I have recently seen many questions about the lack of an equivalent to
the JScript eval() function in C# and VB .Net. This is a good
opportunity to demonstrate the cross-langauge capabilities of .Net

1) Create a file named CustomEval.js (File | New | File | Script) as
follows:

// JScript source code
class CustomEval
{
    static function eval(strExp)
    {
         return eval(strExp);
    }

jsc /t:library CustomEval.js

which should produce CustomEval.dll

3) Reference this assembly from your VB .Net or C# project as well as
the Microsoft.JScript assembly.

4) Use the eval method of CustomEval as follows (since the method is
static, you don't need to instantiate CustomEval.

    result = CustomEval.eval("2+3")

Of course, I'd prefer having this capability implemented in the FCL. Or
did I miss it?

--
Patrick Philippot
MainSoft Consulting Services
www.mainsoft.xx
(replace .xx with .fr when replying by e-mail)

Could you please disassemble using ildasm.exe your resulting EXE and post
here the generated IL source code ?

That may give us the understanding about how it works from IL level.

many thanks,

Antonio

    It should be pointed out that this will only evaluate JavaScript code,
it will not evaluate C# and VB.NET code.

    Also, I don't know that this capability ^should^ be in the FCL (or CLR).
I mean, it is a compiled language, and if you look at a basic JS assembly,
there is a lot of work going on in there to allow evaluated expressions.
Personally, I am of the belief that whatever needs to be done can be done
with things such as abstract classes, interfaces, and good design.

--
               - Nicholas Paldino [.NET/C# MVP]

This is a lot of stuff to post. Since the project can be re-constructed
within two minutes, this can be avoided. You already have the source
code for the DLL (there's nothing more to add). Here is the code that
you can quickly add to a sample VB .Net program:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
    MsgBox(CustomEval.eval("2+2"))
End Sub

--
Patrick Philippot
MainSoft Consulting Services
www.mainsoft.xx
(replace .xx with .fr when replying by e-mail)

--
Patrick Philippot
MainSoft Consulting Services
www.mainsoft.xx
(replace .xx with .fr when replying by e-mail)