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use std::borrow::Cow;
use std::fmt::Display;
use std::path::Path;
use dhall_syntax::{Const, SubExpr};
use crate::core::value::Value;
use crate::core::valuef::ValueF;
use crate::core::var::{AlphaVar, Shift, Subst};
use crate::error::{EncodeError, Error, ImportError, TypeError};
use resolve::ImportRoot;
pub(crate) mod binary;
pub(crate) mod normalize;
pub(crate) mod parse;
pub(crate) mod resolve;
pub(crate) mod typecheck;
pub type ParsedSubExpr = SubExpr<!>;
pub type DecodedSubExpr = SubExpr<!>;
pub type ResolvedSubExpr = SubExpr<Normalized>;
pub type NormalizedSubExpr = SubExpr<Normalized>;
#[derive(Debug, Clone)]
pub struct Parsed(ParsedSubExpr, ImportRoot);
/// An expression where all imports have been resolved
///
/// Invariant: there must be no `Import` nodes or `ImportAlt` operations left.
#[derive(Debug, Clone)]
pub struct Resolved(ResolvedSubExpr);
/// A typed expression
#[derive(Debug, Clone)]
pub struct Typed(Value);
/// A normalized expression.
///
/// Invariant: the contained Typed expression must be in normal form,
#[derive(Debug, Clone)]
pub struct Normalized(Typed);
impl Parsed {
pub fn parse_file(f: &Path) -> Result<Parsed, Error> {
parse::parse_file(f)
}
pub fn parse_str(s: &str) -> Result<Parsed, Error> {
parse::parse_str(s)
}
pub fn parse_binary_file(f: &Path) -> Result<Parsed, Error> {
parse::parse_binary_file(f)
}
pub fn parse_binary(data: &[u8]) -> Result<Parsed, Error> {
parse::parse_binary(data)
}
pub fn resolve(self) -> Result<Resolved, ImportError> {
resolve::resolve(self)
}
pub fn skip_resolve(self) -> Result<Resolved, ImportError> {
resolve::skip_resolve_expr(self)
}
pub fn encode(&self) -> Result<Vec<u8>, EncodeError> {
crate::phase::binary::encode(&self.0)
}
}
impl Resolved {
pub fn typecheck(self) -> Result<Typed, TypeError> {
Ok(typecheck::typecheck(self.0)?.into_typed())
}
pub fn typecheck_with(self, ty: &Typed) -> Result<Typed, TypeError> {
Ok(typecheck::typecheck_with(self.0, ty.to_expr())?.into_typed())
}
}
impl Typed {
/// Reduce an expression to its normal form, performing beta reduction
///
/// `normalize` does not type-check the expression. You may want to type-check
/// expressions before normalizing them since normalization can convert an
/// ill-typed expression into a well-typed expression.
///
/// However, `normalize` will not fail if the expression is ill-typed and will
/// leave ill-typed sub-expressions unevaluated.
pub fn normalize(mut self) -> Normalized {
self.normalize_mut();
Normalized(self)
}
pub(crate) fn from_const(c: Const) -> Self {
Typed(Value::from_const(c))
}
pub fn from_valuef_and_type(v: ValueF, t: Typed) -> Self {
Typed(Value::from_valuef_and_type(v, t.into_value()))
}
pub(crate) fn from_value(th: Value) -> Self {
Typed(th)
}
pub fn const_type() -> Self {
Typed::from_const(Const::Type)
}
pub fn to_expr(&self) -> NormalizedSubExpr {
self.0.to_expr()
}
pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
self.0.to_expr_alpha()
}
pub fn to_value(&self) -> Value {
self.0.clone()
}
pub(crate) fn into_value(self) -> Value {
self.0
}
pub(crate) fn normalize_mut(&mut self) {
self.0.normalize_mut()
}
#[allow(dead_code)]
pub(crate) fn get_type(&self) -> Result<Cow<'_, Typed>, TypeError> {
Ok(Cow::Owned(self.0.get_type()?.into_owned().into_typed()))
}
}
impl Normalized {
pub fn encode(&self) -> Result<Vec<u8>, EncodeError> {
crate::phase::binary::encode(&self.to_expr())
}
pub(crate) fn to_expr(&self) -> NormalizedSubExpr {
self.0.to_expr()
}
#[allow(dead_code)]
pub(crate) fn to_expr_alpha(&self) -> NormalizedSubExpr {
self.0.to_expr_alpha()
}
pub(crate) fn into_typed(self) -> Typed {
self.0
}
}
impl Shift for Typed {
fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
Some(Typed(self.0.shift(delta, var)?))
}
}
impl Shift for Normalized {
fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> {
Some(Normalized(self.0.shift(delta, var)?))
}
}
impl Subst<Value> for Typed {
fn subst_shift(&self, var: &AlphaVar, val: &Value) -> Self {
Typed(self.0.subst_shift(var, val))
}
}
macro_rules! derive_traits_for_wrapper_struct {
($ty:ident) => {
impl std::cmp::PartialEq for $ty {
fn eq(&self, other: &Self) -> bool {
self.0 == other.0
}
}
impl std::cmp::Eq for $ty {}
impl std::fmt::Display for $ty {
fn fmt(
&self,
f: &mut std::fmt::Formatter,
) -> Result<(), std::fmt::Error> {
self.0.fmt(f)
}
}
};
}
derive_traits_for_wrapper_struct!(Parsed);
derive_traits_for_wrapper_struct!(Resolved);
derive_traits_for_wrapper_struct!(Normalized);
impl std::hash::Hash for Normalized {
fn hash<H>(&self, state: &mut H)
where
H: std::hash::Hasher,
{
match self.encode() {
Ok(vec) => vec.hash(state),
Err(_) => {}
}
}
}
impl Eq for Typed {}
impl PartialEq for Typed {
fn eq(&self, other: &Self) -> bool {
self.0 == other.0
}
}
impl Display for Typed {
fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
self.to_expr().fmt(f)
}
}
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