ltsh/typeDB/cut

::cut OPTION... [FILE]... {

    match OPTION... {
        --help { <1 : Help~<Seq Char> ; }
        --version { <1 : VersionInfo~<Seq Char> ; }

        * {
            match OPTION... {
                -f--fields LIST:<Seq ℕ>~CutFieldList~<Seq Char> {

                    ROW-DELIM =
                        match OPTION... {
                            -z--zero-terminated { '\0' }
                            * { '\n' }
                        };

                    IN-COL-DELIM =
                        match OPTION... {
                            -d--delimiter DELIM:Char { DELIM }
                            * { '\t' }
                        };

                    OUT-COL-DELIM =
                        match OPTION... {
                            --output-delimiter STRING:<Seq Char> { STRING }
                            * { IN-COL-DELIM }
                        };

                    FILE : Path
                           ~<Seq PathSegment
                                 ~<Seq Char>>
                           ~<SepSeq Char '/'>
                           ~<Seq Char> ;

                    @FILE : <Seq <* < ITEM~<Seq Char> >... >
                                 ~<Seq <Seq Char>>
                                 ~<SepSeq Char IN-COL-DELIM>
                                 ~<Seq Char>>
                            ~<SepSeq Char ROW-DELIM>
                            ~<Seq Char> ;

                    >0 : <Seq <* <ITEM~<Seq Char>>... >
                              ~<Seq <Seq Char>>
                              ~<SepSeq Char IN-COL-DELIM>
                              ~<Seq Char>>
                         ~<SepSeq Char ROW-DELIM>
                         ~<Seq Char> ;

                    # `[LIST]` means `select all fields contained in LIST from parameter pack`
                    <1 : <Seq <*  <ITEM~<Seq Char>>[LIST]... >
                              ~<Seq <Seq Char>>
                              ~<SepSeq Char OUT-COL-DELIM>
                              ~<Seq Char>>
                         ~<SepSeq Char ROW-DELIM>
                         ~<Seq Char> ;
                }

                * {
                    <1 : Nothing ;
                    <2 : MissingFields~ErrorMessage~<Seq Char> ;
                }
            }
        }
    }
}