Assoc & Lookup

[newdep]

Hello Lutz,



In the philosophy of Assoc and Lookup the search in nested-list have only the first element as 'key-index. In lists I think all elements are key-indexes

to eighother..thats more logical..? I know..there should be always and index

if more possebilites exist, but in that case always the first is returned.



Searching for the second or third value in a nested list could result

in the following..



(setq X '(  ( 1 2 ) ( 3 4 ) ( 5 6 ) ( 7 8 9 ) ))



(assoc 8 X)

>( 7 8 9 )



(lookup 4 X)

> 3



(lookup 8 X)

> 7 true 9   or 7 9



(lookup 7 X)

> true 8 9 or 8 9





Regards, Norman.

[newdep]

Mmmm i think this would impact everything in newlisp, I solved it

personaly using a double / tripple nested list where every element

is the index..



Norman.

[Lutz]

perhaps (ref ...) will do it for you:



(setq X '( ( 1 2 ) ( 3 4 ) ( 5 6 ) ( 7 8 9 ) ))



(ref 8 X) => (3 1)



It gives you a multidimensional index into X, which could have any nesting complexity you want.



You could then extract that element or just look at it:



(pop X '(3 1)) => 8 ; change X



(nth 3 1 X) => 8; leave X how it is



X => ((1 2) (3 4) (5 6) (7 9))



and put something else back:



(push 88 X '(3 1))



X => ((1 2) (3 4) (5 6) (7 88 9))



because 'push' and 'pop' can take multiple indices and they may be in a list, so the result from 'ref' can directly be used in push/pop.



Ref can take any expression as a search key.



(ref '(3 4) X) => (1)



(nth 1 X) => (3 4)





Lutz

[newdep]

HA !..nice nice... thanks...