Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/mbe/src/expander/transcriber.rs')
| -rw-r--r-- | crates/mbe/src/expander/transcriber.rs | 233 |
1 files changed, 140 insertions, 93 deletions
diff --git a/crates/mbe/src/expander/transcriber.rs b/crates/mbe/src/expander/transcriber.rs index 4f5cd0480c..c8b326fa6c 100644 --- a/crates/mbe/src/expander/transcriber.rs +++ b/crates/mbe/src/expander/transcriber.rs @@ -11,21 +11,19 @@ use crate::{ }; impl<S: Span> Bindings<S> { - fn contains(&self, name: &str) -> bool { - self.inner.contains_key(name) - } - fn get(&self, name: &str) -> Result<&Binding<S>, ExpandError> { match self.inner.get(name) { Some(binding) => Ok(binding), - None => Err(ExpandError::binding_error(format!("could not find binding `{name}`"))), + None => Err(ExpandError::UnresolvedBinding(Box::new(Box::from(name)))), } } fn get_fragment( &self, name: &str, + mut span: S, nesting: &mut [NestingState], + marker: impl Fn(&mut S), ) -> Result<Fragment<S>, ExpandError> { macro_rules! binding_err { ($($arg:tt)*) => { ExpandError::binding_error(format!($($arg)*)) }; @@ -48,54 +46,75 @@ impl<S: Span> Bindings<S> { }; } match b { - Binding::Fragment(it) => Ok(it.clone()), - // emit some reasonable default expansion for missing bindings, - // this gives better recovery than emitting the `$fragment-name` verbatim - Binding::Missing(it) => Ok(match it { - MetaVarKind::Stmt => { - Fragment::Tokens(tt::TokenTree::Leaf(tt::Leaf::Punct(tt::Punct { - span: S::DUMMY, - char: ';', - spacing: tt::Spacing::Alone, - }))) - } - MetaVarKind::Block => Fragment::Tokens(tt::TokenTree::Subtree(tt::Subtree { + Binding::Fragment(f @ (Fragment::Path(sub) | Fragment::Expr(sub))) => { + let tt::Subtree { delimiter, token_trees } = sub; + marker(&mut span); + let subtree = tt::Subtree { delimiter: tt::Delimiter { - open: S::DUMMY, - close: S::DUMMY, - kind: tt::DelimiterKind::Brace, + // TODO split span + open: span, + close: span, + kind: delimiter.kind, }, - token_trees: vec![], - })), - // FIXME: Meta and Item should get proper defaults - MetaVarKind::Meta | MetaVarKind::Item | MetaVarKind::Tt | MetaVarKind::Vis => { - Fragment::Tokens(tt::TokenTree::Subtree(tt::Subtree { - delimiter: tt::Delimiter::UNSPECIFIED, + token_trees: token_trees.clone(), + }; + Ok(match f { + Fragment::Tokens(_) => unreachable!(), + Fragment::Expr(_) => Fragment::Expr, + Fragment::Path(_) => Fragment::Path, + }(subtree)) + } + Binding::Fragment(it @ Fragment::Tokens(_)) => Ok(it.clone()), + // emit some reasonable default expansion for missing bindings, + // this gives better recovery than emitting the `$fragment-name` verbatim + Binding::Missing(it) => Ok({ + marker(&mut span); + match it { + MetaVarKind::Stmt => { + Fragment::Tokens(tt::TokenTree::Leaf(tt::Leaf::Punct(tt::Punct { + span, + char: ';', + spacing: tt::Spacing::Alone, + }))) + } + MetaVarKind::Block => Fragment::Tokens(tt::TokenTree::Subtree(tt::Subtree { + delimiter: tt::Delimiter { + open: S::DUMMY, + close: S::DUMMY, + kind: tt::DelimiterKind::Brace, + }, token_trees: vec![], - })) - } - MetaVarKind::Path - | MetaVarKind::Ty - | MetaVarKind::Pat - | MetaVarKind::PatParam - | MetaVarKind::Expr - | MetaVarKind::Ident => { - Fragment::Tokens(tt::TokenTree::Leaf(tt::Leaf::Ident(tt::Ident { - text: SmolStr::new_inline("missing"), - span: S::DUMMY, - }))) - } - MetaVarKind::Lifetime => { - Fragment::Tokens(tt::TokenTree::Leaf(tt::Leaf::Ident(tt::Ident { - text: SmolStr::new_inline("'missing"), - span: S::DUMMY, - }))) - } - MetaVarKind::Literal => { - Fragment::Tokens(tt::TokenTree::Leaf(tt::Leaf::Ident(tt::Ident { - text: SmolStr::new_inline("\"missing\""), - span: S::DUMMY, - }))) + })), + // FIXME: Meta and Item should get proper defaults + MetaVarKind::Meta | MetaVarKind::Item | MetaVarKind::Tt | MetaVarKind::Vis => { + Fragment::Tokens(tt::TokenTree::Subtree(tt::Subtree { + delimiter: tt::Delimiter::UNSPECIFIED, + token_trees: vec![], + })) + } + MetaVarKind::Path + | MetaVarKind::Ty + | MetaVarKind::Pat + | MetaVarKind::PatParam + | MetaVarKind::Expr + | MetaVarKind::Ident => { + Fragment::Tokens(tt::TokenTree::Leaf(tt::Leaf::Ident(tt::Ident { + text: SmolStr::new_inline("missing"), + span, + }))) + } + MetaVarKind::Lifetime => { + Fragment::Tokens(tt::TokenTree::Leaf(tt::Leaf::Ident(tt::Ident { + text: SmolStr::new_inline("'missing"), + span, + }))) + } + MetaVarKind::Literal => { + Fragment::Tokens(tt::TokenTree::Leaf(tt::Leaf::Ident(tt::Ident { + text: SmolStr::new_inline("\"missing\""), + span, + }))) + } } }), Binding::Nested(_) => { @@ -111,10 +130,11 @@ impl<S: Span> Bindings<S> { pub(super) fn transcribe<S: Span>( template: &MetaTemplate<S>, bindings: &Bindings<S>, + marker: impl Fn(&mut S) + Copy, ) -> ExpandResult<tt::Subtree<S>> { let mut ctx = ExpandCtx { bindings, nesting: Vec::new() }; let mut arena: Vec<tt::TokenTree<S>> = Vec::new(); - expand_subtree(&mut ctx, template, None, &mut arena) + expand_subtree(&mut ctx, template, None, &mut arena, marker) } #[derive(Debug)] @@ -139,40 +159,65 @@ fn expand_subtree<S: Span>( template: &MetaTemplate<S>, delimiter: Option<Delimiter<S>>, arena: &mut Vec<tt::TokenTree<S>>, + marker: impl Fn(&mut S) + Copy, ) -> ExpandResult<tt::Subtree<S>> { // remember how many elements are in the arena now - when returning, we want to drain exactly how many elements we added. This way, the recursive uses of the arena get their own "view" of the arena, but will reuse the allocation let start_elements = arena.len(); let mut err = None; 'ops: for op in template.iter() { match op { - Op::Literal(it) => arena.push(tt::Leaf::from(it.clone()).into()), - Op::Ident(it) => arena.push(tt::Leaf::from(it.clone()).into()), + Op::Literal(it) => arena.push( + tt::Leaf::from({ + let mut it = it.clone(); + marker(&mut it.span); + it + }) + .into(), + ), + Op::Ident(it) => arena.push( + tt::Leaf::from({ + let mut it = it.clone(); + marker(&mut it.span); + it + }) + .into(), + ), Op::Punct(puncts) => { for punct in puncts { - arena.push(tt::Leaf::from(*punct).into()); + arena.push( + tt::Leaf::from({ + let mut it = punct.clone(); + marker(&mut it.span); + it + }) + .into(), + ); } } Op::Subtree { tokens, delimiter } => { + let mut delimiter = *delimiter; + marker(&mut delimiter.open); + marker(&mut delimiter.close); let ExpandResult { value: tt, err: e } = - expand_subtree(ctx, tokens, Some(*delimiter), arena); + expand_subtree(ctx, tokens, Some(delimiter), arena, marker); err = err.or(e); arena.push(tt.into()); } Op::Var { name, id, .. } => { - let ExpandResult { value: fragment, err: e } = expand_var(ctx, name, *id); + let ExpandResult { value: fragment, err: e } = expand_var(ctx, name, *id, marker); err = err.or(e); push_fragment(arena, fragment); } Op::Repeat { tokens: subtree, kind, separator } => { let ExpandResult { value: fragment, err: e } = - expand_repeat(ctx, subtree, *kind, separator, arena); + expand_repeat(ctx, subtree, *kind, separator, arena, marker); err = err.or(e); push_fragment(arena, fragment) } Op::Ignore { name, id } => { // Expand the variable, but ignore the result. This registers the repetition count. // FIXME: Any emitted errors are dropped. - expand_var(ctx, name, *id); + expand_var(ctx, name, *id, marker); } Op::Index { depth } => { let index = @@ -258,42 +303,42 @@ fn expand_var<S: Span>( ctx: &mut ExpandCtx<'_, S>, v: &SmolStr, id: S, + marker: impl Fn(&mut S), ) -> ExpandResult<Fragment<S>> { // We already handle $crate case in mbe parser debug_assert!(v != "crate"); - if !ctx.bindings.contains(v) { - // Note that it is possible to have a `$var` inside a macro which is not bound. - // For example: - // ``` - // macro_rules! foo { - // ($a:ident, $b:ident, $c:tt) => { - // macro_rules! bar { - // ($bi:ident) => { - // fn $bi() -> u8 {$c} - // } - // } - // } - // ``` - // We just treat it a normal tokens - let tt = tt::Subtree { - delimiter: tt::Delimiter::UNSPECIFIED, - token_trees: vec![ - tt::Leaf::from(tt::Punct { char: '$', spacing: tt::Spacing::Alone, span: id }) - .into(), - tt::Leaf::from(tt::Ident { text: v.clone(), span: id }).into(), - ], + match ctx.bindings.get_fragment(v, id, &mut ctx.nesting, marker) { + Ok(it) => ExpandResult::ok(it), + Err(ExpandError::UnresolvedBinding(_)) => { + // Note that it is possible to have a `$var` inside a macro which is not bound. + // For example: + // ``` + // macro_rules! foo { + // ($a:ident, $b:ident, $c:tt) => { + // macro_rules! bar { + // ($bi:ident) => { + // fn $bi() -> u8 {$c} + // } + // } + // } + // ``` + // We just treat it a normal tokens + let tt = tt::Subtree { + delimiter: tt::Delimiter::UNSPECIFIED, + token_trees: vec![ + tt::Leaf::from(tt::Punct { char: '$', spacing: tt::Spacing::Alone, span: id }) + .into(), + tt::Leaf::from(tt::Ident { text: v.clone(), span: id }).into(), + ], + } + .into(); + ExpandResult::ok(Fragment::Tokens(tt)) } - .into(); - ExpandResult::ok(Fragment::Tokens(tt)) - } else { - ctx.bindings.get_fragment(v, &mut ctx.nesting).map_or_else( - |e| ExpandResult { - value: Fragment::Tokens(tt::TokenTree::Subtree(tt::Subtree::empty())), - err: Some(e), - }, - ExpandResult::ok, - ) + Err(e) => ExpandResult { + value: Fragment::Tokens(tt::TokenTree::Subtree(tt::Subtree::empty())), + err: Some(e), + }, } } @@ -303,6 +348,7 @@ fn expand_repeat<S: Span>( kind: RepeatKind, separator: &Option<Separator<S>>, arena: &mut Vec<tt::TokenTree<S>>, + marker: impl Fn(&mut S) + Copy, ) -> ExpandResult<Fragment<S>> { let mut buf: Vec<tt::TokenTree<S>> = Vec::new(); ctx.nesting.push(NestingState { idx: 0, at_end: false, hit: false }); @@ -314,7 +360,8 @@ fn expand_repeat<S: Span>( let mut err = None; loop { - let ExpandResult { value: mut t, err: e } = expand_subtree(ctx, template, None, arena); + let ExpandResult { value: mut t, err: e } = + expand_subtree(ctx, template, None, arena, marker); let nesting_state = ctx.nesting.last_mut().unwrap(); if nesting_state.at_end || !nesting_state.hit { break; @@ -391,7 +438,7 @@ fn expand_repeat<S: Span>( fn push_fragment<S: Span>(buf: &mut Vec<tt::TokenTree<S>>, fragment: Fragment<S>) { match fragment { Fragment::Tokens(tt::TokenTree::Subtree(tt)) => push_subtree(buf, tt), - Fragment::Expr(tt::TokenTree::Subtree(mut tt)) => { + Fragment::Expr(mut tt) => { if tt.delimiter.kind == tt::DelimiterKind::Invisible { tt.delimiter = tt::Delimiter { open: S::DUMMY, @@ -401,8 +448,8 @@ fn push_fragment<S: Span>(buf: &mut Vec<tt::TokenTree<S>>, fragment: Fragment<S> } buf.push(tt.into()) } - Fragment::Path(tt::TokenTree::Subtree(tt)) => fix_up_and_push_path_tt(buf, tt), - Fragment::Tokens(tt) | Fragment::Expr(tt) | Fragment::Path(tt) => buf.push(tt), + Fragment::Path(tt) => fix_up_and_push_path_tt(buf, tt), + Fragment::Tokens(tt) => buf.push(tt), } } |