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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
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@ -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 Therefore, there is no automatic conversion from these classes to
\ccc{Object} Rather this is done with the global function \ccc{Object} Rather this is done with the global function
\ccc{make_object()}. This encapsulation mechanism requires the use of \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 \ccExample
In the following example, the object type is used as a return value for 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. possibly different return values.
\ccHtmlLinksOff% \ccHtmlLinksOff%
\begin{cprog} \begin{cprog}
Point_d< Cartesian_d<double> > p; typedef Point_d< Cartesian_d<double> > Point;
Segment_d< Cartesian_d<double> > s, s1, s2; typedef Segment_d< Cartesian_d<double> > Segment;
Segment s1, s2;
std::cin >> s1 >> s2; std::cin >> s1 >> s2;
Object obj = intersection(s1, s2); Object obj = intersection(s1, s2);
if ( assign(p, obj) ) { if (const Point *p = object_cast<Point>(&obj) ) {
/* do something with p */ /* do something with *p */
} else if ( (assign(s, obj) ) { } else if (const Segment *s = object_cast<Segment>(&obj) ) {
/* do something with s */ /* do something with *s */
} }
/* there was no intersection */ /* there was no intersection */
\end{cprog} \end{cprog}

17
Kernel_d/doc_tex/Kernel_d_ref/intersection.tex
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@ -4,9 +4,8 @@
\ccFunction{Object intersection(Type1<R> f1, Type2<R> f2);} {returns \ccFunction{Object intersection(Type1<R> f1, Type2<R> f2);} {returns
the intersection result of $f1$ and $f2$ by means of the polymorphic the intersection result of $f1$ and $f2$ by means of the polymorphic
wrapper type \ccc{Object}. The returned object can be tested for the wrapper type \ccc{Object}. The returned object can be tested for the
intersection result and assigned by means of the operation \ccc{bool intersection result and assigned by means of the \ccc{object_cast}
assign(T& t, Object o)}. \ccPrecond The objects are of the same function. \ccPrecond The objects are of the same dimension.}
dimension.}
The possible value for types \ccStyle{Type1} and \ccStyle{Type2} and The possible value for types \ccStyle{Type1} and \ccStyle{Type2} and
the possible return values wrapped in \ccc{Object} are the following: 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> template <class R>
void foo(Segment_d<R> seg, Line_d<R> lin) void foo(Segment_d<R> seg, Line_d<R> lin)
{ {
Point_d<R> ipnt; Segment_d<R> iseg;
Object result = intersection(seg, lin); Object result = intersection(seg, lin);
if ( assign(ipnt, result) ) { if (const Point_d<R> *ipnt = object_cast<Point_d<R> >(&result) ) {
// handle the point intersection case. // handle the point intersection case with *ipnt.
} else if ( assign(iseg, result) ) { } else if (const Segment_d<R> *iseg = object_cast<Segment_d<R> >(&result) ) {
// handle the segment intersection case. // handle the segment intersection case with *iseg.
} else { } else {
// handle the no intersection case. // handle the no intersection case.
} }
@ -172,6 +170,3 @@ void foo(Segment_d<R> seg, Line_d<R> lin)
\ccSeeAlso \ccSeeAlso
\ccc{do_intersect}, \ccc{Kernel::Intersect_d} \ccc{do_intersect}, \ccc{Kernel::Intersect_d}
\end{ccRefFunction} \end{ccRefFunction}