Re: [NTG-context] ConTeXt Marcro Quesiton

7 Feb 2007


      Wolfgang Schuster wrote:
...
On Tue, 6 Feb 2007 10:36:42 -0500 (EST)
Aditya Mahajan  wrote:
...
On Tue, 6 Feb 2007, Hans Hagen wrote:
...
Aditya Mahajan wrote:
...
...
Can someone suggest a better way to do this?
I found another way, I hope that it has no gotcha's
search for group(ed)(empty|argument) in cont-sys.tex
Did you mean syst-gen.tex? I tied dodoublegroupempty but it did not 
work in one case (see previous post) and I can not figure out why.
Aditya
Hi Aditya,
I tried something similiar and copied a example from core-rul.tex
The following macro use a method copied from textrule and the second
argument between the braces should be optional. I looked into the log
file created with tracingmacros and it seems TeX cannot find the
optional argument.
\long\def\startDEBITS#1\stopDEBITS
  {\bgroup
   \def\debit{\dosingleempty\dodebit}%
   \def\dodebit[##1]%
     {\def\dododebit####1{\dodododebit[##1]{####1}}%
      \dosinglegroupempty\dododebit}%
   \def\dodododebit[##1]##2%
     {\hbox to\hsize{\strut##1\hfill##2}}%
   \vbox{\hsize4cm\hrule#1\hrule}%
   \egroup}
\starttext
%\tracingmacros1
\startDEBITS
\debit [Text] {100} ttt
\debit [Text] {200} xxx
\stopDEBITS
%\tracingmacros0
\stoptext
Hans, can you give us a hint what we are doing wrong or can you make a
simple example to show us how we can create optional arguments between
braces.
\long\def\startDEBITS#1\stopDEBITS
  {\vbox \bgroup
   \hsize4cm
   \def\debit
     {\dosingleempty\dodebit}
   \def\dodebit[##1]%
     {\def\dododebit{\dodododebit[##1]}%
      \permitspacesbetweengroups
      \dosinglegroupempty\dododebit}
   \def\dodododebit[##1]##2%
     {\dontleavehmode\hbox to\hsize{\strut##1\hfill##2}}
   \hrule#1\hrule
   \egroup}

\starttext

\startDEBITS
\debit [Text]{100} ttt
\debit [Text] {200} xxx
\stopDEBITS

the magic is in \permitspacesbetweengroups

i suppose some \par needs to be added someplace 
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