From: Phlip <phlipcpp@...>
Date: 2005-10-01T14:51:45+09:00
Subject: Re: Interest in Boost::Ruby

Phlip wrote:

> The best thing I have done with the VALUE object is very simple: I wrap it 
> in a C++ class that exposes the functions taking a VALUE as simple 
> methods, overloaded operators, etc. Very simple, and I don't pretend it's 
> a C++ class. It makes coding very fast.

Here's that wrapper for Ruby's VALUE object:

        class
    rbValue
    {
    public:

    rbValue(VALUE nuV = Qnil):
            v(nuV)
        {}

    rbValue(char const * gv):
            v(Qnil)
        {
        assert(gv);
        assert('$' == gv[0]);  //  documentation sez this is optional. We
don't agree
        v = rb_gv_get(gv);
        }

        operator VALUE() const {  return v;  }
        rbValue &operator =(VALUE nuV) {  v = nuV;  return *this;  }

        rbValue
    fetch(char const * tag)
        {
        return funcall("fetch", 2, rb_str_new2(tag), Qnil);
        }

        rbValue
    fetch(int idx)
        {
        return funcall("fetch", 2, INT2FIX(idx), Qnil);
        }

        rbValue
    fetch(size_t idx)
        {
        return funcall("fetch", 2, INT2FIX(idx), Qnil);
        }

        VALUE *
    getPtr()
        {
        assert(T_ARRAY == TYPE(v));
        return RARRAY(v)->ptr;
        }

        long
    getLen()
        {
        assert(T_ARRAY == TYPE(v));
        return RARRAY(v)->len;
        }

        rbValue
    getAt(long idx)
        {
        assert(idx < getLen());
        return RARRAY(v)->ptr[idx];
        }

        rbValue
    operator[](long idx)
        {
        return getAt(idx);
        }

        bool isNil()  {  return Qnil == v;  }

        double to_f()
            {
            assert(T_FLOAT == TYPE(v) || T_FIXNUM == TYPE(v));
            return NUM2DBL(v);
            }

        char const * to_s()
            {
            assert(T_STRING == TYPE(v));
            return STR2CSTR(v);
            }

        rbValue
    funcall (
            char const * method,
            int   argc = 0,
            VALUE arg1 = Qnil,
            VALUE arg2 = Qnil,
            VALUE arg3 = Qnil
            )
        {
        return rb_funcall(v, rb_intern(method), argc, arg1, arg2, arg3);
        }

        rbValue
    iv_get(char const * member)
        {
        VALUE iv = rb_iv_get(v, member);
        return iv;
        }

        void
    iv_set(char const * member, VALUE datum)
        {
        rb_iv_set(v, member, datum);
        }

        void
    iv_set(char const * member, int datum)
        {
        iv_set(member, INT2FIX(datum));
        }

    private:
        VALUE v;

    };  //  a smart wrapper for the Ruby VALUE type

Call its members like this:

        void
    push(rbValue xyzIn)
    {
        rbValue str = xyzIn.funcall("inspect");
        OutputDebugStringA(str.to_s());
        OutputDebugStringA("\n");
    }

Google for that code to find its project.

Converting it into a snarl of Boostoidal templates is left as an exercise 
for the obsessed.

-- 
  Phlip
 http://www.greencheese.org/ZeekLand  <-- NOT a blog!!!