Struct rustc_span::symbol::Symbol

source ·
pub struct Symbol(SymbolIndex);
Expand description

An interned string.

Internally, a Symbol is implemented as an index, and all operations (including hashing, equality, and ordering) operate on that index. The use of rustc_index::newtype_index! means that Option<Symbol> only takes up 4 bytes, because rustc_index::newtype_index! reserves the last 256 values for tagging purposes.

Note that Symbol cannot directly be a rustc_index::newtype_index! because it implements fmt::Debug, Encodable, and Decodable in special ways.

Tuple Fields§

§0: SymbolIndex

Implementations§

for use in Decoder only

Maps a string to its interned representation.

Access the underlying string. This is a slowish operation because it requires locking the symbol interner.

Note that the lifetime of the return value is a lie. It’s not the same as &self, but actually tied to the lifetime of the underlying interner. Interners are long-lived, and there are very few of them, and this function is typically used for short-lived things, so in practice it works out ok.

This method is supposed to be used in error messages, so it’s expected to be identical to printing the original identifier token written in source code (token_to_string, Ident::to_string), except that symbols don’t keep the rawness flag or edition, so we have to guess the rawness using the global edition.

A keyword or reserved identifier that can be used as a path segment.

Returns true if the symbol is true or false.

Returns true if this symbol can be a raw identifier.

Is this symbol was interned in compiler’s symbols! macro

Trait Implementations§

Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more
Formats the value using the given formatter. Read more
Feeds this value into the given Hasher. Read more
Feeds a slice of this type into the given Hasher. Read more
This method returns an Ordering between self and other. Read more
Compares and returns the maximum of two values. Read more
Compares and returns the minimum of two values. Read more
Restrict a value to a certain interval. Read more
This method tests for self and other values to be equal, and is used by ==.
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
This method returns an ordering between self and other values if one exists. Read more
This method tests less than (for self and other) and is used by the < operator. Read more
This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
This method tests greater than (for self and other) and is used by the > operator. Read more
This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
Converts the given value to a String. Read more

Auto Trait Implementations§

Blanket Implementations§

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
Converts the given value to a String. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.

Layout§

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference’s “Type Layout” chapter for details on type layout guarantees.

Size: 4 bytes