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) -> AstFragment {
16 fn mac_placeholder() -> ast::Mac {
18 path: ast::Path { span: DUMMY_SP, segments: Vec::new() },
19 tts: TokenStream::default().into(),
20 delim: ast::MacDelimiter::Brace,
22 prior_type_ascription: None,
26 let ident = ast::Ident::invalid();
27 let attrs = Vec::new();
28 let generics = ast::Generics::default();
29 let vis = dummy_spanned(ast::VisibilityKind::Inherited);
31 let expr_placeholder = || P(ast::Expr {
33 attrs: ThinVec::new(),
34 kind: ast::ExprKind::Mac(mac_placeholder()),
36 let ty = || P(ast::Ty {
38 kind: ast::TyKind::Mac(mac_placeholder()),
41 let pat = || P(ast::Pat {
43 kind: ast::PatKind::Mac(mac_placeholder()),
48 AstFragmentKind::Expr => AstFragment::Expr(expr_placeholder()),
49 AstFragmentKind::OptExpr => AstFragment::OptExpr(Some(expr_placeholder())),
50 AstFragmentKind::Items => AstFragment::Items(smallvec![P(ast::Item {
51 id, span, ident, vis, attrs,
52 kind: ast::ItemKind::Mac(mac_placeholder()),
55 AstFragmentKind::TraitItems => AstFragment::TraitItems(smallvec![ast::TraitItem {
56 id, span, ident, vis, attrs, generics,
57 kind: ast::TraitItemKind::Macro(mac_placeholder()),
60 AstFragmentKind::ImplItems => AstFragment::ImplItems(smallvec![ast::ImplItem {
61 id, span, ident, vis, attrs, generics,
62 kind: ast::ImplItemKind::Macro(mac_placeholder()),
63 defaultness: ast::Defaultness::Final,
66 AstFragmentKind::ForeignItems =>
67 AstFragment::ForeignItems(smallvec![ast::ForeignItem {
68 id, span, ident, vis, attrs,
69 kind: ast::ForeignItemKind::Macro(mac_placeholder()),
71 AstFragmentKind::Pat => AstFragment::Pat(P(ast::Pat {
72 id, span, kind: ast::PatKind::Mac(mac_placeholder()),
74 AstFragmentKind::Ty => AstFragment::Ty(P(ast::Ty {
75 id, span, kind: ast::TyKind::Mac(mac_placeholder()),
77 AstFragmentKind::Stmts => AstFragment::Stmts(smallvec![{
78 let mac = P((mac_placeholder(), ast::MacStmtStyle::Braces, ThinVec::new()));
79 ast::Stmt { id, span, kind: ast::StmtKind::Mac(mac) }
81 AstFragmentKind::Arms => AstFragment::Arms(smallvec![
83 attrs: Default::default(),
84 body: expr_placeholder(),
92 AstFragmentKind::Fields => AstFragment::Fields(smallvec![
94 attrs: Default::default(),
95 expr: expr_placeholder(),
100 is_placeholder: true,
103 AstFragmentKind::FieldPats => AstFragment::FieldPats(smallvec![
105 attrs: Default::default(),
111 is_placeholder: true,
114 AstFragmentKind::GenericParams => AstFragment::GenericParams(smallvec![{
116 attrs: Default::default(),
117 bounds: Default::default(),
120 is_placeholder: true,
121 kind: ast::GenericParamKind::Lifetime,
124 AstFragmentKind::Params => AstFragment::Params(smallvec![
126 attrs: Default::default(),
131 is_placeholder: true,
134 AstFragmentKind::StructFields => AstFragment::StructFields(smallvec![
136 attrs: Default::default(),
142 is_placeholder: true,
145 AstFragmentKind::Variants => AstFragment::Variants(smallvec![
147 attrs: Default::default(),
148 data: ast::VariantData::Struct(Default::default(), false),
154 is_placeholder: true,
160 pub struct PlaceholderExpander<'a, 'b> {
161 expanded_fragments: FxHashMap<ast::NodeId, AstFragment>,
162 cx: &'a mut ExtCtxt<'b>,
166 impl<'a, 'b> PlaceholderExpander<'a, 'b> {
167 pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
168 PlaceholderExpander {
170 expanded_fragments: FxHashMap::default(),
175 pub fn add(&mut self, id: ast::NodeId, mut fragment: AstFragment) {
176 fragment.mut_visit_with(self);
177 self.expanded_fragments.insert(id, fragment);
180 fn remove(&mut self, id: ast::NodeId) -> AstFragment {
181 self.expanded_fragments.remove(&id).unwrap()
185 impl<'a, 'b> MutVisitor for PlaceholderExpander<'a, 'b> {
186 fn flat_map_arm(&mut self, arm: ast::Arm) -> SmallVec<[ast::Arm; 1]> {
187 if arm.is_placeholder {
188 self.remove(arm.id).make_arms()
190 noop_flat_map_arm(arm, self)
194 fn flat_map_field(&mut self, field: ast::Field) -> SmallVec<[ast::Field; 1]> {
195 if field.is_placeholder {
196 self.remove(field.id).make_fields()
198 noop_flat_map_field(field, self)
202 fn flat_map_field_pattern(&mut self, fp: ast::FieldPat) -> SmallVec<[ast::FieldPat; 1]> {
203 if fp.is_placeholder {
204 self.remove(fp.id).make_field_patterns()
206 noop_flat_map_field_pattern(fp, self)
210 fn flat_map_generic_param(
212 param: ast::GenericParam
213 ) -> SmallVec<[ast::GenericParam; 1]>
215 if param.is_placeholder {
216 self.remove(param.id).make_generic_params()
218 noop_flat_map_generic_param(param, self)
222 fn flat_map_param(&mut self, p: ast::Param) -> SmallVec<[ast::Param; 1]> {
223 if p.is_placeholder {
224 self.remove(p.id).make_params()
226 noop_flat_map_param(p, self)
230 fn flat_map_struct_field(&mut self, sf: ast::StructField) -> SmallVec<[ast::StructField; 1]> {
231 if sf.is_placeholder {
232 self.remove(sf.id).make_struct_fields()
234 noop_flat_map_struct_field(sf, self)
238 fn flat_map_variant(&mut self, variant: ast::Variant) -> SmallVec<[ast::Variant; 1]> {
239 if variant.is_placeholder {
240 self.remove(variant.id).make_variants()
242 noop_flat_map_variant(variant, self)
246 fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
248 ast::ItemKind::Mac(_) => return self.remove(item.id).make_items(),
249 ast::ItemKind::MacroDef(_) => return smallvec![item],
253 noop_flat_map_item(item, self)
256 fn flat_map_trait_item(&mut self, item: ast::TraitItem) -> SmallVec<[ast::TraitItem; 1]> {
258 ast::TraitItemKind::Macro(_) => self.remove(item.id).make_trait_items(),
259 _ => noop_flat_map_trait_item(item, self),
263 fn flat_map_impl_item(&mut self, item: ast::ImplItem) -> SmallVec<[ast::ImplItem; 1]> {
265 ast::ImplItemKind::Macro(_) => self.remove(item.id).make_impl_items(),
266 _ => noop_flat_map_impl_item(item, self),
270 fn flat_map_foreign_item(&mut self, item: ast::ForeignItem) -> SmallVec<[ast::ForeignItem; 1]> {
272 ast::ForeignItemKind::Macro(_) => self.remove(item.id).make_foreign_items(),
273 _ => noop_flat_map_foreign_item(item, self),
277 fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
279 ast::ExprKind::Mac(_) => *expr = self.remove(expr.id).make_expr(),
280 _ => noop_visit_expr(expr, self),
284 fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
286 ast::ExprKind::Mac(_) => self.remove(expr.id).make_opt_expr(),
287 _ => noop_filter_map_expr(expr, self),
291 fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
292 let (style, mut stmts) = match stmt.kind {
293 ast::StmtKind::Mac(mac) => (mac.1, self.remove(stmt.id).make_stmts()),
294 _ => return noop_flat_map_stmt(stmt, self),
297 if style == ast::MacStmtStyle::Semicolon {
298 if let Some(stmt) = stmts.pop() {
299 stmts.push(stmt.add_trailing_semicolon());
306 fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
308 ast::PatKind::Mac(_) => *pat = self.remove(pat.id).make_pat(),
309 _ => noop_visit_pat(pat, self),
313 fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
315 ast::TyKind::Mac(_) => *ty = self.remove(ty.id).make_ty(),
316 _ => noop_visit_ty(ty, self),
320 fn visit_block(&mut self, block: &mut P<ast::Block>) {
321 noop_visit_block(block, self);
323 for stmt in block.stmts.iter_mut() {
325 assert_eq!(stmt.id, ast::DUMMY_NODE_ID);
326 stmt.id = self.cx.resolver.next_node_id();
331 fn visit_mod(&mut self, module: &mut ast::Mod) {
332 noop_visit_mod(module, self);
333 module.items.retain(|item| match item.kind {
334 ast::ItemKind::Mac(_) if !self.cx.ecfg.keep_macs => false, // remove macro definitions
339 fn visit_mac(&mut self, _mac: &mut ast::Mac) {