syndicate-lang
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syndicate-rs
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Support patterns like <?r <Something _ _ _>>

This commit is contained in:
Tony Garnock-Jones 2022-01-12 12:28:03 +01:00
parent d007da2e94
commit 7fbe6360e7
1 changed files with 24 additions and 9 deletions
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33
syndicate-server/src/script/mod.rs
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@ -241,15 +241,18 @@ impl<'env> PatternInstantiator<'env> {
Value::Record(r) => match parse_attenuation(r)? {
Some((base_name, alternatives)) =>
dlit(self.env.eval_attenuation(base_name, alternatives)?),
None => {
let label = self.instantiate_pattern(r.label())?;
let fields = r.fields().iter().map(|p| self.instantiate_pattern(p))
.collect::<io::Result<Vec<P::Pattern>>>()?;
P::Pattern::DCompound(Box::new(P::DCompound::Rec {
label: drop_literal(&label)
.ok_or(bad_instruction("Record pattern must have literal label"))?,
fields,
}))
None => match self.maybe_binder_with_pattern(r)? {
Some(pat) => pat,
None => {
let label = self.instantiate_pattern(r.label())?;
let fields = r.fields().iter().map(|p| self.instantiate_pattern(p))
.collect::<io::Result<Vec<P::Pattern>>>()?;
P::Pattern::DCompound(Box::new(P::DCompound::Rec {
label: drop_literal(&label)
.ok_or(bad_instruction("Record pattern must have literal label"))?,
fields,
}))
}
}
},
Value::Sequence(v) =>
@ -268,6 +271,18 @@ impl<'env> PatternInstantiator<'env> {
})),
})
}
fn maybe_binder_with_pattern(&mut self, r: &Record<AnyValue>) -> io::Result<Option<P::Pattern>> {
match r.label().value().as_symbol().map(|s| analyze(&s)) {
Some(Symbolic::Binder(formal)) => if r.fields().len() == 1 {
let pattern = self.instantiate_pattern(&r.fields()[0])?;
self.binding_names.push(formal);
return Ok(Some(P::Pattern::DBind(Box::new(P::DBind { pattern }))));
},
_ => (),
}
Ok(None)
}
}
impl Env {