On Thu, 11 Dec 2008, Aditya Mahajan wrote:
On Thu, 11 Dec 2008, Bart C. Wise wrote:
When I run the code below (via minimals), I get the following error, why?
\newcount\startcnt
\newcount\tempcnta
\def\myloop#1{%
\message{enter}
\tempcnta=\the\startcnt%
\loop
\message{loop}
\advance \tempcnta by 1
\ifnum\tempcnta>#1\else \repeat\fi
\message{exit}
}
\starttext
\startcnt=1800
\myloop{2008}
\stoptext
Do you know of \dostepwiserecurse{from}{to}{step}{body}. For example,
\starttext
\dostepwiserecurse{1800}{2008}{1}{We are at \recurselevel \endgraf}
\stoptext
There is also doloop. Documentations from syst-ext.tex
%D \macros
%D {doloop,exitloop}
%D
%D Sometimes loops are not determined by counters, but by
%D (a combinations of) conditions. We therefore implement a
%D straightforward loop, which can only be left when we
%D explictly exit it. Nesting is supported. First we present
%D a more extensive alternative.
%D
%D \starttyping
%D \doloop
%D {Some kind of typesetting punishment \par
%D \ifnum\pageno>100 \exitloop \fi}
%D \stoptyping
%D
%D When needed, one can call for \type{\looplevel} and
%D \type{\loopdepth}.
[...]
%D We don't have to declare new counters for \type{\looplevel}
%D and \type{\loopdepth} because we can use \type{\recurselevel}
%D and \type{\recursedepth}.
(although I could not get recurselevel or looplevel to work)
[...]
%D The loop is executed at least once, so beware of situations
%D like:
%D
%D \starttyping
%D \doloop {\exitloop some commands}
%D \stoptyping
%D
%D It's just a matter of putting the text into the \type{\if}
%D statement that should be there anyway, like in:
%D
%D \starttyping
%D \doloop {\ifwhatever \exitloop \else some commands\fi}
%D \stoptyping
%D
%D You can also quit a loop immediately, by using \type
%D {\exitloopnow} instead. Beware, this is more sensitive
%D for conditional errors.
So, you can write your example as (changed the stopping condition to add
\else, just to illustrate that it works)
\newcount\startcnt
\newcount\tempcnta
\def\myloop#1{%
\message{enter}
\tempcnta=\the\startcnt%
\doloop{
\message{loop \the\tempcnta}
\advance \tempcnta by 1
\ifnum\tempcnta<#1 \else \exitloop \fi}
\message{exit} }
\starttext
\startcnt=1800
\myloop{2009}
\stoptext
Aditya
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