newlispfanclub.alh.net

Posted: **Thu Sep 09, 2021 3:16 pm**

How to filter only the contexts that represent a hash-map?
Example:
(dolist (_el (symbols))
(if (context? (eval _el))
(println (eval _el) {} (length (eval _el)))))
; -> Class 2
; -> MAIN 0
; -> Tree 0
; -> demo 0
; -> myHash 0

(dolist (_el (symbols))
(if (and (context? (eval _el))
(not (= _el 'MAIN))
(not (= _el 'Tree))
(not (= _el 'Class)))
(println (eval _el) {} (eval-string (string "(" _el ")")))))
; -> demo ()
; -> myHash (("1" 1) ("20" 20) ("57" 57) ("59" 59) ("81" 81))

Is there a way that doesn't use "eval-string" to display / count the values of a context representing a hash-map? "

Posted: **Fri Sep 10, 2021 10:23 am**

1) a "hashmap" is a context without default functor, i.e.

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(and (context? S) (nil? (sym (term S) S nil)))

2) using the symbol as functor results in its list if entries, i.e.

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(apply S)

Posted: **Fri Sep 10, 2021 10:25 am**

tried to edit, to wrap the sym term into an eval, but the server doesn't let me...

Posted: **Fri Sep 10, 2021 8:57 pm**

Thank you. I'll do some tests.

Posted: **Sat Sep 18, 2021 10:14 am**

More difficulties:
a context with functor and functions can be a hash-map too.

Posted: **Fri Jan 14, 2022 2:44 pm**

This works for me:

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(define (hash? hash)
  (and (context? (evals hash))
       (not (list? (evals (sym (term hash) hash nil))))))

With "eval" instead of "evals" (to avoid "Internal server error")

newlispfanclub.alh.net

Hash-map e contexts

Hash-map e contexts

Re: Hash-map e contexts

Re: Hash-map e contexts

Re: Hash-map e contexts

Re: Hash-map e contexts

Re: Hash-map e contexts