1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! A Folder represents an AST->AST fold; it accepts an AST piece,
12 //! and returns a piece of the same type. So, for instance, macro
13 //! expansion is a Folder that walks over an AST and produces another
16 //! Note: using a Folder (other than the MacroExpander Folder) on
17 //! an AST before macro expansion is probably a bad idea. For instance,
18 //! a folder renaming item names in a module will miss all of those
19 //! that are created by the expansion of a macro.
23 use attr::{ThinAttributes, ThinAttributesExt};
25 use codemap::{respan, Span, Spanned};
28 use util::small_vector::SmallVector;
29 use util::move_map::MoveMap;
33 pub trait Folder : Sized {
34 // Any additions to this trait should happen in form
35 // of a call to a public `noop_*` function that only calls
36 // out to the folder again, not other `noop_*` functions.
38 // This is a necessary API workaround to the problem of not
39 // being able to call out to the super default method
40 // in an overridden default method.
42 fn fold_crate(&mut self, c: Crate) -> Crate {
43 noop_fold_crate(c, self)
46 fn fold_meta_items(&mut self, meta_items: Vec<P<MetaItem>>) -> Vec<P<MetaItem>> {
47 noop_fold_meta_items(meta_items, self)
50 fn fold_meta_item(&mut self, meta_item: P<MetaItem>) -> P<MetaItem> {
51 noop_fold_meta_item(meta_item, self)
54 fn fold_view_path(&mut self, view_path: P<ViewPath>) -> P<ViewPath> {
55 noop_fold_view_path(view_path, self)
58 fn fold_foreign_item(&mut self, ni: P<ForeignItem>) -> P<ForeignItem> {
59 noop_fold_foreign_item(ni, self)
62 fn fold_item(&mut self, i: P<Item>) -> SmallVector<P<Item>> {
63 noop_fold_item(i, self)
66 fn fold_item_simple(&mut self, i: Item) -> Item {
67 noop_fold_item_simple(i, self)
70 fn fold_struct_field(&mut self, sf: StructField) -> StructField {
71 noop_fold_struct_field(sf, self)
74 fn fold_item_underscore(&mut self, i: Item_) -> Item_ {
75 noop_fold_item_underscore(i, self)
78 fn fold_trait_item(&mut self, i: P<TraitItem>) -> SmallVector<P<TraitItem>> {
79 noop_fold_trait_item(i, self)
82 fn fold_impl_item(&mut self, i: P<ImplItem>) -> SmallVector<P<ImplItem>> {
83 noop_fold_impl_item(i, self)
86 fn fold_fn_decl(&mut self, d: P<FnDecl>) -> P<FnDecl> {
87 noop_fold_fn_decl(d, self)
90 fn fold_block(&mut self, b: P<Block>) -> P<Block> {
91 noop_fold_block(b, self)
94 fn fold_stmt(&mut self, s: P<Stmt>) -> SmallVector<P<Stmt>> {
95 s.and_then(|s| noop_fold_stmt(s, self))
98 fn fold_arm(&mut self, a: Arm) -> Arm {
99 noop_fold_arm(a, self)
102 fn fold_pat(&mut self, p: P<Pat>) -> P<Pat> {
103 noop_fold_pat(p, self)
106 fn fold_decl(&mut self, d: P<Decl>) -> SmallVector<P<Decl>> {
107 noop_fold_decl(d, self)
110 fn fold_expr(&mut self, e: P<Expr>) -> P<Expr> {
111 e.map(|e| noop_fold_expr(e, self))
114 fn fold_opt_expr(&mut self, e: P<Expr>) -> Option<P<Expr>> {
115 noop_fold_opt_expr(e, self)
118 fn fold_exprs(&mut self, es: Vec<P<Expr>>) -> Vec<P<Expr>> {
119 noop_fold_exprs(es, self)
122 fn fold_ty(&mut self, t: P<Ty>) -> P<Ty> {
123 noop_fold_ty(t, self)
126 fn fold_ty_binding(&mut self, t: P<TypeBinding>) -> P<TypeBinding> {
127 noop_fold_ty_binding(t, self)
130 fn fold_mod(&mut self, m: Mod) -> Mod {
131 noop_fold_mod(m, self)
134 fn fold_foreign_mod(&mut self, nm: ForeignMod) -> ForeignMod {
135 noop_fold_foreign_mod(nm, self)
138 fn fold_variant(&mut self, v: P<Variant>) -> P<Variant> {
139 noop_fold_variant(v, self)
142 fn fold_ident(&mut self, i: Ident) -> Ident {
143 noop_fold_ident(i, self)
146 fn fold_usize(&mut self, i: usize) -> usize {
147 noop_fold_usize(i, self)
150 fn fold_path(&mut self, p: Path) -> Path {
151 noop_fold_path(p, self)
154 fn fold_path_parameters(&mut self, p: PathParameters) -> PathParameters {
155 noop_fold_path_parameters(p, self)
158 fn fold_angle_bracketed_parameter_data(&mut self, p: AngleBracketedParameterData)
159 -> AngleBracketedParameterData
161 noop_fold_angle_bracketed_parameter_data(p, self)
164 fn fold_parenthesized_parameter_data(&mut self, p: ParenthesizedParameterData)
165 -> ParenthesizedParameterData
167 noop_fold_parenthesized_parameter_data(p, self)
170 fn fold_local(&mut self, l: P<Local>) -> P<Local> {
171 noop_fold_local(l, self)
174 fn fold_mac(&mut self, _mac: Mac) -> Mac {
175 panic!("fold_mac disabled by default");
176 // NB: see note about macros above.
177 // if you really want a folder that
178 // works on macros, use this
179 // definition in your trait impl:
180 // fold::noop_fold_mac(_mac, self)
183 fn fold_explicit_self(&mut self, es: ExplicitSelf) -> ExplicitSelf {
184 noop_fold_explicit_self(es, self)
187 fn fold_explicit_self_underscore(&mut self, es: ExplicitSelf_) -> ExplicitSelf_ {
188 noop_fold_explicit_self_underscore(es, self)
191 fn fold_lifetime(&mut self, l: Lifetime) -> Lifetime {
192 noop_fold_lifetime(l, self)
195 fn fold_lifetime_def(&mut self, l: LifetimeDef) -> LifetimeDef {
196 noop_fold_lifetime_def(l, self)
199 fn fold_attribute(&mut self, at: Attribute) -> Option<Attribute> {
200 noop_fold_attribute(at, self)
203 fn fold_arg(&mut self, a: Arg) -> Arg {
204 noop_fold_arg(a, self)
207 fn fold_generics(&mut self, generics: Generics) -> Generics {
208 noop_fold_generics(generics, self)
211 fn fold_trait_ref(&mut self, p: TraitRef) -> TraitRef {
212 noop_fold_trait_ref(p, self)
215 fn fold_poly_trait_ref(&mut self, p: PolyTraitRef) -> PolyTraitRef {
216 noop_fold_poly_trait_ref(p, self)
219 fn fold_variant_data(&mut self, vdata: VariantData) -> VariantData {
220 noop_fold_variant_data(vdata, self)
223 fn fold_lifetimes(&mut self, lts: Vec<Lifetime>) -> Vec<Lifetime> {
224 noop_fold_lifetimes(lts, self)
227 fn fold_lifetime_defs(&mut self, lts: Vec<LifetimeDef>) -> Vec<LifetimeDef> {
228 noop_fold_lifetime_defs(lts, self)
231 fn fold_ty_param(&mut self, tp: TyParam) -> TyParam {
232 noop_fold_ty_param(tp, self)
235 fn fold_ty_params(&mut self, tps: P<[TyParam]>) -> P<[TyParam]> {
236 noop_fold_ty_params(tps, self)
239 fn fold_tt(&mut self, tt: &TokenTree) -> TokenTree {
240 noop_fold_tt(tt, self)
243 fn fold_tts(&mut self, tts: &[TokenTree]) -> Vec<TokenTree> {
244 noop_fold_tts(tts, self)
247 fn fold_token(&mut self, t: token::Token) -> token::Token {
248 noop_fold_token(t, self)
251 fn fold_interpolated(&mut self, nt: token::Nonterminal) -> token::Nonterminal {
252 noop_fold_interpolated(nt, self)
255 fn fold_opt_lifetime(&mut self, o_lt: Option<Lifetime>) -> Option<Lifetime> {
256 noop_fold_opt_lifetime(o_lt, self)
259 fn fold_opt_bounds(&mut self, b: Option<TyParamBounds>)
260 -> Option<TyParamBounds> {
261 noop_fold_opt_bounds(b, self)
264 fn fold_bounds(&mut self, b: TyParamBounds)
266 noop_fold_bounds(b, self)
269 fn fold_ty_param_bound(&mut self, tpb: TyParamBound) -> TyParamBound {
270 noop_fold_ty_param_bound(tpb, self)
273 fn fold_mt(&mut self, mt: MutTy) -> MutTy {
274 noop_fold_mt(mt, self)
277 fn fold_field(&mut self, field: Field) -> Field {
278 noop_fold_field(field, self)
281 fn fold_where_clause(&mut self, where_clause: WhereClause)
283 noop_fold_where_clause(where_clause, self)
286 fn fold_where_predicate(&mut self, where_predicate: WherePredicate)
288 noop_fold_where_predicate(where_predicate, self)
291 fn new_id(&mut self, i: NodeId) -> NodeId {
295 fn new_span(&mut self, sp: Span) -> Span {
300 pub fn noop_fold_meta_items<T: Folder>(meta_items: Vec<P<MetaItem>>, fld: &mut T)
301 -> Vec<P<MetaItem>> {
302 meta_items.move_map(|x| fld.fold_meta_item(x))
305 pub fn noop_fold_view_path<T: Folder>(view_path: P<ViewPath>, fld: &mut T) -> P<ViewPath> {
306 view_path.map(|Spanned {node, span}| Spanned {
308 ViewPathSimple(ident, path) => {
309 ViewPathSimple(ident, fld.fold_path(path))
311 ViewPathGlob(path) => {
312 ViewPathGlob(fld.fold_path(path))
314 ViewPathList(path, path_list_idents) => {
315 ViewPathList(fld.fold_path(path),
316 path_list_idents.move_map(|path_list_ident| {
318 node: match path_list_ident.node {
319 PathListIdent { id, name, rename } =>
325 PathListMod { id, rename } =>
331 span: fld.new_span(path_list_ident.span)
336 span: fld.new_span(span)
340 pub fn fold_attrs<T: Folder>(attrs: Vec<Attribute>, fld: &mut T) -> Vec<Attribute> {
341 attrs.move_flat_map(|x| fld.fold_attribute(x))
344 pub fn fold_thin_attrs<T: Folder>(attrs: ThinAttributes, fld: &mut T) -> ThinAttributes {
345 attrs.map_thin_attrs(|v| fold_attrs(v, fld))
348 pub fn noop_fold_arm<T: Folder>(Arm {attrs, pats, guard, body}: Arm, fld: &mut T) -> Arm {
350 attrs: fold_attrs(attrs, fld),
351 pats: pats.move_map(|x| fld.fold_pat(x)),
352 guard: guard.map(|x| fld.fold_expr(x)),
353 body: fld.fold_expr(body),
357 pub fn noop_fold_decl<T: Folder>(d: P<Decl>, fld: &mut T) -> SmallVector<P<Decl>> {
358 d.and_then(|Spanned {node, span}| match node {
359 DeclLocal(l) => SmallVector::one(P(Spanned {
360 node: DeclLocal(fld.fold_local(l)),
361 span: fld.new_span(span)
363 DeclItem(it) => fld.fold_item(it).into_iter().map(|i| P(Spanned {
365 span: fld.new_span(span)
370 pub fn noop_fold_ty_binding<T: Folder>(b: P<TypeBinding>, fld: &mut T) -> P<TypeBinding> {
371 b.map(|TypeBinding { id, ident, ty, span }| TypeBinding {
375 span: fld.new_span(span),
379 pub fn noop_fold_ty<T: Folder>(t: P<Ty>, fld: &mut T) -> P<Ty> {
380 t.map(|Ty {id, node, span}| Ty {
384 TyVec(ty) => TyVec(fld.fold_ty(ty)),
385 TyPtr(mt) => TyPtr(fld.fold_mt(mt)),
386 TyRptr(region, mt) => {
387 TyRptr(fld.fold_opt_lifetime(region), fld.fold_mt(mt))
390 TyBareFn(f.map(|BareFnTy {lifetimes, unsafety, abi, decl}| BareFnTy {
391 lifetimes: fld.fold_lifetime_defs(lifetimes),
394 decl: fld.fold_fn_decl(decl)
397 TyTup(tys) => TyTup(tys.move_map(|ty| fld.fold_ty(ty))),
398 TyParen(ty) => TyParen(fld.fold_ty(ty)),
399 TyPath(qself, path) => {
400 let qself = qself.map(|QSelf { ty, position }| {
406 TyPath(qself, fld.fold_path(path))
408 TyObjectSum(ty, bounds) => {
409 TyObjectSum(fld.fold_ty(ty),
410 fld.fold_bounds(bounds))
412 TyFixedLengthVec(ty, e) => {
413 TyFixedLengthVec(fld.fold_ty(ty), fld.fold_expr(e))
416 TyTypeof(fld.fold_expr(expr))
418 TyPolyTraitRef(bounds) => {
419 TyPolyTraitRef(bounds.move_map(|b| fld.fold_ty_param_bound(b)))
422 TyMac(fld.fold_mac(mac))
425 span: fld.new_span(span)
429 pub fn noop_fold_foreign_mod<T: Folder>(ForeignMod {abi, items}: ForeignMod,
430 fld: &mut T) -> ForeignMod {
433 items: items.move_map(|x| fld.fold_foreign_item(x)),
437 pub fn noop_fold_variant<T: Folder>(v: P<Variant>, fld: &mut T) -> P<Variant> {
438 v.map(|Spanned {node: Variant_ {name, attrs, data, disr_expr}, span}| Spanned {
441 attrs: fold_attrs(attrs, fld),
442 data: fld.fold_variant_data(data),
443 disr_expr: disr_expr.map(|e| fld.fold_expr(e)),
445 span: fld.new_span(span),
449 pub fn noop_fold_ident<T: Folder>(i: Ident, _: &mut T) -> Ident {
453 pub fn noop_fold_usize<T: Folder>(i: usize, _: &mut T) -> usize {
457 pub fn noop_fold_path<T: Folder>(Path {global, segments, span}: Path, fld: &mut T) -> Path {
460 segments: segments.move_map(|PathSegment {identifier, parameters}| PathSegment {
461 identifier: fld.fold_ident(identifier),
462 parameters: fld.fold_path_parameters(parameters),
464 span: fld.new_span(span)
468 pub fn noop_fold_path_parameters<T: Folder>(path_parameters: PathParameters, fld: &mut T)
471 match path_parameters {
472 PathParameters::AngleBracketed(data) =>
473 PathParameters::AngleBracketed(fld.fold_angle_bracketed_parameter_data(data)),
474 PathParameters::Parenthesized(data) =>
475 PathParameters::Parenthesized(fld.fold_parenthesized_parameter_data(data)),
479 pub fn noop_fold_angle_bracketed_parameter_data<T: Folder>(data: AngleBracketedParameterData,
481 -> AngleBracketedParameterData
483 let AngleBracketedParameterData { lifetimes, types, bindings } = data;
484 AngleBracketedParameterData { lifetimes: fld.fold_lifetimes(lifetimes),
485 types: types.move_map(|ty| fld.fold_ty(ty)),
486 bindings: bindings.move_map(|b| fld.fold_ty_binding(b)) }
489 pub fn noop_fold_parenthesized_parameter_data<T: Folder>(data: ParenthesizedParameterData,
491 -> ParenthesizedParameterData
493 let ParenthesizedParameterData { inputs, output, span } = data;
494 ParenthesizedParameterData { inputs: inputs.move_map(|ty| fld.fold_ty(ty)),
495 output: output.map(|ty| fld.fold_ty(ty)),
496 span: fld.new_span(span) }
499 pub fn noop_fold_local<T: Folder>(l: P<Local>, fld: &mut T) -> P<Local> {
500 l.map(|Local {id, pat, ty, init, span, attrs}| Local {
502 ty: ty.map(|t| fld.fold_ty(t)),
503 pat: fld.fold_pat(pat),
504 init: init.map(|e| fld.fold_expr(e)),
505 span: fld.new_span(span),
506 attrs: attrs.map_thin_attrs(|v| fold_attrs(v, fld)),
510 pub fn noop_fold_attribute<T: Folder>(at: Attribute, fld: &mut T) -> Option<Attribute> {
511 let Spanned {node: Attribute_ {id, style, value, is_sugared_doc}, span} = at;
516 value: fld.fold_meta_item(value),
517 is_sugared_doc: is_sugared_doc
519 span: fld.new_span(span)
523 pub fn noop_fold_explicit_self_underscore<T: Folder>(es: ExplicitSelf_, fld: &mut T)
526 SelfStatic | SelfValue(_) => es,
527 SelfRegion(lifetime, m, ident) => {
528 SelfRegion(fld.fold_opt_lifetime(lifetime), m, ident)
530 SelfExplicit(typ, ident) => {
531 SelfExplicit(fld.fold_ty(typ), ident)
536 pub fn noop_fold_explicit_self<T: Folder>(Spanned {span, node}: ExplicitSelf, fld: &mut T)
539 node: fld.fold_explicit_self_underscore(node),
540 span: fld.new_span(span)
545 pub fn noop_fold_mac<T: Folder>(Spanned {node, span}: Mac, fld: &mut T) -> Mac {
548 path: fld.fold_path(node.path),
549 tts: fld.fold_tts(&node.tts),
552 span: fld.new_span(span)
556 pub fn noop_fold_meta_item<T: Folder>(mi: P<MetaItem>, fld: &mut T) -> P<MetaItem> {
557 mi.map(|Spanned {node, span}| Spanned {
559 MetaWord(id) => MetaWord(id),
560 MetaList(id, mis) => {
561 MetaList(id, mis.move_map(|e| fld.fold_meta_item(e)))
563 MetaNameValue(id, s) => MetaNameValue(id, s)
565 span: fld.new_span(span)
569 pub fn noop_fold_arg<T: Folder>(Arg {id, pat, ty}: Arg, fld: &mut T) -> Arg {
572 pat: fld.fold_pat(pat),
577 pub fn noop_fold_tt<T: Folder>(tt: &TokenTree, fld: &mut T) -> TokenTree {
579 TokenTree::Token(span, ref tok) =>
580 TokenTree::Token(span, fld.fold_token(tok.clone())),
581 TokenTree::Delimited(span, ref delimed) => {
582 TokenTree::Delimited(span, Rc::new(
584 delim: delimed.delim,
585 open_span: delimed.open_span,
586 tts: fld.fold_tts(&delimed.tts),
587 close_span: delimed.close_span,
591 TokenTree::Sequence(span, ref seq) =>
592 TokenTree::Sequence(span,
593 Rc::new(SequenceRepetition {
594 tts: fld.fold_tts(&seq.tts),
595 separator: seq.separator.clone().map(|tok| fld.fold_token(tok)),
601 pub fn noop_fold_tts<T: Folder>(tts: &[TokenTree], fld: &mut T) -> Vec<TokenTree> {
602 // FIXME: Does this have to take a tts slice?
603 // Could use move_map otherwise...
604 tts.iter().map(|tt| fld.fold_tt(tt)).collect()
607 // apply ident folder if it's an ident, apply other folds to interpolated nodes
608 pub fn noop_fold_token<T: Folder>(t: token::Token, fld: &mut T) -> token::Token {
610 token::Ident(id, followed_by_colons) => {
611 token::Ident(fld.fold_ident(id), followed_by_colons)
613 token::Lifetime(id) => token::Lifetime(fld.fold_ident(id)),
614 token::Interpolated(nt) => token::Interpolated(fld.fold_interpolated(nt)),
615 token::SubstNt(ident, namep) => {
616 token::SubstNt(fld.fold_ident(ident), namep)
618 token::MatchNt(name, kind, namep, kindp) => {
619 token::MatchNt(fld.fold_ident(name), fld.fold_ident(kind), namep, kindp)
625 /// apply folder to elements of interpolated nodes
627 // NB: this can occur only when applying a fold to partially expanded code, where
628 // parsed pieces have gotten implanted ito *other* macro invocations. This is relevant
629 // for macro hygiene, but possibly not elsewhere.
631 // One problem here occurs because the types for fold_item, fold_stmt, etc. allow the
632 // folder to return *multiple* items; this is a problem for the nodes here, because
633 // they insist on having exactly one piece. One solution would be to mangle the fold
634 // trait to include one-to-many and one-to-one versions of these entry points, but that
635 // would probably confuse a lot of people and help very few. Instead, I'm just going
636 // to put in dynamic checks. I think the performance impact of this will be pretty much
637 // nonexistent. The danger is that someone will apply a fold to a partially expanded
638 // node, and will be confused by the fact that their "fold_item" or "fold_stmt" isn't
639 // getting called on NtItem or NtStmt nodes. Hopefully they'll wind up reading this
640 // comment, and doing something appropriate.
642 // BTW, design choice: I considered just changing the type of, e.g., NtItem to contain
643 // multiple items, but decided against it when I looked at parse_item_or_view_item and
644 // tried to figure out what I would do with multiple items there....
645 pub fn noop_fold_interpolated<T: Folder>(nt: token::Nonterminal, fld: &mut T)
646 -> token::Nonterminal {
648 token::NtItem(item) =>
649 token::NtItem(fld.fold_item(item)
650 // this is probably okay, because the only folds likely
651 // to peek inside interpolated nodes will be renamings/markings,
652 // which map single items to single items
653 .expect_one("expected fold to produce exactly one item")),
654 token::NtBlock(block) => token::NtBlock(fld.fold_block(block)),
655 token::NtStmt(stmt) =>
656 token::NtStmt(fld.fold_stmt(stmt)
657 // this is probably okay, because the only folds likely
658 // to peek inside interpolated nodes will be renamings/markings,
659 // which map single items to single items
660 .expect_one("expected fold to produce exactly one statement")),
661 token::NtPat(pat) => token::NtPat(fld.fold_pat(pat)),
662 token::NtExpr(expr) => token::NtExpr(fld.fold_expr(expr)),
663 token::NtTy(ty) => token::NtTy(fld.fold_ty(ty)),
664 token::NtIdent(id, is_mod_name) =>
665 token::NtIdent(Box::new(Spanned::<Ident>{node: fld.fold_ident(id.node), .. *id}),
667 token::NtMeta(meta_item) => token::NtMeta(fld.fold_meta_item(meta_item)),
668 token::NtPath(path) => token::NtPath(Box::new(fld.fold_path(*path))),
669 token::NtTT(tt) => token::NtTT(P(fld.fold_tt(&tt))),
670 token::NtArm(arm) => token::NtArm(fld.fold_arm(arm)),
671 token::NtImplItem(arm) =>
672 token::NtImplItem(fld.fold_impl_item(arm)
673 .expect_one("expected fold to produce exactly one item")),
674 token::NtTraitItem(arm) =>
675 token::NtTraitItem(fld.fold_trait_item(arm)
676 .expect_one("expected fold to produce exactly one item")),
677 token::NtGenerics(generics) => token::NtGenerics(fld.fold_generics(generics)),
678 token::NtWhereClause(where_clause) =>
679 token::NtWhereClause(fld.fold_where_clause(where_clause)),
680 token::NtArg(arg) => token::NtArg(fld.fold_arg(arg)),
684 pub fn noop_fold_fn_decl<T: Folder>(decl: P<FnDecl>, fld: &mut T) -> P<FnDecl> {
685 decl.map(|FnDecl {inputs, output, variadic}| FnDecl {
686 inputs: inputs.move_map(|x| fld.fold_arg(x)),
687 output: match output {
688 Return(ty) => Return(fld.fold_ty(ty)),
689 DefaultReturn(span) => DefaultReturn(span),
690 NoReturn(span) => NoReturn(span)
696 pub fn noop_fold_ty_param_bound<T>(tpb: TyParamBound, fld: &mut T)
700 TraitTyParamBound(ty, modifier) => TraitTyParamBound(fld.fold_poly_trait_ref(ty), modifier),
701 RegionTyParamBound(lifetime) => RegionTyParamBound(fld.fold_lifetime(lifetime)),
705 pub fn noop_fold_ty_param<T: Folder>(tp: TyParam, fld: &mut T) -> TyParam {
706 let TyParam {id, ident, bounds, default, span} = tp;
710 bounds: fld.fold_bounds(bounds),
711 default: default.map(|x| fld.fold_ty(x)),
716 pub fn noop_fold_ty_params<T: Folder>(tps: P<[TyParam]>, fld: &mut T)
718 tps.move_map(|tp| fld.fold_ty_param(tp))
721 pub fn noop_fold_lifetime<T: Folder>(l: Lifetime, fld: &mut T) -> Lifetime {
723 id: fld.new_id(l.id),
725 span: fld.new_span(l.span)
729 pub fn noop_fold_lifetime_def<T: Folder>(l: LifetimeDef, fld: &mut T)
732 lifetime: fld.fold_lifetime(l.lifetime),
733 bounds: fld.fold_lifetimes(l.bounds),
737 pub fn noop_fold_lifetimes<T: Folder>(lts: Vec<Lifetime>, fld: &mut T) -> Vec<Lifetime> {
738 lts.move_map(|l| fld.fold_lifetime(l))
741 pub fn noop_fold_lifetime_defs<T: Folder>(lts: Vec<LifetimeDef>, fld: &mut T)
742 -> Vec<LifetimeDef> {
743 lts.move_map(|l| fld.fold_lifetime_def(l))
746 pub fn noop_fold_opt_lifetime<T: Folder>(o_lt: Option<Lifetime>, fld: &mut T)
747 -> Option<Lifetime> {
748 o_lt.map(|lt| fld.fold_lifetime(lt))
751 pub fn noop_fold_generics<T: Folder>(Generics {ty_params, lifetimes, where_clause}: Generics,
752 fld: &mut T) -> Generics {
754 ty_params: fld.fold_ty_params(ty_params),
755 lifetimes: fld.fold_lifetime_defs(lifetimes),
756 where_clause: fld.fold_where_clause(where_clause),
760 pub fn noop_fold_where_clause<T: Folder>(
761 WhereClause {id, predicates}: WhereClause,
766 predicates: predicates.move_map(|predicate| {
767 fld.fold_where_predicate(predicate)
772 pub fn noop_fold_where_predicate<T: Folder>(
773 pred: WherePredicate,
777 ast::WherePredicate::BoundPredicate(ast::WhereBoundPredicate{bound_lifetimes,
781 ast::WherePredicate::BoundPredicate(ast::WhereBoundPredicate {
782 bound_lifetimes: fld.fold_lifetime_defs(bound_lifetimes),
783 bounded_ty: fld.fold_ty(bounded_ty),
784 bounds: bounds.move_map(|x| fld.fold_ty_param_bound(x)),
785 span: fld.new_span(span)
788 ast::WherePredicate::RegionPredicate(ast::WhereRegionPredicate{lifetime,
791 ast::WherePredicate::RegionPredicate(ast::WhereRegionPredicate {
792 span: fld.new_span(span),
793 lifetime: fld.fold_lifetime(lifetime),
794 bounds: bounds.move_map(|bound| fld.fold_lifetime(bound))
797 ast::WherePredicate::EqPredicate(ast::WhereEqPredicate{id,
801 ast::WherePredicate::EqPredicate(ast::WhereEqPredicate{
803 path: fld.fold_path(path),
805 span: fld.new_span(span)
811 pub fn noop_fold_variant_data<T: Folder>(vdata: VariantData, fld: &mut T) -> VariantData {
813 ast::VariantData::Struct(fields, id) => {
814 ast::VariantData::Struct(fields.move_map(|f| fld.fold_struct_field(f)),
817 ast::VariantData::Tuple(fields, id) => {
818 ast::VariantData::Tuple(fields.move_map(|f| fld.fold_struct_field(f)),
821 ast::VariantData::Unit(id) => ast::VariantData::Unit(fld.new_id(id))
825 pub fn noop_fold_trait_ref<T: Folder>(p: TraitRef, fld: &mut T) -> TraitRef {
826 let id = fld.new_id(p.ref_id);
832 path: fld.fold_path(path),
837 pub fn noop_fold_poly_trait_ref<T: Folder>(p: PolyTraitRef, fld: &mut T) -> PolyTraitRef {
839 bound_lifetimes: fld.fold_lifetime_defs(p.bound_lifetimes),
840 trait_ref: fld.fold_trait_ref(p.trait_ref),
841 span: fld.new_span(p.span),
845 pub fn noop_fold_struct_field<T: Folder>(f: StructField, fld: &mut T) -> StructField {
846 let StructField {node: StructField_ {id, kind, ty, attrs}, span} = f;
852 attrs: fold_attrs(attrs, fld),
854 span: fld.new_span(span)
858 pub fn noop_fold_field<T: Folder>(Field {ident, expr, span}: Field, folder: &mut T) -> Field {
860 ident: respan(ident.span, folder.fold_ident(ident.node)),
861 expr: folder.fold_expr(expr),
862 span: folder.new_span(span)
866 pub fn noop_fold_mt<T: Folder>(MutTy {ty, mutbl}: MutTy, folder: &mut T) -> MutTy {
868 ty: folder.fold_ty(ty),
873 pub fn noop_fold_opt_bounds<T: Folder>(b: Option<TyParamBounds>, folder: &mut T)
874 -> Option<TyParamBounds> {
875 b.map(|bounds| folder.fold_bounds(bounds))
878 fn noop_fold_bounds<T: Folder>(bounds: TyParamBounds, folder: &mut T)
880 bounds.move_map(|bound| folder.fold_ty_param_bound(bound))
883 pub fn noop_fold_block<T: Folder>(b: P<Block>, folder: &mut T) -> P<Block> {
884 b.map(|Block {id, stmts, expr, rules, span}| Block {
885 id: folder.new_id(id),
886 stmts: stmts.move_flat_map(|s| folder.fold_stmt(s).into_iter()),
887 expr: expr.and_then(|x| folder.fold_opt_expr(x)),
889 span: folder.new_span(span),
893 pub fn noop_fold_item_underscore<T: Folder>(i: Item_, folder: &mut T) -> Item_ {
895 ItemExternCrate(string) => ItemExternCrate(string),
896 ItemUse(view_path) => {
897 ItemUse(folder.fold_view_path(view_path))
899 ItemStatic(t, m, e) => {
900 ItemStatic(folder.fold_ty(t), m, folder.fold_expr(e))
903 ItemConst(folder.fold_ty(t), folder.fold_expr(e))
905 ItemFn(decl, unsafety, constness, abi, generics, body) => {
907 folder.fold_fn_decl(decl),
911 folder.fold_generics(generics),
912 folder.fold_block(body)
915 ItemMod(m) => ItemMod(folder.fold_mod(m)),
916 ItemForeignMod(nm) => ItemForeignMod(folder.fold_foreign_mod(nm)),
917 ItemTy(t, generics) => {
918 ItemTy(folder.fold_ty(t), folder.fold_generics(generics))
920 ItemEnum(enum_definition, generics) => {
923 variants: enum_definition.variants.move_map(|x| folder.fold_variant(x)),
925 folder.fold_generics(generics))
927 ItemStruct(struct_def, generics) => {
928 let struct_def = folder.fold_variant_data(struct_def);
929 ItemStruct(struct_def, folder.fold_generics(generics))
931 ItemDefaultImpl(unsafety, ref trait_ref) => {
932 ItemDefaultImpl(unsafety, folder.fold_trait_ref((*trait_ref).clone()))
934 ItemImpl(unsafety, polarity, generics, ifce, ty, impl_items) => {
935 let new_impl_items = impl_items.move_flat_map(|item| {
936 folder.fold_impl_item(item)
938 let ifce = match ifce {
940 Some(ref trait_ref) => {
941 Some(folder.fold_trait_ref((*trait_ref).clone()))
946 folder.fold_generics(generics),
951 ItemTrait(unsafety, generics, bounds, items) => {
952 let bounds = folder.fold_bounds(bounds);
953 let items = items.move_flat_map(|item| {
954 folder.fold_trait_item(item)
957 folder.fold_generics(generics),
961 ItemMac(m) => ItemMac(folder.fold_mac(m)),
965 pub fn noop_fold_trait_item<T: Folder>(i: P<TraitItem>, folder: &mut T)
966 -> SmallVector<P<TraitItem>> {
967 SmallVector::one(i.map(|TraitItem {id, ident, attrs, node, span}| TraitItem {
968 id: folder.new_id(id),
969 ident: folder.fold_ident(ident),
970 attrs: fold_attrs(attrs, folder),
972 ConstTraitItem(ty, default) => {
973 ConstTraitItem(folder.fold_ty(ty),
974 default.map(|x| folder.fold_expr(x)))
976 MethodTraitItem(sig, body) => {
977 MethodTraitItem(noop_fold_method_sig(sig, folder),
978 body.map(|x| folder.fold_block(x)))
980 TypeTraitItem(bounds, default) => {
981 TypeTraitItem(folder.fold_bounds(bounds),
982 default.map(|x| folder.fold_ty(x)))
985 span: folder.new_span(span)
989 pub fn noop_fold_impl_item<T: Folder>(i: P<ImplItem>, folder: &mut T)
990 -> SmallVector<P<ImplItem>> {
991 SmallVector::one(i.map(|ImplItem {id, ident, attrs, node, vis, span}| ImplItem {
992 id: folder.new_id(id),
993 ident: folder.fold_ident(ident),
994 attrs: fold_attrs(attrs, folder),
997 ast::ImplItemKind::Const(ty, expr) => {
998 ast::ImplItemKind::Const(folder.fold_ty(ty), folder.fold_expr(expr))
1000 ast::ImplItemKind::Method(sig, body) => {
1001 ast::ImplItemKind::Method(noop_fold_method_sig(sig, folder),
1002 folder.fold_block(body))
1004 ast::ImplItemKind::Type(ty) => ast::ImplItemKind::Type(folder.fold_ty(ty)),
1005 ast::ImplItemKind::Macro(mac) => ast::ImplItemKind::Macro(folder.fold_mac(mac))
1007 span: folder.new_span(span)
1011 pub fn noop_fold_mod<T: Folder>(Mod {inner, items}: Mod, folder: &mut T) -> Mod {
1013 inner: folder.new_span(inner),
1014 items: items.move_flat_map(|x| folder.fold_item(x)),
1018 pub fn noop_fold_crate<T: Folder>(Crate {module, attrs, config, mut exported_macros, span}: Crate,
1019 folder: &mut T) -> Crate {
1020 let config = folder.fold_meta_items(config);
1022 let mut items = folder.fold_item(P(ast::Item {
1023 ident: token::special_idents::invalid,
1025 id: ast::DUMMY_NODE_ID,
1028 node: ast::ItemMod(module),
1031 let (module, attrs, span) = match items.next() {
1033 assert!(items.next().is_none(),
1034 "a crate cannot expand to more than one item");
1035 item.and_then(|ast::Item { attrs, span, node, .. }| {
1037 ast::ItemMod(m) => (m, attrs, span),
1038 _ => panic!("fold converted a module to not a module"),
1048 for def in &mut exported_macros {
1049 def.id = folder.new_id(def.id);
1056 exported_macros: exported_macros,
1061 // fold one item into possibly many items
1062 pub fn noop_fold_item<T: Folder>(i: P<Item>, folder: &mut T) -> SmallVector<P<Item>> {
1063 SmallVector::one(i.map(|i| folder.fold_item_simple(i)))
1066 // fold one item into exactly one item
1067 pub fn noop_fold_item_simple<T: Folder>(Item {id, ident, attrs, node, vis, span}: Item,
1068 folder: &mut T) -> Item {
1069 let id = folder.new_id(id);
1070 let node = folder.fold_item_underscore(node);
1071 let ident = match node {
1072 // The node may have changed, recompute the "pretty" impl name.
1073 ItemImpl(_, _, _, ref maybe_trait, ref ty, _) => {
1074 ast_util::impl_pretty_name(maybe_trait, Some(&**ty))
1081 ident: folder.fold_ident(ident),
1082 attrs: fold_attrs(attrs, folder),
1085 span: folder.new_span(span)
1089 pub fn noop_fold_foreign_item<T: Folder>(ni: P<ForeignItem>, folder: &mut T) -> P<ForeignItem> {
1090 ni.map(|ForeignItem {id, ident, attrs, node, span, vis}| ForeignItem {
1091 id: folder.new_id(id),
1092 ident: folder.fold_ident(ident),
1093 attrs: fold_attrs(attrs, folder),
1095 ForeignItemFn(fdec, generics) => {
1096 ForeignItemFn(folder.fold_fn_decl(fdec), folder.fold_generics(generics))
1098 ForeignItemStatic(t, m) => {
1099 ForeignItemStatic(folder.fold_ty(t), m)
1103 span: folder.new_span(span)
1107 pub fn noop_fold_method_sig<T: Folder>(sig: MethodSig, folder: &mut T) -> MethodSig {
1109 generics: folder.fold_generics(sig.generics),
1111 explicit_self: folder.fold_explicit_self(sig.explicit_self),
1112 unsafety: sig.unsafety,
1113 constness: sig.constness,
1114 decl: folder.fold_fn_decl(sig.decl)
1118 pub fn noop_fold_pat<T: Folder>(p: P<Pat>, folder: &mut T) -> P<Pat> {
1119 p.map(|Pat {id, node, span}| Pat {
1120 id: folder.new_id(id),
1123 PatIdent(binding_mode, pth1, sub) => {
1124 PatIdent(binding_mode,
1125 Spanned{span: folder.new_span(pth1.span),
1126 node: folder.fold_ident(pth1.node)},
1127 sub.map(|x| folder.fold_pat(x)))
1129 PatLit(e) => PatLit(folder.fold_expr(e)),
1130 PatEnum(pth, pats) => {
1131 PatEnum(folder.fold_path(pth),
1132 pats.map(|pats| pats.move_map(|x| folder.fold_pat(x))))
1134 PatQPath(qself, pth) => {
1135 let qself = QSelf {ty: folder.fold_ty(qself.ty), .. qself};
1136 PatQPath(qself, folder.fold_path(pth))
1138 PatStruct(pth, fields, etc) => {
1139 let pth = folder.fold_path(pth);
1140 let fs = fields.move_map(|f| {
1141 Spanned { span: folder.new_span(f.span),
1142 node: ast::FieldPat {
1143 ident: f.node.ident,
1144 pat: folder.fold_pat(f.node.pat),
1145 is_shorthand: f.node.is_shorthand,
1148 PatStruct(pth, fs, etc)
1150 PatTup(elts) => PatTup(elts.move_map(|x| folder.fold_pat(x))),
1151 PatBox(inner) => PatBox(folder.fold_pat(inner)),
1152 PatRegion(inner, mutbl) => PatRegion(folder.fold_pat(inner), mutbl),
1153 PatRange(e1, e2) => {
1154 PatRange(folder.fold_expr(e1), folder.fold_expr(e2))
1156 PatVec(before, slice, after) => {
1157 PatVec(before.move_map(|x| folder.fold_pat(x)),
1158 slice.map(|x| folder.fold_pat(x)),
1159 after.move_map(|x| folder.fold_pat(x)))
1161 PatMac(mac) => PatMac(folder.fold_mac(mac))
1163 span: folder.new_span(span)
1167 pub fn noop_fold_expr<T: Folder>(Expr {id, node, span, attrs}: Expr, folder: &mut T) -> Expr {
1169 id: folder.new_id(id),
1172 ExprBox(folder.fold_expr(e))
1174 ExprInPlace(p, e) => {
1175 ExprInPlace(folder.fold_expr(p), folder.fold_expr(e))
1178 ExprVec(folder.fold_exprs(exprs))
1180 ExprRepeat(expr, count) => {
1181 ExprRepeat(folder.fold_expr(expr), folder.fold_expr(count))
1183 ExprTup(exprs) => ExprTup(folder.fold_exprs(exprs)),
1184 ExprCall(f, args) => {
1185 ExprCall(folder.fold_expr(f),
1186 folder.fold_exprs(args))
1188 ExprMethodCall(i, tps, args) => {
1190 respan(folder.new_span(i.span), folder.fold_ident(i.node)),
1191 tps.move_map(|x| folder.fold_ty(x)),
1192 folder.fold_exprs(args))
1194 ExprBinary(binop, lhs, rhs) => {
1196 folder.fold_expr(lhs),
1197 folder.fold_expr(rhs))
1199 ExprUnary(binop, ohs) => {
1200 ExprUnary(binop, folder.fold_expr(ohs))
1202 ExprLit(l) => ExprLit(l),
1203 ExprCast(expr, ty) => {
1204 ExprCast(folder.fold_expr(expr), folder.fold_ty(ty))
1206 ExprType(expr, ty) => {
1207 ExprType(folder.fold_expr(expr), folder.fold_ty(ty))
1209 ExprAddrOf(m, ohs) => ExprAddrOf(m, folder.fold_expr(ohs)),
1210 ExprIf(cond, tr, fl) => {
1211 ExprIf(folder.fold_expr(cond),
1212 folder.fold_block(tr),
1213 fl.map(|x| folder.fold_expr(x)))
1215 ExprIfLet(pat, expr, tr, fl) => {
1216 ExprIfLet(folder.fold_pat(pat),
1217 folder.fold_expr(expr),
1218 folder.fold_block(tr),
1219 fl.map(|x| folder.fold_expr(x)))
1221 ExprWhile(cond, body, opt_ident) => {
1222 ExprWhile(folder.fold_expr(cond),
1223 folder.fold_block(body),
1224 opt_ident.map(|i| folder.fold_ident(i)))
1226 ExprWhileLet(pat, expr, body, opt_ident) => {
1227 ExprWhileLet(folder.fold_pat(pat),
1228 folder.fold_expr(expr),
1229 folder.fold_block(body),
1230 opt_ident.map(|i| folder.fold_ident(i)))
1232 ExprForLoop(pat, iter, body, opt_ident) => {
1233 ExprForLoop(folder.fold_pat(pat),
1234 folder.fold_expr(iter),
1235 folder.fold_block(body),
1236 opt_ident.map(|i| folder.fold_ident(i)))
1238 ExprLoop(body, opt_ident) => {
1239 ExprLoop(folder.fold_block(body),
1240 opt_ident.map(|i| folder.fold_ident(i)))
1242 ExprMatch(expr, arms) => {
1243 ExprMatch(folder.fold_expr(expr),
1244 arms.move_map(|x| folder.fold_arm(x)))
1246 ExprClosure(capture_clause, decl, body) => {
1247 ExprClosure(capture_clause,
1248 folder.fold_fn_decl(decl),
1249 folder.fold_block(body))
1251 ExprBlock(blk) => ExprBlock(folder.fold_block(blk)),
1252 ExprAssign(el, er) => {
1253 ExprAssign(folder.fold_expr(el), folder.fold_expr(er))
1255 ExprAssignOp(op, el, er) => {
1257 folder.fold_expr(el),
1258 folder.fold_expr(er))
1260 ExprField(el, ident) => {
1261 ExprField(folder.fold_expr(el),
1262 respan(folder.new_span(ident.span),
1263 folder.fold_ident(ident.node)))
1265 ExprTupField(el, ident) => {
1266 ExprTupField(folder.fold_expr(el),
1267 respan(folder.new_span(ident.span),
1268 folder.fold_usize(ident.node)))
1270 ExprIndex(el, er) => {
1271 ExprIndex(folder.fold_expr(el), folder.fold_expr(er))
1273 ExprRange(e1, e2) => {
1274 ExprRange(e1.map(|x| folder.fold_expr(x)),
1275 e2.map(|x| folder.fold_expr(x)))
1277 ExprPath(qself, path) => {
1278 let qself = qself.map(|QSelf { ty, position }| {
1280 ty: folder.fold_ty(ty),
1284 ExprPath(qself, folder.fold_path(path))
1286 ExprBreak(opt_ident) => ExprBreak(opt_ident.map(|label|
1287 respan(folder.new_span(label.span),
1288 folder.fold_ident(label.node)))
1290 ExprAgain(opt_ident) => ExprAgain(opt_ident.map(|label|
1291 respan(folder.new_span(label.span),
1292 folder.fold_ident(label.node)))
1294 ExprRet(e) => ExprRet(e.map(|x| folder.fold_expr(x))),
1295 ExprInlineAsm(InlineAsm {
1305 }) => ExprInlineAsm(InlineAsm {
1306 inputs: inputs.move_map(|(c, input)| {
1307 (c, folder.fold_expr(input))
1309 outputs: outputs.move_map(|out| {
1311 constraint: out.constraint,
1312 expr: folder.fold_expr(out.expr),
1314 is_indirect: out.is_indirect,
1318 asm_str_style: asm_str_style,
1321 alignstack: alignstack,
1325 ExprMac(mac) => ExprMac(folder.fold_mac(mac)),
1326 ExprStruct(path, fields, maybe_expr) => {
1327 ExprStruct(folder.fold_path(path),
1328 fields.move_map(|x| folder.fold_field(x)),
1329 maybe_expr.map(|x| folder.fold_expr(x)))
1331 ExprParen(ex) => ExprParen(folder.fold_expr(ex))
1333 span: folder.new_span(span),
1334 attrs: attrs.map_thin_attrs(|v| fold_attrs(v, folder)),
1338 pub fn noop_fold_opt_expr<T: Folder>(e: P<Expr>, folder: &mut T) -> Option<P<Expr>> {
1339 Some(folder.fold_expr(e))
1342 pub fn noop_fold_exprs<T: Folder>(es: Vec<P<Expr>>, folder: &mut T) -> Vec<P<Expr>> {
1343 es.move_flat_map(|e| folder.fold_opt_expr(e))
1346 pub fn noop_fold_stmt<T: Folder>(Spanned {node, span}: Stmt, folder: &mut T)
1347 -> SmallVector<P<Stmt>> {
1348 let span = folder.new_span(span);
1350 StmtDecl(d, id) => {
1351 let id = folder.new_id(id);
1352 folder.fold_decl(d).into_iter().map(|d| P(Spanned {
1353 node: StmtDecl(d, id),
1357 StmtExpr(e, id) => {
1358 let id = folder.new_id(id);
1359 if let Some(e) = folder.fold_opt_expr(e) {
1360 SmallVector::one(P(Spanned {
1361 node: StmtExpr(e, id),
1368 StmtSemi(e, id) => {
1369 let id = folder.new_id(id);
1370 if let Some(e) = folder.fold_opt_expr(e) {
1371 SmallVector::one(P(Spanned {
1372 node: StmtSemi(e, id),
1379 StmtMac(mac, semi, attrs) => SmallVector::one(P(Spanned {
1380 node: StmtMac(mac.map(|m| folder.fold_mac(m)),
1382 attrs.map_thin_attrs(|v| fold_attrs(v, folder))),
1392 use util::parser_testing::{string_to_crate, matches_codepattern};
1398 // this version doesn't care about getting comments or docstrings in.
1399 fn fake_print_crate(s: &mut pprust::State,
1400 krate: &ast::Crate) -> io::Result<()> {
1401 s.print_mod(&krate.module, &krate.attrs)
1404 // change every identifier to "zz"
1405 struct ToZzIdentFolder;
1407 impl Folder for ToZzIdentFolder {
1408 fn fold_ident(&mut self, _: ast::Ident) -> ast::Ident {
1409 token::str_to_ident("zz")
1411 fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
1412 fold::noop_fold_mac(mac, self)
1416 // maybe add to expand.rs...
1417 macro_rules! assert_pred {
1418 ($pred:expr, $predname:expr, $a:expr , $b:expr) => (
1420 let pred_val = $pred;
1423 if !(pred_val(&a_val, &b_val)) {
1424 panic!("expected args satisfying {}, got {} and {}",
1425 $predname, a_val, b_val);
1431 // make sure idents get transformed everywhere
1432 #[test] fn ident_transformation () {
1433 let mut zz_fold = ToZzIdentFolder;
1434 let ast = string_to_crate(
1435 "#[a] mod b {fn c (d : e, f : g) {h!(i,j,k);l;m}}".to_string());
1436 let folded_crate = zz_fold.fold_crate(ast);
1438 matches_codepattern,
1439 "matches_codepattern",
1440 pprust::to_string(|s| fake_print_crate(s, &folded_crate)),
1441 "#[a]mod zz{fn zz(zz:zz,zz:zz){zz!(zz,zz,zz);zz;zz}}".to_string());
1444 // even inside macro defs....
1445 #[test] fn ident_transformation_in_defs () {
1446 let mut zz_fold = ToZzIdentFolder;
1447 let ast = string_to_crate(
1448 "macro_rules! a {(b $c:expr $(d $e:token)f+ => \
1449 (g $(d $d $e)+))} ".to_string());
1450 let folded_crate = zz_fold.fold_crate(ast);
1452 matches_codepattern,
1453 "matches_codepattern",
1454 pprust::to_string(|s| fake_print_crate(s, &folded_crate)),
1455 "zz!zz((zz$zz:zz$(zz $zz:zz)zz+=>(zz$(zz$zz$zz)+)));".to_string());