Struct lrlex::LexerBuilder

pub struct LexerBuilder<'a, StorageT = u32> { /* fields omitted */ }

A LexerBuilder allows one to specify the criteria for building a statically generated lexer.

Implementations

impl<'a, StorageT> LexerBuilder<'a, StorageT> where
    StorageT: Copy + Debug + Eq + Hash + PrimInt + TryFrom<usize> + Unsigned, 

pub fn new() -> Self

Create a new LexerBuilder.

StorageT must be an unsigned integer type (e.g. u8, u16) which is big enough to index all the tokens, rules, and productions in the lexer and less than or equal in size to usize (e.g. on a 64-bit machine u128 would be too big). If you are lexing large files, the additional storage requirements of larger integer types can be noticeable, and in such cases it can be worth specifying a smaller type. StorageT defaults to u32 if unspecified.

Examples

LexerBuilder::<u8>::new()
    .process_file_in_src("grm.l", None)
    .unwrap();

pub fn lexerkind(self, lexerkind: LexerKind) -> Self

Set the type of lexer to be generated to lexerkind.

pub fn mod_name(self, mod_name: &'a str) -> Self

Set the generated module name to mod_name. If no module name is specified, process_file will attempt to create a sensible default based on the input filename.

pub fn visibility(self, vis: Visibility) -> Self

Set the visibility of the generated module to vis. Defaults to Visibility::Private.

pub fn rule_ids_map(self, rule_ids_map: HashMap<String, StorageT>) -> Self

Set this lexer builder's map of rule IDs to rule_ids_map. By default, lexing rules have arbitrary, but distinct, IDs. Setting the map of rule IDs (from rule names to StorageT) allows users to synchronise a lexer and parser and to check that all rules are used by both parts).

pub fn process_file_in_src(
    self,
    srcp: &str
) -> Result<(Option<HashSet<String>>, Option<HashSet<String>>), Box<dyn Error>>

Given the filename a/b.l as input, statically compile the file src/a/b.l into a Rust module which can then be imported using lrlex_mod!("a/b.l"). This is a convenience function around process_file which makes it easier to compile .l files stored in a project's src/ directory: please see process_file for additional constraints and information about the generated files.

pub fn process_file<P, Q>(
    self,
    inp: P,
    outp: Q
) -> Result<(Option<HashSet<String>>, Option<HashSet<String>>), Box<dyn Error>> where
    P: AsRef<Path>,
    Q: AsRef<Path>, 

Statically compile the .l file inp into Rust, placing the output into the file outp. The latter defines a module as follows:

   mod modname {
     pub fn lexerdef() -> LexerDef<StorageT> { ... }

     ...
   }

where:

• modname is either:
  • the module name specified mod_name
  • or, if no module name was explicitly specified, then for the file /a/b/c.l the module name is c_l (i.e. the file's leaf name, minus its extension, with a prefix of _l).

pub fn allow_missing_terms_in_lexer(self, allow: bool) -> Self

If passed false, tokens used in the grammar but not defined in the lexer will cause a panic at lexer generation time. Defaults to false.

pub fn allow_missing_tokens_in_parser(self, allow: bool) -> Self

If passed false, tokens defined in the lexer but not used in the grammar will cause a panic at lexer generation time. Defaults to true (since lexers sometimes define tokens such as reserved words, which are intentionally not in the grammar).