# TODO: GBNF Output Format

When grammars are finalized, output them in GBNF (GGML BNF) format for compatibility with llama.cpp and other inference engines.

GBNF is a BNF-like grammar format used by llama.cpp for constrained decoding. It supports:
- Sequences: `rule ::= token1 token2`
- Alternatives: `rule ::= alt1 | alt2`
- Optional: `rule ::= (token)?`
- Repetition: `rule ::= (token)*`
- Character classes: `[a-z]`, `[^abc]`

Example GBNF:
```
root   ::= ws? item ws?
item   ::= identifier ws? "(" ws? args? ws? ")"
args   ::= identifier (ws? "," ws? identifier)*
identifier ::= [a-zA-Z_][a-zA-Z0-9_]*
ws     ::= [ \t\n]*
```

Map SORE operators to GBNF:
- `r·s` (concatenation) → `rule ::= r s`
- `r|s` (disjunction) → `rule ::= r | s`
- `r*` (star) → `rule ::= (r)*`
- `r?` (optional) → `rule ::= (r)?`
- `r+` (plus) → `rule ::= r (r)*`

Implementation: Add `to_gbnf(sore)` function to `bex/` when ready.