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Recommend object_cast instead of assign

This commit is contained in:
Sylvain Pion 2008-07-29 13:59:20 +00:00
parent c3500b603f
commit 0c9d10baa6
2 changed files with 14 additions and 18 deletions
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15
Kernel_d/doc_tex/Kernel_d/predicates_constructions_d.tex
View File

@ -75,7 +75,7 @@ assignments, so that you can put them in lists or arrays. Note that
Therefore, there is no automatic conversion from these classes to
\ccc{Object} Rather this is done with the global function
\ccc{make_object()}. This encapsulation mechanism requires the use of
\ccc{assign} to unwrap the encapsulated class.
\ccc{object_cast} to unwrap the encapsulated class.
\ccExample
In the following example, the object type is used as a return value for
@ -83,14 +83,15 @@ the \ccHtmlNoLinksFrom{intersection} computation, as there are
possibly different return values.
\ccHtmlLinksOff%
\begin{cprog}
Point_d< Cartesian_d<double> > p;
Segment_d< Cartesian_d<double> > s, s1, s2;
typedef Point_d< Cartesian_d<double> > Point;
typedef Segment_d< Cartesian_d<double> > Segment;
Segment s1, s2;
std::cin >> s1 >> s2;
Object obj = intersection(s1, s2);
if ( assign(p, obj) ) {
/* do something with p */
} else if ( (assign(s, obj) ) {
/* do something with s */
if (const Point *p = object_cast<Point>(&obj) ) {
/* do something with *p */
} else if (const Segment *s = object_cast<Segment>(&obj) ) {
/* do something with *s */
}
/* there was no intersection */
\end{cprog}

17
Kernel_d/doc_tex/Kernel_d_ref/intersection.tex
View File

@ -4,9 +4,8 @@
\ccFunction{Object intersection(Type1<R> f1, Type2<R> f2);} {returns
the intersection result of $f1$ and $f2$ by means of the polymorphic
wrapper type \ccc{Object}. The returned object can be tested for the
intersection result and assigned by means of the operation \ccc{bool
assign(T& t, Object o)}. \ccPrecond The objects are of the same
dimension.}
intersection result and assigned by means of the \ccc{object_cast}
function. \ccPrecond The objects are of the same dimension.}
The possible value for types \ccStyle{Type1} and \ccStyle{Type2} and
the possible return values wrapped in \ccc{Object} are the following:
@ -156,12 +155,11 @@ The following example demonstrates the most common use of
template <class R>
void foo(Segment_d<R> seg, Line_d<R> lin)
{
Point_d<R> ipnt; Segment_d<R> iseg;
Object result = intersection(seg, lin);
if ( assign(ipnt, result) ) {
// handle the point intersection case.
} else if ( assign(iseg, result) ) {
// handle the segment intersection case.
if (const Point_d<R> *ipnt = object_cast<Point_d<R> >(&result) ) {
// handle the point intersection case with *ipnt.
} else if (const Segment_d<R> *iseg = object_cast<Segment_d<R> >(&result) ) {
// handle the segment intersection case with *iseg.
} else {
// handle the no intersection case.
}
@ -172,6 +170,3 @@ void foo(Segment_d<R> seg, Line_d<R> lin)
\ccSeeAlso
\ccc{do_intersect}, \ccc{Kernel::Intersect_d}
\end{ccRefFunction}