[Chicken-users] I'm confused (again)

[William Ramsay]

Hi again,

This may seem like a strange question, but I'm confused about the use of 
set!.    It may be a holdover from my pre-scheme days, but it seems I 
should be declaring a variable before using it with set!.   In other 
words, I would use:

      (let
         ((x  0))

before setting x based on some value not available when x is declared.

But it appears that set! itself declares the variable and the let is not 
needed.   Is this correct or is my code just working magically?
And if set! does declare a variable what is it's scope?    I've been 
writing scheme for a couple of years and just decided I have no idea 
what I'm doing.   (but, then again, that's what makes programming such fun)

Bill