../filter --nice
 -- flags in options / arguments
    Flags in first argument in [flags]

    x or X in arg 1       = 0
    c, C, k or K in arg 1 = 0
    a,b, or c in options  = 0

 -- search(), next() and follow()

    found "--rudimental" = 0
    followed by -1 and -1
    rudimental = nothing -1

 -- variables in section [user-variables]


 -- pseudo function call feature


