Nested list to nested list

[scottbolton]

I've several functions (from others) that interrogate lists but I can't find one that can look at a nested list and rebuild a list in the same format. Confusing, sorry.

How to I take (setq CAPS '(("A" ("B" ("C")) ("D")) ("E"))) and using (strcase get '(("a" ("b" ("c")) ("d")) ("e"))?

S

[martti.halminen · Accepted solution]

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@scottbolton wrote:

I've several functions (from others) that interrogate lists but I can't find one that can look at a nested list and rebuild a list in the same format. Confusing, sorry.

How to I take (setq CAPS '(("A" ("B" ("C")) ("D")) ("E"))) and using (strcase get '(("a" ("b" ("c")) ("d")) ("e"))?

S

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(defun map-tree (func tree)
  (cond
    ((null tree) nil)
    ((vl-consp tree)
     (cons (map-tree func (car tree))
           (map-tree func (cdr tree))))
    (T (func tree))))

 _$ (map-tree (lambda (s)(strcase s t)) caps)
(("a" ("b" ("c")) ("d")) ("e"))

 _$ (map-tree ascii caps)
((65 (66 (67)) (68)) (69))

_$ (map-tree sqrt (cons 56 89))
(7.48331 . 9.43398)

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[scottbolton]

Thanks, Martti. This looks good. I'll need to see how I can modify this to perform a more complex "func" - the (strcase example was simplified.

If I run in to problems I'll be back!

S

[martti.halminen]

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@scottbolton wrote:

 I'll need to see how I can modify this to perform a more complex "func" - the (strcase example was simplified.

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This should work for any single-argument function, as long as it produces a result and doesn't crash.

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[scottbolton · Accepted solution]

Martti,

So this (very simple) function is what I have:

(defun tester (arg)
 (cons arg (strcase arg T))
 )
(map-tree tester '(("A" ("B" ("C")) ("D")) ("E")))

'((("A" . "a") (("B" . "b") (("C" . "c"))) (("D" . "d"))) (("E" . "e")))

Now I can start to go places with it. Thanks for your help.

S