Struct lrlex::LexerDef

pub struct LexerDef<StorageT> { /* fields omitted */ }

This struct represents, in essence, a .l file in memory. From it one can produce a Lexer which actually lexes inputs.

Methods

impl<StorageT: Copy + Eq + Hash + PrimInt + Unsigned> LexerDef<StorageT>

pub fn new(rules: Vec<Rule<StorageT>>) -> LexerDef<StorageT>

pub fn get_rule(&self, idx: usize) -> Option<&Rule<StorageT>>

Get the Rule at index idx.

pub fn get_rule_by_id(&self, tok_id: StorageT) -> &Rule<StorageT>

Get the Rule instance associated with a particular lexeme ID. Panics if no such rule exists.

pub fn get_rule_by_name(&self, n: &str) -> Option<&Rule<StorageT>>

Get the Rule instance associated with a particular name.

pub fn set_rule_ids<'a>(
    &'a mut self,
    rule_ids_map: &HashMap<&'a str, StorageT>
) -> (Option<HashSet<&'a str>>, Option<HashSet<&'a str>>)

Set the id attribute on rules to the corresponding value in map. This is typically used to synchronise a parser's notion of lexeme IDs with the lexers. While doing this, it keeps track of which lexemes:

1. are defined in the lexer but not referenced by the parser
2. and referenced by the parser but not defined in the lexer and returns them as a tuple (Option<HashSet<&str>>, Option<HashSet<&str>>) in the order (defined_in_lexer_missing_from_parser, referenced_in_parser_missing_from_lexer). Since in most cases both sets are expected to be empty, None is returned to avoid a HashSet allocation.

Lexing and parsing can continue if either set is non-empty, so it is up to the caller as to what action they take if either return set is non-empty. A non-empty set #1 is often benign: some lexers deliberately define tokens which are not used (e.g. reserving future keywords). A non-empty set #2 is more likely to be an error since there are parts of the grammar where nothing the user can input will be parseable.

pub fn iter_rules(&self) -> Iter<Rule<StorageT>>

Returns an iterator over all rules in this AST.

pub fn lexer<'a>(&'a self, s: &'a str) -> impl Lexer<StorageT> + 'a

Return a lexer for the String s that will lex relative to this LexerDef.