[plt-scheme] any idea on this please

>
> PLT Schemes
> i used this utility functions i used it to manipulate the stream such as map
> and filter.
>
> > ( define (inc x) (+ 1 x))
> >(define int (make-stream 0 inc )
> >(define sqr x ))

Ask yourself, what is x in (define sqr x)? Where is x declared? Also
ask yourself, what is sqr? I suspect you want sqr to be a function
that squares its input, but that is not what you have written.

Marco