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|
use crate::ast::*;
use crate::checker_state::*;
use std::iter::zip;
use tracing::instrument;
impl CheckerState {
#[instrument(skip(self), level = "debug", fields(%signature))]
pub fn check_signature(&self, signature: Signature) -> Result<Signature, CheckerError> {
match signature {
Signature::Set => Ok(Signature::Set),
Signature::Var(v) => {
let deref = self.lookup_signature(&v)?;
Ok(deref.clone())
}
Signature::Ext { params, codomain } => {
let mut ctx = self.clone();
let params = params
.into_iter()
.map(|p| {
let set = ctx.check_set(p.set.clone())?;
ctx.make_element_binding(p.name.clone(), set.clone())?;
Ok(Param { set, name: p.name })
})
.collect::<Result<Vec<_>, _>>()?;
let codomain = Box::new(ctx.check_signature(*codomain)?);
Ok(Signature::Ext { params, codomain })
}
Signature::Theory(fields) => {
let mut ctx = self.clone();
let fields = fields
.into_iter()
.map(|SigField { signature, name }| {
let signature = ctx.check_signature(signature)?;
// This call handles the special case in the event that signature is Set
ctx.make_instance_binding(name.clone(), signature.clone())?;
Ok(SigField { name, signature })
})
.collect::<Result<Vec<_>, _>>()?;
Ok(Signature::Theory(fields))
}
}
}
#[instrument(skip(self), level = "debug", fields(%instance, %signature))]
pub fn check_instance(
&self,
instance: Instance,
signature: &Signature,
) -> Result<Instance, CheckerError> {
match instance {
Instance::SetCoerce(ref set) => {
if *signature != Signature::Set {
return Err(CheckerError::WrongSignatureForInstance {
value: instance.clone().into(),
real: Signature::Set,
claimed: signature.clone(),
});
};
let set = Box::new(self.check_set(*set.clone())?);
if let Set::ClaimedSet(inner) = *set {
Ok(inner)
} else {
Ok(Instance::SetCoerce(set))
}
}
Instance::Var(ref v) => {
// Exactly the same discipline as for Element::Var, see there
// for some sparse comments
let lookup = self.lookup_instance(&v)?;
if !self.equal(signature, &lookup.container) {
return Err(CheckerError::WrongSignatureForInstance {
value: instance.clone().into(),
claimed: signature.clone(),
real: lookup.container.clone(),
});
}
if let InstanceValue::Concrete(ref deref) = lookup.value {
Ok(deref.clone())
} else {
Ok(Instance::Var(v.clone()))
}
}
Instance::Record(ref assignations) => {
// once again, mutatis mutandis from elements
let rej = |reason| CheckerError::InstanceDoesNotBelong {
instance: instance.clone(),
claimed: signature.clone(),
reason,
};
let fields = if let Signature::Theory(fields) = signature {
Ok(fields)
} else {
Err(rej("instance is a record instance".to_string()))
}?;
let (signature_fnames, signature_fsigs): (Vec<String>, Vec<Signature>) = fields
.iter()
.map(|SigField { name, signature }| (name.clone(), signature.clone()))
.unzip();
let mut signature_fnames_sorted = signature_fnames.clone();
signature_fnames_sorted.sort();
let (instance_fnames, instance_finstances): (Vec<String>, Vec<&Instance>) =
assignations
.iter()
.map(|InstAssign { name, instance }| (name.clone(), instance))
.unzip();
let mut instance_fnames_sorted = instance_fnames.clone();
instance_fnames_sorted.sort();
if signature_fnames_sorted != instance_fnames_sorted {
return Err(rej(format!(
"expected [{}] but found [{}]",
signature_fnames.join(", "),
instance_fnames.join(", "),
)));
}
let sub_els = zip(instance_finstances, signature_fsigs)
.map(|(e_f, e_s)| self.check_instance(e_f.clone(), &e_s))
.collect::<Result<Vec<_>, _>>()?;
let assignations = zip(instance_fnames, sub_els)
.map(|(name, instance)| InstAssign { name, instance })
.collect();
Ok(Instance::Record(assignations))
}
Instance::Project {
ref instance,
ref field,
} => {
let Field {
field: field_signature,
owner: owner_signature,
} = self.lookup_signature_field(&field)?;
if !self.equal(signature, field_signature) {
return Err(CheckerError::WrongSignatureForInstance {
value: (*instance.clone()).into(),
claimed: signature.clone(),
real: field_signature.clone(),
});
}
let inner = self.check_instance(*instance.clone(), owner_signature)?;
match inner {
Instance::Var(_) | Instance::Project { .. } => Ok(Instance::Project {
instance: Box::new(inner),
field: field.clone(),
}),
Instance::Record(assignations) => {
let sub_element = assignations
.into_iter()
.find(|a| a.name == *field)
.expect(
"invariant violation: record missing field that was type-checked",
)
.instance;
Ok(sub_element)
}
_ => panic!(
"invariant violation: check_instance returned neither a record or stuck computation for record set"
),
}
}
Instance::For { params, body } => {
Err(CheckerError::Unimplemented("instance for".to_string()))
}
Instance::App(inst, elem) => {
println!("{}", self);
Err(CheckerError::Unimplemented("instance app".to_string()))
}
}
}
}
|
