Re: Simulating rational number addition/subtraction

[<dsmich@roadrunner.com>]

---- Lawrence Bottorff <borgauf@gmail.com> wrote: 
> With guile (and a few other Schemes/Lisps) you can directly add fractions
> or rational numbers:
> 
> (+ 1/2 1/12)
> => 7/12
> 
> It's like magic, no? Anyway, I'm trying -- for educational purposes -- to
> reproduce this functionality. But right out of the blocks I'm stuck trying
> to figure out how to handle incoming parameters. So far I've got
> 
> (define (myrat a b)
>    . . .)
> 
> (define (myrat a b c d)
>    . . .)
> 
> where numerator and denominator are given separately, as well as
> 
> (define (myrat . fracparams)
>    . . .)
> 
> which still has my basic problem, namely, can one parameter hold both parts
> of a rational number, then allow the numerator and denominator to be peeled
> off and worked on, i.e., something like
> 
> (let ((num1 numepeeler(a))
>        (denom1 denompeeler(a)
> 
> 
> LB

This https://mitpress.mit.edu/sicp/full-text/book/book-Z-H-14.html might be enlightening....

-Dale