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authorNorbert Preining <norbert@preining.info>2020-05-05 03:00:58 +0000
committerNorbert Preining <norbert@preining.info>2020-05-05 03:00:58 +0000
commit12fef7aa53e3695c36d3650fa4fb98f991bc223e (patch)
tree851ce6216775d5d7b763952c5c861e86a7f48a03 /macros/latex/contrib/curve2e/curve2e-manual.tex
parent47af91cb8475b7352015cf05ce881e6b8415112d (diff)
CTAN sync 202005050300
Diffstat (limited to 'macros/latex/contrib/curve2e/curve2e-manual.tex')
-rw-r--r--macros/latex/contrib/curve2e/curve2e-manual.tex40
1 files changed, 26 insertions, 14 deletions
diff --git a/macros/latex/contrib/curve2e/curve2e-manual.tex b/macros/latex/contrib/curve2e/curve2e-manual.tex
index 23a35a8f85..87961a4cd9 100644
--- a/macros/latex/contrib/curve2e/curve2e-manual.tex
+++ b/macros/latex/contrib/curve2e/curve2e-manual.tex
@@ -1279,7 +1279,7 @@ Remember to delete all these subfolders if you decide to install a complete upda
\multiput(50,50)(-15:5){11}{\polygon*(-1,-1)(1,-1)(1,1)(-1,1)}
\end{picture}
\end{minipage}
-\caption{Some examples of the \meta{handler} optional argument}%\label{pag:multiput}
+\caption{Some examples of the \meta{handler} optional argument}\label{pag:multiput}
\end{figure}
A new command |\xmultiput| (not available with the previous versions
@@ -1331,14 +1331,14 @@ Remember to delete all these subfolders if you decide to install a complete upda
\end{figure}
\item This implementation of \pack{curve2e} includes an extension
- to package |xfp|, in the sense that adds two more L3 commands:
- |\fptest| and |\fpdowhile| to the two already contained and
+ to package |xfp|, in the sense that adds three more L3 commands:
+ |\fptest|, |\fpdowhile|, |fpwhiledo| to the two already contained and
documented in the latter package. The syntax of such new commands
is the following
\begin{flushleft}\obeylines
\cs{fptext}\marg{test}\marg{true}\marg{false}
- and
\cs{fpdowhile}\meta{test}\meta{operations to be repeated}
+ \cs{fpwhiledo}\meta{test}\meta{operations to be repeated}
\end{flushleft}
The macro |\fptest| requires two further arguments that contain
what to do if the \meta{test} is true, and what to do if the
@@ -1346,20 +1346,32 @@ Remember to delete all these subfolders if you decide to install a complete upda
The \meta{test} is a logical expressions that connects math relation
expressions, even floating point ones, by means of \emph{logical
operators}; such operators are \verb+||+, \verb|&&|, and \verb|!|,
- respectively for OR, AND, NOT; for example \verb|!<| means “not lower
- than”, which is equivalent to “equal or grater than”. The logical
- expression is parsed left to right and normal parentheses may be
- used to alter this sequence. The logical operators work also
- between logical variables, therefore the \meta{test} may contain
- an interesting mixture of relation and logical operators.
-
- Before using |\fpdowhile| the arguments the \meta{test} depends
- from must be set so that the test is true; during the execution
+ respectively for OR, AND, NOT; math relation expressions contain
+ relation operators, even negated ones: for example \verb|!<| means
+ “not lower than”, which is equivalent to “equal or grater than”, i.e.
+ \verb|=>|. The logical expression is parsed left to right and normal
+ parentheses may be used to alter this sequence. The logical operators
+ work also between logical variables, therefore the \meta{test} may
+ contain an interesting mixture of relation and logical operators.
+
+ Before using |\fpdowhile| and |\fpwhiledo|the arguments of \meta{test}
+ depends on must be set so that the test is true; during the execution
of the \meta{operations to be repeated} there must be some setting
that eventually renders the \meta{test} false. The user should
- pay attention to set the elements that \meta{test} depends from,
+ pay attention to set the elements that \meta{test} depends on,
because the risk is to enter an infinite loop and end up with some
error message stating that the working memory of the program is full.
+ Notice that |\fpdowhile| first puts the \meta{operations to be repeated}
+ into the work flow then checks the \meta{test} and possibly repeats the
+ cycle; on the opposite, |\fpwhiledo| first checks the \meta{test} then
+ possibly inserts the \meta{operations to be repeated} and cycles.
+ Evidently with the same \meta{test} the two while cycles produce
+ different results with a little, but important difference: if the input
+ data are macros defined by previous computations, there is no guarantee
+ that the \meta{test} is initially true; if it sis false, |fpwhiledo|
+ does not do anything, while |\fpdowhile| executes one cycle and produces
+ in the output stream something that might be nonsense. While cycles done
+ with |\fpwhiledo| should be safer and should be preferred.
Nevertheless such commands are very useful also for drawing graphics;
the |xmultiput| already makes use of such L3~functions.