zesterer
Add an IterParser::fold method
It seems the only way I can really "collect" the values from a repeated / separated_by combinator is via .collect? My issue with is that basically requires a heap allocation by using Vec or some alternative data structure that implements Collect. Other patterns I would intuitively expect to work such as .fold do not seem to work for some reason?
// ... more code
choice((
ident.clone().map(ParamExpr::NameRef),
label.clone().map(ParamExpr::FuncRef),
data_ref.clone().map(ParamExpr::DataRef),
u256_value.clone().map(|v| ParamExpr::Num(arena.alloc(v))),
))
.repeated()
// Can't do ?
.fold(BVec::with_capacity_in(16, arena), |mut exprs, expr| {
exprs.push(expr);
exprs
}),
The error message Rust gives me for why .fold isn't working is very unreadable. Any ideas?
Nevermind, figured it out, you can work around using foldl, I thought I wasn't able to get that to work but you can just:
empty().map(|_| BVec::with_capacity_in(DEFAULT_STMT_PARAMS_CAPACITY, arena)).foldl(
choice((
ident.clone().map(ParamExpr::NameRef),
label.clone().map(ParamExpr::FuncRef),
data_ref.clone().map(ParamExpr::DataRef),
u256_value.clone().map(|v| ParamExpr::Num(arena.alloc(v))),
))
.repeated(),
|mut exprs, expr| {
exprs.push(expr);
exprs
},
);
It might be worth implementing a dedicated fold that has this behaviour though... Mind if I change the issue title and reopen?
