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simplify expr in parens

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This commit is contained in:
Folkert 2021-03-17 21:11:37 +01:00
parent e49860c1cd
commit 35e7f01362
1 changed files with 37 additions and 34 deletions
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71
compiler/parse/src/expr.rs
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@ -93,41 +93,44 @@ fn loc_expr_in_parens_help_help<'a>(
fn loc_expr_in_parens_etc_help<'a>(
min_indent: u16,
) -> impl Parser<'a, Located<Expr<'a>>, EExpr<'a>> {
then(
loc!(and!(
move |arena, state: State<'a>| {
let parser = loc!(and!(
specialize(EExpr::InParens, loc_expr_in_parens_help(min_indent)),
and!(
one_of![record_field_access_chain(), |a, s| Ok((
NoProgress,
Vec::new_in(a),
s
))],
// TODO remove the either
optional(
// There may optionally be function args after the ')'
// e.g. ((foo bar) baz)
// loc_function_args_help(min_indent),
// If there aren't any args, there may be a '=' or ':' after it.
//
// (It's a syntax error to write e.g. `foo bar =` - so if there
// were any args, there is definitely no need to parse '=' or ':'!)
//
// Also, there may be a '.' for field access (e.g. `(foo).bar`),
// but we only want to look for that if there weren't any args,
// as if there were any args they'd have consumed it anyway
// e.g. in `((foo bar) baz.blah)` the `.blah` will be consumed by the `baz` parser
map!(
and!(
space0_e(min_indent, EExpr::Space, EExpr::IndentEquals),
equals_with_indent_help()
),
Either::Second
)
)
)
)),
move |arena, state, _progress, parsed| helper_help(arena, state, parsed, min_indent),
)
one_of![record_field_access_chain(), |a, s| Ok((
NoProgress,
Vec::new_in(a),
s
))]
));
let (
_,
Located {
mut region,
value: (loc_expr, field_accesses),
},
state,
) = parser.parse(arena, state)?;
let mut value = loc_expr.value;
// if there are field accesses, include the parentheses in the region
// otherwise, don't include the parentheses
if field_accesses.is_empty() {
region = loc_expr.region;
} else {
for field in field_accesses {
// Wrap the previous answer in the new one, so we end up
// with a nested Expr. That way, `foo.bar.baz` gets represented
// in the AST as if it had been written (foo.bar).baz all along.
value = Expr::Access(arena.alloc(value), field);
}
}
let loc_expr = Located::at(region, value);
Ok((MadeProgress, loc_expr, state))
}
}
fn record_field_access_chain<'a>() -> impl Parser<'a, Vec<'a, &'a str>, EExpr<'a>> {