I'm writing an object to act as a scripting host and trying to test it
out. Currently I don't have a context (item names) and am running the
scripts in the scripting engine's global context.

 I think I'm successfully hosting and what I'd like to do is initially
use scripts as simple math functions, that do some calculations and
return a value.

Everything looks good until I actually run a script (ParseScriptText).

It seems no matter what kind of script I pass to the engine I get an
error (OnScriptError) that says "Invalid Character".

 My scripts are simple...for example I've tried passing...as a test.

Function Celsius(fDegrees)    
        Celsius = (fDegrees - 32) * 5 / 9
End Function

x = Celsius(31)

I've also tried just passing

        Celsius = (fDegrees - 32) * 5 / 9

 What I don't fully understand is my results. How does the script "return
results" from the call to ParseScriptText.

my call looks like

        HRESULT hr = m_Parser->ParseScriptText(theScript, NULL, NULL,
                NULL, 0, 0, 0L, &pvarResult, NULL);

So If I want to write a simple math function, pass it in theScript
variable and get the results back, what does the script look like?

 All I get are errors from the scripting engine.

 I am telling it to use the VBScript engine when I call CoCreateInstance.

 My only other clue is that I don't fully understand dwFlags and the
difference.

dwFlags
        [in] Flags associated with the scriptlet. Can be a combination of
these values:

SCRIPTTEXT_ISEXPRESSION  If the distinction between a computational
expression and a statement is important but syntactically ambiguous in
the script language, this flag specifies that the scriptlet is to be
interpreted as an expression, rather than as a statement or list of
statements. By default, statements are assumed unless the correct choice
can be determined from the syntax of the scriptlet text.  

SCRIPTTEXT_ISPERSISTENT  Indicates that the code added during this call
should be saved if the scripting engine is saved (for example, through a
call to IPersist*::Save), or if the scripting engine is reset by way of a
transition back to the initialized state.  

SCRIPTTEXT_ISVISIBLE  Indicates that the script text should be visible
(and, therefore, callable by name) as a global method in the name space
of the script.  

 To make this long story short, I think I'm correctly hosting the
scripting engine (I am getting script errors) but I don't know what
"form" a script takes when there is no context. I just want it to return
values right now.

 thanks
mike

Re: "Illegal character error"

You are passing a _Unicode_ string for the source, right?  ParseScriptText
takes an OLECHAR* for the source code, not a char*.

Re: script engine flags:

You list three of the flags along with a pretty concise description of their
meanings.   What exactly is your question?

Re: how does the script "return results"?

If you are asking the script engine to evaluate an expression then it will
fill in the result in pvarRes.  I'm a little confused about what exactly you
are trying to make the script engine do here.  Can you explain a little
better?

Also, something is wrong with your code -- I note in your code that you say
"&pvarRes" -- if your variable pvarRes is a VARIANT * then you are passing
this wrong -- you are passing a VARIANT * * to a function that expects a
VARIANT *.  On the other hand, if pvarRes is a VARIANT, then you have named
a VARIANT using the naming convention for a VARIANT*.

Let me know if you have any other questions.

Eric

If it makes you feel any better, I consider myself reasonably
sharp and I have a hell of a time with the scripting API docs. I
think "you had to be there" during the evolution of the API in
the Denali/pre-IE3 days in order to grok the true meaning of
what's there, and divine what's not there :-)

  -- Bob

 I'm currently hosting the scripting engine within a COM object and for now am reading
the scripts from disk using ifstream into a char buffer (char str[8192]). Being new
to COM I don't know the best way to get from my char buffer to OLECHAR*.

 I will eventually be pulling the scripts out of the database from within the COM object.

 I read;
or NULL if the caller expects no result (that is, the
   SCRIPTTEXT_ISEXPRESSION value is set).

 and what is printed at the end is.
   SCRIPTTEXT_ISEXPRESSION value is not set).

 so now I understand.

 In the end I think the first issue is still what's holding me up. I don't understand
how to read a script from disk, from withing a COM object (no mfc) and get the script
into an OLECHAR*

 thanks
mike

Eric

  -- Bob

Regards,
-cap.

Dude, I _was_ there, and I am still confused.  :-)  No doubt -- Active
Scripting is a complicated interface.

Eric

As far as I recall, that someone promised to do this not after but for the
PDC ;-)
There is supposed to be some interesting material on the PDC DVD, but those
of us that didn't attend are sort of out of luck.
Please put this stuff on MSDN or your web site!

Cyril

        VARIANT* pVarJan;

I then allocate the VARIANT, and since I don't know how big I might need it
I allocate some memory and cast it as the VARIANT like:

         if (pVarJan == 0)
          pVarJan = (VARIANT*)CoTaskMemAlloc(4096);

         if (pVarJan == 0) // alloc failed
          return E_OUTOFMEMORY;

Then issue the call to the VB Script Engine (dwFlags = 0).

 HRESULT hr = STDCOMCALL(m_pActiveScriptParse, ParseScriptText(
  pstrCode,
  pstrItemName,
  punkContext,
  pstrEndDelimiter,
  dwSourceContextCookie,
  ulStartingLineNumber,
  dwFlags,
  pVarJan,
  pexcepinfo));

I know the script executes (because I get an error when I purposely put in a
syntax error), but I always get back VT_Empty in the VARIANT.  My script
looks like:

    Function Eval()
        Eval = "Hello from Script"
    End Function

    Eval

So how do I get the script engine to give me back the "Hello from Script"
string?  Even if I initialize the pVarJan as a string, it still return
empty.  What should be different?

Jan Wiewiora
Unisys Corporation