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parse default optional expressions in pattern matches

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Folkert 2020-07-20 00:52:16 +02:00 • committed by Richard Feldman
parent 6d40de7430
commit d779e68773
6 changed files with 209 additions and 26 deletions
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49
compiler/can/src/pattern.rs
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@ -1,5 +1,5 @@
use crate::env::Env;
use crate::expr::Expr;
use crate::expr::{canonicalize_expr, Expr};
use crate::num::{finish_parsing_base, finish_parsing_float, finish_parsing_int};
use crate::scope::Scope;
use roc_module::ident::{Ident, Lowercase, TagName};
@ -302,6 +302,48 @@ pub fn canonicalize_pattern<'a>(
},
});
}
OptionalField(label, loc_default) => {
// an optional DOES introduce the label into scope!
match scope.introduce(
label.into(),
&env.exposed_ident_ids,
&mut env.ident_ids,
region,
) {
Ok(symbol) => {
// TODO use output?
let (can_default, _output) = canonicalize_expr(
env,
var_store,
scope,
loc_default.region,
&loc_default.value,
);
destructs.push(Located {
region: loc_pattern.region,
value: RecordDestruct {
var: var_store.fresh(),
label: Lowercase::from(label),
symbol,
typ: DestructType::Optional(var_store.fresh(), can_default),
},
});
}
Err((original_region, shadow)) => {
env.problem(Problem::RuntimeError(RuntimeError::Shadowing {
original_region,
shadow: shadow.clone(),
}));
// No matter what the other patterns
// are, we're definitely shadowed and will
// get a runtime exception as soon as we
// encounter the first bad pattern.
opt_erroneous = Some(Pattern::Shadowed(original_region, shadow));
}
};
}
_ => unreachable!("Any other pattern should have given a parse error"),
}
}
@ -315,7 +357,10 @@ pub fn canonicalize_pattern<'a>(
})
}
RequiredField(_name, _loc_pattern) | OptionalField(_name, _loc_pattern) => {
RequiredField(_name, _loc_pattern) => {
unreachable!("should have been handled in RecordDestructure");
}
OptionalField(_name, _loc_pattern) => {
unreachable!("should have been handled in RecordDestructure");
}