class ExecJS::Runtime::Context

context.call("CoffeeScript.compile", "1 + 1")
context.call("function(a, b) { return a + b }", 1, 1) # => 2

The function will be evaluated with the global object as +this+.
+function+), and calls the function with the given arguments.
Evaluates +source+ as an expression (which should be of type

def call(source, *args)
  raise NotImplementedError
end