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/*****
* callable.h
* Tom Prince 2005/06/19
*
* Runtime representation of functions.
*****/
#ifndef CALLABLE_H
#define CALLABLE_H
#include "common.h"
#include "item.h"
#include "inst.h"
namespace vm {
class stack;
typedef void (*bltin)(stack *s);
struct callable : public gc
{
virtual void call(stack *) = 0;
virtual ~callable();
virtual bool compare(callable*) { return false; }
// For debugging:
virtual void print(ostream& out) = 0;
};
class nullfunc : public callable
{
private:
nullfunc() {}
static nullfunc func;
public:
virtual void call (stack*);
virtual bool compare(callable*);
static callable* instance() { return &func; }
void print(ostream& out);
};
// How a function reference to a non-builtin function is stored.
struct func : public callable {
lambda *body;
frame *closure;
func () : body(), closure() {}
virtual void call (stack*);
virtual bool compare(callable*);
void print(ostream& out);
};
class bfunc : public callable
{
public:
bfunc(bltin b) : func(b) {}
virtual void call (stack *s) { func(s); }
virtual bool compare(callable*);
void print(ostream& out);
private:
bltin func;
};
class thunk : public callable
{
public:
thunk(callable *f, item i) : func(f), arg(i) {}
virtual void call (stack*);
void print(ostream& out);
private:
callable *func;
item arg;
};
inline ostream& operator<< (ostream& out, callable &c) {
c.print(out);
return out;
}
} // namespace vm
GC_DECLARE_PTRFREE(vm::nullfunc);
// I believe this is safe, as pointers to C++ functions do not point to
// the heap.
GC_DECLARE_PTRFREE(vm::bfunc);
#endif // CALLABLE_H
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