1 //! A MutVisitor represents an AST modification; it accepts an AST piece and
2 //! and mutates it in place. So, for instance, macro expansion is a MutVisitor
3 //! that walks over an AST and modifies it.
5 //! Note: using a MutVisitor (other than the MacroExpander MutVisitor) on
6 //! an AST before macro expansion is probably a bad idea. For instance,
7 //! a MutVisitor renaming item names in a module will miss all of those
8 //! that are created by the expansion of a macro.
11 use crate::source_map::{Spanned, respan};
12 use crate::parse::token::{self, Token};
15 use crate::tokenstream::*;
16 use crate::util::map_in_place::MapInPlace;
18 use smallvec::{smallvec, Array, SmallVec};
21 use rustc_data_structures::sync::Lrc;
22 use std::ops::DerefMut;
23 use std::{panic, process, ptr};
25 pub trait ExpectOne<A: Array> {
26 fn expect_one(self, err: &'static str) -> A::Item;
29 impl<A: Array> ExpectOne<A> for SmallVec<A> {
30 fn expect_one(self, err: &'static str) -> A::Item {
31 assert!(self.len() == 1, err);
32 self.into_iter().next().unwrap()
36 pub trait MutVisitor: Sized {
37 // Methods in this trait have one of three forms:
39 // fn visit_t(&mut self, t: &mut T); // common
40 // fn flat_map_t(&mut self, t: T) -> SmallVec<[T; 1]>; // rare
41 // fn filter_map_t(&mut self, t: T) -> Option<T>; // rarest
43 // Any additions to this trait should happen in form of a call to a public
44 // `noop_*` function that only calls out to the visitor again, not other
45 // `noop_*` functions. This is a necessary API workaround to the problem of
46 // not being able to call out to the super default method in an overridden
49 // When writing these methods, it is better to use destructuring like this:
51 // fn visit_abc(&mut self, ABC { a, b, c: _ }: &mut ABC) {
56 // than to use field access like this:
58 // fn visit_abc(&mut self, abc: &mut ABC) {
59 // visit_a(&mut abc.a);
60 // visit_b(&mut abc.b);
64 // As well as being more concise, the former is explicit about which fields
65 // are skipped. Furthermore, if a new field is added, the destructuring
66 // version will cause a compile error, which is good. In comparison, the
67 // field access version will continue working and it would be easy to
68 // forget to add handling for it.
70 fn visit_crate(&mut self, c: &mut Crate) {
71 noop_visit_crate(c, self)
74 fn visit_meta_list_item(&mut self, list_item: &mut NestedMetaItem) {
75 noop_visit_meta_list_item(list_item, self);
78 fn visit_meta_item(&mut self, meta_item: &mut MetaItem) {
79 noop_visit_meta_item(meta_item, self);
82 fn visit_use_tree(&mut self, use_tree: &mut UseTree) {
83 noop_visit_use_tree(use_tree, self);
86 fn flat_map_foreign_item(&mut self, ni: ForeignItem) -> SmallVec<[ForeignItem; 1]> {
87 noop_flat_map_foreign_item(ni, self)
90 fn flat_map_item(&mut self, i: P<Item>) -> SmallVec<[P<Item>; 1]> {
91 noop_flat_map_item(i, self)
94 fn visit_fn_header(&mut self, header: &mut FnHeader) {
95 noop_visit_fn_header(header, self);
98 fn visit_struct_field(&mut self, sf: &mut StructField) {
99 noop_visit_struct_field(sf, self);
102 fn visit_item_kind(&mut self, i: &mut ItemKind) {
103 noop_visit_item_kind(i, self);
106 fn flat_map_trait_item(&mut self, i: TraitItem) -> SmallVec<[TraitItem; 1]> {
107 noop_flat_map_trait_item(i, self)
110 fn flat_map_impl_item(&mut self, i: ImplItem) -> SmallVec<[ImplItem; 1]> {
111 noop_flat_map_impl_item(i, self)
114 fn visit_fn_decl(&mut self, d: &mut P<FnDecl>) {
115 noop_visit_fn_decl(d, self);
118 fn visit_asyncness(&mut self, a: &mut IsAsync) {
119 noop_visit_asyncness(a, self);
122 fn visit_block(&mut self, b: &mut P<Block>) {
123 noop_visit_block(b, self);
126 fn flat_map_stmt(&mut self, s: Stmt) -> SmallVec<[Stmt; 1]> {
127 noop_flat_map_stmt(s, self)
130 fn visit_arm(&mut self, a: &mut Arm) {
131 noop_visit_arm(a, self);
134 fn visit_guard(&mut self, g: &mut Guard) {
135 noop_visit_guard(g, self);
138 fn visit_pat(&mut self, p: &mut P<Pat>) {
139 noop_visit_pat(p, self);
142 fn visit_anon_const(&mut self, c: &mut AnonConst) {
143 noop_visit_anon_const(c, self);
146 fn visit_expr(&mut self, e: &mut P<Expr>) {
147 noop_visit_expr(e, self);
150 fn filter_map_expr(&mut self, e: P<Expr>) -> Option<P<Expr>> {
151 noop_filter_map_expr(e, self)
154 fn visit_generic_arg(&mut self, arg: &mut GenericArg) {
155 noop_visit_generic_arg(arg, self);
158 fn visit_ty(&mut self, t: &mut P<Ty>) {
159 noop_visit_ty(t, self);
162 fn visit_lifetime(&mut self, l: &mut Lifetime) {
163 noop_visit_lifetime(l, self);
166 fn visit_ty_constraint(&mut self, t: &mut AssocTyConstraint) {
167 noop_visit_ty_constraint(t, self);
170 fn visit_mod(&mut self, m: &mut Mod) {
171 noop_visit_mod(m, self);
174 fn visit_foreign_mod(&mut self, nm: &mut ForeignMod) {
175 noop_visit_foreign_mod(nm, self);
178 fn visit_variant(&mut self, v: &mut Variant) {
179 noop_visit_variant(v, self);
182 fn visit_ident(&mut self, i: &mut Ident) {
183 noop_visit_ident(i, self);
186 fn visit_path(&mut self, p: &mut Path) {
187 noop_visit_path(p, self);
190 fn visit_qself(&mut self, qs: &mut Option<QSelf>) {
191 noop_visit_qself(qs, self);
194 fn visit_generic_args(&mut self, p: &mut GenericArgs) {
195 noop_visit_generic_args(p, self);
198 fn visit_angle_bracketed_parameter_data(&mut self, p: &mut AngleBracketedArgs) {
199 noop_visit_angle_bracketed_parameter_data(p, self);
202 fn visit_parenthesized_parameter_data(&mut self, p: &mut ParenthesizedArgs) {
203 noop_visit_parenthesized_parameter_data(p, self);
206 fn visit_local(&mut self, l: &mut P<Local>) {
207 noop_visit_local(l, self);
210 fn visit_mac(&mut self, _mac: &mut Mac) {
211 panic!("visit_mac disabled by default");
212 // N.B., see note about macros above. If you really want a visitor that
213 // works on macros, use this definition in your trait impl:
214 // mut_visit::noop_visit_mac(_mac, self);
217 fn visit_macro_def(&mut self, def: &mut MacroDef) {
218 noop_visit_macro_def(def, self);
221 fn visit_label(&mut self, label: &mut Label) {
222 noop_visit_label(label, self);
225 fn visit_attribute(&mut self, at: &mut Attribute) {
226 noop_visit_attribute(at, self);
229 fn visit_arg(&mut self, a: &mut Arg) {
230 noop_visit_arg(a, self);
233 fn visit_generics(&mut self, generics: &mut Generics) {
234 noop_visit_generics(generics, self);
237 fn visit_trait_ref(&mut self, tr: &mut TraitRef) {
238 noop_visit_trait_ref(tr, self);
241 fn visit_poly_trait_ref(&mut self, p: &mut PolyTraitRef) {
242 noop_visit_poly_trait_ref(p, self);
245 fn visit_variant_data(&mut self, vdata: &mut VariantData) {
246 noop_visit_variant_data(vdata, self);
249 fn visit_generic_param(&mut self, param: &mut GenericParam) {
250 noop_visit_generic_param(param, self);
253 fn visit_generic_params(&mut self, params: &mut Vec<GenericParam>) {
254 noop_visit_generic_params(params, self);
257 fn visit_tt(&mut self, tt: &mut TokenTree) {
258 noop_visit_tt(tt, self);
261 fn visit_tts(&mut self, tts: &mut TokenStream) {
262 noop_visit_tts(tts, self);
265 fn visit_token(&mut self, t: &mut Token) {
266 noop_visit_token(t, self);
269 fn visit_interpolated(&mut self, nt: &mut token::Nonterminal) {
270 noop_visit_interpolated(nt, self);
273 fn visit_param_bound(&mut self, tpb: &mut GenericBound) {
274 noop_visit_param_bound(tpb, self);
277 fn visit_mt(&mut self, mt: &mut MutTy) {
278 noop_visit_mt(mt, self);
281 fn visit_field(&mut self, field: &mut Field) {
282 noop_visit_field(field, self);
285 fn visit_where_clause(&mut self, where_clause: &mut WhereClause) {
286 noop_visit_where_clause(where_clause, self);
289 fn visit_where_predicate(&mut self, where_predicate: &mut WherePredicate) {
290 noop_visit_where_predicate(where_predicate, self);
293 fn visit_vis(&mut self, vis: &mut Visibility) {
294 noop_visit_vis(vis, self);
297 fn visit_id(&mut self, _id: &mut NodeId) {
301 fn visit_span(&mut self, _sp: &mut Span) {
306 /// Use a map-style function (`FnOnce(T) -> T`) to overwrite a `&mut T`. Useful
307 /// when using a `flat_map_*` or `filter_map_*` method within a `visit_`
308 /// method. Abort the program if the closure panics.
310 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
311 pub fn visit_clobber<T, F>(t: &mut T, f: F) where F: FnOnce(T) -> T {
313 // Safe because `t` is used in a read-only fashion by `read()` before
314 // being overwritten by `write()`.
315 let old_t = ptr::read(t);
316 let new_t = panic::catch_unwind(panic::AssertUnwindSafe(|| f(old_t)))
317 .unwrap_or_else(|_| process::abort());
318 ptr::write(t, new_t);
322 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
324 pub fn visit_vec<T, F>(elems: &mut Vec<T>, mut visit_elem: F) where F: FnMut(&mut T) {
330 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
332 pub fn visit_opt<T, F>(opt: &mut Option<T>, mut visit_elem: F) where F: FnMut(&mut T) {
333 if let Some(elem) = opt {
338 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
339 pub fn visit_attrs<T: MutVisitor>(attrs: &mut Vec<Attribute>, vis: &mut T) {
340 visit_vec(attrs, |attr| vis.visit_attribute(attr));
343 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
344 pub fn visit_thin_attrs<T: MutVisitor>(attrs: &mut ThinVec<Attribute>, vis: &mut T) {
345 for attr in attrs.iter_mut() {
346 vis.visit_attribute(attr);
350 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
351 pub fn visit_exprs<T: MutVisitor>(exprs: &mut Vec<P<Expr>>, vis: &mut T) {
352 exprs.flat_map_in_place(|expr| vis.filter_map_expr(expr))
355 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
356 pub fn visit_bounds<T: MutVisitor>(bounds: &mut GenericBounds, vis: &mut T) {
357 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
360 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
361 pub fn visit_method_sig<T: MutVisitor>(MethodSig { header, decl }: &mut MethodSig, vis: &mut T) {
362 vis.visit_fn_header(header);
363 vis.visit_fn_decl(decl);
366 pub fn noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T) {
367 let UseTree { prefix, kind, span } = use_tree;
368 vis.visit_path(prefix);
370 UseTreeKind::Simple(rename, id1, id2) => {
371 visit_opt(rename, |rename| vis.visit_ident(rename));
375 UseTreeKind::Nested(items) => {
376 for (tree, id) in items {
377 vis.visit_use_tree(tree);
381 UseTreeKind::Glob => {}
383 vis.visit_span(span);
386 pub fn noop_visit_arm<T: MutVisitor>(
387 Arm { attrs, pats, guard, body, span }: &mut Arm,
390 visit_attrs(attrs, vis);
391 visit_vec(pats, |pat| vis.visit_pat(pat));
392 visit_opt(guard, |guard| vis.visit_guard(guard));
393 vis.visit_expr(body);
394 vis.visit_span(span);
397 pub fn noop_visit_guard<T: MutVisitor>(g: &mut Guard, vis: &mut T) {
399 Guard::If(e) => vis.visit_expr(e),
403 pub fn noop_visit_ty_constraint<T: MutVisitor>(
404 AssocTyConstraint { id, ident, kind, span }: &mut AssocTyConstraint,
408 vis.visit_ident(ident);
410 AssocTyConstraintKind::Equality { ref mut ty } => {
413 AssocTyConstraintKind::Bound { ref mut bounds } => {
414 visit_bounds(bounds, vis);
417 vis.visit_span(span);
420 pub fn noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T) {
421 let Ty { id, node, span } = ty.deref_mut();
424 TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err |
425 TyKind::Never | TyKind::CVarArgs => {}
426 TyKind::Slice(ty) => vis.visit_ty(ty),
427 TyKind::Ptr(mt) => vis.visit_mt(mt),
428 TyKind::Rptr(lt, mt) => {
429 visit_opt(lt, |lt| noop_visit_lifetime(lt, vis));
432 TyKind::BareFn(bft) => {
433 let BareFnTy { unsafety: _, abi: _, generic_params, decl } = bft.deref_mut();
434 vis.visit_generic_params(generic_params);
435 vis.visit_fn_decl(decl);
437 TyKind::Tup(tys) => visit_vec(tys, |ty| vis.visit_ty(ty)),
438 TyKind::Paren(ty) => vis.visit_ty(ty),
439 TyKind::Path(qself, path) => {
440 vis.visit_qself(qself);
441 vis.visit_path(path);
443 TyKind::Array(ty, length) => {
445 vis.visit_anon_const(length);
447 TyKind::Typeof(expr) => vis.visit_anon_const(expr),
448 TyKind::TraitObject(bounds, _syntax) =>
449 visit_vec(bounds, |bound| vis.visit_param_bound(bound)),
450 TyKind::ImplTrait(id, bounds) => {
452 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
454 TyKind::Mac(mac) => vis.visit_mac(mac),
456 vis.visit_span(span);
459 pub fn noop_visit_foreign_mod<T: MutVisitor>(foreign_mod: &mut ForeignMod, vis: &mut T) {
460 let ForeignMod { abi: _, items} = foreign_mod;
461 items.flat_map_in_place(|item| vis.flat_map_foreign_item(item));
464 pub fn noop_visit_variant<T: MutVisitor>(variant: &mut Variant, vis: &mut T) {
465 let Spanned { node: Variant_ { ident, attrs, id, data, disr_expr }, span } = variant;
466 vis.visit_ident(ident);
467 visit_attrs(attrs, vis);
469 vis.visit_variant_data(data);
470 visit_opt(disr_expr, |disr_expr| vis.visit_anon_const(disr_expr));
471 vis.visit_span(span);
474 pub fn noop_visit_ident<T: MutVisitor>(Ident { name: _, span }: &mut Ident, vis: &mut T) {
475 vis.visit_span(span);
478 pub fn noop_visit_path<T: MutVisitor>(Path { segments, span }: &mut Path, vis: &mut T) {
479 vis.visit_span(span);
480 for PathSegment { ident, id, args } in segments {
481 vis.visit_ident(ident);
483 visit_opt(args, |args| vis.visit_generic_args(args));
487 pub fn noop_visit_qself<T: MutVisitor>(qself: &mut Option<QSelf>, vis: &mut T) {
488 visit_opt(qself, |QSelf { ty, path_span, position: _ }| {
490 vis.visit_span(path_span);
494 pub fn noop_visit_generic_args<T: MutVisitor>(generic_args: &mut GenericArgs, vis: &mut T) {
496 GenericArgs::AngleBracketed(data) => vis.visit_angle_bracketed_parameter_data(data),
497 GenericArgs::Parenthesized(data) => vis.visit_parenthesized_parameter_data(data),
501 pub fn noop_visit_generic_arg<T: MutVisitor>(arg: &mut GenericArg, vis: &mut T) {
503 GenericArg::Lifetime(lt) => vis.visit_lifetime(lt),
504 GenericArg::Type(ty) => vis.visit_ty(ty),
505 GenericArg::Const(ct) => vis.visit_anon_const(ct),
509 pub fn noop_visit_angle_bracketed_parameter_data<T: MutVisitor>(data: &mut AngleBracketedArgs,
511 let AngleBracketedArgs { args, constraints, span } = data;
512 visit_vec(args, |arg| vis.visit_generic_arg(arg));
513 visit_vec(constraints, |constraint| vis.visit_ty_constraint(constraint));
514 vis.visit_span(span);
517 pub fn noop_visit_parenthesized_parameter_data<T: MutVisitor>(args: &mut ParenthesizedArgs,
519 let ParenthesizedArgs { inputs, output, span } = args;
520 visit_vec(inputs, |input| vis.visit_ty(input));
521 visit_opt(output, |output| vis.visit_ty(output));
522 vis.visit_span(span);
525 pub fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
526 let Local { id, pat, ty, init, span, attrs } = local.deref_mut();
529 visit_opt(ty, |ty| vis.visit_ty(ty));
530 visit_opt(init, |init| vis.visit_expr(init));
531 vis.visit_span(span);
532 visit_thin_attrs(attrs, vis);
535 pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
536 let Attribute { id: _, style: _, path, tokens, is_sugared_doc: _, span } = attr;
537 vis.visit_path(path);
538 vis.visit_tts(tokens);
539 vis.visit_span(span);
542 pub fn noop_visit_mac<T: MutVisitor>(Spanned { node, span }: &mut Mac, vis: &mut T) {
543 let Mac_ { path, delim: _, tts } = node;
544 vis.visit_path(path);
546 vis.visit_span(span);
549 pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {
550 let MacroDef { tokens, legacy: _ } = macro_def;
551 vis.visit_tts(tokens);
554 pub fn noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T) {
556 NestedMetaItem::MetaItem(mi) => vis.visit_meta_item(mi),
557 NestedMetaItem::Literal(_lit) => {}
561 pub fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
562 let MetaItem { path: _, node, span } = mi;
564 MetaItemKind::Word => {}
565 MetaItemKind::List(mis) => visit_vec(mis, |mi| vis.visit_meta_list_item(mi)),
566 MetaItemKind::NameValue(_s) => {}
568 vis.visit_span(span);
571 pub fn noop_visit_arg<T: MutVisitor>(Arg { id, pat, ty }: &mut Arg, vis: &mut T) {
577 pub fn noop_visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T) {
579 TokenTree::Token(token) => {
580 vis.visit_token(token);
582 TokenTree::Delimited(DelimSpan { open, close }, _delim, tts) => {
583 vis.visit_span(open);
584 vis.visit_span(close);
590 pub fn noop_visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T) {
591 visit_opt(tts, |tts| {
592 let tts = Lrc::make_mut(tts);
593 visit_vec(tts, |(tree, _is_joint)| vis.visit_tt(tree));
597 // Apply ident visitor if it's an ident, apply other visits to interpolated nodes.
598 // In practice the ident part is not actually used by specific visitors right now,
599 // but there's a test below checking that it works.
600 pub fn noop_visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T) {
601 let Token { kind, span } = t;
603 token::Ident(name, _) | token::Lifetime(name) => {
604 let mut ident = Ident::new(*name, *span);
605 vis.visit_ident(&mut ident);
608 return; // avoid visiting the span for the second time
610 token::Interpolated(nt) => {
611 let mut nt = Lrc::make_mut(nt);
612 vis.visit_interpolated(&mut nt);
616 vis.visit_span(span);
619 /// Apply visitor to elements of interpolated nodes.
621 // N.B., this can occur only when applying a visitor to partially expanded
622 // code, where parsed pieces have gotten implanted ito *other* macro
623 // invocations. This is relevant for macro hygiene, but possibly not elsewhere.
625 // One problem here occurs because the types for flat_map_item, flat_map_stmt,
626 // etc. allow the visitor to return *multiple* items; this is a problem for the
627 // nodes here, because they insist on having exactly one piece. One solution
628 // would be to mangle the MutVisitor trait to include one-to-many and
629 // one-to-one versions of these entry points, but that would probably confuse a
630 // lot of people and help very few. Instead, I'm just going to put in dynamic
631 // checks. I think the performance impact of this will be pretty much
632 // nonexistent. The danger is that someone will apply a MutVisitor to a
633 // partially expanded node, and will be confused by the fact that their
634 // "flat_map_item" or "flat_map_stmt" isn't getting called on NtItem or NtStmt
635 // nodes. Hopefully they'll wind up reading this comment, and doing something
638 // BTW, design choice: I considered just changing the type of, e.g., NtItem to
639 // contain multiple items, but decided against it when I looked at
640 // parse_item_or_view_item and tried to figure out what I would do with
641 // multiple items there....
642 pub fn noop_visit_interpolated<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T) {
644 token::NtItem(item) =>
645 visit_clobber(item, |item| {
646 // This is probably okay, because the only visitors likely to
647 // peek inside interpolated nodes will be renamings/markings,
648 // which map single items to single items.
649 vis.flat_map_item(item).expect_one("expected visitor to produce exactly one item")
651 token::NtBlock(block) => vis.visit_block(block),
652 token::NtStmt(stmt) =>
653 visit_clobber(stmt, |stmt| {
654 // See reasoning above.
655 vis.flat_map_stmt(stmt).expect_one("expected visitor to produce exactly one item")
657 token::NtPat(pat) => vis.visit_pat(pat),
658 token::NtExpr(expr) => vis.visit_expr(expr),
659 token::NtTy(ty) => vis.visit_ty(ty),
660 token::NtIdent(ident, _is_raw) => vis.visit_ident(ident),
661 token::NtLifetime(ident) => vis.visit_ident(ident),
662 token::NtLiteral(expr) => vis.visit_expr(expr),
663 token::NtMeta(meta) => vis.visit_meta_item(meta),
664 token::NtPath(path) => vis.visit_path(path),
665 token::NtTT(tt) => vis.visit_tt(tt),
666 token::NtImplItem(item) =>
667 visit_clobber(item, |item| {
668 // See reasoning above.
669 vis.flat_map_impl_item(item)
670 .expect_one("expected visitor to produce exactly one item")
672 token::NtTraitItem(item) =>
673 visit_clobber(item, |item| {
674 // See reasoning above.
675 vis.flat_map_trait_item(item)
676 .expect_one("expected visitor to produce exactly one item")
678 token::NtVis(visib) => vis.visit_vis(visib),
679 token::NtForeignItem(item) =>
680 visit_clobber(item, |item| {
681 // See reasoning above.
682 vis.flat_map_foreign_item(item)
683 .expect_one("expected visitor to produce exactly one item")
688 pub fn noop_visit_asyncness<T: MutVisitor>(asyncness: &mut IsAsync, vis: &mut T) {
690 IsAsync::Async { closure_id, return_impl_trait_id } => {
691 vis.visit_id(closure_id);
692 vis.visit_id(return_impl_trait_id);
694 IsAsync::NotAsync => {}
698 pub fn noop_visit_fn_decl<T: MutVisitor>(decl: &mut P<FnDecl>, vis: &mut T) {
699 let FnDecl { inputs, output, c_variadic: _ } = decl.deref_mut();
700 visit_vec(inputs, |input| vis.visit_arg(input));
702 FunctionRetTy::Default(span) => vis.visit_span(span),
703 FunctionRetTy::Ty(ty) => vis.visit_ty(ty),
707 pub fn noop_visit_param_bound<T: MutVisitor>(pb: &mut GenericBound, vis: &mut T) {
709 GenericBound::Trait(ty, _modifier) => vis.visit_poly_trait_ref(ty),
710 GenericBound::Outlives(lifetime) => noop_visit_lifetime(lifetime, vis),
714 pub fn noop_visit_generic_param<T: MutVisitor>(param: &mut GenericParam, vis: &mut T) {
715 let GenericParam { id, ident, attrs, bounds, kind } = param;
717 vis.visit_ident(ident);
718 visit_thin_attrs(attrs, vis);
719 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
721 GenericParamKind::Lifetime => {}
722 GenericParamKind::Type { default } => {
723 visit_opt(default, |default| vis.visit_ty(default));
725 GenericParamKind::Const { ty } => {
731 pub fn noop_visit_generic_params<T: MutVisitor>(params: &mut Vec<GenericParam>, vis: &mut T){
732 visit_vec(params, |param| vis.visit_generic_param(param));
735 pub fn noop_visit_label<T: MutVisitor>(Label { ident }: &mut Label, vis: &mut T) {
736 vis.visit_ident(ident);
739 fn noop_visit_lifetime<T: MutVisitor>(Lifetime { id, ident }: &mut Lifetime, vis: &mut T) {
741 vis.visit_ident(ident);
744 pub fn noop_visit_generics<T: MutVisitor>(generics: &mut Generics, vis: &mut T) {
745 let Generics { params, where_clause, span } = generics;
746 vis.visit_generic_params(params);
747 vis.visit_where_clause(where_clause);
748 vis.visit_span(span);
751 pub fn noop_visit_where_clause<T: MutVisitor>(wc: &mut WhereClause, vis: &mut T) {
752 let WhereClause { id, predicates, span } = wc;
754 visit_vec(predicates, |predicate| vis.visit_where_predicate(predicate));
755 vis.visit_span(span);
758 pub fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis: &mut T) {
760 WherePredicate::BoundPredicate(bp) => {
761 let WhereBoundPredicate { span, bound_generic_params, bounded_ty, bounds } = bp;
762 vis.visit_span(span);
763 vis.visit_generic_params(bound_generic_params);
764 vis.visit_ty(bounded_ty);
765 visit_vec(bounds, |bound| vis.visit_param_bound(bound));
767 WherePredicate::RegionPredicate(rp) => {
768 let WhereRegionPredicate { span, lifetime, bounds } = rp;
769 vis.visit_span(span);
770 noop_visit_lifetime(lifetime, vis);
771 visit_vec(bounds, |bound| noop_visit_param_bound(bound, vis));
773 WherePredicate::EqPredicate(ep) => {
774 let WhereEqPredicate { id, span, lhs_ty, rhs_ty } = ep;
776 vis.visit_span(span);
777 vis.visit_ty(lhs_ty);
778 vis.visit_ty(rhs_ty);
783 pub fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T) {
785 VariantData::Struct(fields, ..) => visit_vec(fields, |field| vis.visit_struct_field(field)),
786 VariantData::Tuple(fields, id) => {
787 visit_vec(fields, |field| vis.visit_struct_field(field));
790 VariantData::Unit(id) => vis.visit_id(id),
794 pub fn noop_visit_trait_ref<T: MutVisitor>(TraitRef { path, ref_id }: &mut TraitRef, vis: &mut T) {
795 vis.visit_path(path);
796 vis.visit_id(ref_id);
799 pub fn noop_visit_poly_trait_ref<T: MutVisitor>(p: &mut PolyTraitRef, vis: &mut T) {
800 let PolyTraitRef { bound_generic_params, trait_ref, span } = p;
801 vis.visit_generic_params(bound_generic_params);
802 vis.visit_trait_ref(trait_ref);
803 vis.visit_span(span);
806 pub fn noop_visit_struct_field<T: MutVisitor>(f: &mut StructField, visitor: &mut T) {
807 let StructField { span, ident, vis, id, ty, attrs } = f;
808 visitor.visit_span(span);
809 visit_opt(ident, |ident| visitor.visit_ident(ident));
810 visitor.visit_vis(vis);
811 visitor.visit_id(id);
812 visitor.visit_ty(ty);
813 visit_attrs(attrs, visitor);
816 pub fn noop_visit_field<T: MutVisitor>(f: &mut Field, vis: &mut T) {
817 let Field { ident, expr, span, is_shorthand: _, attrs } = f;
818 vis.visit_ident(ident);
819 vis.visit_expr(expr);
820 vis.visit_span(span);
821 visit_thin_attrs(attrs, vis);
824 pub fn noop_visit_mt<T: MutVisitor>(MutTy { ty, mutbl: _ }: &mut MutTy, vis: &mut T) {
828 pub fn noop_visit_block<T: MutVisitor>(block: &mut P<Block>, vis: &mut T) {
829 let Block { id, stmts, rules: _, span } = block.deref_mut();
831 stmts.flat_map_in_place(|stmt| vis.flat_map_stmt(stmt));
832 vis.visit_span(span);
835 pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
837 ItemKind::ExternCrate(_orig_name) => {}
838 ItemKind::Use(use_tree) => vis.visit_use_tree(use_tree),
839 ItemKind::Static(ty, _mut, expr) => {
841 vis.visit_expr(expr);
843 ItemKind::Const(ty, expr) => {
845 vis.visit_expr(expr);
847 ItemKind::Fn(decl, header, generics, body) => {
848 vis.visit_fn_decl(decl);
849 vis.visit_fn_header(header);
850 vis.visit_generics(generics);
851 vis.visit_block(body);
853 ItemKind::Mod(m) => vis.visit_mod(m),
854 ItemKind::ForeignMod(nm) => vis.visit_foreign_mod(nm),
855 ItemKind::GlobalAsm(_ga) => {}
856 ItemKind::Ty(ty, generics) => {
858 vis.visit_generics(generics);
860 ItemKind::Existential(bounds, generics) => {
861 visit_bounds(bounds, vis);
862 vis.visit_generics(generics);
864 ItemKind::Enum(EnumDef { variants }, generics) => {
865 visit_vec(variants, |variant| vis.visit_variant(variant));
866 vis.visit_generics(generics);
868 ItemKind::Struct(variant_data, generics) |
869 ItemKind::Union(variant_data, generics) => {
870 vis.visit_variant_data(variant_data);
871 vis.visit_generics(generics);
873 ItemKind::Impl(_unsafety, _polarity, _defaultness, generics, trait_ref, ty, items) => {
874 vis.visit_generics(generics);
875 visit_opt(trait_ref, |trait_ref| vis.visit_trait_ref(trait_ref));
877 items.flat_map_in_place(|item| vis.flat_map_impl_item(item));
879 ItemKind::Trait(_is_auto, _unsafety, generics, bounds, items) => {
880 vis.visit_generics(generics);
881 visit_bounds(bounds, vis);
882 items.flat_map_in_place(|item| vis.flat_map_trait_item(item));
884 ItemKind::TraitAlias(generics, bounds) => {
885 vis.visit_generics(generics);
886 visit_bounds(bounds, vis);
888 ItemKind::Mac(m) => vis.visit_mac(m),
889 ItemKind::MacroDef(def) => vis.visit_macro_def(def),
893 pub fn noop_flat_map_trait_item<T: MutVisitor>(mut item: TraitItem, vis: &mut T)
894 -> SmallVec<[TraitItem; 1]>
896 let TraitItem { id, ident, attrs, generics, node, span, tokens: _ } = &mut item;
898 vis.visit_ident(ident);
899 visit_attrs(attrs, vis);
900 vis.visit_generics(generics);
902 TraitItemKind::Const(ty, default) => {
904 visit_opt(default, |default| vis.visit_expr(default));
906 TraitItemKind::Method(sig, body) => {
907 visit_method_sig(sig, vis);
908 visit_opt(body, |body| vis.visit_block(body));
910 TraitItemKind::Type(bounds, default) => {
911 visit_bounds(bounds, vis);
912 visit_opt(default, |default| vis.visit_ty(default));
914 TraitItemKind::Macro(mac) => {
918 vis.visit_span(span);
923 pub fn noop_flat_map_impl_item<T: MutVisitor>(mut item: ImplItem, visitor: &mut T)
924 -> SmallVec<[ImplItem; 1]>
926 let ImplItem { id, ident, vis, defaultness: _, attrs, generics, node, span, tokens: _ } =
928 visitor.visit_id(id);
929 visitor.visit_ident(ident);
930 visitor.visit_vis(vis);
931 visit_attrs(attrs, visitor);
932 visitor.visit_generics(generics);
934 ImplItemKind::Const(ty, expr) => {
935 visitor.visit_ty(ty);
936 visitor.visit_expr(expr);
938 ImplItemKind::Method(sig, body) => {
939 visit_method_sig(sig, visitor);
940 visitor.visit_block(body);
942 ImplItemKind::Type(ty) => visitor.visit_ty(ty),
943 ImplItemKind::Existential(bounds) => visit_bounds(bounds, visitor),
944 ImplItemKind::Macro(mac) => visitor.visit_mac(mac),
946 visitor.visit_span(span);
951 pub fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
952 let FnHeader { unsafety: _, asyncness, constness: _, abi: _ } = header;
953 vis.visit_asyncness(&mut asyncness.node);
956 pub fn noop_visit_mod<T: MutVisitor>(Mod { inner, items, inline: _ }: &mut Mod, vis: &mut T) {
957 vis.visit_span(inner);
958 items.flat_map_in_place(|item| vis.flat_map_item(item));
961 pub fn noop_visit_crate<T: MutVisitor>(krate: &mut Crate, vis: &mut T) {
962 visit_clobber(krate, |Crate { module, attrs, span }| {
964 ident: Ident::invalid(),
967 vis: respan(span.shrink_to_lo(), VisibilityKind::Public),
969 node: ItemKind::Mod(module),
972 let items = vis.flat_map_item(item);
974 let len = items.len();
976 let module = Mod { inner: span, items: vec![], inline: true };
977 Crate { module, attrs: vec![], span }
979 let Item { attrs, span, node, .. } = items.into_iter().next().unwrap().into_inner();
981 ItemKind::Mod(module) => Crate { module, attrs, span },
982 _ => panic!("visitor converted a module to not a module"),
985 panic!("a crate cannot expand to more than one item");
990 // Mutate one item into possibly many items.
991 pub fn noop_flat_map_item<T: MutVisitor>(mut item: P<Item>, visitor: &mut T)
992 -> SmallVec<[P<Item>; 1]> {
993 let Item { ident, attrs, id, node, vis, span, tokens: _ } = item.deref_mut();
994 visitor.visit_ident(ident);
995 visit_attrs(attrs, visitor);
996 visitor.visit_id(id);
997 visitor.visit_item_kind(node);
998 visitor.visit_vis(vis);
999 visitor.visit_span(span);
1001 // FIXME: if `tokens` is modified with a call to `vis.visit_tts` it causes
1002 // an ICE during resolve... odd!
1007 pub fn noop_flat_map_foreign_item<T: MutVisitor>(mut item: ForeignItem, visitor: &mut T)
1008 -> SmallVec<[ForeignItem; 1]>
1010 let ForeignItem { ident, attrs, node, id, span, vis } = &mut item;
1011 visitor.visit_ident(ident);
1012 visit_attrs(attrs, visitor);
1014 ForeignItemKind::Fn(fdec, generics) => {
1015 visitor.visit_fn_decl(fdec);
1016 visitor.visit_generics(generics);
1018 ForeignItemKind::Static(t, _m) => visitor.visit_ty(t),
1019 ForeignItemKind::Ty => {}
1020 ForeignItemKind::Macro(mac) => visitor.visit_mac(mac),
1022 visitor.visit_id(id);
1023 visitor.visit_span(span);
1024 visitor.visit_vis(vis);
1029 pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
1030 let Pat { id, node, span } = pat.deref_mut();
1034 PatKind::Ident(_binding_mode, ident, sub) => {
1035 vis.visit_ident(ident);
1036 visit_opt(sub, |sub| vis.visit_pat(sub));
1038 PatKind::Lit(e) => vis.visit_expr(e),
1039 PatKind::TupleStruct(path, pats, _ddpos) => {
1040 vis.visit_path(path);
1041 visit_vec(pats, |pat| vis.visit_pat(pat));
1043 PatKind::Path(qself, path) => {
1044 vis.visit_qself(qself);
1045 vis.visit_path(path);
1047 PatKind::Struct(path, fields, _etc) => {
1048 vis.visit_path(path);
1049 for Spanned { node: FieldPat { ident, pat, is_shorthand: _, attrs }, span } in fields {
1050 vis.visit_ident(ident);
1052 visit_thin_attrs(attrs, vis);
1053 vis.visit_span(span);
1056 PatKind::Tuple(elts, _ddpos) => visit_vec(elts, |elt| vis.visit_pat(elt)),
1057 PatKind::Box(inner) => vis.visit_pat(inner),
1058 PatKind::Ref(inner, _mutbl) => vis.visit_pat(inner),
1059 PatKind::Range(e1, e2, Spanned { span: _, node: _ }) => {
1062 vis.visit_span(span);
1064 PatKind::Slice(before, slice, after) => {
1065 visit_vec(before, |pat| vis.visit_pat(pat));
1066 visit_opt(slice, |slice| vis.visit_pat(slice));
1067 visit_vec(after, |pat| vis.visit_pat(pat));
1069 PatKind::Paren(inner) => vis.visit_pat(inner),
1070 PatKind::Mac(mac) => vis.visit_mac(mac),
1072 vis.visit_span(span);
1075 pub fn noop_visit_anon_const<T: MutVisitor>(AnonConst { id, value }: &mut AnonConst, vis: &mut T) {
1077 vis.visit_expr(value);
1080 pub fn noop_visit_expr<T: MutVisitor>(Expr { node, id, span, attrs }: &mut Expr, vis: &mut T) {
1082 ExprKind::Box(expr) => vis.visit_expr(expr),
1083 ExprKind::Array(exprs) => visit_exprs(exprs, vis),
1084 ExprKind::Repeat(expr, count) => {
1085 vis.visit_expr(expr);
1086 vis.visit_anon_const(count);
1088 ExprKind::Tup(exprs) => visit_exprs(exprs, vis),
1089 ExprKind::Call(f, args) => {
1091 visit_exprs(args, vis);
1093 ExprKind::MethodCall(PathSegment { ident, id, args }, exprs) => {
1094 vis.visit_ident(ident);
1096 visit_opt(args, |args| vis.visit_generic_args(args));
1097 visit_exprs(exprs, vis);
1099 ExprKind::Binary(_binop, lhs, rhs) => {
1100 vis.visit_expr(lhs);
1101 vis.visit_expr(rhs);
1103 ExprKind::Unary(_unop, ohs) => vis.visit_expr(ohs),
1104 ExprKind::Lit(_lit) => {}
1105 ExprKind::Cast(expr, ty) => {
1106 vis.visit_expr(expr);
1109 ExprKind::Type(expr, ty) => {
1110 vis.visit_expr(expr);
1113 ExprKind::AddrOf(_m, ohs) => vis.visit_expr(ohs),
1114 ExprKind::If(cond, tr, fl) => {
1115 vis.visit_expr(cond);
1116 vis.visit_block(tr);
1117 visit_opt(fl, |fl| vis.visit_expr(fl));
1119 ExprKind::IfLet(pats, expr, tr, fl) => {
1120 visit_vec(pats, |pat| vis.visit_pat(pat));
1121 vis.visit_expr(expr);
1122 vis.visit_block(tr);
1123 visit_opt(fl, |fl| vis.visit_expr(fl));
1125 ExprKind::While(cond, body, label) => {
1126 vis.visit_expr(cond);
1127 vis.visit_block(body);
1128 visit_opt(label, |label| vis.visit_label(label));
1130 ExprKind::WhileLet(pats, expr, body, label) => {
1131 visit_vec(pats, |pat| vis.visit_pat(pat));
1132 vis.visit_expr(expr);
1133 vis.visit_block(body);
1134 visit_opt(label, |label| vis.visit_label(label));
1136 ExprKind::ForLoop(pat, iter, body, label) => {
1138 vis.visit_expr(iter);
1139 vis.visit_block(body);
1140 visit_opt(label, |label| vis.visit_label(label));
1142 ExprKind::Loop(body, label) => {
1143 vis.visit_block(body);
1144 visit_opt(label, |label| vis.visit_label(label));
1146 ExprKind::Match(expr, arms) => {
1147 vis.visit_expr(expr);
1148 visit_vec(arms, |arm| vis.visit_arm(arm));
1150 ExprKind::Closure(_capture_by, asyncness, _movability, decl, body, span) => {
1151 vis.visit_asyncness(asyncness);
1152 vis.visit_fn_decl(decl);
1153 vis.visit_expr(body);
1154 vis.visit_span(span);
1156 ExprKind::Block(blk, label) => {
1157 vis.visit_block(blk);
1158 visit_opt(label, |label| vis.visit_label(label));
1160 ExprKind::Async(_capture_by, node_id, body) => {
1161 vis.visit_id(node_id);
1162 vis.visit_block(body);
1164 ExprKind::Await(_origin, expr) => vis.visit_expr(expr),
1165 ExprKind::Assign(el, er) => {
1169 ExprKind::AssignOp(_op, el, er) => {
1173 ExprKind::Field(el, ident) => {
1175 vis.visit_ident(ident);
1177 ExprKind::Index(el, er) => {
1181 ExprKind::Range(e1, e2, _lim) => {
1182 visit_opt(e1, |e1| vis.visit_expr(e1));
1183 visit_opt(e2, |e2| vis.visit_expr(e2));
1185 ExprKind::Path(qself, path) => {
1186 vis.visit_qself(qself);
1187 vis.visit_path(path);
1189 ExprKind::Break(label, expr) => {
1190 visit_opt(label, |label| vis.visit_label(label));
1191 visit_opt(expr, |expr| vis.visit_expr(expr));
1193 ExprKind::Continue(label) => {
1194 visit_opt(label, |label| vis.visit_label(label));
1196 ExprKind::Ret(expr) => {
1197 visit_opt(expr, |expr| vis.visit_expr(expr));
1199 ExprKind::InlineAsm(asm) => {
1200 let InlineAsm { asm: _, asm_str_style: _, outputs, inputs, clobbers: _, volatile: _,
1201 alignstack: _, dialect: _, ctxt: _ } = asm.deref_mut();
1202 for out in outputs {
1203 let InlineAsmOutput { constraint: _, expr, is_rw: _, is_indirect: _ } = out;
1204 vis.visit_expr(expr);
1206 visit_vec(inputs, |(_c, expr)| vis.visit_expr(expr));
1208 ExprKind::Mac(mac) => vis.visit_mac(mac),
1209 ExprKind::Struct(path, fields, expr) => {
1210 vis.visit_path(path);
1211 visit_vec(fields, |field| vis.visit_field(field));
1212 visit_opt(expr, |expr| vis.visit_expr(expr));
1214 ExprKind::Paren(expr) => {
1215 vis.visit_expr(expr);
1217 // Nodes that are equal modulo `Paren` sugar no-ops should have the same ids.
1219 vis.visit_span(span);
1220 visit_thin_attrs(attrs, vis);
1223 ExprKind::Yield(expr) => {
1224 visit_opt(expr, |expr| vis.visit_expr(expr));
1226 ExprKind::Try(expr) => vis.visit_expr(expr),
1227 ExprKind::TryBlock(body) => vis.visit_block(body),
1231 vis.visit_span(span);
1232 visit_thin_attrs(attrs, vis);
1235 pub fn noop_filter_map_expr<T: MutVisitor>(mut e: P<Expr>, vis: &mut T) -> Option<P<Expr>> {
1236 Some({ vis.visit_expr(&mut e); e })
1239 pub fn noop_flat_map_stmt<T: MutVisitor>(Stmt { node, mut span, mut id }: Stmt, vis: &mut T)
1240 -> SmallVec<[Stmt; 1]>
1242 vis.visit_id(&mut id);
1243 vis.visit_span(&mut span);
1244 noop_flat_map_stmt_kind(node, vis).into_iter().map(|node| {
1245 Stmt { id, node, span }
1249 pub fn noop_flat_map_stmt_kind<T: MutVisitor>(node: StmtKind, vis: &mut T)
1250 -> SmallVec<[StmtKind; 1]> {
1252 StmtKind::Local(mut local) =>
1253 smallvec![StmtKind::Local({ vis.visit_local(&mut local); local })],
1254 StmtKind::Item(item) => vis.flat_map_item(item).into_iter().map(StmtKind::Item).collect(),
1255 StmtKind::Expr(expr) => {
1256 vis.filter_map_expr(expr).into_iter().map(StmtKind::Expr).collect()
1258 StmtKind::Semi(expr) => {
1259 vis.filter_map_expr(expr).into_iter().map(StmtKind::Semi).collect()
1261 StmtKind::Mac(mut mac) => {
1262 let (mac_, _semi, attrs) = mac.deref_mut();
1263 vis.visit_mac(mac_);
1264 visit_thin_attrs(attrs, vis);
1265 smallvec![StmtKind::Mac(mac)]
1270 pub fn noop_visit_vis<T: MutVisitor>(Spanned { node, span }: &mut Visibility, vis: &mut T) {
1272 VisibilityKind::Public | VisibilityKind::Crate(_) | VisibilityKind::Inherited => {}
1273 VisibilityKind::Restricted { path, id } => {
1274 vis.visit_path(path);
1278 vis.visit_span(span);
1284 use crate::ast::{self, Ident};
1285 use crate::util::parser_testing::{string_to_crate, matches_codepattern};
1286 use crate::print::pprust;
1287 use crate::mut_visit;
1288 use crate::with_default_globals;
1291 // this version doesn't care about getting comments or docstrings in.
1292 fn fake_print_crate(s: &mut pprust::State<'_>,
1293 krate: &ast::Crate) -> io::Result<()> {
1294 s.print_mod(&krate.module, &krate.attrs)
1297 // change every identifier to "zz"
1298 struct ToZzIdentMutVisitor;
1300 impl MutVisitor for ToZzIdentMutVisitor {
1301 fn visit_ident(&mut self, ident: &mut ast::Ident) {
1302 *ident = Ident::from_str("zz");
1304 fn visit_mac(&mut self, mac: &mut ast::Mac) {
1305 mut_visit::noop_visit_mac(mac, self)
1309 // maybe add to expand.rs...
1310 macro_rules! assert_pred {
1311 ($pred:expr, $predname:expr, $a:expr , $b:expr) => (
1313 let pred_val = $pred;
1316 if !(pred_val(&a_val, &b_val)) {
1317 panic!("expected args satisfying {}, got {} and {}",
1318 $predname, a_val, b_val);
1324 // make sure idents get transformed everywhere
1325 #[test] fn ident_transformation () {
1326 with_default_globals(|| {
1327 let mut zz_visitor = ToZzIdentMutVisitor;
1328 let mut krate = string_to_crate(
1329 "#[a] mod b {fn c (d : e, f : g) {h!(i,j,k);l;m}}".to_string());
1330 zz_visitor.visit_crate(&mut krate);
1332 matches_codepattern,
1333 "matches_codepattern",
1334 pprust::to_string(|s| fake_print_crate(s, &krate)),
1335 "#[zz]mod zz{fn zz(zz:zz,zz:zz){zz!(zz,zz,zz);zz;zz}}".to_string());
1339 // even inside macro defs....
1340 #[test] fn ident_transformation_in_defs () {
1341 with_default_globals(|| {
1342 let mut zz_visitor = ToZzIdentMutVisitor;
1343 let mut krate = string_to_crate(
1344 "macro_rules! a {(b $c:expr $(d $e:token)f+ => \
1345 (g $(d $d $e)+))} ".to_string());
1346 zz_visitor.visit_crate(&mut krate);
1348 matches_codepattern,
1349 "matches_codepattern",
1350 pprust::to_string(|s| fake_print_crate(s, &krate)),
1351 "macro_rules! zz((zz$zz:zz$(zz $zz:zz)zz+=>(zz$(zz$zz$zz)+)));".to_string());