Snake parser (https://carrotflakes.github.io/Snake-Parser/) を使ってコードネームのパーサを作成（メジャーコードのみ完成）

search_chord_major.txt

// Grammer

start = search<chord>

chord
    =
    {
        root: `root
        quality
        ?slash
        bass: `?bass
    }

root
    = [A-G] ?[♯＃#♭b]

quality
    =   type: `(?ct_major '6')
        space
        tension: @?tn_maj6
    |   type: `(ct_major '7')
        space
        tension: @?tn_maj7
    |   type: `(ct_major '9')
        space
        tension: @?tn_maj9
    |   type: `(?ct_major)
        space
        tension: @?tn_maj

bass
    = [A-G] ?[♯＃#♭b]

ct_major
    = 'M'
    | '△'
    | 'maj'

tn_maj6
    =
    '('
    `'9'
    ')'

tn_maj7
    = !'()'
    '('
    ?(`'9' delimiter)
    ?(`(dg_sharp '11') delimiter)
    ?(`'13' delimiter)
    ')'

tn_maj9
    = !'()'
    '('
    ?(`(dg_sharp '11') delimiter)
    ?(`'13' delimiter)
    ')'

tn_maj
    =
    '('
    `(dg_sharp '5')
    ')'

dg_sharp
    = '♯'
    | '＃'
    | '#'
    | '+'
    | '＋'

dg_flat
    = '♭'
    | 'b'
    | '-'
    | '−'

delimiter
    = &')'
    | ', '
    | ','
    | ' '

slash
    = space ('/' | '／' | 'on') space

space
    = *' '

search<x> = @(*(!x .) *(x *(!x .)))

// Input text
// eg)  CM7(#11) D♯M9 (+11 13) EonG# F / C