The Reflection Registry

The registry maps an actor type identifier (ati) to a function that posts the corresponding constraint. The type of these post functions is defined in the registry as

class Registry {
public:
    typedef void (*poster) (Gecode::Space*,
                            Gecode::Reflection::VarMap&,
                            const Gecode::Reflection::ActorSpec&);
};

There are two kinds of post functions in the registry:

• One function per actor instance. These functions correspond directly to individual propagators and branchings. For instance, the registry contains a function for the ati Int::Distinct::Dom<Int::OffsetView>. Each propagator registers one post function per instance. The registry is populated with these post functions as soon as the library in which the propagator is defined is loaded.

• One function per constraint post function (the functions found in gecode/int.hh or gecode/set.hh, for example). The functions are useful for interfacing to Gecode, as they provide a higher-level interface to the propagators. For example, the registry contains a post function for the ati Gecode::rel. Depending on the arguments given in the ActorSpec, this function can post any of the rel constraints found in gecode/int.hh and gecode/set.hh. All high-level post functions are registered when the serialization library is loaded, which can be triggered by callling Gecode::Serialization::initRegistry.

Mapping arguments to ActorSpecs

The high-level post functions are generated automatically from the post functions in gecode/int.hh and gecode/set.hh. The argument types are mapped automatically to Gecode::Reflection::Arg terms.

C++ argument type	Reflection::Arg type	Comment
int	INT
unsigned int	INT
bool	INT
IntVar	VAR
BoolVar	VAR
SetVar	VAR
IntVarArgs	[VAR,...,VAR]
BoolVarArgs	[VAR,...,VAR]
SetVarArgs	[VAR,...,VAR]
IntArgs	[INT,...,INT]
IntSet	[INT,...,INT]	Two consecutive integers are interpreted as a range
IntSetArgs	[[INT,...,INT],...,[INT,...,INT]]	Same representation as for IntSet
Any enumeration	STRING	The string representation of the enum value, e.g. "IRT_EQ"