diff options
author | Nadrieril | 2019-05-09 16:32:30 +0200 |
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committer | Nadrieril | 2019-05-09 16:32:30 +0200 |
commit | 7538e29275720407ac172bb05cdbc028d95ff921 (patch) | |
tree | 79ad968a7ef6e36e5a4e7fc19df281c46ac68f6c /dhall/src/phase/mod.rs | |
parent | 2020d41874f7681ba948a40d8e8f8993d651a81c (diff) |
Make shift fallible and improve shift ergonomics
Diffstat (limited to 'dhall/src/phase/mod.rs')
-rw-r--r-- | dhall/src/phase/mod.rs | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs index db0a2b9..50103a0 100644 --- a/dhall/src/phase/mod.rs +++ b/dhall/src/phase/mod.rs @@ -238,26 +238,26 @@ impl Normalized { } impl Shift for Typed { - fn shift(&self, delta: isize, var: &AlphaVar) -> Self { - match self { + fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> { + Some(match self { Typed::Value(th, t) => Typed::Value( - th.shift(delta, var), - t.as_ref().map(|x| x.shift(delta, var)), + th.shift(delta, var)?, + t.as_ref().map(|x| Ok(x.shift(delta, var)?)).transpose()?, ), Typed::Const(c) => Typed::Const(*c), - } + }) } } impl Shift for Type { - fn shift(&self, delta: isize, var: &AlphaVar) -> Self { - Type(Box::new(self.0.shift(delta, var))) + fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> { + Some(Type(Box::new(self.0.shift(delta, var)?))) } } impl Shift for Normalized { - fn shift(&self, delta: isize, var: &AlphaVar) -> Self { - Normalized(self.0.shift(delta, var)) + fn shift(&self, delta: isize, var: &AlphaVar) -> Option<Self> { + Some(Normalized(self.0.shift(delta, var)?)) } } |