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#![allow(dead_code)]
use crate::semantics::core::var::AlphaVar;
use crate::semantics::phase::typecheck::rc;
use crate::semantics::phase::Normalized;
use crate::semantics::phase::{NormalizedExpr, ToExprOptions};
use crate::semantics::Value;
use crate::syntax::{ExprKind, Label, Span, V};
pub(crate) type Type = Value;
// An expression with inferred types at every node and resolved variables.
pub(crate) struct TyExpr {
kind: Box<TyExprKind>,
ty: Option<Type>,
span: Span,
}
pub(crate) enum TyExprKind {
Var(AlphaVar),
// Forbidden ExprKind variants: Var
Expr(ExprKind<TyExpr, Normalized>),
}
impl TyExpr {
pub fn new(kind: TyExprKind, ty: Option<Type>, span: Span) -> Self {
TyExpr {
kind: Box::new(kind),
ty,
span,
}
}
pub fn kind(&self) -> &TyExprKind {
&*self.kind
}
/// Converts a value back to the corresponding AST expression.
pub fn to_expr<'a>(&'a self, opts: ToExprOptions) -> NormalizedExpr {
tyexpr_to_expr(self, opts, &Vec::new())
}
}
// TODO: mutate context once map_ref gets simplified
fn tyexpr_to_expr<'a>(
tyexpr: &'a TyExpr,
opts: ToExprOptions,
ctx: &Vec<&'a Label>,
) -> NormalizedExpr {
rc(match tyexpr.kind() {
TyExprKind::Var(v) if opts.alpha => {
ExprKind::Var(V("_".into(), v.idx()))
}
TyExprKind::Var(v) => {
let name = ctx[ctx.len() - 1 - v.idx()];
let mut idx = 0;
for l in ctx.iter().rev().take(v.idx()) {
if *l == name {
idx += 1;
}
}
ExprKind::Var(V(name.clone(), idx))
}
TyExprKind::Expr(e) => {
let e = e.map_ref_with_special_handling_of_binders(
|tye| tyexpr_to_expr(tye, opts, ctx),
|l, tye| {
let ctx = ctx.iter().copied().chain(Some(l)).collect();
tyexpr_to_expr(tye, opts, &ctx)
},
);
match e {
ExprKind::Lam(_, t, e) if opts.alpha => {
ExprKind::Lam("_".into(), t, e)
}
ExprKind::Pi(_, t, e) if opts.alpha => {
ExprKind::Pi("_".into(), t, e)
}
e => e,
}
}
})
}
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