[Ironruby-core] Throwing Exceptions defined in Ruby from C#

Tomas Matousek Tomas.Matousek at microsoft.com
Fri Feb 13 13:34:31 EST 2009


You can use KernelOps.RaiseException:

public static void RaiseException(RespondToStorage/*!*/ respondToStorage, UnaryOpStorage/*!*/ storage0, BinaryOpStorage/*!*/ storage1, 
            RubyContext/*!*/ context, object self, object/*!*/ obj, [Optional]object arg, [Optional]RubyArray backtrace) {


You'll need to allocate local site storages to do so. The storages are allocated automatically for methods called from Ruby.
I assume you have some entry point to the C# part of the parser that you call from Ruby. That method should declare the storages and pass them thru to the place where you want to raise the exception.

It might be easier to change your C# implementation not to throw Ruby exceptions. You can throw a C# exception, catch it in Ruby and rethrow the corresponding Ruby exception. This way your C# code would be usable from C# apps as well, not only from Ruby code.

Tomas

-----Original Message-----
From: ironruby-core-bounces at rubyforge.org [mailto:ironruby-core-bounces at rubyforge.org] On Behalf Of Shri Borde
Sent: Friday, February 13, 2009 9:56 AM
To: ironruby-core at rubyforge.org
Subject: Re: [Ironruby-core] Throwing Exceptions defined in Ruby from C#

I don't think your code below will work as multiple Ruby types share the same underlying CLR type. If you want to do things in a strongly-bound way, you would need to use the RubyUtils and other runtime helpers to find the method "new", invoke it, etc. instead of using System.Reflection.

An alternative is to just do an eval. Something like:
   RubyUtils.Evaluate("raise JSONError", scope)

-----Original Message-----
From: ironruby-core-bounces at rubyforge.org [mailto:ironruby-core-bounces at rubyforge.org] On Behalf Of Daniele Alessandri
Sent: Thursday, February 12, 2009 11:59 PM
To: ironruby-core at rubyforge.org
Subject: Re: [Ironruby-core] Throwing Exceptions defined in Ruby from C#

Yes it is meant to be used primarily from ruby as it is a port of a
rather widespread library, and a dependency for a bunch of other
libraries (see http://json.rubyforge.org/).

The reason is simply to maintain compatibility with the ruby bits of
the original json library in which exceptions are defined inside a
common.rb file: this is due to the fact that this lib comes in two
flavours, json-pure (everything is ruby) and json-ext (the generator
and parser are implemented in C, the rest is ruby), so there are parts
of the code that are shared between the two and eventually invoked
from within the native code.

Anyway I'm curious, I haven't found other means to do that in a much
cleaner way :)


On Fri, Feb 13, 2009 at 04:33, Tomas Matousek
<Tomas.Matousek at microsoft.com> wrote:
> Why don't you declare the exceptions in C#? I assume the library is primarily to be used from Ruby code, not from C#, right?
>
> Tomas
>
> -----Original Message-----
> From: ironruby-core-bounces at rubyforge.org [mailto:ironruby-core-bounces at rubyforge.org] On Behalf Of Daniele Alessandri
> Sent: Thursday, February 12, 2009 6:31 AM
> To: ironruby-core at rubyforge.org
> Subject: [Ironruby-core] Throwing Exceptions defined in Ruby from C#
>
> Hi,
>
> I'm refactoring and polishing the source code of my port of json/ext
> to IronRuby (it's feature complete by now) but I'm wondering if there
> is a better way to throw an Exception defined in ruby from C# compared
> to the only solution I've came up with so far. Here is the code I'm
> using right now, stripped down of checks and condensed in one method
> just for the sake of brevity:
>
> ----- ruby -----
>
> module JSON
>    class JSONError < StandardError; end
>    class ParserError < JSONError; end
> end
>
> ----- C# -----
>
> public static void RaiseParserError(RubyScope scope, String msg) {
>    RubyModule eParserError;
>
>    scope.RubyContext.TryGetModule(scope.GlobalScope,
>        "JSON::ParserError",
>        out eParserError
>    );
>
>    RubyClass exceptionClass = eParserError as RubyClass;
>    Type underlyingType = exceptionClass.GetUnderlyingSystemType();
>
>    BindingFlags bindingFlags = BindingFlags.NonPublic |
>                                BindingFlags.Public |
>                                BindingFlags.Instance;
>
>    ConstructorInfo constructor = underlyingType.GetConstructor(
>        bindingFlags,
>        null,
>        new[] { typeof(RubyClass), typeof(String) },
>        null
>    );
>
>    Exception exceptionInstance = constructor.Invoke(
>        new object[] { exceptionClass, msg }
>    ) as Exception;
>
>    throw exceptionInstance;
> }
>
>
> --
> Daniele Alessandri
> http://www.clorophilla.net/blog/
> _______________________________________________
> Ironruby-core mailing list
> Ironruby-core at rubyforge.org
> http://rubyforge.org/mailman/listinfo/ironruby-core
>
> _______________________________________________
> Ironruby-core mailing list
> Ironruby-core at rubyforge.org
> http://rubyforge.org/mailman/listinfo/ironruby-core
>



-- 
Daniele Alessandri
http://www.clorophilla.net/blog/
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