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Merged
tausbn merged 4 commits into from
Oct 21, 2026
+324 −230
Merged

yeast: Add nicer location syntax #22842

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578d477
yeast: Add special `location` field
tausbn Oct 16, 2026
2ed43ae
Unified: Rewrite swift.rs to use nicer location syntax
tausbn Oct 16, 2026
70fb3a6
yeast: Remove now-redundant `tree_at!` and `tree_spanning!` macros
tausbn Oct 16, 2026
f48bd79
yeast: Evaluate fields and locations in order
tausbn Oct 20, 2026
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7 changes: 6 additions & 1 deletion shared/yeast-macros/src/ast.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -108,7 +108,7 @@ pub(crate) struct Node {
/// Optional leaf content such as `"foo"` or `#{name}` in
/// `(identifier "foo")` or `(identifier #{name})`.
pub(crate) content: Option<Content>,
/// Named fields such as `method: {name}` in `(call method: {name})`.
/// Named fields and source-location metadata.
pub(crate) fields: Vec<Field>,
}

Expand All @@ -131,4 +131,9 @@ pub(crate) enum Field {
/// Whether the field value has a trailing `?`.
optional: bool,
},
/// Source-location metadata such as `location: {source}`.
Location {
/// A Rust block yielding the node or nodes whose locations should be combined.
block: syn::Block,
},
}
34 changes: 2 additions & 32 deletions shared/yeast-macros/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -65,6 +65,8 @@ pub fn query(input: TokenStream) -> TokenStream {
/// field: {expr} - extend a named field with `{expr}`'s ids
/// field: (kind ...)? - set the field only if every `#{expr}`
/// beneath it has a value (see below)
/// location: {expr} - override this node's source range with the
/// span of one or more nodes; may be repeated
/// ```
///
/// # Optional fields
Expand Down Expand Up @@ -125,38 +127,6 @@ pub fn trees(input: TokenStream) -> TokenStream {
}
}

/// Build one AST node whose root uses another node's source range.
///
/// Uses the `BuildCtx` binding named `ctx` from the surrounding scope:
///
/// ```text
/// tree_at!(source, (kind ...))
/// ```
#[proc_macro]
pub fn tree_at(input: TokenStream) -> TokenStream {
let input2: TokenStream2 = input.into();
match parse::parse_tree_at_top(input2) {
Ok(output) => output.into(),
Err(err) => err.to_compile_error().into(),
}
}

/// Build one AST node whose root spans a collection of nodes.
///
/// Uses the `BuildCtx` binding named `ctx` from the surrounding scope:
///
/// ```text
/// tree_spanning!(sources, (kind ...))
/// ```
#[proc_macro]
pub fn tree_spanning(input: TokenStream) -> TokenStream {
let input2: TokenStream2 = input.into();
match parse::parse_tree_spanning_top(input2) {
Ok(output) => output.into(),
Err(err) => err.to_compile_error().into(),
}
}

/// Define a desugaring rule with query and transform in one declaration.
///
/// ```text
Expand Down
137 changes: 84 additions & 53 deletions shared/yeast-macros/src/lower.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -319,8 +319,8 @@ impl Node {
let ctx = Ident::new("ctx", Span::call_site());
let kind_str = self.kind.to_string();

if let Some(content) = &self.content {
return match content {
let node_init = if let Some(content) = &self.content {
let node = match content {
Content::Static(lit) => quote! { #ctx.literal(#kind_str, #lit) },
Content::Computed(block) => {
let block = rust_block(block);
Expand Down Expand Up @@ -362,74 +362,105 @@ impl Node {
}
}
};
}
quote! { let __node: yeast::Id = #node; }
} else {
TokenStream::new()
};

let mut stmts = Vec::new();
let mut field_args = Vec::new();

for (field_counter, field) in self.fields.iter().enumerate() {
let Field::Named {
name,
value,
optional,
} = field;
let field_name = name.to_string();
let field_str = field_name
.strip_prefix("r#")
.unwrap_or(&field_name)
.to_string();
let temp = Ident::new(
&format!("__field_{field_str}_{field_counter}"),
Span::call_site(),
);

match value {
Template::Splice(block) => {
debug_assert!(!optional);
match field {
Field::Location { block } => {
let block = rust_block(block);
stmts.push(quote! {
let mut #temp: Vec<yeast::Id> = Vec::new();
yeast::IntoFieldIds::extend_into(#block, &mut #temp);
});
field_args.push(quote! {
if !#temp.is_empty() {
__fields.push((#field_str, #temp));
}
yeast::IntoFieldIds::extend_into(#block, &mut __location_ids);
});
}
Template::Node(child) if *optional => {
let label = fresh_fallible_label();
let value = child.lower(&LoweringContext {
fallible_scope: Some(&label),
});
stmts.push(quote! {
#[allow(unused_labels)]
let #temp: ::std::option::Option<yeast::Id> = #label: {
::std::option::Option::Some(#value)
};
});
field_args.push(quote! {
if let ::std::option::Option::Some(__id) = #temp {
__fields.push((#field_str, vec![__id]));
Field::Named {
name,
value,
optional,
} => {
let field_name = name.to_string();
let field_str = field_name
.strip_prefix("r#")
.unwrap_or(&field_name)
.to_string();
let temp = Ident::new(
&format!("__field_{field_str}_{field_counter}"),
Span::call_site(),
);

match value {
Template::Splice(block) => {
debug_assert!(!optional);
let block = rust_block(block);
stmts.push(quote! {
let mut #temp: Vec<yeast::Id> = Vec::new();
yeast::IntoFieldIds::extend_into(#block, &mut #temp);
});
field_args.push(quote! {
if !#temp.is_empty() {
__fields.push((#field_str, #temp));
}
});
}
});
}
Template::Node(child) => {
let value = child.lower(context);
stmts.push(quote! { let #temp: yeast::Id = #value; });
field_args.push(quote! {
__fields.push((#field_str, vec![#temp]));
});
Template::Node(child) if *optional => {
let label = fresh_fallible_label();
let value = child.lower(&LoweringContext {
fallible_scope: Some(&label),
});
stmts.push(quote! {
#[allow(unused_labels)]
let #temp: ::std::option::Option<yeast::Id> = #label: {
::std::option::Option::Some(#value)
};
});
field_args.push(quote! {
if let ::std::option::Option::Some(__id) = #temp {
__fields.push((#field_str, vec![__id]));
}
});
}
Template::Node(child) => {
let value = child.lower(context);
stmts.push(quote! { let #temp: yeast::Id = #value; });
field_args.push(quote! {
__fields.push((#field_str, vec![#temp]));
});
}
}
}
}
}

let build_node = if self.content.is_none() {
quote! {
let mut __fields: Vec<(&str, Vec<yeast::Id>)> = Vec::new();
#(#field_args)*
let __node: yeast::Id = #ctx.node(#kind_str, __fields);
}
} else {
TokenStream::new()
};

quote! {
{
let mut __location_ids: Vec<yeast::Id> = Vec::new();
#node_init
#(#stmts)*
let mut __fields: Vec<(&str, Vec<yeast::Id>)> = Vec::new();
#(#field_args)*
#ctx.node(#kind_str, __fields)
#build_node
let __source_range = __location_ids
.into_iter()
.filter_map(|__source| {
#ctx.ast
.get_node(__source)
.and_then(|__node| __node.source_range())
})
.reduce(yeast::Range::union);
#ctx.set_node_source_range(__node, __source_range)
}
}
}
Expand Down
59 changes: 0 additions & 59 deletions shared/yeast-macros/src/parse.rs
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Original file line number Diff line number Diff line change
@@ -1,9 +1,5 @@
use proc_macro2::{Span, TokenStream, TokenTree};
use quote::quote;
use syn::{
parse::{Parse, ParseStream},
Expr, Token,
};

type Result<T> = std::result::Result<T, syn::Error>;

Expand All @@ -28,47 +24,6 @@ pub fn parse_trees_top(input: TokenStream) -> Result<TokenStream> {
Ok(crate::ast::Template::lower_list(&templates))
}

pub fn parse_tree_at_top(input: TokenStream) -> Result<TokenStream> {
let LocatedTreeInput { source, template } = syn::parse2(input)?;
let template = crate::template_parse::parse_template(template)?;
let node = template.lower_root();
let ctx = syn::Ident::new("ctx", Span::call_site());

Ok(quote! {
{
let __yeast_source: yeast::Id = { #source };
let __yeast_source_range = #ctx
.ast
.get_node(__yeast_source)
.and_then(|node| node.source_range());
let __yeast_node: yeast::Id = #node;
#ctx.set_node_source_range(__yeast_node, __yeast_source_range)
}
})
}

pub fn parse_tree_spanning_top(input: TokenStream) -> Result<TokenStream> {
let LocatedTreeInput {
source: sources,
template,
} = syn::parse2(input)?;
let template = crate::template_parse::parse_template(template)?;
let node = template.lower_root();
let ctx = syn::Ident::new("ctx", Span::call_site());

Ok(quote! {
{
let __yeast_source_range = ::std::iter::IntoIterator::into_iter({ #sources })
.filter_map(|source: yeast::Id| {
#ctx.ast.get_node(source).and_then(|node| node.source_range())
})
.reduce(yeast::Range::union);
let __yeast_node: yeast::Id = #node;
#ctx.set_node_source_range(__yeast_node, __yeast_source_range)
}
})
}

pub fn parse_rule_top(input: TokenStream) -> Result<TokenStream> {
Ok(crate::rule_parse::parse_rule(input)?.lower())
}
Expand Down Expand Up @@ -127,20 +82,6 @@ pub fn parse_rules_top(input: TokenStream) -> Result<TokenStream> {
})
}

struct LocatedTreeInput {
source: Expr,
template: TokenStream,
}

impl Parse for LocatedTreeInput {
fn parse(input: ParseStream<'_>) -> syn::Result<Self> {
let source = input.parse()?;
input.parse::<Token![,]>()?;
let template = input.parse()?;
Ok(Self { source, template })
}
}

struct NamedString {
value: String,
}
Expand Down
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