1 use crate::base::ExtCtxt;
2 use crate::expand::{AstFragment, AstFragmentKind};
5 use syntax::source_map::{DUMMY_SP, dummy_spanned};
6 use syntax::tokenstream::TokenStream;
7 use syntax::mut_visit::*;
11 use smallvec::{smallvec, SmallVec};
13 use rustc_data_structures::fx::FxHashMap;
15 pub fn placeholder(kind: AstFragmentKind, id: ast::NodeId, vis: Option<ast::Visibility>)
17 fn mac_placeholder() -> ast::Mac {
19 path: ast::Path { span: DUMMY_SP, segments: Vec::new() },
20 tts: TokenStream::default().into(),
21 delim: ast::MacDelimiter::Brace,
23 prior_type_ascription: None,
27 let ident = ast::Ident::invalid();
28 let attrs = Vec::new();
29 let generics = ast::Generics::default();
30 let vis = vis.unwrap_or_else(|| dummy_spanned(ast::VisibilityKind::Inherited));
32 let expr_placeholder = || P(ast::Expr {
34 attrs: ThinVec::new(),
35 kind: ast::ExprKind::Mac(mac_placeholder()),
37 let ty = || P(ast::Ty {
39 kind: ast::TyKind::Mac(mac_placeholder()),
42 let pat = || P(ast::Pat {
44 kind: ast::PatKind::Mac(mac_placeholder()),
49 AstFragmentKind::Expr => AstFragment::Expr(expr_placeholder()),
50 AstFragmentKind::OptExpr => AstFragment::OptExpr(Some(expr_placeholder())),
51 AstFragmentKind::Items => AstFragment::Items(smallvec![P(ast::Item {
52 id, span, ident, vis, attrs,
53 kind: ast::ItemKind::Mac(mac_placeholder()),
56 AstFragmentKind::TraitItems => AstFragment::TraitItems(smallvec![ast::TraitItem {
57 id, span, ident, vis, attrs, generics,
58 kind: ast::TraitItemKind::Macro(mac_placeholder()),
61 AstFragmentKind::ImplItems => AstFragment::ImplItems(smallvec![ast::ImplItem {
62 id, span, ident, vis, attrs, generics,
63 kind: ast::ImplItemKind::Macro(mac_placeholder()),
64 defaultness: ast::Defaultness::Final,
67 AstFragmentKind::ForeignItems =>
68 AstFragment::ForeignItems(smallvec![ast::ForeignItem {
69 id, span, ident, vis, attrs,
70 kind: ast::ForeignItemKind::Macro(mac_placeholder()),
72 AstFragmentKind::Pat => AstFragment::Pat(P(ast::Pat {
73 id, span, kind: ast::PatKind::Mac(mac_placeholder()),
75 AstFragmentKind::Ty => AstFragment::Ty(P(ast::Ty {
76 id, span, kind: ast::TyKind::Mac(mac_placeholder()),
78 AstFragmentKind::Stmts => AstFragment::Stmts(smallvec![{
79 let mac = P((mac_placeholder(), ast::MacStmtStyle::Braces, ThinVec::new()));
80 ast::Stmt { id, span, kind: ast::StmtKind::Mac(mac) }
82 AstFragmentKind::Arms => AstFragment::Arms(smallvec![
84 attrs: Default::default(),
85 body: expr_placeholder(),
93 AstFragmentKind::Fields => AstFragment::Fields(smallvec![
95 attrs: Default::default(),
96 expr: expr_placeholder(),
101 is_placeholder: true,
104 AstFragmentKind::FieldPats => AstFragment::FieldPats(smallvec![
106 attrs: Default::default(),
112 is_placeholder: true,
115 AstFragmentKind::GenericParams => AstFragment::GenericParams(smallvec![{
117 attrs: Default::default(),
118 bounds: Default::default(),
121 is_placeholder: true,
122 kind: ast::GenericParamKind::Lifetime,
125 AstFragmentKind::Params => AstFragment::Params(smallvec![
127 attrs: Default::default(),
132 is_placeholder: true,
135 AstFragmentKind::StructFields => AstFragment::StructFields(smallvec![
137 attrs: Default::default(),
143 is_placeholder: true,
146 AstFragmentKind::Variants => AstFragment::Variants(smallvec![
148 attrs: Default::default(),
149 data: ast::VariantData::Struct(Default::default(), false),
155 is_placeholder: true,
161 pub struct PlaceholderExpander<'a, 'b> {
162 expanded_fragments: FxHashMap<ast::NodeId, AstFragment>,
163 cx: &'a mut ExtCtxt<'b>,
167 impl<'a, 'b> PlaceholderExpander<'a, 'b> {
168 pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
169 PlaceholderExpander {
171 expanded_fragments: FxHashMap::default(),
176 pub fn add(&mut self, id: ast::NodeId, mut fragment: AstFragment) {
177 fragment.mut_visit_with(self);
178 self.expanded_fragments.insert(id, fragment);
181 fn remove(&mut self, id: ast::NodeId) -> AstFragment {
182 self.expanded_fragments.remove(&id).unwrap()
186 impl<'a, 'b> MutVisitor for PlaceholderExpander<'a, 'b> {
187 fn flat_map_arm(&mut self, arm: ast::Arm) -> SmallVec<[ast::Arm; 1]> {
188 if arm.is_placeholder {
189 self.remove(arm.id).make_arms()
191 noop_flat_map_arm(arm, self)
195 fn flat_map_field(&mut self, field: ast::Field) -> SmallVec<[ast::Field; 1]> {
196 if field.is_placeholder {
197 self.remove(field.id).make_fields()
199 noop_flat_map_field(field, self)
203 fn flat_map_field_pattern(&mut self, fp: ast::FieldPat) -> SmallVec<[ast::FieldPat; 1]> {
204 if fp.is_placeholder {
205 self.remove(fp.id).make_field_patterns()
207 noop_flat_map_field_pattern(fp, self)
211 fn flat_map_generic_param(
213 param: ast::GenericParam
214 ) -> SmallVec<[ast::GenericParam; 1]>
216 if param.is_placeholder {
217 self.remove(param.id).make_generic_params()
219 noop_flat_map_generic_param(param, self)
223 fn flat_map_param(&mut self, p: ast::Param) -> SmallVec<[ast::Param; 1]> {
224 if p.is_placeholder {
225 self.remove(p.id).make_params()
227 noop_flat_map_param(p, self)
231 fn flat_map_struct_field(&mut self, sf: ast::StructField) -> SmallVec<[ast::StructField; 1]> {
232 if sf.is_placeholder {
233 self.remove(sf.id).make_struct_fields()
235 noop_flat_map_struct_field(sf, self)
239 fn flat_map_variant(&mut self, variant: ast::Variant) -> SmallVec<[ast::Variant; 1]> {
240 if variant.is_placeholder {
241 self.remove(variant.id).make_variants()
243 noop_flat_map_variant(variant, self)
247 fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
249 ast::ItemKind::Mac(_) => return self.remove(item.id).make_items(),
250 ast::ItemKind::MacroDef(_) => return smallvec![item],
254 noop_flat_map_item(item, self)
257 fn flat_map_trait_item(&mut self, item: ast::TraitItem) -> SmallVec<[ast::TraitItem; 1]> {
259 ast::TraitItemKind::Macro(_) => self.remove(item.id).make_trait_items(),
260 _ => noop_flat_map_trait_item(item, self),
264 fn flat_map_impl_item(&mut self, item: ast::ImplItem) -> SmallVec<[ast::ImplItem; 1]> {
266 ast::ImplItemKind::Macro(_) => self.remove(item.id).make_impl_items(),
267 _ => noop_flat_map_impl_item(item, self),
271 fn flat_map_foreign_item(&mut self, item: ast::ForeignItem) -> SmallVec<[ast::ForeignItem; 1]> {
273 ast::ForeignItemKind::Macro(_) => self.remove(item.id).make_foreign_items(),
274 _ => noop_flat_map_foreign_item(item, self),
278 fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
280 ast::ExprKind::Mac(_) => *expr = self.remove(expr.id).make_expr(),
281 _ => noop_visit_expr(expr, self),
285 fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
287 ast::ExprKind::Mac(_) => self.remove(expr.id).make_opt_expr(),
288 _ => noop_filter_map_expr(expr, self),
292 fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
293 let (style, mut stmts) = match stmt.kind {
294 ast::StmtKind::Mac(mac) => (mac.1, self.remove(stmt.id).make_stmts()),
295 _ => return noop_flat_map_stmt(stmt, self),
298 if style == ast::MacStmtStyle::Semicolon {
299 if let Some(stmt) = stmts.pop() {
300 stmts.push(stmt.add_trailing_semicolon());
307 fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
309 ast::PatKind::Mac(_) => *pat = self.remove(pat.id).make_pat(),
310 _ => noop_visit_pat(pat, self),
314 fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
316 ast::TyKind::Mac(_) => *ty = self.remove(ty.id).make_ty(),
317 _ => noop_visit_ty(ty, self),
321 fn visit_block(&mut self, block: &mut P<ast::Block>) {
322 noop_visit_block(block, self);
324 for stmt in block.stmts.iter_mut() {
326 assert_eq!(stmt.id, ast::DUMMY_NODE_ID);
327 stmt.id = self.cx.resolver.next_node_id();
332 fn visit_mod(&mut self, module: &mut ast::Mod) {
333 noop_visit_mod(module, self);
334 module.items.retain(|item| match item.kind {
335 ast::ItemKind::Mac(_) if !self.cx.ecfg.keep_macs => false, // remove macro definitions
340 fn visit_mac(&mut self, _mac: &mut ast::Mac) {