Re: [boost] [function] Anything to adapt a boost::function object?

From: Chris Uzdavinis (chris_at_[hidden])
Date: 2006-04-21 09:56:27

Maxim Yegorushkin <maxim.yegorushkin_at_[hidden]> writes:

> Can it be done in a straightforward way?
>
> #include <boost/bind.hpp>
> #include <boost/function.hpp>
> #include <boost/lexical_cast.hpp>
> #include <string>
> #include <iostream>
>
> struct caster
> {
>      std::string s;
>      template<class T>
>      operator T() const { return boost::lexical_cast<T>(s); }
>      caster(std::string const& s) : s(s) {}
>      caster(char const* s) : s(s) {}
> };
>
> void f(int i, double d)
> {
>      std::cout << i << char(0xa) << d << char(0xa);
>      // sorry, my back-slash key does not work
> }
>
> int main()
> {
>      boost::function<void(caster, caster)> g(f);
>      g("123", "3.13");
> }

That's pretty clever.  So simple--I like it!  (I'll try this out and
see how it goes.)

>> My motivation for wanting this is to implement a "simple" command
>> interpreter for a socket-based administrative interface.  I
>> pre-register a bunch of function objects, then whenever someone sends
>> a command down the socket, it arrives as a string.  The function
>> object is looked up by name, and then the call-operator is invoked
>> given the string arguments.  Internally, the proper string-to-type
>> converstions occur, and the boost::function is called with those
>> values.  (If the conversion fails, an exception would be perfectly
>> reasonable.)
>
> Don't you have to tokenize the input first? While doing so you might 
> parse it as well.

Actually, the data would be arriving in a CORBA sequence of strings,
which is similar to a vector.  Thus, the args would already be
"tokenized". 

Thanks again for the idea!

-- 
Chris