Re: how to inject some code inside function.

From:

Yechezkel Mett <ymett.on.usenet@gmail.com>

Newsgroups:

comp.lang.c++.moderated

Date:

Mon, 16 Feb 2009 09:18:23 CST

Message-ID:

<152251f2-070c-4433-a274-d4532d361487@j1g2000yqi.googlegroups.com>

On Feb 16, 2:08 am, german diago <germandi...@gmail.com> wrote:

What I'm looking
for (if it's possible),
is a way to avoid this:

void operator()(value v1, ...)
     if (v1.get_type() == "int")
       dosomething<int>(f)
     else if...

}

I'm doing this because I want to do argument marshalling. For basic
types, this is not a problem.
The problem is that I want to register new types at runtime, and I'd
like them to be marshalled too.
I mean, using function call operator with this prototype:

void operator()(value v1, value v2, value v3);

  Where value holds any registered type in my type system,
I want to be able to add new types at runtime, for use with this kind
of function. And to use it, I must
do argument marshalling inside the function. Anyone knows how to do
this? It's being quite difficult for me.

With a map.

typedef std::map<std::string, boost::function<void()> > DispatchMap;
DispatchMap dispatchMap;

// fill the map as necessary

void operator()(value v1)
{
     DispatchMap::iterator f = dispatchMap.find(v1.get_type());
     if (f != dispatchMap.end())
         f(v1);
}

Yechezkel Mett

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