[Mono-list] CSharp interpreter feedback, and a gift

Doug Blank doug.blank at gmail.com
Fri Jan 28 08:51:43 EST 2011

On Fri, Jan 28, 2011 at 7:03 AM, Doug Blank <doug.blank at gmail.com> wrote:
> Thanks for the feedback. Some comments below. Note that I'm doing this
> from IronPython, so this is a slightly different context that the
> typical. The code for this 76-line wrapper is here:
> http://svn.cs.brynmawr.edu/viewvc/Pyjama/trunk/languages/CSharpLanguage.py?view=markup
> On Fri, Jan 28, 2011 at 1:40 AM, Miguel de Icaza <miguel at novell.com> wrote:
>>> 1) a single evaluate function which could handle expressions and statements.
>> This is already the case.
> I should be more precise: If you use Evaluate(), and don't get back a
> result, you have to catch the exception. If you use Run(), you can't
> get back anything. It would be nice if there was one function, and if
> there were an exception, it was from the underlying code, not that the
> Evaluate didn't return something.
>>> 2) able to evaluate multiple statements, without evaluating them one by one.
>> That is also the case.
> Ok, then I must be missing something. It looks like in the csharp.exe
> code that it is handing Evaluate one expression at a time. This does
> not work for me from IronPython.
> evaluator.Evaluate("int a;\n int b;")

My bad; that works. This doesn't: evaluator.Evaluate("using System;\n
int b;") nor evaluator.Run("using System;\n int b;") I'm assuming
because the "using System;" is not an expression?

Is there a method to make this work, rather than breaking it up into
two statements, something that I am missing?


>>> 3) handle errors through a return or raised exception, rather than
>>> through a side-effect print to Console.Out, or Console.Error
>> I have to look into this one in particular, are these compilation
>> errors, or the execution errors?
> Both are currently sent to Out or Error. I would like it better if
> they were thrown or returned.
>> You can control where the error messages go by assigning a TextWriter
>> object to the InteractiveBase class's Output and Error properties.
> Yes, but this can get complicated in IronPython, and for some reason
> this isn't currently working in Pyjama. If I could handle these
> messages myself, that would give me more control. It may be that I
> need to load things in a different order.
>>> I haven't looked into how the Csharp interpreter actually works, but
>>> it would be excellent if the user could define functions and classes,
>>> in the environment. Would that be possible?
>> It is not currently possible.   This requires some work on the
>> compiler to enable the feature.
> Pointers much appreciated!
> -Doug
>> Miguel.

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