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,
356 link_llvm_intrinsics,
364 macro_at_most_once_rep,
367 macro_lifetime_matcher,
368 macro_literal_matcher,
379 match_beginning_vert,
380 match_default_bindings,
390 movbe_target_feature,
424 omit_gdb_pretty_printer_section,
431 optin_builtin_traits,
439 overlapping_marker_traits,
444 panic_implementation,
461 poll_with_tls_context,
462 powerpc_target_feature,
463 precise_pointer_size_matching,
467 proc_dash_macro: "proc-macro",
469 proc_macro_attribute,
476 proc_macro_non_items,
477 proc_macro_path_invoc,
481 quad_precision_float,
494 reexport_test_harness_main,
504 re_rebalance_coherence,
517 rustc_allocator_nounwind,
518 rustc_allow_const_fn_ptr,
519 rustc_args_required_const,
522 rustc_const_unstable,
523 rustc_conversion_suggestion,
524 rustc_copy_clone_marker,
527 rustc_diagnostic_macros,
529 rustc_doc_only_macro,
531 rustc_dump_env_program_clauses,
532 rustc_dump_program_clauses,
533 rustc_dump_user_substs,
535 rustc_expected_cgu_reuse,
536 rustc_if_this_changed,
537 rustc_inherit_overflow_checks,
539 rustc_layout_scalar_valid_range_end,
540 rustc_layout_scalar_valid_range_start,
542 rustc_nonnull_optimization_guaranteed,
543 rustc_object_lifetime_default,
544 rustc_on_unimplemented,
547 rustc_partition_codegened,
548 rustc_partition_reused,
550 rustc_peek_definite_init,
551 rustc_peek_maybe_init,
552 rustc_peek_maybe_uninit,
554 rustc_proc_macro_decls,
558 rustc_std_internal_symbol,
562 rustc_then_this_would_need,
563 rustc_transparent_macro,
567 rust_eh_unwind_resume,
569 __rust_unstable_column,
570 rvalue_static_promotion,
586 sse4a_target_feature,
597 stmt_expr_attributes,
599 struct_field_attributes,
611 termination_trait_test,
614 test_accepted_feature,
616 test_removed_feature,
638 type_alias_enum_variants,
648 underscore_const_names,
650 underscore_lifetimes,
652 universal_impl_trait,
655 unrestricted_attribute_tokens,
656 unsafe_destructor_blind_to_params,
659 unsized_tuple_coercion,
674 visible_private_types,
677 warn_directory_ownership,
687 #[derive(Copy, Clone, Eq)]
695 /// Constructs a new identifier from a symbol and a span.
696 pub const fn new(name: Symbol, span: Span) -> Ident {
700 /// Constructs a new identifier with an empty syntax context.
702 pub const fn with_empty_ctxt(name: Symbol) -> Ident {
703 Ident::new(name, DUMMY_SP)
707 pub fn invalid() -> Ident {
708 Ident::with_empty_ctxt(kw::Invalid)
711 /// Maps an interned string to an identifier with an empty syntax context.
712 pub fn from_interned_str(string: InternedString) -> Ident {
713 Ident::with_empty_ctxt(string.as_symbol())
716 /// Maps a string to an identifier with an empty span.
717 pub fn from_str(string: &str) -> Ident {
718 Ident::with_empty_ctxt(Symbol::intern(string))
721 /// Maps a string and a span to an identifier.
722 pub fn from_str_and_span(string: &str, span: Span) -> Ident {
723 Ident::new(Symbol::intern(string), span)
726 /// Replaces `lo` and `hi` with those from `span`, but keep hygiene context.
727 pub fn with_span_pos(self, span: Span) -> Ident {
728 Ident::new(self.name, span.with_ctxt(self.span.ctxt()))
731 pub fn without_first_quote(self) -> Ident {
732 Ident::new(Symbol::intern(self.as_str().trim_start_matches('\'')), self.span)
735 /// "Normalize" ident for use in comparisons using "item hygiene".
736 /// Identifiers with same string value become same if they came from the same "modern" macro
737 /// (e.g., `macro` item, but not `macro_rules` item) and stay different if they came from
738 /// different "modern" macros.
739 /// Technically, this operation strips all non-opaque marks from ident's syntactic context.
740 pub fn modern(self) -> Ident {
741 Ident::new(self.name, self.span.modern())
744 /// "Normalize" ident for use in comparisons using "local variable hygiene".
745 /// Identifiers with same string value become same if they came from the same non-transparent
746 /// macro (e.g., `macro` or `macro_rules!` items) and stay different if they came from different
747 /// non-transparent macros.
748 /// Technically, this operation strips all transparent marks from ident's syntactic context.
749 pub fn modern_and_legacy(self) -> Ident {
750 Ident::new(self.name, self.span.modern_and_legacy())
753 /// Transforms an identifier into one with the same name, but gensymed.
754 pub fn gensym(self) -> Ident {
755 let name = with_interner(|interner| interner.gensymed(self.name));
756 Ident::new(name, self.span)
759 /// Transforms an underscore identifier into one with the same name, but
760 /// gensymed. Leaves non-underscore identifiers unchanged.
761 pub fn gensym_if_underscore(self) -> Ident {
762 if self.name == kw::Underscore { self.gensym() } else { self }
765 // WARNING: this function is deprecated and will be removed in the future.
766 pub fn is_gensymed(self) -> bool {
767 with_interner(|interner| interner.is_gensymed(self.name))
770 pub fn as_str(self) -> LocalInternedString {
774 pub fn as_interned_str(self) -> InternedString {
775 self.name.as_interned_str()
779 impl PartialEq for Ident {
780 fn eq(&self, rhs: &Self) -> bool {
781 self.name == rhs.name && self.span.ctxt() == rhs.span.ctxt()
785 impl Hash for Ident {
786 fn hash<H: Hasher>(&self, state: &mut H) {
787 self.name.hash(state);
788 self.span.ctxt().hash(state);
792 impl fmt::Debug for Ident {
793 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
794 write!(f, "{}{:?}", self.name, self.span.ctxt())
798 impl fmt::Display for Ident {
799 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
800 fmt::Display::fmt(&self.name, f)
804 impl Encodable for Ident {
805 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
806 if self.span.ctxt().modern() == SyntaxContext::empty() {
807 s.emit_str(&self.as_str())
808 } else { // FIXME(jseyfried): intercrate hygiene
809 let mut string = "#".to_owned();
810 string.push_str(&self.as_str());
816 impl Decodable for Ident {
817 fn decode<D: Decoder>(d: &mut D) -> Result<Ident, D::Error> {
818 let string = d.read_str()?;
819 Ok(if !string.starts_with('#') {
820 Ident::from_str(&string)
821 } else { // FIXME(jseyfried): intercrate hygiene
822 Ident::from_str(&string[1..]).gensym()
827 /// A symbol is an interned or gensymed string. A gensym is a symbol that is
828 /// never equal to any other symbol.
830 /// Conceptually, a gensym can be thought of as a normal symbol with an
831 /// invisible unique suffix. Gensyms are useful when creating new identifiers
832 /// that must not match any existing identifiers, e.g. during macro expansion
833 /// and syntax desugaring. Because gensyms should always be identifiers, all
834 /// gensym operations are on `Ident` rather than `Symbol`. (Indeed, in the
835 /// future the gensym-ness may be moved from `Symbol` to hygiene data.)
839 /// assert_eq!(Ident::from_str("x"), Ident::from_str("x"))
840 /// assert_ne!(Ident::from_str("x").gensym(), Ident::from_str("x"))
841 /// assert_ne!(Ident::from_str("x").gensym(), Ident::from_str("x").gensym())
843 /// Internally, a symbol is implemented as an index, and all operations
844 /// (including hashing, equality, and ordering) operate on that index. The use
845 /// of `newtype_index!` means that `Option<Symbol>` only takes up 4 bytes,
846 /// because `newtype_index!` reserves the last 256 values for tagging purposes.
848 /// Note that `Symbol` cannot directly be a `newtype_index!` because it
849 /// implements `fmt::Debug`, `Encodable`, and `Decodable` in special ways.
850 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
851 pub struct Symbol(SymbolIndex);
854 pub struct SymbolIndex { .. }
858 const fn new(n: u32) -> Self {
859 Symbol(SymbolIndex::from_u32_const(n))
862 /// Maps a string to its interned representation.
863 pub fn intern(string: &str) -> Self {
864 with_interner(|interner| interner.intern(string))
867 pub fn as_str(self) -> LocalInternedString {
868 with_interner(|interner| unsafe {
869 LocalInternedString {
870 string: std::mem::transmute::<&str, &str>(interner.get(self))
875 pub fn as_interned_str(self) -> InternedString {
876 with_interner(|interner| InternedString {
877 symbol: interner.interned(self)
881 pub fn as_u32(self) -> u32 {
886 impl fmt::Debug for Symbol {
887 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
888 let is_gensymed = with_interner(|interner| interner.is_gensymed(*self));
890 write!(f, "{}({:?})", self, self.0)
892 write!(f, "{}", self)
897 impl fmt::Display for Symbol {
898 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
899 fmt::Display::fmt(&self.as_str(), f)
903 impl Encodable for Symbol {
904 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
905 s.emit_str(&self.as_str())
909 impl Decodable for Symbol {
910 fn decode<D: Decoder>(d: &mut D) -> Result<Symbol, D::Error> {
911 Ok(Symbol::intern(&d.read_str()?))
915 // The `&'static str`s in this type actually point into the arena.
917 // Note that normal symbols are indexed upward from 0, and gensyms are indexed
918 // downward from SymbolIndex::MAX_AS_U32.
920 pub struct Interner {
921 arena: DroplessArena,
922 names: FxHashMap<&'static str, Symbol>,
923 strings: Vec<&'static str>,
924 gensyms: Vec<Symbol>,
928 fn prefill(init: &[&'static str]) -> Self {
930 strings: init.into(),
931 names: init.iter().copied().zip((0..).map(Symbol::new)).collect(),
936 pub fn intern(&mut self, string: &str) -> Symbol {
937 if let Some(&name) = self.names.get(string) {
941 let name = Symbol::new(self.strings.len() as u32);
943 // `from_utf8_unchecked` is safe since we just allocated a `&str` which is known to be
945 let string: &str = unsafe {
946 str::from_utf8_unchecked(self.arena.alloc_slice(string.as_bytes()))
948 // It is safe to extend the arena allocation to `'static` because we only access
949 // these while the arena is still alive.
950 let string: &'static str = unsafe {
951 &*(string as *const str)
953 self.strings.push(string);
954 self.names.insert(string, name);
958 fn interned(&self, symbol: Symbol) -> Symbol {
959 if (symbol.0.as_usize()) < self.strings.len() {
962 self.gensyms[(SymbolIndex::MAX_AS_U32 - symbol.0.as_u32()) as usize]
966 fn gensymed(&mut self, symbol: Symbol) -> Symbol {
967 self.gensyms.push(symbol);
968 Symbol::new(SymbolIndex::MAX_AS_U32 - self.gensyms.len() as u32 + 1)
971 fn is_gensymed(&mut self, symbol: Symbol) -> bool {
972 symbol.0.as_usize() >= self.strings.len()
975 // Get the symbol as a string. `Symbol::as_str()` should be used in
976 // preference to this function.
977 pub fn get(&self, symbol: Symbol) -> &str {
978 match self.strings.get(symbol.0.as_usize()) {
979 Some(string) => string,
981 let symbol = self.gensyms[(SymbolIndex::MAX_AS_U32 - symbol.0.as_u32()) as usize];
982 self.strings[symbol.0.as_usize()]
988 // This module has a very short name because it's used a lot.
994 // This module has a very short name because it's used a lot.
996 use std::convert::TryInto;
1001 // Get the symbol for an integer. The first few non-negative integers each
1002 // have a static symbol and therefore are fast.
1003 pub fn integer<N: TryInto<usize> + Copy + ToString>(n: N) -> Symbol {
1004 if let Result::Ok(idx) = n.try_into() {
1005 if let Option::Some(&sym) = digits_array.get(idx) {
1009 Symbol::intern(&n.to_string())
1014 fn is_used_keyword_2018(self) -> bool {
1018 fn is_unused_keyword_2018(self) -> bool {
1019 self >= kw::Async && self <= kw::Try
1022 /// Used for sanity checking rustdoc keyword sections.
1023 pub fn is_doc_keyword(self) -> bool {
1027 /// A keyword or reserved identifier that can be used as a path segment.
1028 pub fn is_path_segment_keyword(self) -> bool {
1029 self == kw::Super ||
1030 self == kw::SelfLower ||
1031 self == kw::SelfUpper ||
1032 self == kw::Crate ||
1033 self == kw::PathRoot ||
1034 self == kw::DollarCrate
1037 /// This symbol can be a raw identifier.
1038 pub fn can_be_raw(self) -> bool {
1039 self != kw::Invalid && self != kw::Underscore && !self.is_path_segment_keyword()
1044 // Returns `true` for reserved identifiers used internally for elided lifetimes,
1045 // unnamed method parameters, crate root module, error recovery etc.
1046 pub fn is_special(self) -> bool {
1047 self.name <= kw::Underscore
1050 /// Returns `true` if the token is a keyword used in the language.
1051 pub fn is_used_keyword(self) -> bool {
1052 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
1053 self.name >= kw::As && self.name <= kw::While ||
1054 self.name.is_used_keyword_2018() && self.span.rust_2018()
1057 /// Returns `true` if the token is a keyword reserved for possible future use.
1058 pub fn is_unused_keyword(self) -> bool {
1059 // Note: `span.edition()` is relatively expensive, don't call it unless necessary.
1060 self.name >= kw::Abstract && self.name <= kw::Yield ||
1061 self.name.is_unused_keyword_2018() && self.span.rust_2018()
1064 /// Returns `true` if the token is either a special identifier or a keyword.
1065 pub fn is_reserved(self) -> bool {
1066 self.is_special() || self.is_used_keyword() || self.is_unused_keyword()
1069 /// A keyword or reserved identifier that can be used as a path segment.
1070 pub fn is_path_segment_keyword(self) -> bool {
1071 self.name.is_path_segment_keyword()
1074 /// We see this identifier in a normal identifier position, like variable name or a type.
1075 /// How was it written originally? Did it use the raw form? Let's try to guess.
1076 pub fn is_raw_guess(self) -> bool {
1077 self.name.can_be_raw() && self.is_reserved()
1081 // If an interner exists, return it. Otherwise, prepare a fresh one.
1083 fn with_interner<T, F: FnOnce(&mut Interner) -> T>(f: F) -> T {
1084 GLOBALS.with(|globals| f(&mut *globals.symbol_interner.lock()))
1087 /// An alternative to `Symbol` and `InternedString`, useful when the chars
1088 /// within the symbol need to be accessed. It is best used for temporary
1091 /// Because the interner outlives any thread which uses this type, we can
1092 /// safely treat `string` which points to interner data, as an immortal string,
1093 /// as long as this type never crosses between threads.
1095 // FIXME: ensure that the interner outlives any thread which uses
1096 // `LocalInternedString`, by creating a new thread right after constructing the
1098 #[derive(Clone, Copy, Hash, PartialOrd, Eq, Ord)]
1099 pub struct LocalInternedString {
1100 string: &'static str,
1103 impl LocalInternedString {
1104 /// Maps a string to its interned representation.
1105 pub fn intern(string: &str) -> Self {
1106 let string = with_interner(|interner| {
1107 let symbol = interner.intern(string);
1108 interner.strings[symbol.0.as_usize()]
1110 LocalInternedString {
1111 string: unsafe { std::mem::transmute::<&str, &str>(string) }
1115 pub fn as_interned_str(self) -> InternedString {
1117 symbol: Symbol::intern(self.string)
1121 pub fn get(&self) -> &str {
1122 // This returns a valid string since we ensure that `self` outlives the interner
1123 // by creating the interner on a thread which outlives threads which can access it.
1124 // This type cannot move to a thread which outlives the interner since it does
1125 // not implement Send.
1130 impl<U: ?Sized> std::convert::AsRef<U> for LocalInternedString
1132 str: std::convert::AsRef<U>
1134 fn as_ref(&self) -> &U {
1135 self.string.as_ref()
1139 impl<T: std::ops::Deref<Target = str>> std::cmp::PartialEq<T> for LocalInternedString {
1140 fn eq(&self, other: &T) -> bool {
1141 self.string == other.deref()
1145 impl std::cmp::PartialEq<LocalInternedString> for str {
1146 fn eq(&self, other: &LocalInternedString) -> bool {
1147 self == other.string
1151 impl<'a> std::cmp::PartialEq<LocalInternedString> for &'a str {
1152 fn eq(&self, other: &LocalInternedString) -> bool {
1153 *self == other.string
1157 impl std::cmp::PartialEq<LocalInternedString> for String {
1158 fn eq(&self, other: &LocalInternedString) -> bool {
1159 self == other.string
1163 impl<'a> std::cmp::PartialEq<LocalInternedString> for &'a String {
1164 fn eq(&self, other: &LocalInternedString) -> bool {
1165 *self == other.string
1169 impl !Send for LocalInternedString {}
1170 impl !Sync for LocalInternedString {}
1172 impl std::ops::Deref for LocalInternedString {
1174 fn deref(&self) -> &str { self.string }
1177 impl fmt::Debug for LocalInternedString {
1178 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1179 fmt::Debug::fmt(self.string, f)
1183 impl fmt::Display for LocalInternedString {
1184 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1185 fmt::Display::fmt(self.string, f)
1189 impl Decodable for LocalInternedString {
1190 fn decode<D: Decoder>(d: &mut D) -> Result<LocalInternedString, D::Error> {
1191 Ok(LocalInternedString::intern(&d.read_str()?))
1195 impl Encodable for LocalInternedString {
1196 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1197 s.emit_str(self.string)
1201 /// An alternative to `Symbol` that is focused on string contents. It has two
1202 /// main differences to `Symbol`.
1204 /// First, its implementations of `Hash`, `PartialOrd` and `Ord` work with the
1205 /// string chars rather than the symbol integer. This is useful when hash
1206 /// stability is required across compile sessions, or a guaranteed sort
1207 /// ordering is required.
1209 /// Second, gensym-ness is irrelevant. E.g.:
1211 /// assert_ne!(Symbol::gensym("x"), Symbol::gensym("x"))
1212 /// assert_eq!(Symbol::gensym("x").as_interned_str(), Symbol::gensym("x").as_interned_str())
1214 #[derive(Clone, Copy, PartialEq, Eq)]
1215 pub struct InternedString {
1219 impl InternedString {
1220 /// Maps a string to its interned representation.
1221 pub fn intern(string: &str) -> Self {
1223 symbol: Symbol::intern(string)
1227 pub fn with<F: FnOnce(&str) -> R, R>(self, f: F) -> R {
1228 let str = with_interner(|interner| {
1229 interner.get(self.symbol) as *const str
1231 // This is safe because the interner keeps string alive until it is dropped.
1232 // We can access it because we know the interner is still alive since we use a
1233 // scoped thread local to access it, and it was alive at the beginning of this scope
1237 fn with2<F: FnOnce(&str, &str) -> R, R>(self, other: &InternedString, f: F) -> R {
1238 let (self_str, other_str) = with_interner(|interner| {
1239 (interner.get(self.symbol) as *const str,
1240 interner.get(other.symbol) as *const str)
1242 // This is safe for the same reason that `with` is safe.
1243 unsafe { f(&*self_str, &*other_str) }
1246 pub fn as_symbol(self) -> Symbol {
1250 pub fn as_str(self) -> LocalInternedString {
1251 self.symbol.as_str()
1255 impl Hash for InternedString {
1256 fn hash<H: Hasher>(&self, state: &mut H) {
1257 self.with(|str| str.hash(state))
1261 impl PartialOrd<InternedString> for InternedString {
1262 fn partial_cmp(&self, other: &InternedString) -> Option<Ordering> {
1263 if self.symbol == other.symbol {
1264 return Some(Ordering::Equal);
1266 self.with2(other, |self_str, other_str| self_str.partial_cmp(other_str))
1270 impl Ord for InternedString {
1271 fn cmp(&self, other: &InternedString) -> Ordering {
1272 if self.symbol == other.symbol {
1273 return Ordering::Equal;
1275 self.with2(other, |self_str, other_str| self_str.cmp(other_str))
1279 impl fmt::Debug for InternedString {
1280 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1281 self.with(|str| fmt::Debug::fmt(&str, f))
1285 impl fmt::Display for InternedString {
1286 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1287 self.with(|str| fmt::Display::fmt(&str, f))
1291 impl Decodable for InternedString {
1292 fn decode<D: Decoder>(d: &mut D) -> Result<InternedString, D::Error> {
1293 Ok(InternedString::intern(&d.read_str()?))
1297 impl Encodable for InternedString {
1298 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
1299 self.with(|string| s.emit_str(string))
1310 fn interner_tests() {
1311 let mut i: Interner = Interner::default();
1312 // first one is zero:
1313 assert_eq!(i.intern("dog"), Symbol::new(0));
1314 // re-use gets the same entry:
1315 assert_eq!(i.intern("dog"), Symbol::new(0));
1316 // different string gets a different #:
1317 assert_eq!(i.intern("cat"), Symbol::new(1));
1318 assert_eq!(i.intern("cat"), Symbol::new(1));
1319 // dog is still at zero
1320 assert_eq!(i.intern("dog"), Symbol::new(0));
1321 let z = i.intern("zebra");
1322 assert_eq!(i.gensymed(z), Symbol::new(SymbolIndex::MAX_AS_U32));
1323 // gensym of same string gets new number:
1324 assert_eq!(i.gensymed(z), Symbol::new(SymbolIndex::MAX_AS_U32 - 1));
1325 // gensym of *existing* string gets new number:
1326 let d = i.intern("dog");
1327 assert_eq!(i.gensymed(d), Symbol::new(SymbolIndex::MAX_AS_U32 - 2));
1331 fn without_first_quote_test() {
1332 GLOBALS.set(&Globals::new(edition::DEFAULT_EDITION), || {
1333 let i = Ident::from_str("'break");
1334 assert_eq!(i.without_first_quote().name, kw::Break);