1 //! An "interner" is a data structure that associates values with usize tags and
2 //! allows bidirectional lookup; i.e., given a value, one can easily find the
3 //! type, and vice versa.
5 use arena::DroplessArena;
6 use rustc_data_structures::fx::FxHashMap;
7 use rustc_data_structures::indexed_vec::Idx;
8 use rustc_data_structures::newtype_index;
9 use rustc_macros::symbols;
10 use serialize::{Decodable, Decoder, Encodable, Encoder};
12 use std::cmp::{PartialEq, Ordering, PartialOrd, Ord};
14 use std::hash::{Hash, Hasher};
17 use crate::hygiene::SyntaxContext;
18 use crate::{Span, DUMMY_SP, GLOBALS};
21 // After modifying this list adjust `is_special`, `is_used_keyword`/`is_unused_keyword`,
22 // this should be rarely necessary though if the keywords are kept in alphabetic order.
24 // Special reserved identifiers used internally for elided lifetimes,
25 // unnamed method parameters, crate root module, error recovery etc.
28 DollarCrate: "$crate",
31 // Keywords that are used in stable Rust.
68 // Keywords that are used in unstable Rust or reserved for future use.
82 // Edition-specific keywords that are used in stable Rust.
83 Dyn: "dyn", // >= 2018 Edition only
85 // Edition-specific keywords that are used in unstable Rust or reserved for future use.
86 Async: "async", // >= 2018 Edition only
87 Await: "await", // >= 2018 Edition only
88 Try: "try", // >= 2018 Edition only
90 // Special lifetime names
91 UnderscoreLifetime: "'_",
92 StaticLifetime: "'static",
94 // Weak keywords, have special meaning only in specific contexts.
98 Existential: "existential",
102 // Symbols that can be referred to with syntax_pos::sym::*. The symbol is
103 // the stringified identifier unless otherwise specified (e.g.
104 // `proc_dash_macro` represents "proc-macro").
106 // As well as the symbols listed, there are symbols for the the strings
107 // "0", "1", ..., "9", which are accessible via `sym::integer`.
109 aarch64_target_feature,
112 abi_msp430_interrupt,
120 advanced_slice_patterns,
132 allow_internal_unsafe,
133 allow_internal_unstable,
134 allow_internal_unstable_backcompat_hack,
138 arbitrary_self_types,
144 associated_type_bounds,
145 associated_type_defaults,
151 augmented_assignments,
152 automatically_derived,
153 avx512_target_feature,
158 bind_by_move_pattern_guards,
160 borrowck_graphviz_postflow,
161 borrowck_graphviz_preflow,
164 braced_empty_structs,
171 cfg_target_has_atomic,
172 cfg_target_thread_local,
178 closure_to_fn_coercion,
180 cmpxchg16b_target_feature,
185 conservative_impl_trait,
187 const_compare_raw_pointers,
196 const_raw_ptr_to_usize_cast,
208 crate_visibility_modifier,
211 custom_inner_attributes,
212 custom_test_frameworks,
216 default_lib_allocator,
217 default_type_parameter_fallback,
230 document_private_items,
231 dotdoteq_in_patterns,
232 dotdot_in_tuple_patterns,
233 double_braced_crate: "{{crate}}",
234 double_braced_impl: "{{impl}}",
235 double_braced_misc: "{{misc}}",
236 double_braced_closure: "{{closure}}",
237 double_braced_constructor: "{{constructor}}",
238 double_braced_constant: "{{constant}}",
239 double_braced_opaque: "{{opaque}}",
241 dropck_parametricity,
252 exclusive_range_pattern,
253 exhaustive_integer_patterns,
259 extern_absolute_paths,
261 extern_crate_item_prelude,
272 field_init_shorthand,
292 generic_associated_types,
301 hexagon_target_feature,
303 homogeneous_aggregate,
317 if_while_or_patterns,
319 impl_header_lifetime_elision,
320 impl_trait_in_bindings,
326 inclusive_range_syntax,
327 infer_outlives_requirements,
328 infer_static_outlives_requirements,
335 irrefutable_let_patterns,
338 issue_5723_bootstrap,
339 issue_tracker_base_url,
357 link_llvm_intrinsics,
365 macro_at_most_once_rep,
368 macro_lifetime_matcher,
369 macro_literal_matcher,
380 match_beginning_vert,
381 match_default_bindings,
391 movbe_target_feature,
425 omit_gdb_pretty_printer_section,
432 optin_builtin_traits,
440 overlapping_marker_traits,
445 panic_implementation,
462 poll_with_tls_context,
463 powerpc_target_feature,
464 precise_pointer_size_matching,
468 proc_dash_macro: "proc-macro",
470 proc_macro_attribute,
477 proc_macro_non_items,
478 proc_macro_path_invoc,
482 quad_precision_float,
495 reexport_test_harness_main,
505 re_rebalance_coherence,
519 rustc_allocator_nounwind,
520 rustc_allow_const_fn_ptr,
521 rustc_args_required_const,
524 rustc_const_unstable,
525 rustc_conversion_suggestion,
526 rustc_copy_clone_marker,
529 rustc_diagnostic_macros,
531 rustc_doc_only_macro,
533 rustc_dump_env_program_clauses,
534 rustc_dump_program_clauses,
535 rustc_dump_user_substs,
537 rustc_expected_cgu_reuse,
538 rustc_if_this_changed,
539 rustc_inherit_overflow_checks,
541 rustc_layout_scalar_valid_range_end,
542 rustc_layout_scalar_valid_range_start,
544 rustc_nonnull_optimization_guaranteed,
545 rustc_object_lifetime_default,
546 rustc_on_unimplemented,
549 rustc_partition_codegened,
550 rustc_partition_reused,
552 rustc_peek_definite_init,
553 rustc_peek_maybe_init,
554 rustc_peek_maybe_uninit,
556 rustc_proc_macro_decls,
560 rustc_std_internal_symbol,
564 rustc_then_this_would_need,
565 rustc_transparent_macro,
569 rust_eh_unwind_resume,
571 __rust_unstable_column,
572 rvalue_static_promotion,
588 sse4a_target_feature,
599 stmt_expr_attributes,
601 struct_field_attributes,
613 termination_trait_test,
616 test_accepted_feature,
618 test_removed_feature,
640 type_alias_enum_variants,
650 underscore_const_names,
652 underscore_lifetimes,
654 universal_impl_trait,
657 unrestricted_attribute_tokens,
658 unsafe_destructor_blind_to_params,
661 unsized_tuple_coercion,
676 visible_private_types,
679 warn_directory_ownership,
689 #[derive(Copy, Clone, Eq)]
697 /// Constructs a new identifier from a symbol and a span.
698 pub const fn new(name: Symbol, span: Span) -> Ident {
702 /// Constructs a new identifier with an empty syntax context.
704 pub const fn with_empty_ctxt(name: Symbol) -> Ident {
705 Ident::new(name, DUMMY_SP)
709 pub fn invalid() -> Ident {
710 Ident::with_empty_ctxt(kw::Invalid)
713 /// Maps an interned string to an identifier with an empty syntax context.
714 pub fn from_interned_str(string: InternedString) -> Ident {
715 Ident::with_empty_ctxt(string.as_symbol())
718 /// Maps a string to an identifier with an empty span.
719 pub fn from_str(string: &str) -> Ident {
720 Ident::with_empty_ctxt(Symbol::intern(string))
723 /// Maps a string and a span to an identifier.
724 pub fn from_str_and_span(string: &str, span: Span) -> Ident {
725 Ident::new(Symbol::intern(string), span)
728 /// Replaces `lo` and `hi` with those from `span`, but keep hygiene context.
729 pub fn with_span_pos(self, span: Span) -> Ident {
730 Ident::new(self.name, span.with_ctxt(self.span.ctxt()))
733 pub fn without_first_quote(self) -> Ident {
734 Ident::new(Symbol::intern(self.as_str().trim_start_matches('\'')), self.span)
737 /// "Normalize" ident for use in comparisons using "item hygiene".
738 /// Identifiers with same string value become same if they came from the same "modern" macro
739 /// (e.g., `macro` item, but not `macro_rules` item) and stay different if they came from
740 /// different "modern" macros.
741 /// Technically, this operation strips all non-opaque marks from ident's syntactic context.
742 pub fn modern(self) -> Ident {
743 Ident::new(self.name, self.span.modern())
746 /// "Normalize" ident for use in comparisons using "local variable hygiene".
747 /// Identifiers with same string value become same if they came from the same non-transparent
748 /// macro (e.g., `macro` or `macro_rules!` items) and stay different if they came from different
749 /// non-transparent macros.
750 /// Technically, this operation strips all transparent marks from ident's syntactic context.
751 pub fn modern_and_legacy(self) -> Ident {
752 Ident::new(self.name, self.span.modern_and_legacy())
755 /// Transforms an identifier into one with the same name, but gensymed.
756 pub fn gensym(self) -> Ident {
757 let name = with_interner(|interner| interner.gensymed(self.name));
758 Ident::new(name, self.span)
761 /// Transforms an underscore identifier into one with the same name, but
762 /// gensymed. Leaves non-underscore identifiers unchanged.
763 pub fn gensym_if_underscore(self) -> Ident {
764 if self.name == kw::Underscore { self.gensym() } else { self }
767 // WARNING: this function is deprecated and will be removed in the future.
768 pub fn is_gensymed(self) -> bool {
769 with_interner(|interner| interner.is_gensymed(self.name))
772 pub fn as_str(self) -> LocalInternedString {
776 pub fn as_interned_str(self) -> InternedString {
777 self.name.as_interned_str()
781 impl PartialEq for Ident {
782 fn eq(&self, rhs: &Self) -> bool {
783 self.name == rhs.name && self.span.ctxt() == rhs.span.ctxt()
787 impl Hash for Ident {
788 fn hash<H: Hasher>(&self, state: &mut H) {
789 self.name.hash(state);
790 self.span.ctxt().hash(state);
794 impl fmt::Debug for Ident {
795 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
796 write!(f, "{}{:?}", self.name, self.span.ctxt())
800 impl fmt::Display for Ident {
801 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
802 fmt::Display::fmt(&self.name, f)
806 impl Encodable for Ident {
807 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
808 if self.span.ctxt().modern() == SyntaxContext::empty() {
809 s.emit_str(&self.as_str())
810 } else { // FIXME(jseyfried): intercrate hygiene
811 let mut string = "#".to_owned();
812 string.push_str(&self.as_str());
818 impl Decodable for Ident {
819 fn decode<D: Decoder>(d: &mut D) -> Result<Ident, D::Error> {
820 let string = d.read_str()?;
821 Ok(if !string.starts_with('#') {
822 Ident::from_str(&string)
823 } else { // FIXME(jseyfried): intercrate hygiene
824 Ident::from_str(&string[1..]).gensym()
829 /// A symbol is an interned or gensymed string. A gensym is a symbol that is
830 /// never equal to any other symbol.
832 /// Conceptually, a gensym can be thought of as a normal symbol with an
833 /// invisible unique suffix. Gensyms are useful when creating new identifiers
834 /// that must not match any existing identifiers, e.g. during macro expansion
835 /// and syntax desugaring. Because gensyms should always be identifiers, all
836 /// gensym operations are on `Ident` rather than `Symbol`. (Indeed, in the
837 /// future the gensym-ness may be moved from `Symbol` to hygiene data.)
841 /// assert_eq!(Ident::from_str("x"), Ident::from_str("x"))
842 /// assert_ne!(Ident::from_str("x").gensym(), Ident::from_str("x"))
843 /// assert_ne!(Ident::from_str("x").gensym(), Ident::from_str("x").gensym())
845 /// Internally, a symbol is implemented as an index, and all operations
846 /// (including hashing, equality, and ordering) operate on that index. The use
847 /// of `newtype_index!` means that `Option<Symbol>` only takes up 4 bytes,
848 /// because `newtype_index!` reserves the last 256 values for tagging purposes.
850 /// Note that `Symbol` cannot directly be a `newtype_index!` because it
851 /// implements `fmt::Debug`, `Encodable`, and `Decodable` in special ways.
852 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
853 pub struct Symbol(SymbolIndex);
856 pub struct SymbolIndex { .. }
860 const fn new(n: u32) -> Self {
861 Symbol(SymbolIndex::from_u32_const(n))
864 /// Maps a string to its interned representation.
865 pub fn intern(string: &str) -> Self {
866 with_interner(|interner| interner.intern(string))
869 pub fn as_str(self) -> LocalInternedString {
870 with_interner(|interner| unsafe {
871 LocalInternedString {
872 string: std::mem::transmute::<&str, &str>(interner.get(self))
877 pub fn as_interned_str(self) -> InternedString {
878 with_interner(|interner| InternedString {
879 symbol: interner.interned(self)
883 pub fn as_u32(self) -> u32 {
888 impl fmt::Debug for Symbol {
889 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
890 let is_gensymed = with_interner(|interner| interner.is_gensymed(*self));
892 write!(f, "{}({:?})", self, self.0)
894 write!(f, "{}", self)
899 impl fmt::Display for Symbol {
900 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
901 fmt::Display::fmt(&self.as_str(), f)
905 impl Encodable for Symbol {
906 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
907 s.emit_str(&self.as_str())
911 impl Decodable for Symbol {
912 fn decode<D: Decoder>(d: &mut D) -> Result<Symbol, D::Error> {
913 Ok(Symbol::intern(&d.read_str()?))
917 // The `&'static str`s in this type actually point into the arena.
919 // Note that normal symbols are indexed upward from 0, and gensyms are indexed
920 // downward from SymbolIndex::MAX_AS_U32.
922 pub struct Interner {
923 arena: DroplessArena,
924 names: FxHashMap<&'static str, Symbol>,
925 strings: Vec<&'static str>,
926 gensyms: Vec<Symbol>,
930 fn prefill(init: &[&'static str]) -> Self {
932 strings: init.into(),
933 names: init.iter().copied().zip((0..).map(Symbol::new)).collect(),
938 pub fn intern(&mut self, string: &str) -> Symbol {
939 if let Some(&name) = self.names.get(string) {
943 let name = Symbol::new(self.strings.len() as u32);
945 // `from_utf8_unchecked` is safe since we just allocated a `&str` which is known to be
947 let string: &str = unsafe {
948 str::from_utf8_unchecked(self.arena.alloc_slice(string.as_bytes()))
950 // It is safe to extend the arena allocation to `'static` because we only access
951 // these while the arena is still alive.
952 let string: &'static str = unsafe {
953 &*(string as *const str)
955 self.strings.push(string);
956 self.names.insert(string, name);
960 fn interned(&self, symbol: Symbol) -> Symbol {
961 if (symbol.0.as_usize()) < self.strings.len() {
964 self.gensyms[(SymbolIndex::MAX_AS_U32 - symbol.0.as_u32()) as usize]
968 fn gensymed(&mut self, symbol: Symbol) -> Symbol {
969 self.gensyms.push(symbol);
970 Symbol::new(SymbolIndex::MAX_AS_U32 - self.gensyms.len() as u32 + 1)
973 fn is_gensymed(&mut self, symbol: Symbol) -> bool {
974 symbol.0.as_usize() >= self.strings.len()
977 // Get the symbol as a string. `Symbol::as_str()` should be used in
978 // preference to this function.
979 pub fn get(&self, symbol: Symbol) -> &str {
980 match self.strings.get(symbol.0.as_usize()) {
981 Some(string) => string,
983 let symbol = self.gensyms[(SymbolIndex::MAX_AS_U32 - symbol.0.as_u32()) as usize];
984 self.strings[symbol.0.as_usize()]
990 // This module has a very short name because it's used a lot.
996 // This module has a very short name because it's used a lot.
998 use std::convert::TryInto;
1003 // Get the symbol for an integer. The first few non-negative integers each
1004 // have a static symbol and therefore are fast.
1005 pub fn integer<N: TryInto<usize> + Copy + ToString>(n: N) -> Symbol {
1006 if let Result::Ok(idx) = n.try_into() {
1007 if let Option::Some(&sym) = digits_array.get(idx) {
1011 Symbol::intern(&n.to_string())
1016 fn is_used_keyword_2018(self) -> bool {
1020 fn is_unused_keyword_2018(self) -> bool {
1021 self >= kw::Async && self <= kw::Try
1024 /// Used for sanity checking rustdoc keyword sections.
1025 pub fn is_doc_keyword(self) -> bool {
1029 /// A keyword or reserved identifier that can be used as a path segment.
1030 pub fn is_path_segment_keyword(self) -> bool {
1031 self == kw::Super ||
1032 self == kw::SelfLower ||
1033 self == kw::SelfUpper ||
1034 self == kw::Crate ||
1035 self == kw::PathRoot ||
1036 self == kw::DollarCrate
1039 /// This symbol can be a raw identifier.
1040 pub fn can_be_raw(self) -> bool {
1041 self != kw::Invalid && self != kw::Underscore && !self.is_path_segment_keyword()
1046 // Returns `true` for reserved identifiers used internally for elided lifetimes,
1047 // unnamed method parameters, crate root module, error recovery etc.
1048 pub fn is_special(self) -> bool {
1049 self.name <= kw::Underscore
1052 /// Returns `true` if the token is a keyword used in the language.
1053 pub fn is_used_keyword(self) -> bool {
1054 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
1055 self.name >= kw::As && self.name <= kw::While ||
1056 self.name.is_used_keyword_2018() && self.span.rust_2018()
1059 /// Returns `true` if the token is a keyword reserved for possible future use.
1060 pub fn is_unused_keyword(self) -> bool {
1061 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
1062 self.name >= kw::Abstract && self.name <= kw::Yield ||
1063 self.name.is_unused_keyword_2018() && self.span.rust_2018()
1066 /// Returns `true` if the token is either a special identifier or a keyword.
1067 pub fn is_reserved(self) -> bool {
1068 self.is_special() || self.is_used_keyword() || self.is_unused_keyword()
1071 /// A keyword or reserved identifier that can be used as a path segment.
1072 pub fn is_path_segment_keyword(self) -> bool {
1073 self.name.is_path_segment_keyword()
1076 /// We see this identifier in a normal identifier position, like variable name or a type.
1077 /// How was it written originally? Did it use the raw form? Let's try to guess.
1078 pub fn is_raw_guess(self) -> bool {
1079 self.name.can_be_raw() && self.is_reserved()
1083 // If an interner exists, return it. Otherwise, prepare a fresh one.
1085 fn with_interner<T, F: FnOnce(&mut Interner) -> T>(f: F) -> T {
1086 GLOBALS.with(|globals| f(&mut *globals.symbol_interner.lock()))
1089 /// An alternative to `Symbol` and `InternedString`, useful when the chars
1090 /// within the symbol need to be accessed. It is best used for temporary
1093 /// Because the interner outlives any thread which uses this type, we can
1094 /// safely treat `string` which points to interner data, as an immortal string,
1095 /// as long as this type never crosses between threads.
1097 // FIXME: ensure that the interner outlives any thread which uses
1098 // `LocalInternedString`, by creating a new thread right after constructing the
1100 #[derive(Clone, Copy, Hash, PartialOrd, Eq, Ord)]
1101 pub struct LocalInternedString {
1102 string: &'static str,
1105 impl LocalInternedString {
1106 /// Maps a string to its interned representation.
1107 pub fn intern(string: &str) -> Self {
1108 let string = with_interner(|interner| {
1109 let symbol = interner.intern(string);
1110 interner.strings[symbol.0.as_usize()]
1112 LocalInternedString {
1113 string: unsafe { std::mem::transmute::<&str, &str>(string) }
1117 pub fn as_interned_str(self) -> InternedString {
1119 symbol: Symbol::intern(self.string)
1123 pub fn get(&self) -> &str {
1124 // This returns a valid string since we ensure that `self` outlives the interner
1125 // by creating the interner on a thread which outlives threads which can access it.
1126 // This type cannot move to a thread which outlives the interner since it does
1127 // not implement Send.
1132 impl<U: ?Sized> std::convert::AsRef<U> for LocalInternedString
1134 str: std::convert::AsRef<U>
1136 fn as_ref(&self) -> &U {
1137 self.string.as_ref()
1141 impl<T: std::ops::Deref<Target = str>> std::cmp::PartialEq<T> for LocalInternedString {
1142 fn eq(&self, other: &T) -> bool {
1143 self.string == other.deref()
1147 impl std::cmp::PartialEq<LocalInternedString> for str {
1148 fn eq(&self, other: &LocalInternedString) -> bool {
1149 self == other.string
1153 impl<'a> std::cmp::PartialEq<LocalInternedString> for &'a str {
1154 fn eq(&self, other: &LocalInternedString) -> bool {
1155 *self == other.string
1159 impl std::cmp::PartialEq<LocalInternedString> for String {
1160 fn eq(&self, other: &LocalInternedString) -> bool {
1161 self == other.string
1165 impl<'a> std::cmp::PartialEq<LocalInternedString> for &'a String {
1166 fn eq(&self, other: &LocalInternedString) -> bool {
1167 *self == other.string
1171 impl !Send for LocalInternedString {}
1172 impl !Sync for LocalInternedString {}
1174 impl std::ops::Deref for LocalInternedString {
1176 fn deref(&self) -> &str { self.string }
1179 impl fmt::Debug for LocalInternedString {
1180 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1181 fmt::Debug::fmt(self.string, f)
1185 impl fmt::Display for LocalInternedString {
1186 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1187 fmt::Display::fmt(self.string, f)
1191 impl Decodable for LocalInternedString {
1192 fn decode<D: Decoder>(d: &mut D) -> Result<LocalInternedString, D::Error> {
1193 Ok(LocalInternedString::intern(&d.read_str()?))
1197 impl Encodable for LocalInternedString {
1198 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1199 s.emit_str(self.string)
1203 /// An alternative to `Symbol` that is focused on string contents. It has two
1204 /// main differences to `Symbol`.
1206 /// First, its implementations of `Hash`, `PartialOrd` and `Ord` work with the
1207 /// string chars rather than the symbol integer. This is useful when hash
1208 /// stability is required across compile sessions, or a guaranteed sort
1209 /// ordering is required.
1211 /// Second, gensym-ness is irrelevant. E.g.:
1213 /// assert_ne!(Symbol::gensym("x"), Symbol::gensym("x"))
1214 /// assert_eq!(Symbol::gensym("x").as_interned_str(), Symbol::gensym("x").as_interned_str())
1216 #[derive(Clone, Copy, PartialEq, Eq)]
1217 pub struct InternedString {
1221 impl InternedString {
1222 /// Maps a string to its interned representation.
1223 pub fn intern(string: &str) -> Self {
1225 symbol: Symbol::intern(string)
1229 pub fn with<F: FnOnce(&str) -> R, R>(self, f: F) -> R {
1230 let str = with_interner(|interner| {
1231 interner.get(self.symbol) as *const str
1233 // This is safe because the interner keeps string alive until it is dropped.
1234 // We can access it because we know the interner is still alive since we use a
1235 // scoped thread local to access it, and it was alive at the beginning of this scope
1239 fn with2<F: FnOnce(&str, &str) -> R, R>(self, other: &InternedString, f: F) -> R {
1240 let (self_str, other_str) = with_interner(|interner| {
1241 (interner.get(self.symbol) as *const str,
1242 interner.get(other.symbol) as *const str)
1244 // This is safe for the same reason that `with` is safe.
1245 unsafe { f(&*self_str, &*other_str) }
1248 pub fn as_symbol(self) -> Symbol {
1252 pub fn as_str(self) -> LocalInternedString {
1253 self.symbol.as_str()
1257 impl Hash for InternedString {
1258 fn hash<H: Hasher>(&self, state: &mut H) {
1259 self.with(|str| str.hash(state))
1263 impl PartialOrd<InternedString> for InternedString {
1264 fn partial_cmp(&self, other: &InternedString) -> Option<Ordering> {
1265 if self.symbol == other.symbol {
1266 return Some(Ordering::Equal);
1268 self.with2(other, |self_str, other_str| self_str.partial_cmp(other_str))
1272 impl Ord for InternedString {
1273 fn cmp(&self, other: &InternedString) -> Ordering {
1274 if self.symbol == other.symbol {
1275 return Ordering::Equal;
1277 self.with2(other, |self_str, other_str| self_str.cmp(other_str))
1281 impl fmt::Debug for InternedString {
1282 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1283 self.with(|str| fmt::Debug::fmt(&str, f))
1287 impl fmt::Display for InternedString {
1288 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1289 self.with(|str| fmt::Display::fmt(&str, f))
1293 impl Decodable for InternedString {
1294 fn decode<D: Decoder>(d: &mut D) -> Result<InternedString, D::Error> {
1295 Ok(InternedString::intern(&d.read_str()?))
1299 impl Encodable for InternedString {
1300 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1301 self.with(|string| s.emit_str(string))
1312 fn interner_tests() {
1313 let mut i: Interner = Interner::default();
1314 // first one is zero:
1315 assert_eq!(i.intern("dog"), Symbol::new(0));
1316 // re-use gets the same entry:
1317 assert_eq!(i.intern("dog"), Symbol::new(0));
1318 // different string gets a different #:
1319 assert_eq!(i.intern("cat"), Symbol::new(1));
1320 assert_eq!(i.intern("cat"), Symbol::new(1));
1321 // dog is still at zero
1322 assert_eq!(i.intern("dog"), Symbol::new(0));
1323 let z = i.intern("zebra");
1324 assert_eq!(i.gensymed(z), Symbol::new(SymbolIndex::MAX_AS_U32));
1325 // gensym of same string gets new number:
1326 assert_eq!(i.gensymed(z), Symbol::new(SymbolIndex::MAX_AS_U32 - 1));
1327 // gensym of *existing* string gets new number:
1328 let d = i.intern("dog");
1329 assert_eq!(i.gensymed(d), Symbol::new(SymbolIndex::MAX_AS_U32 - 2));
1333 fn without_first_quote_test() {
1334 GLOBALS.set(&Globals::new(edition::DEFAULT_EDITION), || {
1335 let i = Ident::from_str("'break");
1336 assert_eq!(i.without_first_quote().name, kw::Break);