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
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