/**
-Base class for data loaders. To enable objects of a certain class to be loaded
-from datafiles, create a public Loader class in it, derived from this class.
-Typically the Loader class contains a reference to the object being loaded. If
-you want to load data members of the object directly, the Loader class must
-have a member function get_object() returning that reference.
+Base class for data loaders. To give loading capabilities to a class, create a
+public Loader class in it, derived from this class. Typically a loader object
+contains a reference to the loaded object. To make use of loading directly
+into data members, the Loader class must have a get_object() member function,
+returning that reference.
*/
class Loader
{
protected:
Loader(): cur_st(0) { }
+ /**
+ Adds a keyword that is loaded with a zero-argument function.
+ */
template<typename L>
void add(const std::string &k, void (L::*func)())
{ actions.insert(typename ActionMap::value_type(k, new LoaderFunc0<L>(func))); }
void add(const std::string &k, void (L::*func)(A0, A1, A2, A3))
{ actions.insert(typename ActionMap::value_type(k, new LoaderFunc4<L, A0, A1, A2, A3>(func))); }
+ /**
+ Adds a keyword that is loaded into a variable of the loaded object.
+ */
template<typename L, typename T0>
void add(const std::string &k, T0 L::*p0)
{ actions.insert(typename ActionMap::value_type(k, new LoadValue1<L, T0>(p0))); }
void add(const std::string &k, T0 L::*p0, T1 L::*p1)
{ actions.insert(typename ActionMap::value_type(k, new LoadValue2<L, T0, T1>(p0, p1))); }
+ /**
+ Adds a keyword that is recognized but ignored.
+ */
void add(const std::string &k)
{ actions.insert(ActionMap::value_type(k, 0)); }
/**
- Loads a sub-object from the statement being currently processed. The Loader
- class of the sub-object is automatically used.
+ Loads a sub-object from the statement being processed. The Loader class of
+ the sub-object is automatically used.
*/
template<typename S>
void load_sub(S &s)
loader.load(*cur_st);
}
+ template<typename S, typename T>
+ void load_sub(S &s, T &p)
+ { load_sub<typename S::Loader, S, T>(s, p); }
+
/**
Loads a sub-object with a custom Loader class that takes one argument in
addition to to object to be loaded.
L loader(s, p);
loader.load(*cur_st);
}
+
+ /**
+ Returns the source of the statement being processed. This can be used to
+ implement relative paths in include-like statements. Note that the source
+ may not necessarily be a file.
+ */
+ const std::string &get_source() const
+ {
+ if(!cur_st)
+ throw InvalidState("get_source called without current statement");
+ return cur_st->source;
+ }
private:
typedef std::map<std::string, LoaderAction *> ActionMap;