grammars: x{min,max} repetition operator (#6640)

* grammars: x{min,max} repetition operator + tweak +/*/? to avoid duplication of original over alternates

* grammars: handle `x{n}` and fix `x{n,n}`

* grammars: document new repetition operators

* grammars: uniform use of int for min & max

* grammars: refactor parser test

* grammar: parsing tests w/ natural pretty print of updated expectations

* grammars: much prettier print of expectations (+ TEST_GRAMMAR_PARSER_PRINT_ALL=1 to force all)

* grammars: improve test pretty print again

* grammars: pretty print rules and chars

* grammars: fix copy rule skipping

* grammars: disallow `a{,}` (not allowed in regexps)

* Update common/grammar-parser.cpp

Co-authored-by: Clint Herron <hanclinto@gmail.com>

* grammars: fix copy rule skipping (again) & display of expectations

* grammars: more test cases

* grammars: update reps parsing to bring ? / * / + closer to before

* json: use new GBNF repetitions{m,n} syntax

* grammars: update performance gotchas w/ repetition advice

* Update examples/json_schema_to_grammar.py

Co-authored-by: Clint Herron <hanclinto@gmail.com>

* Update examples/server/public/json-schema-to-grammar.mjs

Co-authored-by: Clint Herron <hanclinto@gmail.com>

* grammars: comment on rule repetitions

* grammars: ensure unambiguous number alternatives

* grammar: nit typo switched error msgs

* grammar: nit numbering in comment

* json: update numeric rule to be unambiguous

* Apply suggestions from code review

Co-authored-by: Clint Herron <hanclinto@gmail.com>

* Update examples/server/public/json-schema-to-grammar.mjs

Co-authored-by: Clint Herron <hanclinto@gmail.com>

* json: fix integral-part

* grammar: add repetition tests

---------

Co-authored-by: Clint Herron <hanclinto@gmail.com>
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Olivier Chafik 2024-06-06 10:07:06 +01:00 committed by GitHub
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@ -59,9 +59,13 @@ Parentheses `()` can be used to group sequences, which allows for embedding alte
## Repetition and Optional Symbols
- `*` after a symbol or sequence means that it can be repeated zero or more times.
- `+` denotes that the symbol or sequence should appear one or more times.
- `?` makes the preceding symbol or sequence optional.
- `*` after a symbol or sequence means that it can be repeated zero or more times (equivalent to `{0,}`).
- `+` denotes that the symbol or sequence should appear one or more times (equivalent to `{1,}`).
- `?` makes the preceding symbol or sequence optional (equivalent to `{0,1}`).
- `{m}` repeats the precedent symbol or sequence exactly `m` times
- `{m,}` repeats the precedent symbol or sequence at least `m` times
- `{m,n}` repeats the precedent symbol or sequence at between `m` and `n` times (included)
- `{0,n}` repeats the precedent symbol or sequence at most `n` times (included)
## Comments and newlines
@ -98,4 +102,4 @@ Grammars currently have performance gotchas (see https://github.com/ggerganov/ll
A common pattern is to allow repetitions of a pattern `x` up to N times.
While semantically correct, the syntax `x? x? x?.... x?` (with N repetitions) will result in extremely slow inference. Instead, you can write `(x (x (x ... (x)?...)?)?)?` (w/ N-deep nesting)
While semantically correct, the syntax `x? x? x?.... x?` (with N repetitions) may result in extremely slow sampling. Instead, you can write `x{0,N}` (or `(x (x (x ... (x)?...)?)?)?` w/ N-deep nesting in earlier llama.cpp versions).