On Sun, Feb 9, 2020 at 9:33 AM Thomas Morley <thomasmorle...@gmail.com> wrote:
> Am So., 9. Feb. 2020 um 15:02 Uhr schrieb Freeman Gilmore > <freeman.gilm...@gmail.com>: > > > > > > > > This is taken from the "Scheme Book". > > > > Question why double parenthesis for let ((rand (random 100))) ? > > > > Thank you, ƒg > > Well, every expression needs to be wrapped into parenthesis. > > One pair for the let-expression: > (let ...) > > One pair for all local-bindings: > (let (all-local-bindings) ...) > I understand the above and below but not this let ((rand (random 100))) Put in your form: (let ((rand (random 100))) ...) Here is another example from the book, why double parenthesis ((assq 'col-darkblue colors)). Thank for all you work here, ƒg One pair for each single local binding, note every local binding is of > type key-value: > (let ( (key1 value1) (key2 value2) ) ...) > > Every value my be a procedure call, with the need for another pair of > parenthesis: > (let ( (key1 (proc1 args1)) (key2 (proc2 args2)) ) ...) > > Proper indentation increases readability: > (let ( > (key1 (proc1 args1)) > (key2 (proc2 args2)) > ) > ... > ) > > HTH, > Harm >
