Struct ion_rs::SymbolTable

pub struct SymbolTable { /* private fields */ }

Stores mappings from Symbol IDs to text and vice-versa.

Implementations

impl SymbolTable

pub fn new() -> SymbolTable

Constructs a new symbol table pre-populated with the system symbols defined in the spec.

pub fn reset(&mut self)

pub fn intern<A: AsRef<str>>(&mut self, text: A) -> SymbolId

If text is already in the symbol table, returns the corresponding SymbolId. Otherwise, adds text to the symbol table and returns the newly assigned SymbolId.

pub fn add_placeholder(&mut self) -> SymbolId

Assigns unknown text to the next available symbol ID. This is used when an Ion reader encounters null or non-string values in a stream’s symbol table.

pub fn intern_or_add_placeholder<A: AsRef<str>>(
    &mut self,
    maybe_text: Option<A>
) -> SymbolId

If maybe_text is Some(text), this method is equivalent to intern(text). If maybe_text is None, this method is equivalent to add_placeholder().

pub fn sid_for<A: AsRef<str>>(&self, text: &A) -> Option<SymbolId>

If defined, returns the Symbol ID associated with the provided text.

pub fn text_for(&self, sid: SymbolId) -> Option<&str>

If defined, returns the text associated with the provided Symbol ID.

pub fn symbol_for(&self, sid: SymbolId) -> Option<&Symbol>

If defined, returns the Symbol associated with the provided Symbol ID.

pub fn sid_is_valid(&self, sid: SymbolId) -> bool

Returns true if the provided symbol ID maps to an entry in the symbol table (i.e. it is in the range of known symbols: 0 to max_id)

Note that a symbol ID can be valid but map to unknown text. If a symbol table contains a null or non-string value, that entry in the table will be defined but not have text associated with it.

This method allows users to distinguish between a SID with unknown text and a SID that is invalid.

pub fn symbols(&self) -> &[Option<Symbol>]

Returns a slice of references to the symbol text stored in the table.

The symbol table can contain symbols with unknown text; if the text for a given symbol is unknown, the corresponding entry in the slice will be None.

pub fn symbols_tail(&self, start: usize) -> &[Option<Symbol>]

Returns a slice of references to the symbol text stored in the table starting at the given symbol ID. If a symbol table append occurs during reading, this function can be used to easily view the new symbols that has been added to the table.

The symbol table can contain symbols with unknown text; if the text for a given symbol is unknown, the corresponding entry in the slice will be None.

pub fn len(&self) -> usize

Returns the number of symbols defined in the table.

Trait Implementations

impl Default for SymbolTable

fn default() -> Self

Returns the “default value” for a type.