[Workable solution found]

After more exploration, the following seems to solve the problem of creating a simple 2x2 quad chart; thanks for the explanation that the \bTD requires a matching \eTD in the immediate (not future expanded) evaluation context. I prefer the \start* and \stop* model but for the moment this solution works for my current purpose. The good part is that it does abstract out the interface so that I can change it in the future without needing to change the slide text. I may investigate a better (parametrizable/reconfigurable) solution later if I end up needing a more complex paned-layout environment that doesn't need direct access to the TABLE (or some other more relevant) interface.

MWE demonstrator; there's other cruft in the actual definitions for my purposes.

\starttext
    \define\startPaneSlide{\bTABLE}
    \define\stopPaneSlide{\eTABLE}
    \long\def\PaneRow#1{\bTR #1 \eTR}
    \long\def\Pane#1{\bTD #1 \eTD}

    \startPaneSlide
        \PaneRow{\Pane{aaa bbb ccc ddd}\Pane{eee fff ggg hhh}}
        \PaneRow{\Pane{iii jjj kkk lll}\Pane{mmm nnn ooo ppp}}
    \stopPaneSlide
\stoptext


Kevin W. Rudd, Ph.D.
CAPT, USN (Ret)

Computer Architecture & Computer Engineering 
Advanced Computing Systems (ACS) Research Program 
Laboratory for Physical Sciences (LPS) 

443-654-7878 
kevin@lps.umd.edu

Visiting Research Professor
United States Naval Academy

rudd@usna.edu


On Sep 9, 2020, at 09:02, Rudd, Kevin <kevin@lps.umd.edu> wrote:

True. There is also a

 \define\continuePaneRow{\eTD\bTD}

definition as well for that reason but that wasn't necessary for the MWE to (fail while) embed(ing) TABLE elements in macros.

Is it the case that I can bundle at least the table setup commands to avoid some level of replication? Or is there a better way to creat the various table begin--end pairs that is cleaner?

Thanks,
---K

Kevin W. Rudd, Ph.D.
CAPT, USN (Ret)
Computer Architecture & Computer Engineering (CACE)
Advanced Computing Systems (ACS) Research Program
Laboratory for Physical Sciences (LPS)
443-654-7878
Visiting Research Professor
Electrical and Computer Engineering
United States Naval Academy


From: Wolfgang Schuster <wolfgang.schuster.lists@gmail.com>
Sent: Wednesday, September 9, 2020 1:57:36 AM
To: Rudd, Kevin <kevin@lps.umd.edu>
Cc: mailing list for ConTeXt users <ntg-context@ntg.nl>
Subject: Re: [NTG-context] problem embedding TABLE macros within wrapper macros "to reduce repetitive complexity")
 
Rudd, Kevin schrieb am 09.09.2020 um 00:30:
Thanks. The immediate goal is to make a �quad chart� w/ different pains in the four (2x2 => NW, NE, SW, SE) quadrants. It seemed that the concept was scalable to any NxM (even with multi-cell spreads---useful for larger structured posters) based on TABLE. But I'd settle for 2x2 at the moment; at one point I'd thought of 2x2+1 having a spanning block for publication references per slide but decided a separate publications slide was a better idea visualy..

If they have to see an end command, would before/after tags work around a framedtext or buffer structure?

1. 2x2 panes, layout order not important, all panes independent; no flow (like Framemaker used to do) requiredbetween panes.
2. was going to have inner frames (i.e. + frame for 2x2 which was trivial to specify in TABLE) to separate the panes
3. other than wanting the + frame, inner margins &c. for panes wsn't an issue either way.

When you need one than single block per line this definition

\define\startPaneRow{bTR\bTD}
\define\stopPaneRow{\eTD\eTR}

doesn't make sense because you limit yourself and after each table cell there is a new row.

While you can write code which moves your blocks around you should ask yourself the question is it worth it. When you have only two or three posters in this format use the extra commands for table rows and cells because it takes more time to write something which does the work.

Wolfgang