[racket] htdp/2e: on the choice of some names

On Jan 15, 2015, at 10:56 AM, Daniel Bastos <dbastos at toledo.com> wrote:

> (*) Curiosity
> 
> 1. I wonder what BS stands for in this definition.
> 
> ; A BS is one of:
> ; — "hello",
> ; — "world", or
> ; — pi.
> 
> Is it just a synonym for nonsense?


Nothing in particular but I should change it because of its bad connotation. 
The point of the section is to say "data definitions introduce names. What 
do these names stand for?" [Sets/collections/classes of data]


> 2. I figure "MT" means "empty" because of how it sounds. Is that it?
> 
> ; an empty scene:
> (define MT (empty-scene 100 100))


MT is just a reasonable mnemonic here for 'empty scene'. 


> 3. I figure "posn" comes from the word "position". Is that it?


Yeap. (It was named a long time ago and there is nothing we can do about it.) 





> 
> Thank you.
> ____________________
>  Racket Users list:
>  http://lists.racket-lang.org/users