Returning value from a function

Dear all,

I have written the function below, which only checks if a given file exists or not, and I would like it to return the value stored into retValue.

As far as I know, SKILL returns the value of the last line of code (is this correct ?).

If I write the code as below, I will get the error:

*** Error in routine eval:
Message: *Error* eval: unbound variable - retValue

However, if I replace retValue by retValue=isFileName(myFilePath) it will work,but, from my point of view, this is an example of ugly code, since I am evaluating the function twice. Is there another way to do this ?

If the variable retValue retains always the correct value, why does it get unbound after the if instruction end ?

Thanks in advance,

José

procedure(fileExists(myFilePath)
                   let((retValue)
                   retValue=isFileName(myFilePath) ; Test if the file exists

                   ; Check if config file exists
                   if((retValue==t) then
                          printf("fileExists: File Exists !")
                   else
                         printf("fileExists: File does not Exist !")
                   ); end if
                   ); End letmypath
                   retValue                              ; Return Value
); End procedure