Function emit_antlr 

pub fn emit_antlr(
    grammar: &Grammar,
) -> Result<(String, EmitReport), GrammarEmitError>

Emits a combined ANTLR v4 grammar.

Normal rules become parser rules (lower-case first letter), token and atomic rules become lexer rules (upper-case first letter) and silent rules become fragment lexer rules. Rule names are adjusted deterministically to ANTLR’s case conventions and reserved words; every rename is recorded in EmitReport::lossy as ANTLR renamed rule "a" to "b".

Ordered choice is written as ANTLR alternation, negative lookahead as the ~ complement (a lookahead over a set followed by any character becomes a complemented set), case-insensitive literals as per-letter sets, counted repetition as copies with nested optionals, and captures as label= element labels. Positive lookahead and anonymous captures have no ANTLR form and are dropped. Every lowering and drop is recorded in the report, so import_antlr of the output reproduces the grammar modulo the recorded notes, and emitting the re-imported grammar reproduces the same text.

Rule documentation is written as comments above each rule; a trailing -> command documentation part of a lexer rule, as produced by import_antlr, is written back as the lexer command.

Errors

Returns GrammarEmitError::Unsupported for empty non-negated character classes, descending character ranges, repetitions whose maximum is below their minimum, and counted repetitions that would expand to more than 256 copies of their operand.