VB.Net - Ruby interop

Ruby IronRuby
1

Hi,

A couple of technical questions regarding how to leverage Ruby from
VB.Net
and vice versa:

  1. Is the ScriptScope the only option for passing object refs into Ruby?
    I
    mean can they also be passed as parameters to the Ruby methods called by
    InvokeMember?

  2. Ruby has no need for passing parameters “ByRef” like you can in VB
    because Ruby’s return statement so naturally returns an arbitrary list
    of
    objects as an array, and Ruby supports multiple assignment on a single
    line.
    But I have legacy VB methods with ByRef parameters that really do change
    which objects the parameters reference in the caller. I would like to be
    able to call these VB methods from Ruby code, but since Ruby has no such
    thing as ByRef, I don’t know what kind of behavior I should expect. Can
    the
    Ruby variables passed as parameters get reassigned by VB code to point
    to VB
    objects without any additional shenanigans? If not, then is there an
    established workaround for ByRef parameters? Has this odd situation been
    addressed yet? (I don’t want to rewrite/retest legacy code that already
    works just fine).

Thanks,

Julian.

2 
  1.  Yes, you can pass parameters via InvokeMember.

  2.  You can call methods with ByRefs from Ruby. An example could be

Dictionary<int, int>.TryGetValue:

dict = System::Collections::Generic::Dictionary[Fixnum, Fixnum].new
=> System.Collections.Generic.Dictionary`2[System.Int32,System.Int32]
dict.add 1,2
=> nil
dict.try_get_value 1
=> [true, 2]

The second parameter to TryGetvalue is an ByRef. You can either
omit an argument for such parameter or pass an instance of
System.Runtime.CompilerServices.StrongBox. If you omit the argument
the result is returned in the return value (as shown above). If you pass
an instance of StrongBox the value is updated in situ.

Similarly for in-out ByRef parameters. You pass in the input value and
either get the output value in the resulting array or the StrongBox
value if you use a StrongBox instance.

Tomas

From: [email protected]
[mailto:[email protected]] On Behalf Of Julian Bishop
Sent: Sunday, June 06, 2010 10:33 PM
To: [email protected]
Subject: [Ironruby-core] VB.Net - Ruby interop

Hi,

A couple of technical questions regarding how to leverage Ruby from
VB.Net and vice versa:

  1. Is the ScriptScope the only option for passing object refs into Ruby?
    I mean can they also be passed as parameters to the Ruby methods called
    by InvokeMember?

  2. Ruby has no need for passing parameters “ByRef” like you can in VB
    because Ruby’s return statement so naturally returns an arbitrary list
    of objects as an array, and Ruby supports multiple assignment on a
    single line. But I have legacy VB methods with ByRef parameters that
    really do change which objects the parameters reference in the caller. I
    would like to be able to call these VB methods from Ruby code, but since
    Ruby has no such thing as ByRef, I don’t know what kind of behavior I
    should expect. Can the Ruby variables passed as parameters get
    reassigned by VB code to point to VB objects without any additional
    shenanigans? If not, then is there an established workaround for ByRef
    parameters? Has this odd situation been addressed yet? (I don’t want to
    rewrite/retest legacy code that already works just fine).

Thanks,

Julian.