Problem: TeX catcode

Code: TeX+catcode/tails_1657864520

Nibbles version: 0.2 | 0.21 | 0.22 | 0.23 | 0.24 | 0.25 | 1.00

Format: Compact | Simple | +Type | Table | JSON | .nbl (DeBruijn) | .nbl (names)

. (map) 
    @ (= fstLine) 
    ? (if/else) <--arg( A ) 
        ? (index) 
            "\\{}$&\\#^_\\ \\\\~%" (string) 
            $ (= A) 
        - (subtract) <--arg( B ) 
            $ (= B) 
            ~ (auto = 1) 
        - (subtract) 
            12 (integer) 
            , (length) 
                \ (char class) 
                    $ (= A) 
                    a (isAlpha)