Script

<..script at start of tables..>
 \let\:EndHTableScript=\:EndHTblScript
 \let\:HTableScript=\:HTblScript
 \let\:HTbleAtt=\:HTblAtt
 <.nullify script.>%
 -_-_-

<..nullify script..>
 \let\:EndHTblScript=\empty
 \let\:HTblScript=\empty
 \let\:HTblAtt=\empty
 -_-_-

<..HTable..>+
 \def\HTableScript{\futurelet\:temp\tblScrpt:}
 \def\tblScrpt:{\ifx [\:temp  \expandafter\:tblScrpt
                \else  \expand:after{\:tblScrpt[]}\fi }
 \long\def\:tblScrpt[#1]#2#3{%
     \def\:HTblAtt{#1}%
     \def\:HTblScript{#2\go:out\empty<.par del.>\:out}%
     \def\:EndHTblScript{#3}}
 <.nullify script.>
 -_-_-

<..HTable..>+
 \def\go:out#1{\expand:after{\g:out#1}}
 \long\def\g:out#1#2\:out{#1}
 -_-_-