I'm trying to integrate my C++ program with Ruby using SWIG

Ruby
1

All I can find is some outdated docs with command line instructions
that don’t work. Can someone please point in differenct direction?

Thanks.

2

bryanedds wrote:

All I can find is some outdated docs with command line instructions
that don’t work. Can someone please point in differenct direction?

Raw Ruby is easier than SWIG - even when you need all of SWIG’s
features.

Here’s some of my integrational code. First, we have a super-thin
wrapper
for the Ruby VALUE type, the root type of all Ruby expressions:

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;  }  //  TODO  deprecate me
rbValue &operator =(VALUE nuV) {  v = nuV;  return *this;  }  //

TODO
deprecate me

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

You simply use it the way you think to use a Ruby value, and (like Ruby)
it
will defend the actual wrapped type at runtime. Unlike Ruby, it will
defend
by breaking an assertion. You might like to throw, or you might write
strongly-typed code and never break.

Read the Ruby documentation for extending to C. Extend to C-style C++,
and
call a Ruby script. If it creates a global variable called $egg, you can
retrieve this variable and use it in C++ like this:

egg = rbValue("$egg");

if (egg.isNil())
    return false;

out = rbValue("$out");

assert(!out.isNil());
ax = egg.iv_get("@rootAxioms").funcall(“first”); assert(!ax
.isNil());

And so on. The result looks like Ruby, but with extra iv_get() and
funcall()
between everything. From here, writing new C++ to drive Ruby is very
easy,
and converting Ruby to Ruby-style C++ is also super easy.

3

bryanedds wrote:

All I can find is some outdated docs with command line instructions
that don’t work. Can someone please point in differenct direction?

Thanks.
Do you have the most recent version of SWIG? I think the current
development version is 1.3.29. There are detailed instructions in the
source and on line for both the Windows interface and the Ruby
interface.

Older versions of SWIG don’t support C++ very well.