Re: [Boost-users] [lambda]Predicate construction

Peter Dimov wrote:

Anakreon wrote:

...

struct event_locator: public unary_function { int tId; event_locator(const int tid) : tId(tid) {} const bool operator() (Event* e) { return e->hasTransaction() && e->getTransaction().getId() == tId; } };

The best (IMO) approach would be to define

bool has_transaction_with_id( Event /*const?*/ * e, int id ) { return e->hasTransaction() && e->getTransaction().getId() == id; }

I intended to use lambda in order to avoid declaration of functions or structs for STL algorithms. If I need to declare the function above then I find no reason to use lambda at all.

You can use

bind( &Event::hasTransaction, _1 ) && bind( &Transaction::getId, bind( &Event::getTransaction, _1 ) ) == tid

but I'm not sure that you'd want to. It looks to complex.

Thanks Peter for the response.