<div dir="ltr">You may want to look at generic programming to solve your problem.<div><a href="http://www.cs.rpi.edu/~musser/gp/GPtutorial/GPtutorial-print.pdf">http://www.cs.rpi.edu/~musser/gp/GPtutorial/GPtutorial-print.pdf</a><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Jul 2, 2018 at 4:31 PM, Todd via vtk-developers <span dir="ltr"><<a href="mailto:vtk-developers@public.kitware.com" target="_blank">vtk-developers@public.kitware.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="auto"><span class=""><div><br><div class="gmail_extra"><br><div class="gmail_quote">On 3 Jul 2018 9:07 a.m., Paul Douglas Hahn <<a href="mailto:pdhahn@compintensehpc.com" target="_blank">pdhahn@compintensehpc.com</a>> wrote:<br type="attribution"><blockquote class="m_5047362915493203470quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div>
revise "base classes" -> "interface classes"<br>
<br>
<div>On 07/02/2018 04:04 PM, Paul Douglas
Hahn wrote:<br>
</div>
<blockquote>
Just one caveat (you probably already know and agree with this).
In my experience using C++ multiple inheritance, I think you
should try to avoid situations where you have common base classes
in the inheritance pathways. Virtual base classes are the usual
recommendation to resolve certain problems that arise in such
cases, but IMHO having experience with that, I generally recommend
against it.<br>
<br>
So I recommend your base classes should be of the "<u>mix-in</u>"
interface category, not relaying on any common base class. The
approach works fine for me in almost every situation.<br>
</blockquote></div></blockquote></div></div></div><div dir="auto"><br></div></span><div dir="auto">Thanks Paul. That sounds exactly like what I have done with the vtkCellWithEdges and vtkCellWithFaces classes introduced in the aforementioned merge request.</div><span class=""><div dir="auto"><div class="gmail_extra"><div class="gmail_quote"><blockquote class="m_5047362915493203470quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><blockquote><br>
- Paul<br>
<br>
<div>On 07/02/2018 12:44 AM, Todd Martin
via vtk-developers wrote:<br>
</div>
<blockquote>
<div style="font-family:'helvetica neue','helvetica','arial',sans-serif;font-size:16px">
<div style="font-family:'helvetica neue','helvetica','arial',sans-serif;font-size:16px">
<div>
<div>Single inheritance languages like Java and C# utilize
<i>interfaces</i> extensively. Python 2.7+ handles the
same concept with abstract base classes, ABCs.<br>
<div><br>
<div>
<div>
<div>Is there any interest in supporting<i>
interfaces</i> in VTK via multiple inheritance
from abstract classes (which do not inherit from
vtkObject) while retaining the single
inheritance model?<br>
<div><br>
In my view there are good reasons to do so.
For example vtkCell has methods like
GetNumberOfEdges(), GetEdge(),
GetNumberOfFaces(), GetFace() etc. which
really only apply to multi-dimensional cells
(both linear and non-linear); i.e. not points
and lines. These methods are forced on the
base class design by a single inheritance
structure and the linear/non-linear cell
sub-types. In my view it would be better if
they were distributed across the sub-classes
via the concept of interfaces. So I'm
suggesting a limited use of multiple
inheritance here, not a free-for-all approach.
What do others think about this?<br>
<div>
<div>
<div>
<div><br>
</div>
For an example please see this merge
request <a href="https://gitlab.kitware.com/vtk/vtk/merge_requests/4372" target="_blank">Add missing
size hints and bug fix point arrays
for non-linear cells (!4372) · Merge
Requests · VTK / VTK</a></div>
</div>
</div>
</div>
</div>
</div>
<div><br>
</div>
<div style="max-width:400px;font-family:'neue' 'segoe ui arial',sans-serif"><a href="https://gitlab.kitware.com/vtk/vtk/merge_requests/4372" style="text-decoration:none!important;color:#000!important" target="_blank">
<table style="max-width:400px" border="0" cellspacing="0" cellpadding="0"><tbody><tr><td width="400">
<table style="max-width:400px;border-width:1px;border-style:solid;border-color:rgb(224,228,233);border-radius:2px" width="100%" border="0" cellspacing="0" cellpadding="0"><tbody><tr><td style="background-color:rgb(0,0,0);background-repeat:no-repeat;border-radius:2px 2px 0px 0px;min-height:175px" height="175" valign="top" bgcolor="#000000">
<table style="width:100%" border="0" cellspacing="0" cellpadding="0"><tbody><tr><td style="background-color:transparent;border-radius:2px 2px 0px 0px;min-height:175px" valign="top" bgcolor="transparent">
<table style="width:100%;min-height:175px" border="0"><tbody><tr><td style="text-align:left;padding:15px 0 0 15px;vertical-align:top"><br>
</td><td style="text-align:right;padding:15px 15px 0 0;vertical-align:top"><br>
</td></tr></tbody></table>
</td></tr></tbody></table>
</td></tr><tr><td>
<table style="background-color:rgb(255,255,255);background-image:none;background-repeat:repeat;width:100%;max-width:400px;border-radius:0px 0px 2px 2px;border-top:1px solid rgb(224,228,233)" border="0" cellspacing="0" cellpadding="0" align="center"><tbody><tr><td style="background-color:#ffffff;padding:16px 0 16px 12px;vertical-align:top;border-radius:0 0 0 2px"><br>
</td><td style="vertical-align:middle;padding:12px 24px 16px 12px;width:99%;font-family:'neue' 'segoe ui arial',sans-serif;border-radius:0 0 2px 0">
<h2 style="font-size:14px;line-height:19px;margin:0 0 6px 0;font-family:'neue' 'segoe ui','helvetica','arial',sans-serif;color:#26282a">Add
missing size hints and
bug fix point arrays
for non-linear cells
(!4...</h2>
<p style="font-size:12px;line-height:16px;margin:0px;color:#979ba7">I've
added size hints for
concrete public
methods
GetParametricCoords(),
GetEdgePoints() and
GetFacePoints() in ...</p>
</td></tr></tbody></table>
</td></tr></tbody></table>
</td></tr></tbody></table>
</a></div>
<div><br>
</div>
<div><br>
</div>
</div>
</div>
</div>
<div><br>
</div>
<div>
<div style="font-size:16px;font-family:'helvetica','arial',sans-serif">
<div>Todd Martin, PhD.<br>
</div>
<div><i>Freelance Engineer/Software Architect.</i></div>
<br>
</div>
</div>
</div>
</div>
</div>
<br>
<fieldset></fieldset>
<br>
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</blockquote>
<br>
<br>
<pre>--
Paul D. Hahn
CompIntense HPC, LLC
</pre>
</blockquote>
<br>
<br>
<pre>--
Paul D. Hahn
CompIntense HPC, LLC
</pre>
</div>
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