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cleanup: use DummyResult to implement MacroGenerable::dummy

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This commit is contained in:
Jeffrey Seyfried 2016-06-17 11:02:42 +00:00
parent b968ee3656
commit 2dc15f2b96
2 changed files with 17 additions and 19 deletions
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4
src/libsyntax/ext/base.rs
View File

@ -443,6 +443,10 @@ impl MacResult for DummyResult {
span: self.span,
}))
}
fn make_ty(self: Box<DummyResult>) -> Option<P<ast::Ty>> {
Some(DummyResult::raw_ty(self.span))
}
}
/// An enum representing the different kinds of syntax extensions.

32
src/libsyntax/ext/expand.rs
View File

@ -43,18 +43,19 @@ trait MacroGenerable: Sized {
fn fold_with<F: Folder>(self, folder: &mut F) -> Self;
fn visit_with<V: Visitor>(&self, visitor: &mut V);
// Return a placeholder expansion to allow compilation to continue after an erroring expansion.
fn dummy(span: Span) -> Self;
// The user-friendly name of the node type (e.g. "expression", "item", etc.) for diagnostics.
fn kind_name() -> &'static str;
// Return a placeholder expansion to allow compilation to continue after an erroring expansion.
fn dummy(span: Span) -> Self {
Self::make_with(DummyResult::any(span)).unwrap()
}
}
macro_rules! impl_macro_generable {
($($ty:ty: $kind_name:expr, .$make:ident,
$(.$fold:ident)* $(lift .$fold_elt:ident)*,
$(.$visit:ident)* $(lift .$visit_elt:ident)*,
|$span:ident| $dummy:expr;)*) => { $(
$(.$visit:ident)* $(lift .$visit_elt:ident)*;)*) => { $(
impl MacroGenerable for $ty {
fn kind_name() -> &'static str { $kind_name }
fn make_with<'a>(result: Box<MacResult + 'a>) -> Option<Self> { result.$make() }
@ -66,31 +67,24 @@ macro_rules! impl_macro_generable {
$( visitor.$visit(self) )*
$( for item in self.as_slice() { visitor. $visit_elt (item) } )*
}
fn dummy($span: Span) -> Self { $dummy }
}
)* }
}
impl_macro_generable! {
P<ast::Pat>: "pattern", .make_pat, .fold_pat, .visit_pat, |span| P(DummyResult::raw_pat(span));
P<ast::Ty>: "type", .make_ty, .fold_ty, .visit_ty, |span| DummyResult::raw_ty(span);
P<ast::Expr>:
"expression", .make_expr, .fold_expr, .visit_expr, |span| DummyResult::raw_expr(span);
SmallVector<ast::Stmt>:
"statement", .make_stmts, lift .fold_stmt, lift .visit_stmt, |_span| SmallVector::zero();
SmallVector<P<ast::Item>>:
"item", .make_items, lift .fold_item, lift .visit_item, |_span| SmallVector::zero();
P<ast::Expr>: "expression", .make_expr, .fold_expr, .visit_expr;
P<ast::Pat>: "pattern", .make_pat, .fold_pat, .visit_pat;
P<ast::Ty>: "type", .make_ty, .fold_ty, .visit_ty;
SmallVector<ast::Stmt>: "statement", .make_stmts, lift .fold_stmt, lift .visit_stmt;
SmallVector<P<ast::Item>>: "item", .make_items, lift .fold_item, lift .visit_item;
SmallVector<ast::TraitItem>:
"trait item", .make_trait_items, lift .fold_trait_item, lift .visit_trait_item,
|_span| SmallVector::zero();
"trait item", .make_trait_items, lift .fold_trait_item, lift .visit_trait_item;
SmallVector<ast::ImplItem>:
"impl item", .make_impl_items, lift .fold_impl_item, lift .visit_impl_item,
|_span| SmallVector::zero();
"impl item", .make_impl_items, lift .fold_impl_item, lift .visit_impl_item;
}
impl MacroGenerable for Option<P<ast::Expr>> {
fn kind_name() -> &'static str { "expression" }
fn dummy(_span: Span) -> Self { None }
fn make_with<'a>(result: Box<MacResult + 'a>) -> Option<Self> {
result.make_expr().map(Some)
}