The original has been defined as global, probbaly because it was in a group hiding ‘\+’. I couldn’t locate that group. I protectd the problematic parts here from the if-else of the first pass with \expandafter.
<..latex lttab..>
<.TABLE tabbing.>
<.TABLE tabbing Config util.>
<.all html latex tabs.>
\pend:defI\extracolsep{\a:extracolsep{##1}}
\NewConfigure{extracolsep}[1]{\def\a:extracolsep##1{#1}}
\Configure{extracolsep}{}
-_-_-
The pic-tabbing’ option asks for pictures just for tabbing environments that have the \’ tabbing command.
The above order of insertions is important for \tab:N nd ‘\LikeRef’ to be recognized.
<..all html latex tabs..>
\HAssign\tab:N=0
\pend:def\tabbing{\let\dot:tab=\empty \gHAdvance\tab:N by 1}
\append:def\endtabbing{\Tag{<.tabbing tag.>.}{\dot:tab}}
\pend:def\@tablab{\xdef\dot:tab{.}}
-_-_-
Tabbing enironments can’t be nested (latex 181).
Can we get rid of the following pictoral part by using ConfigureEnv?
<..TABLE tabbing..>
\let\:tempc=\tabbing
\pend:def\:tempc{\Configure{HtmlPar}{}{}{}{}%
\edef\ln:tab{\LikeRef{<.tabbing tag.>} 0 }%
\let\TABBING=\ln:tab \gdef\locs:tab{}}
\HLet\tabbing=\:tempc
\let\:tempc=\endtabbing
\append:def\:tempc{%
\Tag{<.tabbing tag.>}{\locs:tab}%
\def\:temp{.}\ifx \:temp\dot:tab
\:warning{\noexpand\’ ignored in tabbing}
\fi}
\HLet\endtabbing=\:tempc
-_-_-
The lengths of the fields are recorded in \locs:tab, send into xref with tag ‘\tab:N’, and loaded into \ln:tag for use.