Optionalbatch_Reductions buffered per crossing when a transformer is given (default
128, matching the Python binding). The folded result is identical for any
value; 1 opts into exact reduce/callback interleaving for
side-effecting transformers, at ~2x the crossing cost on large inputs.
Ignored behind a custom lexer: that route has no reduce seam and folds
the finished tree, so callbacks fire after the parse.
OptionalbatchAlias of batch_size.
Optionalon_Cold-path LALR error-recovery callback: true resumes, false re-raises.
lark's parse(text, on_error=...).
OptionalonAlias of on_error.
OptionalstartEntry rule (omit for the sole declared start).
OptionaltransformerFold the parse through a reduce-time transformer (returns its host value
instead of a Tree).
Options for the public
parse(text, opts?). A key not named here is refused (ConfigurationError: Unknown options: ...), as at construction, and so is a value the option cannot use.nullis absent for every field, so the default stands. Where lark has the kwarg its spelling is canonical (on_error); the camelCase form is an accepted alias, and passing both spellings of one option is an error.