Orfeo-0.1.0.bnf

<Orfeo_0.1.0>               ::= <keyword_score> <ws>+ <music_expr>
<music_expr>                ::= <left_curly_bracket> <ws>* (<voice_expr> (<ws>* <comma> <ws>* <voice_expr>)* (<ws>* <comma>)?)? <ws>* <right_curly_bracket>
<voice_expr_content>        ::= <datum> | <voice_expr>
<voice_expr>                ::= <left_parenthesis> <ws>* (<duration>? | ((<duration> <ws>+)? <voice_expr_content> (<ws+ <voice_expr_content>)*)) <ws>* <right_parenthesis>
<duration_sigil>            ::= ':'
<duration_equal>            ::= <duration_sigil> "="
<duration_nonnegative_int>  ::= <duration_sigil> <nonnegative_int>
<duration_nonnegative_real> ::= <duration_sigil> <nonnegative_real>
<duration_time_signature>   ::= <duration_sigil> <time_signature>
<duration>                  ::= <duration_time_signature> | <duration_nonnegative_real> | <duration_nonnegative_int> | <duration_equal>
<positive_int>              ::= <nonzero_digit>+ <digit>*
<nonnegative_int>           ::= <zero> | <positive_int>
<positive_real>             ::= <positive_int> <period> <nonnegative_int> | <nonnegative_int> <period> <positive_int>
<nonnegative-real>          ::= <zero> | <positive_real>
<time_signature>            ::= (<nonnegativ_int> | <nonnegative_real>) <division> (<positive_int> | <positive_real>)
<datum_dots>                ::= "."+
<datum_flags>               ::= "^"+
<datum>                     ::= <datum_flags>? <datum_body> <datum_dots>?
<datum_body_strict>         ::= <underscore | <alphanumeric> | <square_bracket> | <division> | "#" | "-"
<datum_body_loose>          ::= <period> | <datum_body_strict>
<datum_body>                ::= <datum_body_loose>* <datum_body_strict> | <string>
<char>                      ::= <lowercase_char> | <uppercase_char>
<digit>                     ::= <zero> | <nonzero_digit>
<alphanumeric>              ::= <char> | <digit>
<square_bracket>            ::= <left_square_bracket> | <right_square_bracket>
<string>                    ::= <double_quote> <any_char> <double_quote>
<double_quote>              ::= "\""
<any_char>                  ::= [.*]
<keyword_score>             ::= "score"
<ws>                        ::= " "
<hyphen>                    ::= "-"
<underscore>                ::= "_"
<period>                    ::= "."
<comma>                     ::= ","
<colon>                     ::= ":"
<equal>                     ::= "="
<division>                  ::= "/"
<caret>                     ::= "^"
<left_parenthesis>          ::= "("
<right_parenthesis>         ::= ")"
<left_curly_bracket>        ::= "{"
<right_curly_bracket>       ::= "}"
<left_square_bracket>       ::= "["
<right_square_bracket>      ::= "]"
<lowercase_char>            ::= [a-z]
<uppercase_char>            ::= [a-Z]
<zero>                      ::= "0"
<nonzero_digit>             ::= [1-9]