Struct GrammarBuilder 

pub struct GrammarBuilder { /* private fields */ }

Helper class to build a BNF grammar.

Equivalent to xgrammar’s GrammarBuilder. Holds the in-progress rule list and CSR expression store, plus a name→id index.

Implementations

impl GrammarBuilder

pub fn add_rule(&mut self, rule: Rule) -> Result<i32, BuilderError>

Add a fully-formed rule and return its id.

Returns Err if a rule of the same name already exists.

pub fn add_rule_named( &mut self, name: impl Into<String>, body_expr_id: i32, ) -> Result<i32, BuilderError>

Add a rule with the given name and body_expr_id.

pub fn add_rule_with_hint( &mut self, name_hint: &str, body_expr_id: i32, ) -> Result<i32, BuilderError>

Add a rule with a body, deriving a unique name from name_hint.

pub fn num_rules(&self) -> i32

Number of rules.

pub fn get_rule(&self, rule_id: i32) -> &Rule

The rule with the given id.

pub fn add_empty_rule( &mut self, name: impl Into<String>, ) -> Result<i32, BuilderError>

Add a body-less rule (body_expr_id = -1). The body must be set later with GrammarBuilder::update_rule_body. Useful when the rule id is needed to build the body (recursive rules).

pub fn add_empty_rule_with_hint( &mut self, name_hint: &str, ) -> Result<i32, BuilderError>

Add a body-less rule with a unique name derived from name_hint.

pub fn update_rule_body( &mut self, rule_id: i32, body_expr_id: i32, ) -> Result<(), BuilderError>

Set the body of rule rule_id.

Returns Err if rule_id is out of range.

pub fn update_rule_body_named( &mut self, rule_name: &str, body_expr_id: i32, ) -> Result<(), BuilderError>

Set the body of the rule named rule_name.

pub fn update_lookahead_assertion( &mut self, rule_id: i32, lookahead_assertion_id: i32, ) -> Result<(), BuilderError>

Set the lookahead-assertion expr id of rule rule_id. An id of -1 means no assertion.

pub fn update_lookahead_assertion_named( &mut self, rule_name: &str, lookahead_assertion_id: i32, ) -> Result<(), BuilderError>

Set the lookahead-assertion expr id of the rule named rule_name.

pub fn update_lookahead_exact( &mut self, rule_id: i32, is_exact: bool, ) -> Result<(), BuilderError>

Mark the lookahead assertion of rule rule_id as exact.

pub fn get_new_rule_name(&self, name_hint: &str) -> String

Find an unused rule name starting from name_hint, appending an integer suffix (_1, _2, …) on collision.

The first probed suffix is read from next_cnt_per_hint (a cache of the last suffix reached for this hint) rather than restarting from 1 every call. This makes repeated calls with the same hint amortized O(1) instead of O(N) — see the field doc on GrammarBuilder. Behavior is unchanged: every candidate is still verified absent from rule_name_to_id, and the cache only advances (never skips a still-free lower suffix, because suffixes for a given hint are only ever consumed in increasing order).

pub fn get_rule_id(&self, name: &str) -> i32

Rule id of the rule named name, or -1 if absent.

impl GrammarBuilder

pub fn new() -> Self

Create an empty builder.

pub fn get(self, root_rule_name: &str) -> Result<GrammarData, BuilderError>

Finish building and return the GrammarData, setting the root rule to the rule with root_rule_name.

Returns Err if the named rule is not present.

pub fn get_by_id(self, root_rule_id: i32) -> Result<GrammarData, BuilderError>

Finish building and return the GrammarData, setting the root rule to root_rule_id.

Returns Err if root_rule_id is out of bounds.

pub fn add_grammar_expr(&mut self, kind: GrammarExprType, data: &[i32]) -> i32

Append a raw (type, data[]) expression to the CSR store and return its expr id.

pub fn add_byte_string_bytes(&mut self, bytes: &[i32]) -> i32

Add a ByteString expr from raw bytes (each 0..=255).

pub fn add_byte_string(&mut self, s: &str) -> i32

Add a ByteString expr from a Rust string (UTF-8 bytes).

pub fn add_character_class( &mut self, elements: &[CharacterClassElement], is_negative: bool, ) -> i32

Add a CharacterClass expr, e.g. [a-z] / [^a-z].

pub fn add_character_class_star( &mut self, elements: &[CharacterClassElement], is_negative: bool, ) -> i32

Add a CharacterClassStar expr, e.g. [a-z]*.

pub fn add_empty_str(&mut self) -> i32

Add an EmptyStr expr (the empty string "").

pub fn add_rule_ref(&mut self, rule_id: i32) -> i32

Add a RuleRef expr pointing at rule_id.

pub fn add_sequence(&mut self, elements: &[i32]) -> i32

Add a Sequence expr (concatenation of sub-expr ids).

pub fn add_choices(&mut self, choices: &[i32]) -> i32

Add a Choices expr (alternation of sub-expr ids).

pub fn add_repeat( &mut self, ref_rule_id: i32, min_repeat: i32, max_repeat: i32, ) -> i32

Add a Repeat expr [rule_id, min, max].

pub fn add_tag_dispatch(&mut self, spec: &TagDispatchSpec) -> i32

Add a TagDispatch expr. Tag strings and stop/exclude string lists are interned as ByteString/Choices sub-exprs first, matching the CSR layout decoded by GrammarData::tag_dispatch.

pub fn num_grammar_exprs(&self) -> i32

Number of expressions stored so far.

pub fn get_grammar_expr(&self, expr_id: i32) -> GrammarExpr<'_>

Borrowed view of expr expr_id. Panics if out of bounds — the builder is internal and ids it returns are always valid.

Trait Implementations

impl Debug for GrammarBuilder

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for GrammarBuilder

fn default() -> GrammarBuilder

Returns the “default value” for a type.