diff options
| -rw-r--r-- | dhall/src/normalize.rs | 104 |
1 files changed, 63 insertions, 41 deletions
diff --git a/dhall/src/normalize.rs b/dhall/src/normalize.rs index 85df5e2..dbae481 100644 --- a/dhall/src/normalize.rs +++ b/dhall/src/normalize.rs @@ -5,7 +5,7 @@ use std::rc::Rc; use dhall_proc_macros as dhall; use dhall_syntax::context::Context; use dhall_syntax::{ - rc, BinOp, Builtin, Const, ExprF, Integer, InterpolatedText, + rc, BinOp, Builtin, Const, ExprF, Integer, InterpolatedTextContents, Label, Natural, Span, SubExpr, V, X, }; @@ -396,36 +396,17 @@ impl Value { .collect(), )), Value::TextLit(elts) => { - fn normalize_textlit( - elts: &Vec<InterpolatedTextContents<Thunk>>, - alpha: bool, - ) -> InterpolatedText<OutputSubExpr> { + use InterpolatedTextContents::{Expr, Text}; + rc(ExprF::TextLit( elts.iter() - .flat_map(|contents| { - use InterpolatedTextContents::{Expr, Text}; - let new_interpolated = match contents { - Expr(n) => match &*n.normalize_nf() { - Value::TextLit(elts2) => { - normalize_textlit(elts2, alpha) - } - e => InterpolatedText::from(( - String::new(), - vec![( - e.normalize_to_expr_maybe_alpha( - alpha, - ), - String::new(), - )], - )), - }, - Text(s) => InterpolatedText::from(s.clone()), - }; - new_interpolated.into_iter() + .map(|contents| match contents { + Expr(e) => { + Expr(e.normalize_to_expr_maybe_alpha(alpha)) + } + Text(s) => Text(s.clone()), }) - .collect() - } - - rc(ExprF::TextLit(normalize_textlit(elts, alpha))) + .collect(), + )) } Value::PartialExpr(e) => { rc(e.map_ref_simple(|v| v.normalize_to_expr_maybe_alpha(alpha))) @@ -658,6 +639,16 @@ impl Value { Label::clone, )) } + // Retry normalizing since substituting may allow progress + Value::TextLit(elts) => { + Value::TextLit(squash_textlit(elts.iter().map(|contents| { + use InterpolatedTextContents::{Expr, Text}; + match contents { + Expr(th) => Expr(th.subst_shift(var, val)), + Text(s) => Text(s.clone()), + } + }))) + } Value::Lam(x, t, e) => Value::Lam( x.clone(), t.subst_shift(var, val), @@ -734,17 +725,6 @@ impl Value { }) .collect(), ), - Value::TextLit(elts) => Value::TextLit( - elts.iter() - .map(|contents| { - use InterpolatedTextContents::{Expr, Text}; - match contents { - Expr(th) => Expr(th.subst_shift(var, val)), - Text(s) => Text(s.clone()), - } - }) - .collect(), - ), } } } @@ -1283,6 +1263,48 @@ fn apply_any(f: Thunk, a: Thunk) -> Value { } } +fn squash_textlit( + elts: impl Iterator<Item = InterpolatedTextContents<Thunk>>, +) -> Vec<InterpolatedTextContents<Thunk>> { + use std::mem::replace; + use InterpolatedTextContents::{Expr, Text}; + + fn inner( + elts: impl Iterator<Item = InterpolatedTextContents<Thunk>>, + crnt_str: &mut String, + ret: &mut Vec<InterpolatedTextContents<Thunk>>, + ) { + for contents in elts { + match contents { + Text(s) => crnt_str.push_str(&s), + Expr(e) => { + let e_borrow = e.as_value(); + match &*e_borrow { + Value::TextLit(elts2) => { + inner(elts2.iter().cloned(), crnt_str, ret) + } + _ => { + drop(e_borrow); + if !crnt_str.is_empty() { + ret.push(Text(replace(crnt_str, String::new()))) + } + ret.push(Expr(e.clone())) + } + } + } + } + } + } + + let mut crnt_str = String::new(); + let mut ret = Vec::new(); + inner(elts, &mut crnt_str, &mut ret); + if !crnt_str.is_empty() { + ret.push(Text(replace(&mut crnt_str, String::new()))) + } + ret +} + /// Reduces the imput expression to a Value. Evaluates as little as possible. fn normalize_whnf(ctx: NormalizationContext, expr: InputSubExpr) -> Value { match expr.as_ref() { @@ -1371,7 +1393,7 @@ fn normalize_one_layer(expr: ExprF<Thunk, Label, X>) -> Value { )), ExprF::TextLit(elts) => { use InterpolatedTextContents::Expr; - let elts: Vec<_> = elts.into_iter().collect(); + let elts: Vec<_> = squash_textlit(elts.into_iter()); // Simplify bare interpolation if let [Expr(th)] = elts.as_slice() { RetThunk(th.clone()) |