Rename Value to Nir

1 files changed, 0 insertions, 526 deletions

diff --git a/dhall/src/semantics/nze/value.rs b/dhall/src/semantics/nze/value.rs
deleted file mode 100644
index 7084af6..0000000
--- a/dhall/src/semantics/nze/value.rs
+++ /dev/null
@@ -1,526 +0,0 @@
-use std::collections::HashMap;
-use std::rc::Rc;
-
-use crate::semantics::nze::lazy;
-use crate::semantics::{
-    apply_any, normalize_hir_whnf, normalize_one_layer, squash_textlit, Binder,
-    BuiltinClosure, Hir, HirKind, NzEnv, NzVar, TyEnv, Type, Universe, VarEnv,
-};
-use crate::syntax::{
-    BinOp, Builtin, Const, ExprKind, InterpolatedTextContents, Label, LitKind,
-    Span,
-};
-use crate::{NormalizedExpr, ToExprOptions};
-
-/// Stores a possibly unevaluated value. Gets (partially) normalized on-demand, sharing computation
-/// automatically. Uses a Rc<RefCell> to share computation.
-/// If you compare for equality two `Value`s, then equality will be up to alpha-equivalence
-/// (renaming of bound variables) and beta-equivalence (normalization). It will recursively
-/// normalize as needed.
-#[derive(Clone)]
-pub(crate) struct Value(Rc<ValueInternal>);
-
-#[derive(Debug)]
-struct ValueInternal {
-    kind: lazy::Lazy<Thunk, ValueKind>,
-    span: Span,
-}
-
-/// An unevaluated subexpression
-#[derive(Debug, Clone)]
-pub(crate) enum Thunk {
-    /// A completely unnormalized expression.
-    Thunk { env: NzEnv, body: Hir },
-    /// A partially normalized expression that may need to go through `normalize_one_layer`.
-    PartialExpr { env: NzEnv, expr: ExprKind<Value> },
-}
-
-/// An unevaluated subexpression that takes an argument.
-#[derive(Debug, Clone)]
-pub(crate) enum Closure {
-    /// Normal closure
-    Closure { env: NzEnv, body: Hir },
-    /// Closure that ignores the argument passed
-    ConstantClosure { body: Value },
-}
-
-/// A text literal with interpolations.
-// Invariant: this must not contain interpolations that are themselves TextLits, and contiguous
-// text values must be merged.
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub(crate) struct TextLit(Vec<InterpolatedTextContents<Value>>);
-
-/// This represents a value in Weak Head Normal Form (WHNF). This means that the value is
-/// normalized up to the first constructor, but subexpressions may not be fully normalized.
-/// When all the Values in a ValueKind are in WHNF, and recursively so, then the ValueKind is in
-/// Normal Form (NF). This is because WHNF ensures that we have the first constructor of the NF; so
-/// if we have the first constructor of the NF at all levels, we actually have the NF.
-/// In particular, this means that once we get a `ValueKind`, it can be considered immutable, and
-/// we only need to recursively normalize its sub-`Value`s to get to the NF.
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub(crate) enum ValueKind {
-    /// Closures
-    LamClosure {
-        binder: Binder,
-        annot: Value,
-        closure: Closure,
-    },
-    PiClosure {
-        binder: Binder,
-        annot: Value,
-        closure: Closure,
-    },
-    AppliedBuiltin(BuiltinClosure<Value>),
-
-    Var(NzVar),
-    Const(Const),
-    Lit(LitKind),
-    EmptyOptionalLit(Value),
-    NEOptionalLit(Value),
-    // EmptyListLit(t) means `[] : List t`, not `[] : t`
-    EmptyListLit(Value),
-    NEListLit(Vec<Value>),
-    RecordType(HashMap<Label, Value>),
-    RecordLit(HashMap<Label, Value>),
-    UnionType(HashMap<Label, Option<Value>>),
-    UnionConstructor(Label, HashMap<Label, Option<Value>>),
-    UnionLit(Label, Value, HashMap<Label, Option<Value>>),
-    TextLit(TextLit),
-    Equivalence(Value, Value),
-    /// Invariant: evaluation must not be able to progress with `normalize_one_layer`.
-    PartialExpr(ExprKind<Value>),
-}
-
-impl Value {
-    /// Construct a Value from a completely unnormalized expression.
-    pub(crate) fn new_thunk(env: NzEnv, hir: Hir) -> Value {
-        let span = hir.span();
-        ValueInternal::from_thunk(Thunk::new(env, hir), span).into_value()
-    }
-    /// Construct a Value from a partially normalized expression that's not in WHNF.
-    pub(crate) fn from_partial_expr(e: ExprKind<Value>) -> Value {
-        // TODO: env
-        let env = NzEnv::new();
-        ValueInternal::from_thunk(
-            Thunk::from_partial_expr(env, e),
-            Span::Artificial,
-        )
-        .into_value()
-    }
-    /// Make a Value from a ValueKind
-    pub(crate) fn from_kind(v: ValueKind) -> Value {
-        ValueInternal::from_whnf(v, Span::Artificial).into_value()
-    }
-    pub(crate) fn from_const(c: Const) -> Self {
-        let v = ValueKind::Const(c);
-        ValueInternal::from_whnf(v, Span::Artificial).into_value()
-    }
-    pub(crate) fn from_builtin(b: Builtin) -> Self {
-        Self::from_builtin_env(b, &NzEnv::new())
-    }
-    pub(crate) fn from_builtin_env(b: Builtin, env: &NzEnv) -> Self {
-        Value::from_kind(ValueKind::from_builtin_env(b, env.clone()))
-    }
-    pub(crate) fn from_text(txt: impl ToString) -> Self {
-        Value::from_kind(ValueKind::TextLit(TextLit::from_text(
-            txt.to_string(),
-        )))
-    }
-
-    pub(crate) fn as_const(&self) -> Option<Const> {
-        match &*self.kind() {
-            ValueKind::Const(c) => Some(*c),
-            _ => None,
-        }
-    }
-
-    /// This is what you want if you want to pattern-match on the value.
-    pub(crate) fn kind(&self) -> &ValueKind {
-        self.0.kind()
-    }
-
-    pub(crate) fn to_type(&self, u: impl Into<Universe>) -> Type {
-        Type::new(self.clone(), u.into())
-    }
-    /// Converts a value back to the corresponding AST expression.
-    pub(crate) fn to_expr(&self, opts: ToExprOptions) -> NormalizedExpr {
-        if opts.normalize {
-            self.normalize();
-        }
-        self.to_hir_noenv().to_expr(opts)
-    }
-    pub(crate) fn to_expr_tyenv(&self, tyenv: &TyEnv) -> NormalizedExpr {
-        self.to_hir(tyenv.as_varenv()).to_expr_tyenv(tyenv)
-    }
-
-    pub(crate) fn normalize(&self) {
-        self.0.normalize()
-    }
-
-    pub(crate) fn app(&self, v: Value) -> Value {
-        Value::from_kind(apply_any(self.clone(), v))
-    }
-
-    pub fn to_hir(&self, venv: VarEnv) -> Hir {
-        let map_uniontype = |kts: &HashMap<Label, Option<Value>>| {
-            ExprKind::UnionType(
-                kts.iter()
-                    .map(|(k, v)| {
-                        (k.clone(), v.as_ref().map(|v| v.to_hir(venv)))
-                    })
-                    .collect(),
-            )
-        };
-
-        let hir = match &*self.kind() {
-            ValueKind::Var(v) => HirKind::Var(venv.lookup(v)),
-            ValueKind::AppliedBuiltin(closure) => closure.to_hirkind(venv),
-            self_kind => HirKind::Expr(match self_kind {
-                ValueKind::Var(..) | ValueKind::AppliedBuiltin(..) => {
-                    unreachable!()
-                }
-                ValueKind::LamClosure {
-                    binder,
-                    annot,
-                    closure,
-                } => ExprKind::Lam(
-                    binder.to_label(),
-                    annot.to_hir(venv),
-                    closure.to_hir(venv),
-                ),
-                ValueKind::PiClosure {
-                    binder,
-                    annot,
-                    closure,
-                } => ExprKind::Pi(
-                    binder.to_label(),
-                    annot.to_hir(venv),
-                    closure.to_hir(venv),
-                ),
-                ValueKind::Const(c) => ExprKind::Const(*c),
-                ValueKind::Lit(l) => ExprKind::Lit(l.clone()),
-                ValueKind::EmptyOptionalLit(n) => ExprKind::App(
-                    Value::from_builtin(Builtin::OptionalNone).to_hir(venv),
-                    n.to_hir(venv),
-                ),
-                ValueKind::NEOptionalLit(n) => {
-                    ExprKind::SomeLit(n.to_hir(venv))
-                }
-                ValueKind::EmptyListLit(n) => ExprKind::EmptyListLit(Hir::new(
-                    HirKind::Expr(ExprKind::App(
-                        Value::from_builtin(Builtin::List).to_hir(venv),
-                        n.to_hir(venv),
-                    )),
-                    Span::Artificial,
-                )),
-                ValueKind::NEListLit(elts) => ExprKind::NEListLit(
-                    elts.iter().map(|v| v.to_hir(venv)).collect(),
-                ),
-                ValueKind::TextLit(elts) => ExprKind::TextLit(
-                    elts.iter()
-                        .map(|t| t.map_ref(|v| v.to_hir(venv)))
-                        .collect(),
-                ),
-                ValueKind::RecordLit(kvs) => ExprKind::RecordLit(
-                    kvs.iter()
-                        .map(|(k, v)| (k.clone(), v.to_hir(venv)))
-                        .collect(),
-                ),
-                ValueKind::RecordType(kts) => ExprKind::RecordType(
-                    kts.iter()
-                        .map(|(k, v)| (k.clone(), v.to_hir(venv)))
-                        .collect(),
-                ),
-                ValueKind::UnionType(kts) => map_uniontype(kts),
-                ValueKind::UnionConstructor(l, kts) => ExprKind::Field(
-                    Hir::new(
-                        HirKind::Expr(map_uniontype(kts)),
-                        Span::Artificial,
-                    ),
-                    l.clone(),
-                ),
-                ValueKind::UnionLit(l, v, kts) => ExprKind::App(
-                    Hir::new(
-                        HirKind::Expr(ExprKind::Field(
-                            Hir::new(
-                                HirKind::Expr(map_uniontype(kts)),
-                                Span::Artificial,
-                            ),
-                            l.clone(),
-                        )),
-                        Span::Artificial,
-                    ),
-                    v.to_hir(venv),
-                ),
-                ValueKind::Equivalence(x, y) => ExprKind::BinOp(
-                    BinOp::Equivalence,
-                    x.to_hir(venv),
-                    y.to_hir(venv),
-                ),
-                ValueKind::PartialExpr(e) => e.map_ref(|v| v.to_hir(venv)),
-            }),
-        };
-
-        Hir::new(hir, self.0.span.clone())
-    }
-    pub fn to_hir_noenv(&self) -> Hir {
-        self.to_hir(VarEnv::new())
-    }
-}
-
-impl ValueInternal {
-    fn from_whnf(k: ValueKind, span: Span) -> Self {
-        ValueInternal {
-            kind: lazy::Lazy::new_completed(k),
-            span,
-        }
-    }
-    fn from_thunk(th: Thunk, span: Span) -> Self {
-        ValueInternal {
-            kind: lazy::Lazy::new(th),
-            span,
-        }
-    }
-    fn into_value(self) -> Value {
-        Value(Rc::new(self))
-    }
-
-    fn kind(&self) -> &ValueKind {
-        &self.kind
-    }
-    fn normalize(&self) {
-        self.kind().normalize();
-    }
-}
-
-impl ValueKind {
-    pub(crate) fn into_value(self) -> Value {
-        Value::from_kind(self)
-    }
-
-    pub(crate) fn normalize(&self) {
-        match self {
-            ValueKind::Var(..) | ValueKind::Const(_) | ValueKind::Lit(_) => {}
-
-            ValueKind::EmptyOptionalLit(tth) | ValueKind::EmptyListLit(tth) => {
-                tth.normalize();
-            }
-
-            ValueKind::NEOptionalLit(th) => {
-                th.normalize();
-            }
-            ValueKind::LamClosure { annot, closure, .. }
-            | ValueKind::PiClosure { annot, closure, .. } => {
-                annot.normalize();
-                closure.normalize();
-            }
-            ValueKind::AppliedBuiltin(closure) => closure.normalize(),
-            ValueKind::NEListLit(elts) => {
-                for x in elts.iter() {
-                    x.normalize();
-                }
-            }
-            ValueKind::RecordLit(kvs) => {
-                for x in kvs.values() {
-                    x.normalize();
-                }
-            }
-            ValueKind::RecordType(kvs) => {
-                for x in kvs.values() {
-                    x.normalize();
-                }
-            }
-            ValueKind::UnionType(kts) | ValueKind::UnionConstructor(_, kts) => {
-                for x in kts.values().flat_map(|opt| opt) {
-                    x.normalize();
-                }
-            }
-            ValueKind::UnionLit(_, v, kts) => {
-                v.normalize();
-                for x in kts.values().flat_map(|opt| opt) {
-                    x.normalize();
-                }
-            }
-            ValueKind::TextLit(tlit) => tlit.normalize(),
-            ValueKind::Equivalence(x, y) => {
-                x.normalize();
-                y.normalize();
-            }
-            ValueKind::PartialExpr(e) => {
-                e.map_ref(Value::normalize);
-            }
-        }
-    }
-
-    pub(crate) fn from_builtin(b: Builtin) -> ValueKind {
-        ValueKind::from_builtin_env(b, NzEnv::new())
-    }
-    pub(crate) fn from_builtin_env(b: Builtin, env: NzEnv) -> ValueKind {
-        ValueKind::AppliedBuiltin(BuiltinClosure::new(b, env))
-    }
-}
-
-impl Thunk {
-    fn new(env: NzEnv, body: Hir) -> Self {
-        Thunk::Thunk { env, body }
-    }
-    fn from_partial_expr(env: NzEnv, expr: ExprKind<Value>) -> Self {
-        Thunk::PartialExpr { env, expr }
-    }
-    fn eval(self) -> ValueKind {
-        match self {
-            Thunk::Thunk { env, body } => normalize_hir_whnf(&env, &body),
-            Thunk::PartialExpr { env, expr } => normalize_one_layer(expr, &env),
-        }
-    }
-}
-
-impl Closure {
-    pub fn new(env: &NzEnv, body: Hir) -> Self {
-        Closure::Closure {
-            env: env.clone(),
-            body,
-        }
-    }
-    /// New closure that ignores its argument
-    pub fn new_constant(body: Value) -> Self {
-        Closure::ConstantClosure { body }
-    }
-
-    pub fn apply(&self, val: Value) -> Value {
-        match self {
-            Closure::Closure { env, body, .. } => {
-                body.eval(env.insert_value(val, ()))
-            }
-            Closure::ConstantClosure { body, .. } => body.clone(),
-        }
-    }
-    fn apply_var(&self, var: NzVar) -> Value {
-        match self {
-            Closure::Closure { .. } => {
-                self.apply(Value::from_kind(ValueKind::Var(var)))
-            }
-            Closure::ConstantClosure { body, .. } => body.clone(),
-        }
-    }
-
-    // TODO: somehow normalize the body. Might require to pass an env.
-    pub fn normalize(&self) {}
-
-    /// Convert this closure to a Hir expression
-    pub fn to_hir(&self, venv: VarEnv) -> Hir {
-        self.apply_var(NzVar::new(venv.size()))
-            .to_hir(venv.insert())
-    }
-    /// If the closure variable is free in the closure, return Err. Otherwise, return the value
-    /// with that free variable remove.
-    pub fn remove_binder(&self) -> Result<Value, ()> {
-        match self {
-            Closure::Closure { .. } => {
-                let v = NzVar::fresh();
-                // TODO: handle case where variable is used in closure
-                // TODO: return information about where the variable is used
-                Ok(self.apply_var(v))
-            }
-            Closure::ConstantClosure { body, .. } => Ok(body.clone()),
-        }
-    }
-}
-
-impl TextLit {
-    pub fn new(
-        elts: impl Iterator<Item = InterpolatedTextContents<Value>>,
-    ) -> Self {
-        TextLit(squash_textlit(elts))
-    }
-    pub fn interpolate(v: Value) -> TextLit {
-        TextLit(vec![InterpolatedTextContents::Expr(v)])
-    }
-    pub fn from_text(s: String) -> TextLit {
-        TextLit(vec![InterpolatedTextContents::Text(s)])
-    }
-
-    pub fn concat(&self, other: &TextLit) -> TextLit {
-        TextLit::new(self.iter().chain(other.iter()).cloned())
-    }
-    pub fn is_empty(&self) -> bool {
-        self.0.is_empty()
-    }
-    /// If the literal consists of only one interpolation and not text, return the interpolated
-    /// value.
-    pub fn as_single_expr(&self) -> Option<&Value> {
-        use InterpolatedTextContents::Expr;
-        if let [Expr(v)] = self.0.as_slice() {
-            Some(v)
-        } else {
-            None
-        }
-    }
-    /// If there are no interpolations, return the corresponding text value.
-    pub fn as_text(&self) -> Option<String> {
-        use InterpolatedTextContents::Text;
-        if self.is_empty() {
-            Some(String::new())
-        } else if let [Text(s)] = self.0.as_slice() {
-            Some(s.clone())
-        } else {
-            None
-        }
-    }
-    pub fn iter(
-        &self,
-    ) -> impl Iterator<Item = &InterpolatedTextContents<Value>> {
-        self.0.iter()
-    }
-    /// Normalize the contained values. This does not break the invariant because we have already
-    /// ensured that no contained values normalize to a TextLit.
-    pub fn normalize(&self) {
-        for x in self.0.iter() {
-            x.map_ref(Value::normalize);
-        }
-    }
-}
-
-impl lazy::Eval<ValueKind> for Thunk {
-    fn eval(self) -> ValueKind {
-        self.eval()
-    }
-}
-
-/// Compare two values for equality modulo alpha/beta-equivalence.
-impl std::cmp::PartialEq for Value {
-    fn eq(&self, other: &Self) -> bool {
-        Rc::ptr_eq(&self.0, &other.0) || self.kind() == other.kind()
-    }
-}
-impl std::cmp::Eq for Value {}
-
-impl std::cmp::PartialEq for Thunk {
-    fn eq(&self, _other: &Self) -> bool {
-        unreachable!(
-            "Trying to compare thunks but we should only compare WHNFs"
-        )
-    }
-}
-impl std::cmp::Eq for Thunk {}
-
-impl std::cmp::PartialEq for Closure {
-    fn eq(&self, other: &Self) -> bool {
-        let v = NzVar::fresh();
-        self.apply_var(v) == other.apply_var(v)
-    }
-}
-impl std::cmp::Eq for Closure {}
-
-impl std::fmt::Debug for Value {
-    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        let vint: &ValueInternal = &self.0;
-        let kind = vint.kind();
-        if let ValueKind::Const(c) = kind {
-            return write!(fmt, "{:?}", c);
-        }
-        let mut x = fmt.debug_struct(&format!("Value@WHNF"));
-        x.field("kind", kind);
-        x.finish()
-    }
-}