From 0f2522aadcc81481b14c8611db2777670a85ab32 Mon Sep 17 00:00:00 2001 From: Basile Henry Date: Sun, 18 Oct 2020 21:51:38 +0200 Subject: Refactor Text/replace eval --- dhall/src/builtins.rs | 71 +++++++++++++++++++++------------------------------ 1 file changed, 29 insertions(+), 42 deletions(-) diff --git a/dhall/src/builtins.rs b/dhall/src/builtins.rs index ed58e14..e80bf6b 100644 --- a/dhall/src/builtins.rs +++ b/dhall/src/builtins.rs @@ -410,51 +410,38 @@ fn apply_builtin(b: Builtin, args: Vec, env: NzEnv) -> NirKind { _ => Ret::DoneAsIs, }, (Builtin::TextReplace, [needle, replacement, haystack]) => { - match (&*needle.kind(), &*haystack.kind()) { - (TextLit(n_lit), TextLit(h_lit)) => { - // The needle and the haystack need to be fully - // evaluated as Text otherwise no progress can be made - match (n_lit.as_text(), h_lit.as_text()) { - (Some(n), Some(h)) => { - // Helper to match a Nir as a text literal - fn nir_to_string(n: &Nir) -> Option { - match &*n.kind() { - TextLit(r_lit) => r_lit.as_text(), - _ => None, - } - } + // Helper to match a Nir as a text literal + fn nir_to_string(n: &Nir) -> Option { + match &*n.kind() { + TextLit(n_lit) => n_lit.as_text(), + _ => None, + } + } - // When the needle is empty the haystack is returned untouched - if n.is_empty() { - Ret::Nir(haystack.clone()) - // Fast case when replacement is fully evaluated - } else if let Some(r) = nir_to_string(replacement) { - Ret::Nir(Nir::from_text(h.replace(&n, &r))) - } else { - use std::iter::{once, repeat}; + // The needle and the haystack need to be fully + // evaluated as Text otherwise no progress can be made + match (nir_to_string(needle), nir_to_string(haystack)) { + (Some(n), Some(h)) => { + // When the needle is empty the haystack is returned untouched + if n.is_empty() { + Ret::Nir(haystack.clone()) + // Fast case when replacement is fully evaluated + } else if let Some(r) = nir_to_string(replacement) { + Ret::Nir(Nir::from_text(h.replace(&n, &r))) + } else { + use itertools::Itertools; - let mut parts = h.split(&n).map(|s| { - InterpolatedTextContents::Text( - s.to_string(), - ) - }); - let replacement = - InterpolatedTextContents::Expr( - replacement.clone(), - ); - let first = parts.next(); - let rest = repeat(replacement) - .zip(parts) - .flat_map(|(r, p)| once(r).chain(once(p))); + let parts = h.split(&n).map(|s| { + InterpolatedTextContents::Text(s.to_string()) + }); + let replacement = + InterpolatedTextContents::Expr(replacement.clone()); - Ret::Nir(Nir::from_kind(NirKind::TextLit( - nze::nir::TextLit::new( - first.into_iter().chain(rest), - ), - ))) - } - } - _ => Ret::DoneAsIs, + Ret::Nir(Nir::from_kind(NirKind::TextLit( + nze::nir::TextLit::new( + parts.intersperse(replacement), + ), + ))) } } _ => Ret::DoneAsIs, -- cgit v1.2.3