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- Newsgroups: comp.lang.functional
- Path: sparky!uunet!mcsun!sunic!sics.se!eua.ericsson.se!erix.ericsson.se!joe
- From: joe@erix.ericsson.se (Joe Armstrong)
- Subject: Re: Is efficient backtracking feasible in functional languages?
- Message-ID: <1992Nov11.171742.18783@eua.ericsson.se>
- Sender: news@eua.ericsson.se
- Nntp-Posting-Host: gordons.eua.ericsson.se
- Nntp-Posting-User: joe
- Organization: Ellemtel Telecom Systems Labs, Stockholm, Sweden
- References: <1992Nov10.164456.18062@email.tuwien.ac.at> <TMB.92Nov11104119@arolla.idiap.ch>
- Date: Wed, 11 Nov 1992 17:17:42 GMT
- Lines: 31
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-
- |>
- |> strangesucc n = hd [x|x<-[0..];x>n];
- |>
- ....
- |>
- |> - Stream.head(Stream.filter(fn x => x > 1000000,Stream.iota()));
- |>
- |> [Major collection... 21% used (3397260/15733684), 1920 msec]
- |>
- |> [Major collection... 21% used (3397288/15730836), 1910 msec]
- |>
- |> [Major collection... 21% used (3397288/15730948), 1920 msec]
- |>
- |> [Major collection... 21% used (3397288/15730888), 1920 msec]
- |>
- |> [Major collection... 21% used (3397288/15730888), 1910 msec]
- |> val it = 1000001 : int
- |> -
-
- Wonderfull !!
-
- This is the kind of stuff that gives FP a bad name :-)
-
- Is their a transformation system which can prove that
-
- strangesucc x == x + 1 ?
-
- Joe
-
-
-