CShell: A simple, yet powerful, C# scripting IDE (opens in new tab)

The title would have been better if it said C# REPL. Then you wouldn't have experienced that confusion.

To be fair, the SharpDevelop people did just that and it's actually quite good. Of course it doesn't measure up to VS.Net but if VS.Net didn't exist it would be really impressive.

It probably should have been named CSShell :-)

I must be old, too.

And considered it harmful.

The sweet spot between a more full featured IDE like VS, LINQPad, or SharpDevelop and a REPL environment has not been explored very much so far. Even ScriptCS is more of one-off execution kind of setup, although they do have a REPL.

Filling this gap is what I tried to achieve with CShell. When I started, the Mono REPL was quite a bit ahead of Roslyn still, but now Roslyn overtook it. I'm planning to switch to Roslyn for the execution engine and use NRefactory for the code completion still (especially now that Roslyn is open source).

Where I want CShell to go, is it being a light-weight IDE with a focus on iterative execution. I use LINQPad evey day for DB stuff for example, but when I want to write progressing code, usually exploring some kind of data space - where I test each line, plot some charts, look at the data the variables contain - then there's no real competitor so far for C#. Either you have Matlab, R one one side, or linear code execution environments on the other.

Maybe it really means "C Sharp Hell".

These tools straddle some Venn circles, so the developer pitch can be confusing.

For example, I make use of both ipython and bpython, both of which I refer to as either shells or REPLs; though neither program is a proper shell (in the /bin/chsh sense), and though people also call them “interpreters” (technically, the python interpreter still interprets), “environments” (vague) or even “IDEs” (wat?) – the concept behind the tools is popular and well-understood.

Personally I think it’s particularly funny to call these Enhanced REPL Shell Interpreter Environments (or what have you) “IDEs” and lump them in with Eclipse or Visual Studio or those other behemoth coding tools; I like bpython and ipython for the myriad ways they are un-Eclipse-y, and if I did C# I would presumably get into CSharp for the same reasons. All of which, like many bicycle-shed innovations, are mere matters of taste.

There are a few hedge funds that are quite happy to contribute open-source to the world.

Blue Mountain Capital for example;

https://github.com/BlueMountainCapital

One of their projects is Deedle; an F#/C#-equivalent of the Python 'Pandas' data frame package. Which would in fact make a nice complement to CShell I imagine.

Jane Street would be another choice: http://janestreet.github.io/

Their work on OCaml is currently trending on HN.

There are others I am sure, don't have any links handy.

Who'd a thunk it, hedge funds occasionally produce some social good ;-)

Although it could be improved with intellisense.

    Action<object> print = Console.WriteLine;

I mean, it's not perfect but you can also create a .Dump() extension method for all objects like Linqpad does. It comes really handy.

Also, I like Scala REPL's automatic labels for the results.

    scala > 7 * 7
    res0:Int = 49
    
    scala > res0 - 9
    res1:Int = 40

Saves a lot of typing.

Yep, I see the tutorial is not clear, will change it.

Anyhow what you need to do is simply select line 35-45 with your cursor, then press Alt+Enter.

And then, after that, execute MyMath.Fibonacci(12);

Same here. No idea. If there were any docs (other than the "tutorial" itself) I'd try to look it up :))

ScriptCS does have REPL. Maybe it didn't at the time of that article. http://scriptcs.net/

Looks like uppercased CS is a play on a file extension and a shortcut sometimes used for C#. Personally, I read it as CS-hell.

Agreed I would have gone with SharpShell

After fiddling around for a short while I got an index out of range exception and it crashed. It seems like a good idea, but the execution is not that powerful yet. Not stable, so I'll pass for the time being.

Error 2014-05-09 15:42:45.8796 AppBootstrapper Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index at System.Collections.ArrayList.get_Item(Int32 index) at CShell.Modules.Repl.Controls.CSRepl.ShowPreviousCommand() in c:\Users\luke\Dev\GitHub\CShell\Src\CShell\Modules\Repl\Controls\CSRepl.xaml.cs:line 241 at CShell.Modules.Repl.Controls.CSRepl.TextAreaOnPreviewKeyDown(Object sender, KeyEventArgs keyEventArgs) in c:\Users\luke\Dev\GitHub\CShell\Src\CShell\Modules\Repl\Controls\CSRepl.xaml.cs:line 377 at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target) at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised) at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args) at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args) at System.Windows.Input.InputManager.ProcessStagingArea() at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input) at System.Windows.Interop.HwndKeyboardInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawKeyboardActions actions, Int32 scanCode, Boolean isExtendedKey, Boolean isSystemKey, Int32 virtualKey) at System.Windows.Interop.HwndKeyboardInputProvider.ProcessKeyAction(MSG& msg, Boolean& handled) at System.Windows.Interop.HwndSource.CriticalTranslateAccelerator(MSG& msg, ModifierKeys modifiers) at System.Windows.Interop.HwndSource.OnPreprocessMessage(Object param) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs) at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)

the thing is you can't really mix class definitions and straight scripting lines in one execution. So what you need to do, is execute the class first and then execute the other part.

For the MyMath example you'd just select the lines for that class, press Alt+Enter. And then run: > MyMath.Fibonacci(12);

With your example, you would enter following in the REPL: > public static class Foo { public static string B; } > Foo.B = "hi" > Foo.B hi >

well it's as useful as any other REPL ;)

Though for things like Python the REPL serves for me mainly as a 'figure out what type this thing is here' and 'does this work'... things that static typing solve pretty well.

Wouldn't that more or less be the Immediate Window that Visual Studio already has? Other than the multiple lines you mention. :)

I took a look at this to see if it can replace LinqPad, which is similar. LinqPad allows for more than C# alone (VB.net, SQL, C# and F#) but it has no code completion (unless you buy it) which CShell does have.

This seems like a useful tool!

Looks to me like the description of `System.IO.IOException`, which is the possible exception.

I would guess the tool tips are slightly broken in that it doesn't list the exception class name or put it on a new line.

There you go, simple thing to contribute a fix for!

That's what an IOException means. I suspect the hint text stems from a very minimal XML parse of the documentation.

If your language has you type more because it has a static ype system then it's just poor at inferring types and/or it's syntax has you write out things that it could infer anyway. You may have to write types in C# from time to time, but often you don't have to:

// This an array of integers.

var x = new[]{1, 2, 3};

// This is a list of integers.

var y = x.ToList();

// This is an anonymous type.

var pet = new { Age = 10, Name = "Fluffy" };

Zero type names there. Not all types can be inferred by literals though, most annoyingly dictionaries:

var myDict = new Dictionary<string, string>{ { "test", "test" }, { "test2", "test2" } };

although I'm sure that could also have been created without typing out the name if you really wanted.

Scala, OCaml/F#, and Haskell beg to differ.

It depends. I mostly use PowerShell when trying out things with .NET, sometimes before or while I'm implementing them in C# as well. But depending on what I want to do, LINQ is a very nice thing to have, even though PowerShell has similar capabilities with the pipeline. (Can't really point to anything specific right now – there are instances when I prefer PowerShell and those where I prefer LINQ.)

One major reason might be speed, though. PowerShell can be very slow on large-ish data sets. And var in C# saves you from a lot of type-typing.

>static typed languages are inadequate when using them in shell. You really don't want to type all that

I'm not sure I understand, what is wrong with dynamic in C#? You've got the anonymous types for quick data structures.

Did you even look at the link? It is about a REPL for C#.