[REBOL] Essay on Associative Data Stores Re:
From: ole_f:post3:tele:dk at: 18-Sep-2000 12:45
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Hi Joel, 16-Sep-2000 you wrote:
>1.1. Keys and values are not distinguised.
>1.2. Storage management/economy require extra code to
> handle replacement of values for existing keys.
>1.3. The block! type doesn't appear to be supported as a key
> in a manner consistent with other data types.
I've attached some functions for manipulating with an associative data
structure. I personally think they suffice for my normal uses, but I'm
looking forward to your comments (though, please keep it short then, I don't
have the time to read through all that ASCII ;-) ).
BTW, using a hash! for the "keys" array would probably be a better idea than
just using a block!, as I currently do. _If_ find/only works faster on hash!
lists, that is (it should be, but I don't know).
Kind regards,
--
Ole Friis <[ole_f--post3--tele--dk]>
Amiga is a trademark of Amiga Inc.
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REBOL []
create-ads: func [
"Creates a new associative data structure"
][
make object! [
keys: copy []
values: copy []
]
]
lookup-ads: func [
"Returns the value associated with the key"
ads [object!] "The associative data structure"
key [any-type!] "Key"
/local t-list
][
if found? t-list: find/only ads/keys key [
pick ads/values index? t-list
]
]
associate-ads: func [
"Appends the new key/value pair in the data structure"
ads [object!] "The associative data structure"
key [any-type!] "Key"
value [any-type!] "Value"
/local t-list
][
either found? t-list: find/only ads/keys key [
change/only at ads/values index? t-list value
][
append/only ads/keys key
append/only ads/values value
]
]
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