Now I have an adverb mc that creates "mutable constants" for tacit verbs:
NB. database solution for forum
mc =: 1 : '3 : (m;'':'';m)' NB. 'pronoun' mc is "mutable constant"
]d =: 7 3 $ 'dogbowwowpuprufcurgrr' NB. database
dog
bow
wow
pup
ruf
cur
grr
r =: d"_ {~ ] |~ [: # d"_ NB. circular retrieve
r3 =: ('d' mc) {~ ] |~ [: # ('d' mc) NB. likewise
r (d i. 'cur') + i. 5 NB. circular retrieve continues from top of d
cur
grr
dog
bow
wow
r3 (d i. 'cur') + i. 5 NB. likewise
cur
grr
dog
bow
wow
NB. See what happens when you amend d
]d =: d , 'kty',:'mew'
dog
bow
wow
pup
ruf
cur
grr
kty
mew
r (d i. 'kty') + i. 5 NB. circular retrieve from old d, not what I want
dog
bow
wow
pup
ruf
r3 (d i. 'kty') + i. 5 NB. circular retrieve from new d, yes!
kty
mew
dog
bow
wow
Kip Murray wrote:
> Below I add my solution, verbs r2 and thedata , to the puzzle about retrieval
> verb r's inability to notice changes in the database d. I like r2 plus
> thedata
> because they identify and remove the problem in a simple way. Verb r2 is
> tacit.
> Confirming Dan's analysis, verb thedata is explicit. /Kip Murray
>
> NB. database puzzle for forum
>
> ]d =: 7 3 $ 'dogbowwowpuprufcurgrr'
> dog
> bow
> wow
> pup
> ruf
> cur
> grr
>
> r =: (d"_ {~ ] |~ [: # d"_)"0
>
>
> r1 =: 3 : 'd {~ y |~ #d' NB. Dan Bron
>
> r2 =: thedata {~ ] |~ [: # thedata NB. Kip Murray
>
> thedata =: 3 : 'd' NB. Kip Murray
>
>
> NB. Hint. See what happens when you do
>
> ]d =: d , 'kty',:'mew'
> dog
> bow
> wow
> pup
> ruf
> cur
> grr
> kty
> mew
>
> d i. 'kty' NB. locate 'kty' in d
> 7
>
> r NB. verb r has old d "hardcoded"
> ((7 3$'dogbowwowpuprufcurgrr')"_ {~ ] |~ [: # (7
> 3$'dogbowwowpuprufcurgrr')"_)"0
>
> r 7 + i. 5 NB. r retrieves from old d (circles to top of old d)
> dog
> bow
> wow
> pup
> ruf
>
> r1 7 + i. 5 NB. r1 retrieves from new d
> kty
> mew
> dog
> bow
> wow
>
> r2 7 + i. 5 NB. r2 retrieves from new d
> kty
> mew
> dog
> bow
> wow
>
>
> Kip Murray wrote:
>> This puzzle has two parts (a) what is the error in verb r, and (b) how do
>> you
>> fix it? I have an answer for the fix, but there may be better ones.
>>
>> Verb r retrieves data from the database d. However, there is no index error
>> for
>> an out of bounds index. Instead, r treats d as a circle, and keeps going
>> around
>> the circle as dictated by the index.
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