Installing Cucumber on IronRuby (native json issue)

Question

I am trying to install Cucumber on IronRuby 1.1.3 using gem install cucumber but I keep getting the following error:

Building native extensions.  This could take a while...
ERROR:  Error installing cucumber:
        ERROR: Failed to build gem native extension.

"d:/Program Files (x86)/IronRuby 1.1/bin/ir.exe" extconf.rb
d:/Program Files (x86)/IronRuby 1.1/Lib/ruby/1.9.1/mkmf.rb:9:in `const_missing':
 uninitialized constant RbConfig::MAKEFILE_CONFIG (NameError)
        from d:/Program Files (x86)/IronRuby 1.1/Lib/ruby/1.9.1/mkmf.rb:9
        from d:/Program Files (x86)/IronRuby 1.1/Lib/ruby/1.9.1/rubygems/custom_
require.rb:29:in `require'
        from d:/Program Files (x86)/IronRuby 1.1/Lib/ruby/1.9.1/rubygems/custom_
require.rb:29:in `require'
        from extconf.rb:1

Answer 1

Here's the problem:

Failed to build gem native extension

Some gems when they get installed compile C extensions as part of the process; the above library is one of them. Other examples are Nokogiri and Gherkin. The resulting libraries are not .net-based and as such can't be used by IronRuby. IronRuby only deals in managed code so you can only use 'pure' ruby gems, or .net DLLs.