Re: [Chicken-users] lambda's in a hash table

[Thomas Chust]

On 2014-04-05 01:54, Claude Marinier wrote:
> [...]
> I would like to have the compiler do some of this for me. I probably
> cannot write a literal hash table but I expected to be able to write a
> literal association list. I have tried this but it does not work.
> [...]
> (define a-list
>  `(
>     (dot  . ,(lambda () (display "dot\n")))
>     (dash . ,(lambda () (display "dash\n")))
>   ))
> [...]

Hello,

what you have written down here is not a literal list, but a
quasiquotation, which is just syntactic sugar that expands to an
expression dynamically constructing a list.

Nevertheless, the program you posted works just fine as it is. The only
problem I can see with it is that nothing visible happens because

> [...]
> (let ((func-dot (hash-table-ref dict 'dot))
>       (func-dash (hash-table-ref dict 'dash)))
>   func-dot
>   func-dash)
> [...]

doesn't call the two procedures. To actually run the procedures, you
would have to write something like

(let ((func-dot (hash-table-ref dict 'dot))
      (func-dash (hash-table-ref dict 'dash)))
  (func-dot)
  (func-dash))

Ciao,
Thomas


-- 
When C++ is your hammer, every problem looks like your thumb.