + }, + (ListReverse, [_, l]) => match &*l.as_whnf() { + EmptyListLit(n) => Ret::ValueKind(EmptyListLit(n.clone())), + NEListLit(xs) => { + Ret::ValueKind(NEListLit(xs.iter().rev().cloned().collect())) + } + _ => Ret::DoneAsIs, + }, + (ListIndexed, [_, l]) => { + let l_whnf = l.as_whnf(); + match &*l_whnf { + EmptyListLit(_) | NEListLit(_) => { + // Extract the type of the list elements + let t = match &*l_whnf { + EmptyListLit(t) => t.clone(), + NEListLit(xs) => xs[0].get_type_not_sort(), + _ => unreachable!(), + }; + + // Construct the returned record type: { index: Natural, value: t } + let mut kts = HashMap::new(); + kts.insert("index".into(), Value::from_builtin(Natural)); + kts.insert("value".into(), t.clone()); + let t = Value::from_kind_and_type( + RecordType(kts), + Value::from_const(Type), + ); + + // Construct the new list, with added indices + let list = match &*l_whnf { + EmptyListLit(_) => EmptyListLit(t), + NEListLit(xs) => NEListLit( + xs.iter() + .enumerate() + .map(|(i, e)| { + let mut kvs = HashMap::new(); + kvs.insert( + "index".into(), + Value::from_kind_and_type( + NaturalLit(i), + Value::from_builtin( + Builtin::Natural, + ), + ), + ); + kvs.insert("value".into(), e.clone()); + Value::from_kind_and_type( + RecordLit(kvs), + t.clone(), + ) + }) + .collect(), + ), + _ => unreachable!(), + }; + Ret::ValueKind(list) + } + _ => Ret::DoneAsIs, + } + } + (ListBuild, [t, f]) => { + let list_t = Value::from_builtin(List).app(t.clone()); + Ret::Value( + f.app(list_t.clone()) + .app( + make_closure(make_closure!( + λ(T : Type) -> + λ(a : var(T)) -> + λ(as : List var(T)) -> + [ var(a) ] # var(as) + )) + .app(t.clone()), + ) + .app(EmptyListLit(t.clone()).into_value_with_type(list_t)), + ) + } + (ListFold, [_, l, _, cons, nil, r @ ..]) => match &*l.as_whnf() { + EmptyListLit(_) => Ret::ValueWithRemainingArgs(r, nil.clone()), + NEListLit(xs) => { + let mut v = nil.clone(); + for x in xs.iter().cloned().rev() { + v = cons.app(x).app(v); + } + Ret::ValueWithRemainingArgs(r, v) + } + _ => Ret::DoneAsIs, + }, + (OptionalBuild, [t, f]) => { + let optional_t = Value::from_builtin(Optional).app(t.clone()); + Ret::Value( + f.app(optional_t.clone()) + .app( + make_closure(make_closure!( + λ(T : Type) -> + λ(a : var(T)) -> + Some(var(a)) + )) + .app(t.clone()), + ) + .app( + EmptyOptionalLit(t.clone()) + .into_value_with_type(optional_t), + ), + ) + } + (OptionalFold, [_, v, _, just, nothing, r @ ..]) => match &*v.as_whnf() + { + EmptyOptionalLit(_) => { + Ret::ValueWithRemainingArgs(r, nothing.clone()) + } + NEOptionalLit(x) => { + Ret::ValueWithRemainingArgs(r, just.app(x.clone())) + } + _ => Ret::DoneAsIs, + }, + (NaturalBuild, [f]) => Ret::Value( + f.app(Value::from_builtin(Natural)) + .app(make_closure(make_closure!( + λ(x : Natural) -> + 1 + var(x) + ))) + .app( + NaturalLit(0) + .into_value_with_type(Value::from_builtin(Natural)), + ), + ), + + (NaturalFold, [n, t, succ, zero, r @ ..]) => match &*n.as_whnf() { + NaturalLit(0) => Ret::ValueWithRemainingArgs(r, zero.clone()), + NaturalLit(n) => { + let fold = Value::from_builtin(NaturalFold) + .app( + NaturalLit(n - 1) + .into_value_with_type(Value::from_builtin(Natural)), + ) + .app(t.clone()) + .app(succ.clone()) + .app(zero.clone()); + Ret::ValueWithRemainingArgs(r, succ.app(fold)) + } + _ => Ret::DoneAsIs, + }, + _ => Ret::DoneAsIs, + }; + match ret { + Ret::ValueKind(v) => v, + Ret::Value(v) => v.to_whnf_check_type(ty), + Ret::ValueWithRemainingArgs(unconsumed_args, mut v) => { + let n_consumed_args = args.len() - unconsumed_args.len(); + for x in args.into_iter().skip(n_consumed_args) { + v = v.app(x); + } + v.to_whnf_check_type(ty) + } + Ret::DoneAsIs => AppliedBuiltin(b, args, types, env), + } +} -- cgit v1.2.3