VBScript code cannot access nested types

Hello,

I have just discovered ClearScript, and think it's great. But I am having trouble exposing enums and consts to my scripts.

for example: I created a basic class with an enum defined.

Public Class test
    Public Enum Numbers
        one
        two
        three
    End Enum
End Class

I then add this to my engine

scriptEngine.AddHostType("test", GetType(test))

but I am unable to reference numbers in my scripts e.g.

test.Numbers.one

I would expect this to be an integer with a value of one? But instead get an error

Public member 'Numbers' on type 'HostType' not found.

Does ClearScript support enums? Any help appreciated.

Thanks

[ClearScriptLib]

Hi @NickJWilliams,

ClearScript does support enums, but you found a bug. This bug affects only nested types, and only when accessed from VBScript. You can work around it by exposing your nested type directly:

scriptEngine.AddHostType("test", GetType(test))
scriptEngine.AddHostType("Numbers", GetType(test.Numbers))

Unfortunately this means that your script code will have to use Numbers.one instead of test.Numbers.one for now. We'll post a fix shortly. Thanks for reporting this bug!

One more thing. ClearScript does not expose enums as integers. Its aim has always been to give script code full access to all the capabilities of exposed .NET objects, and since .NET enums are not integers, it wouldn't be correct to expose them as such. One consequence of this is that you must use is to compare them instead of the equality operator.

Good luck!

Glad I could help :-)

Just wondering how I can use the enum values in a bit wise scenario? e.g.

somefunc.test = Numbers.one + Numbers.two

Thanks
Nick

[ClearScriptLib]

@NickJWilliams Unfortunately ClearScript can neither override VBScript's operators nor expose .NET's. It provides the generic HostFunctions.flags for combining bitwise enum members, but if that's not sufficient, you'll have to expose a helper class or some functions that perform these operations in managed code.

Thanks, lastly should I be able to access Const's in my host objects/types?

[ClearScriptLib]

@NickJWilliams If the constant is a public member of an exposed class, structure, or module, it should be accessible from script code.

Hi thanks for fixing my issue, how do I go about updating my project. I am currently referencing ClearScript via NuGet.

I am also having trouble creating new instances of objects from defined types.

e.g.

Dim obj
set obj = new test

I am getting

Class not defined: 'test'

Thanks
Nick

Just to add to the above, I thought I would try using Microsoft.ClearScript.Windows.JScriptEngine.

This appears to work as expected. But we need to use VBScript as other applications we are working with use VBScript and ideally we want to keep everything consistent.

Thanks
Nick

[ClearScriptLib]

Hi Nick,

We don't provide ClearScript binaries. You can try contacting the NuGet project owners or building ClearScript yourself (instructions here).

Unfortunately, unlike JScript, VBScript doesn't allow the host to override the new keyword, but ClearScript provides a function for instantiating host types:

engine.Script.host = new HostFunctions();
engine.AddHostType(typeof(test));
engine.Execute(@"
    set obj = host.newObj(test)
");

If you need to interface with legacy code that uses new, you can create a VBScript wrapper class for your host class.

Good luck!