a question from a newcomer to this language

[Steve Horsley]

Michael Chermside wrote:
> Shankar writes:
> 
>>Is there any way to convert a string into an instruction that will be
>>executed?
> 
> 
> Short answer:
>     Yes. The exec statement does what you want:
> 
> 
>>>>x = 3
>>>>y = 4
>>>>exec "z = x * y"
>>>>print z
> 
> 12
> 

Ooh! I didn't know that one. I have to admit that it gives me an 
uneasy feeling. How woud the author of "z = x * y" know that z 
was safe to assign to?

To Shankar:
An intermediate is eval:
     z = eval("x * y")
but even this is unsafe if you do not vet the input strings:
     String s = "system('format c: /y')"
     z = eval(s)

Steve