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Merged
jongiddy merged 1 commit into from
Dec 11, 2025
Merged

Do not allocate iterator when expanding typle macro #19

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7 changes: 7 additions & 0 deletions Cargo.lock
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1 change: 1 addition & 0 deletions Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@ rust-version = "1.68.2"
proc-macro = true

[dependencies]
either = "1"
proc-macro2 = "1"
quote = "1"
syn = { version = "2.0.43", features = ["full", "extra-traits"] }
Expand Down
2 changes: 1 addition & 1 deletion README.md
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Expand Up @@ -58,7 +58,7 @@ struct MultipleHandlers<T> {
#[typle(Tuple for 0..=3)]
impl<T> HandleStuff for MultipleHandlers<T>
where
T: Tuple, // `T`` is a tuple with 0 to 12 components.
T: Tuple, // `T`` is a tuple with 0 to 3 components.
T<_>: HandleStuff, // All components implement `HandleStuff`.
{
type Output = (typle!(i in .. => T<{i}>::Output));
Expand Down
14 changes: 9 additions & 5 deletions src/context.rs
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Expand Up @@ -23,7 +23,7 @@ use syn::{
use zip_clone::ZipClone as _;

use crate::constant::{evaluate_bool, evaluate_range, evaluate_usize};
use crate::context::shared::{abort, Replacement};
use crate::context::shared::{abort, Replacements};
use crate::syn_ext::GeneralFunction;
use crate::TypleMacro;

Expand Down Expand Up @@ -184,7 +184,7 @@ impl TypleContext {
let path = &trait_bound.path;
if path.leading_colon.is_none() && path.segments.len() == 1 {
if let Some(segment) = path.segments.first() {
if segment.ident == self.typle_macro.ident {
if segment.ident == self.typle_macro.trait_ident {
match &segment.arguments {
PathArguments::None => {
if result.is_some() {
Expand Down Expand Up @@ -491,7 +491,8 @@ impl TypleContext {
None,
) = (segments.get(0), segments.get(1), segments.get(2))
{
if *ident1 == self.typle_macro.ident && ident2 == "Bounds"
if *ident1 == self.typle_macro.trait_ident
&& ident2 == "Bounds"
{
let token_stream = std::mem::take(&mut mac.tokens);
let predicates =
Expand Down Expand Up @@ -554,7 +555,10 @@ impl TypleContext {
Ok(())
}

fn expand_predicates(&self, token_stream: TokenStream) -> Replacement<WherePredicate> {
fn expand_predicates(
&self,
token_stream: TokenStream,
) -> Replacements<impl Iterator<Item = syn::Result<WherePredicate>>> {
self.expand_typle_macro(token_stream, |context, token_stream| {
// Divide the token_stream at the first single :
let mut bounded = Vec::new();
Expand Down Expand Up @@ -808,7 +812,7 @@ impl TypleContext {
}),
ReturnType::Type(_, t) => *t,
};
let typle_trait_name = &self.typle_macro.ident;
let typle_trait_name = &self.typle_macro.trait_ident;

// A method body is moved to a trait implementation on a dfferent type.
// Any instances of `Self` in the method body are converted to the
Expand Down
71 changes: 38 additions & 33 deletions src/context/expr.rs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,6 @@
use crate::context::shared::Replacement;
use either::Either;

use crate::context::shared::Replacements;

use super::*;

Expand Down Expand Up @@ -466,7 +468,7 @@ impl TypleContext {
&mut paren.expr,
Expr::Verbatim(TokenStream::new()),
)) {
Replacement::Singleton(inner) => {
Replacements::Singleton(Ok(inner)) => {
paren.expr = Box::new(inner);
}
iter => {
Expand Down Expand Up @@ -565,19 +567,24 @@ impl TypleContext {
Ok(())
}

pub(super) fn replace_expr_in_list(&self, mut expr: Expr) -> Replacement<Expr> {
pub(super) fn replace_expr_in_list(
&self,
mut expr: Expr,
) -> Replacements<impl Iterator<Item = syn::Result<Expr>>> {
let mut state = BlockState::default();
match &mut expr {
Expr::Macro(syn::ExprMacro { mac, .. }) => {
if let Some(ident) = mac.path.get_ident() {
if ident == "typle" || ident == "typle_args" {
let token_stream = std::mem::take(&mut mac.tokens);
return self.expand_typle_macro(token_stream, |context, token_stream| {
let mut expr = syn::parse2::<Expr>(token_stream)?;
let mut state = BlockState::default();
context.replace_expr(&mut expr, &mut state)?;
Ok(expr)
});
return self
.expand_typle_macro(token_stream, |context, token_stream| {
let mut expr = syn::parse2::<Expr>(token_stream)?;
let mut state = BlockState::default();
context.replace_expr(&mut expr, &mut state)?;
Ok(expr)
})
.map_iterator(Either::Left);
}
}
}
Expand All @@ -587,64 +594,62 @@ impl TypleContext {
let mut iter = array.elems.iter_mut().fuse();
if let (Some(field), None) = (iter.next(), iter.next()) {
if let Err(e) = self.replace_expr(field, &mut state) {
return Replacement::Error(e);
return Replacements::Singleton(Err(e));
}
if let Some((start, end)) = evaluate_range(field) {
let start = match start {
Bound::Included(Err(span)) | Bound::Excluded(Err(span)) => {
return Replacement::Error(syn::Error::new(
return Replacements::Singleton(Err(syn::Error::new(
span,
"expected integer for start of range",
));
)));
}
Bound::Included(Ok(start)) => start,
Bound::Excluded(Ok(start)) => start.saturating_add(1),
Bound::Unbounded => 0,
};
let end = match end {
Bound::Included(Err(span)) | Bound::Excluded(Err(span)) => {
return Replacement::Error(syn::Error::new(
return Replacements::Singleton(Err(syn::Error::new(
span,
"expected integer for end of range",
));
)));
}
Bound::Included(Ok(end)) => end.saturating_add(1),
Bound::Excluded(Ok(end)) => end,
Bound::Unbounded => match self.typle_len {
Some(end) => end,
None => {
return Replacement::Error(syn::Error::new(
return Replacements::Singleton(Err(syn::Error::new(
expr.span(),
"need an explicit range end",
));
)));
}
},
};
return Replacement::Iterator({
return Replacements::Iterator(Either::Right({
let span = index.span();
Box::new((start..end).zip_clone(expr.clone()).map(
move |(i, base)| {
Ok(Expr::Field(syn::ExprField {
attrs: Vec::new(),
base,
dot_token: token::Dot::default(),
member: Member::Unnamed(syn::Index {
index: i as u32,
span,
}),
}))
},
))
});
(start..end).zip_clone(expr.clone()).map(move |(i, base)| {
Ok(Expr::Field(syn::ExprField {
attrs: Vec::new(),
base,
dot_token: token::Dot::default(),
member: Member::Unnamed(syn::Index {
index: i as u32,
span,
}),
}))
})
}));
}
}
}
}
_ => {}
}
match self.replace_expr(&mut expr, &mut state) {
Ok(()) => Replacement::Singleton(expr),
Err(e) => Replacement::Error(e),
Ok(()) => Replacements::Singleton(Ok(expr)),
Err(e) => Replacements::Singleton(Err(e)),
}
}

Expand Down
13 changes: 8 additions & 5 deletions src/context/pat.rs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
use crate::context::shared::Replacement;
use crate::context::shared::Replacements;

use super::*;

Expand All @@ -21,7 +21,7 @@ impl TypleContext {
&mut paren.pat,
Pat::Verbatim(TokenStream::new()),
)) {
Replacement::Singleton(inner) => {
Replacements::Singleton(Ok(inner)) => {
paren.pat = Box::new(inner);
}
iter => {
Expand Down Expand Up @@ -111,7 +111,10 @@ impl TypleContext {
Ok(())
}

pub(super) fn replace_pat_in_list(&self, mut pat: Pat) -> Replacement<Pat> {
pub(super) fn replace_pat_in_list(
&self,
mut pat: Pat,
) -> Replacements<impl Iterator<Item = syn::Result<Pat>>> {
let mut state = BlockState::default();
match &mut pat {
Pat::Macro(syn::PatMacro { mac, .. }) => {
Expand All @@ -130,8 +133,8 @@ impl TypleContext {
_ => {}
}
match self.replace_pat(&mut pat, &mut state) {
Ok(()) => Replacement::Singleton(pat),
Err(e) => Replacement::Error(e),
Ok(()) => Replacements::Singleton(Ok(pat)),
Err(e) => Replacements::Singleton(Err(e)),
}
}

Expand Down
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