Hi everybody
I´m studying Martín Salias’ example “A poor man's database server”

http://www.utmag.com/July2002/Page22.asp

Where the component receives a string as a parameter and then runs it.
Trying to make it a bit more functional, I did as follows

DEFINE CLASS Executor AS Session OLEPUBLIC
 
*!* Original example
PROCEDURE SqlCommand( tcCommand as String ) as String
 
        local lcReturn
        lcReturn = ""
 
        Close Databases all

        &tcCommand
 
        If Empty( Alias() ) or Reccount() = 0
            * Nothing to do
 
        Else
            CursorToXML( Alias(), "lcReturn", 1, 1 + 8, 0, "1")
        endif
 
        Return lcReturn
ENDPROC
 
*!* My contribution
PROCEDURE ScriptCommand(  tcCommand as String, ;
                          tuParam1 as Variant, ;
                          tuParam2 as Variant, ;
                          tuParam3 as Variant, ;
                          tuParam4 as Variant  ;
                          ) as String           
 
        Return=EXECSCRIPT(  tcCommand, ;
                            tuParam1,  ;
                            tuParam2,  ;
                            tuParam3,  ;
                            tuParam4 )
ENDPROC
 
ENDDEFINE


The string passed as parameter (tcCommand) is generated in the client side with
 

TEXT TO lcText NOSHOW TEXTMERGE PRETEXT 7
.....
.....
.....
ENDTEXT


 
The idea is to have a kind of running a little process, 
and not only a single command, on the server´s machine.
In fact, it works.

I know that I must be care of using any visual object, and kept it stateless.
The first is quite simple, but I’m not so sure how to keep the component stateless.

If I declare some local variables, am I going against the stateless rule?
And what about error handling? Can I do it inside the process, 
or I have to catch it and inform the client, with a return string, 
that something wrong has happened?
In a word, am I against some rule of thumb? 
What other considerations do you believe must I take 
in mind when writing the process

TIA

Ricardo Aidelman
Software Developer
Praxis Computación
Buenos Aires, Argentina