Rik Kabel schrieb am 16.10.2024 um 23:18:

Hello Hans and developers,

I have been trying to convert some two- and three-step macros (as shown below) to single-step macros using the LMTX syntax given in the low-level macros manual. I have succeeded in many cases, but failed when the macro follows one particular group of patterns.

The group of patterns is similar to this macro to process

\MyMacro[optional]{Required}{Required}{Optional}

In this the number of arguments can be 2, 3, or 4.

A three-step solution might be as follows, which I use for a list of persons:

\defineregister[Bindex] \setupregister [Bindex][n=1,                         balance=no,                         method=default, % or New follows Newton!                         compress=no, % yes if not note number+q                         expansion=yes,                         pagecommand=\gobbleoneargument                        ]

\starttexdefinition unexpanded Bi   \dosingleempty\doBindex \stoptexdefinition

\starttexdefinition unexpanded doBindex [#SORTAS]#INDEXED   \def\SortAs{#SORTAS}%   \def\Indexed{#INDEXED}%   \dodoublegroupempty\doBindexFull \stoptexdefinition

\starttexdefinition doBindexFull #BD#MORE   \doifemptyelse{#MORE}     {\Bindex[\SortAs]{\Indexed\ #BD}}     {\Bindex[\SortAs]{\Indexed\ #BD\\ #MORE}} \stoptexdefinition

with input like:

\Bi{Rumble, Walker}{1938|–|}% \Bi{Runia, David Theunis}{1951|–|}{Classicist}% \Bi{Rutherford, Ernest (Baron Rutherford of Nelson)}{1871|–|1937}{Physicist}% \Bi{Saenger, Paul}{1945|–|}% \Bi{Saldarini, Anthony J.}{1941|–|2001}% \Bi{Salter, William M.}{1853|–|1931}% \Bi[Saint-Exupery]{de Saint-Exupéry, Antoine}{1900|–|1944}% \Bi{Santayana, George}{1863|–|1952}% \Bi{Sapir, Edward}{1884|–|1939}{Linguist}% \Bi[Schrodinger]{Schrödinger, Erwin}{1887|–|1961}{Physicist}% \Bi[Spinoza]{de Spinoza, Baruch (Benedict de Spinoza, Bento de Espinosa)}{1632|–|1677}%

The best I can get with the newer syntax is a two-step:

\starttexdefinition unexpanded Bi   \dosingleempty\doBindex \stoptexdefinition \tolerant\def\doBindex [#1]#=#=#=%   {\doifemptyelse{#4}     {\Bindex[#1]{#2\ #3}}%     {\Bindex[#1]{#2\ #3\\ #4}}%   }

In the low-level macros manual, near the end of chapter 2, it says that some day there may be a use for #?, #!, #<, or #>. If I am not missing something in the manual about how to provide that first optional argument as an empty value, I think I have one. Could [#?] always return a value (perhaps empty)? That would allow something like:

\tolerant\def\doBindex [#?]#=#=#=%   {\doifemptyelse{#4}     {\Bindex[#1]{#2\ #3}}%     {\Bindex[#1]{#2\ #3\\ #4}}%   }

When you have argument after square brackets you have to use #: to continues scanning for arguments of the command. For the mandatory argument you should just use #2 and keep #= for the optional arguments which are only used when text enclosed in curly braces appears. The #* between the third and fourth argument allows spaces between them. %%%% begin example \tolerant\protected\def\Bi[#1]#:#2#*#=#*#=% {(1=#1)% (2=#2)% (3=#3)% (4=#4)} \starttext [\Bi[one]{two}{three}{four}] [\Bi [one] {two} {three} {four}] [\Bi [one] {two} {three}] [\Bi [one] {two}] [\Bi {two}] [\Bi [one] {two}] \stoptext %%%% end example To check whether a argument is empty or not you can use the \ifparameter command with the parameter to check (i.e. #1) as argument (don't forget the \or) but \doifempty etc. work as well. %%%% begin example \tolerant\protected\def\Bi[#1]#:#2#*#=#*#=% {\ifparameter#1\or First argument is used. \else First argument is missing or empty. \fi} \starttext \Bi {bar} \Bi [] {bar} \Bi [foo] {bar} \stoptext %%%% end example Wolfgang