[function] How to extract a tuple<A0,A1> of arguments from a boost::function<>?
Short question: As the Subject says, given a boost::function{1..N}<>, how can I extract a tuple of all its arguments? Long question: Anyway, what I'm really trying to do is this: Given some classes with different methods: struct X { void f(int n ) ; } ; struct Y { void g(char c, double d ) ; } ; I want to easly create _polymorphic_ closures binding member functions of X /Y with instances of X/Y and function arguments. The goal is the have a deferred 'action' list for easy backtracing of an algorithm. That is, instead of directly calling: X x ; Y y ; x.f(1); y.g('a',1.2); I want to do something that would look like: X x; Y y; ActionList actions; actions.push_back( make_closure(&X::f, x,1) ); actions.push_back( make_closure(&Y::g, y,'a',1.2) ); std::for_each(actions.begin(),actions.end(),execute_action()); TIA Fernando Cacciola
Fernando Cacciola wrote:
That is, instead of directly calling:
X x ; Y y ; x.f(1); y.g('a',1.2);
I want to do something that would look like:
X x; Y y; ActionList actions; actions.push_back( make_closure(&X::f, x,1) ); actions.push_back( make_closure(&Y::g, y,'a',1.2) ); std::for_each(actions.begin(),actions.end(),execute_action());
typedef std::list< boost::function<void()> > ActionList; #define make_closure boost::bind struct execute_action { template<class F> void operator()(F & f) const { f(); } }; ActionList actions; actions.push_back( make_closure(&X::f, &x, 1) ); actions.push_back( make_closure(&Y::g, &y, 'a', 1.2) ); std::for_each(actions.begin(),actions.end(),execute_action()); &x and &y since I'm assuming that you don't want x and y copied and stored in the closure.
Peter Dimov <pdimov@mmltd.net> wrote in message news:001101c35d0a$e1cab440$1d00a8c0@pdimov2...
Fernando Cacciola wrote:
That is, instead of directly calling:
X x ; Y y ; x.f(1); y.g('a',1.2);
I want to do something that would look like:
X x; Y y; ActionList actions; actions.push_back( make_closure(&X::f, x,1) ); actions.push_back( make_closure(&Y::g, y,'a',1.2) ); std::for_each(actions.begin(),actions.end(),execute_action());
typedef std::list< boost::function<void()> > ActionList; #define make_closure boost::bind
struct execute_action { template<class F> void operator()(F & f) const { f(); } };
ActionList actions; actions.push_back( make_closure(&X::f, &x, 1) ); actions.push_back( make_closure(&Y::g, &y, 'a', 1.2) ); std::for_each(actions.begin(),actions.end(),execute_action());
Beautyful! Just copy-pasted and it worked just as you wrote it.
&x and &y since I'm assuming that you don't want x and y copied and stored in the closure.
Yes... Thanks Fernando Cacciola
participants (3)
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Fernando Cacciola -
Peter Dimov