diff options
Diffstat (limited to 'src/chomp/check/infer.rs')
-rw-r--r-- | src/chomp/check/infer.rs | 92 |
1 files changed, 0 insertions, 92 deletions
diff --git a/src/chomp/check/infer.rs b/src/chomp/check/infer.rs deleted file mode 100644 index 941ddba..0000000 --- a/src/chomp/check/infer.rs +++ /dev/null @@ -1,92 +0,0 @@ -use super::super::{ - ast::{Alt, Call, Cat, Epsilon, Fix, Literal, Parameter, Variable}, - context::Context, - error::{AltError, CatError, FixError, TypeError}, - set::{FirstSet, FlastSet}, - typed::Type, - visit::{Visitable, Visitor}, -}; - -#[derive(Debug)] -pub struct TypeInfer<'a> { - pub context: &'a mut Context, -} - -impl Visitor for TypeInfer<'_> { - type Out = Result<Type, TypeError>; - - fn visit_epsilon(&mut self, _eps: &Epsilon) -> Self::Out { - Ok(Type::new(true, FirstSet::default(), FlastSet::default())) - } - - fn visit_literal(&mut self, lit: &Literal) -> Self::Out { - Ok(Type::of_str(&lit.value())) - } - - fn visit_cat(&mut self, cat: &Cat) -> Self::Out { - let first = cat.first().visit(self)?; - let second = self - .context - .with_unguard(|context| cat.second().visit(&mut TypeInfer { context }))?; - - if first.nullable() { - Err(TypeError::Cat(CatError::FirstNullable(cat.clone()))) - } else if !first - .flast_set() - .intersect_first(second.first_set()) - .is_empty() - { - Err(TypeError::Cat(CatError::FirstFlastOverlap(cat.clone()))) - } else { - Ok(first.cat(second)) - } - } - - fn visit_alt(&mut self, alt: &Alt) -> Self::Out { - let left = alt.left().visit(self)?; - let right = alt.right().visit(self)?; - - if left.nullable() && right.nullable() { - Err(TypeError::Alt(AltError::BothNullable(alt.clone()))) - } else if !left.first_set().intersect(right.first_set()).is_empty() { - Err(TypeError::Alt(AltError::FirstOverlap(alt.clone()))) - } else { - Ok(left.alt(right)) - } - } - - fn visit_fix(&mut self, fix: &Fix) -> Self::Out { - let mut res = Type::default(); - let mut last = None; - - while last.map(|r| r != res).unwrap_or(true) { - last = Some(res); - res = self - .context - .with_variable_type(last.as_ref().cloned().unwrap(), |context| { - fix.inner().visit(&mut TypeInfer { context }) - }) - .map_err(|e| { - TypeError::Fix(FixError( - fix.clone(), - last.as_ref().cloned().unwrap(), - Box::new(e), - )) - })?; - } - - Ok(res) - } - - fn visit_variable(&mut self, var: &Variable) -> Self::Out { - Ok(self.context.get_variable_type(&var)?.clone()) - } - - fn visit_parameter(&mut self, _param: &Parameter) -> Self::Out { - todo!() - } - - fn visit_call(&mut self, _call: &Call) -> Self::Out { - todo!() - } -} |