Re: JESS: Lisp is maddening

On 18 September 2010 15:38, Ernest Friedman-Hill <[email protected]> wrote:

> That's extremely close; the only problem is on the last line of the
> defglobal: (?hash-set) is an attempt to call the function whose name is in
> ?hash-set. That's not a function name, it's a map, so it doesn't work (the
> error is "method name expected, as Jess tries to call a method on that
> object). You want the progn to return "?hash-set", not "(?hash-set)" -- just
> drop those parentheses and you're good to go.
>
> Another way to do this that would involve less typing: Jess lists turn into
> arrays when passed to Java functions. So you could do this:
>
> (import java.util.*)
> (defglobal ?*usps-state-code* =
>    (new HashSet (call Arrays asList (list "AL" "AK" "AS" ...))))


Better golfing: You can omit the quotes ;-)

Actually, the difference between a Java HashSet and a Jess list isn't hefty,
I've clocked this, and the list is slower by 15% only. This test was based
on testing all list/set elements with equal frequency.

Since this won't be true in reality, I have used a list ordered by
decreasing population, and used a set of test cases where lookups were
proportional to the distribution of the population. Then, there is no
difference between a Jess list and HashSet.

I compared these lookup functions:
   (deffunction testList (?sc) (member$ ?sc ?*sclist*))
   (deffunction testSet (?sc) (?*scset* contains ?sc))

@Donald: Why is New York (NY) omitted from the list?

-W

>
>
>
>
> On Sep 18, 2010, at 9:24 AM, Donald Winston wrote:
>
>  Why doesn't this work?
>>
>> (defglobal ?*usps-state-codes* = (progn
>>    (bind ?hash-set (new java.util.HashSet 59))
>>    (call ?hash-set add "AL") (call ?hash-set add "AK") (call ?hash-set add
>> "AS") (call ?hash-set add "AZ")
>>    (call ?hash-set add "CA") (call ?hash-set add "CO") (call ?hash-set add
>> "CT") (call ?hash-set add "DE")
>>    (call ?hash-set add "DC") (call ?hash-set add "FM") (call ?hash-set add
>> "FL") (call ?hash-set add "GA")
>>    (call ?hash-set add "GU") (call ?hash-set add "HI") (call ?hash-set add
>> "ID") (call ?hash-set add "IL")
>>    (call ?hash-set add "IN") (call ?hash-set add "IA") (call ?hash-set add
>> "KS") (call ?hash-set add "KY")
>>    (call ?hash-set add "LA") (call ?hash-set add "ME") (call ?hash-set add
>> "MH") (call ?hash-set add "MD")
>>    (call ?hash-set add "MA") (call ?hash-set add "MI") (call ?hash-set add
>> "MN") (call ?hash-set add "MS")
>>    (call ?hash-set add "MO") (call ?hash-set add "MT") (call ?hash-set add
>> "NE") (call ?hash-set add "NV")
>>    (call ?hash-set add "NH") (call ?hash-set add "NJ") (call ?hash-set add
>> "NM") (call ?hash-set add "NC")
>>    (call ?hash-set add "ND") (call ?hash-set add "MP") (call ?hash-set add
>> "OH") (call ?hash-set add "OK")
>>    (call ?hash-set add "OR") (call ?hash-set add "PW") (call ?hash-set add
>> "PA") (call ?hash-set add "PR")
>>    (call ?hash-set add "RI") (call ?hash-set add "SC") (call ?hash-set add
>> "SD") (call ?hash-set add "TN")
>>    (call ?hash-set add "TX") (call ?hash-set add "UT") (call ?hash-set add
>> "VT") (call ?hash-set add "VI")
>>    (call ?hash-set add "VA") (call ?hash-set add "WA") (call ?hash-set add
>> "WV") (call ?hash-set add "WI")
>>    (call ?hash-set add "WY")
>>    (?hash-set)))
>>
>> (printout t (call ?*usps-state-codes* contains "VA") crlf)
>>
>> I need to have a global variable that will contain state code values after
>> a (reset). list "AL" "AK" ... works but a HashSet would be more efficient. A
>> jess list is not a collection so I can't use the HashSet(Collection)
>> constructor.
>>
>>
> ---------------------------------------------------------
> Ernest Friedman-Hill
> Informatics & Decision Sciences, Sandia National Laboratories
> PO Box 969, MS 9012, Livermore, CA 94550
> http://www.jessrules.com
>
>
>
>
>
>
>
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