1 use crate::ast::{self, NodeId};
2 use crate::source_map::{DUMMY_SP, dummy_spanned};
3 use crate::ext::base::ExtCtxt;
4 use crate::ext::expand::{AstFragment, AstFragmentKind};
5 use crate::tokenstream::TokenStream;
6 use crate::mut_visit::*;
10 use smallvec::{smallvec, SmallVec};
12 use rustc_data_structures::fx::FxHashMap;
14 pub fn placeholder(kind: AstFragmentKind, id: ast::NodeId) -> AstFragment {
15 fn mac_placeholder() -> ast::Mac {
17 path: ast::Path { span: DUMMY_SP, segments: Vec::new() },
18 tts: TokenStream::empty().into(),
19 delim: ast::MacDelimiter::Brace,
21 prior_type_ascription: None,
25 let ident = ast::Ident::invalid();
26 let attrs = Vec::new();
27 let generics = ast::Generics::default();
28 let vis = dummy_spanned(ast::VisibilityKind::Inherited);
30 let expr_placeholder = || P(ast::Expr {
32 attrs: ThinVec::new(),
33 kind: ast::ExprKind::Mac(mac_placeholder()),
37 kind: ast::TyKind::Mac(mac_placeholder()),
40 let pat = P(ast::Pat {
42 kind: ast::PatKind::Mac(mac_placeholder()),
47 AstFragmentKind::Expr => AstFragment::Expr(expr_placeholder()),
48 AstFragmentKind::OptExpr => AstFragment::OptExpr(Some(expr_placeholder())),
49 AstFragmentKind::Items => AstFragment::Items(smallvec![P(ast::Item {
50 id, span, ident, vis, attrs,
51 node: ast::ItemKind::Mac(mac_placeholder()),
54 AstFragmentKind::TraitItems => AstFragment::TraitItems(smallvec![ast::TraitItem {
55 id, span, ident, attrs, generics,
56 kind: ast::TraitItemKind::Macro(mac_placeholder()),
59 AstFragmentKind::ImplItems => AstFragment::ImplItems(smallvec![ast::ImplItem {
60 id, span, ident, vis, attrs, generics,
61 kind: ast::ImplItemKind::Macro(mac_placeholder()),
62 defaultness: ast::Defaultness::Final,
65 AstFragmentKind::ForeignItems =>
66 AstFragment::ForeignItems(smallvec![ast::ForeignItem {
67 id, span, ident, vis, attrs,
68 node: ast::ForeignItemKind::Macro(mac_placeholder()),
70 AstFragmentKind::Pat => AstFragment::Pat(P(ast::Pat {
71 id, span, kind: ast::PatKind::Mac(mac_placeholder()),
73 AstFragmentKind::Ty => AstFragment::Ty(P(ast::Ty {
74 id, span, kind: ast::TyKind::Mac(mac_placeholder()),
76 AstFragmentKind::Stmts => AstFragment::Stmts(smallvec![{
77 let mac = P((mac_placeholder(), ast::MacStmtStyle::Braces, ThinVec::new()));
78 ast::Stmt { id, span, kind: ast::StmtKind::Mac(mac) }
80 AstFragmentKind::Arms => AstFragment::Arms(smallvec![
82 attrs: Default::default(),
83 body: expr_placeholder(),
91 AstFragmentKind::Fields => AstFragment::Fields(smallvec![
93 attrs: Default::default(),
94 expr: expr_placeholder(),
102 AstFragmentKind::FieldPats => AstFragment::FieldPats(smallvec![
104 attrs: Default::default(),
110 is_placeholder: true,
113 AstFragmentKind::GenericParams => AstFragment::GenericParams(smallvec![{
115 attrs: Default::default(),
116 bounds: Default::default(),
119 is_placeholder: true,
120 kind: ast::GenericParamKind::Lifetime,
123 AstFragmentKind::Params => AstFragment::Params(smallvec![
125 attrs: Default::default(),
130 is_placeholder: true,
133 AstFragmentKind::StructFields => AstFragment::StructFields(smallvec![
135 attrs: Default::default(),
141 is_placeholder: true,
144 AstFragmentKind::Variants => AstFragment::Variants(smallvec![
146 attrs: Default::default(),
147 data: ast::VariantData::Struct(Default::default(), false),
152 is_placeholder: true,
158 pub struct PlaceholderExpander<'a, 'b> {
159 expanded_fragments: FxHashMap<ast::NodeId, AstFragment>,
160 cx: &'a mut ExtCtxt<'b>,
164 impl<'a, 'b> PlaceholderExpander<'a, 'b> {
165 pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
166 PlaceholderExpander {
168 expanded_fragments: FxHashMap::default(),
173 pub fn add(&mut self, id: ast::NodeId, mut fragment: AstFragment, placeholders: Vec<NodeId>) {
174 fragment.mut_visit_with(self);
175 if let AstFragment::Items(mut items) = fragment {
176 for placeholder in placeholders {
177 match self.remove(placeholder) {
178 AstFragment::Items(derived_items) => items.extend(derived_items),
182 fragment = AstFragment::Items(items);
184 self.expanded_fragments.insert(id, fragment);
187 fn remove(&mut self, id: ast::NodeId) -> AstFragment {
188 self.expanded_fragments.remove(&id).unwrap()
192 impl<'a, 'b> MutVisitor for PlaceholderExpander<'a, 'b> {
193 fn flat_map_arm(&mut self, arm: ast::Arm) -> SmallVec<[ast::Arm; 1]> {
194 if arm.is_placeholder {
195 self.remove(arm.id).make_arms()
197 noop_flat_map_arm(arm, self)
201 fn flat_map_field(&mut self, field: ast::Field) -> SmallVec<[ast::Field; 1]> {
202 if field.is_placeholder {
203 self.remove(field.id).make_fields()
205 noop_flat_map_field(field, self)
209 fn flat_map_field_pattern(&mut self, fp: ast::FieldPat) -> SmallVec<[ast::FieldPat; 1]> {
210 if fp.is_placeholder {
211 self.remove(fp.id).make_field_patterns()
213 noop_flat_map_field_pattern(fp, self)
217 fn flat_map_generic_param(
219 param: ast::GenericParam
220 ) -> SmallVec<[ast::GenericParam; 1]>
222 if param.is_placeholder {
223 self.remove(param.id).make_generic_params()
225 noop_flat_map_generic_param(param, self)
229 fn flat_map_param(&mut self, p: ast::Param) -> SmallVec<[ast::Param; 1]> {
230 if p.is_placeholder {
231 self.remove(p.id).make_params()
233 noop_flat_map_param(p, self)
237 fn flat_map_struct_field(&mut self, sf: ast::StructField) -> SmallVec<[ast::StructField; 1]> {
238 if sf.is_placeholder {
239 self.remove(sf.id).make_struct_fields()
241 noop_flat_map_struct_field(sf, self)
245 fn flat_map_variant(&mut self, variant: ast::Variant) -> SmallVec<[ast::Variant; 1]> {
246 if variant.is_placeholder {
247 self.remove(variant.id).make_variants()
249 noop_flat_map_variant(variant, self)
253 fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
255 ast::ItemKind::Mac(_) => return self.remove(item.id).make_items(),
256 ast::ItemKind::MacroDef(_) => return smallvec![item],
260 noop_flat_map_item(item, self)
263 fn flat_map_trait_item(&mut self, item: ast::TraitItem) -> SmallVec<[ast::TraitItem; 1]> {
265 ast::TraitItemKind::Macro(_) => self.remove(item.id).make_trait_items(),
266 _ => noop_flat_map_trait_item(item, self),
270 fn flat_map_impl_item(&mut self, item: ast::ImplItem) -> SmallVec<[ast::ImplItem; 1]> {
272 ast::ImplItemKind::Macro(_) => self.remove(item.id).make_impl_items(),
273 _ => noop_flat_map_impl_item(item, self),
277 fn flat_map_foreign_item(&mut self, item: ast::ForeignItem) -> SmallVec<[ast::ForeignItem; 1]> {
279 ast::ForeignItemKind::Macro(_) => self.remove(item.id).make_foreign_items(),
280 _ => noop_flat_map_foreign_item(item, self),
284 fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
286 ast::ExprKind::Mac(_) => *expr = self.remove(expr.id).make_expr(),
287 _ => noop_visit_expr(expr, self),
291 fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
293 ast::ExprKind::Mac(_) => self.remove(expr.id).make_opt_expr(),
294 _ => noop_filter_map_expr(expr, self),
298 fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
299 let (style, mut stmts) = match stmt.kind {
300 ast::StmtKind::Mac(mac) => (mac.1, self.remove(stmt.id).make_stmts()),
301 _ => return noop_flat_map_stmt(stmt, self),
304 if style == ast::MacStmtStyle::Semicolon {
305 if let Some(stmt) = stmts.pop() {
306 stmts.push(stmt.add_trailing_semicolon());
313 fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
315 ast::PatKind::Mac(_) => *pat = self.remove(pat.id).make_pat(),
316 _ => noop_visit_pat(pat, self),
320 fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
322 ast::TyKind::Mac(_) => *ty = self.remove(ty.id).make_ty(),
323 _ => noop_visit_ty(ty, self),
327 fn visit_block(&mut self, block: &mut P<ast::Block>) {
328 noop_visit_block(block, self);
330 for stmt in block.stmts.iter_mut() {
332 assert_eq!(stmt.id, ast::DUMMY_NODE_ID);
333 stmt.id = self.cx.resolver.next_node_id();
338 fn visit_mod(&mut self, module: &mut ast::Mod) {
339 noop_visit_mod(module, self);
340 module.items.retain(|item| match item.node {
341 ast::ItemKind::Mac(_) if !self.cx.ecfg.keep_macs => false, // remove macro definitions
346 fn visit_mac(&mut self, _mac: &mut ast::Mac) {