Re^3: How will you use state declared variables in Perl6?

Hmm, why a hash? And why not optimize assuming the current value is already in @seen? Also, declarators need not be separate statements. So I'd probably write it like this:

    sub fib (Int $n) {
        return 1 if $n < 2;
        state @seen[$n] //= fib($n-1) + fib($n-2);
    }
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I think that may be a little clearer as well. If I wanted to golf it just a bit more I'd say:

    sub fib (Int $n) {
        $n < 2 or state @seen[$n] //= fib($n-1) + fib($n-2);
    }
[download]

If I wanted to golf it a lot more I'd say:

    my&fib:={$_<2or state@s[$_]//=fib($_-1)+fib $_-2}
[download]

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Re^4: How will you use state declared variables in Perl6? by BrowserUk (Patriarch) on Nov 05, 2006 at 10:39 UTC
Um. Er...? `pugs>sub fib (Int $n) { return 1 if $n < 2; state @seen[$n] //= fib($n +-1) + fib($n-2); } Internal error while running expression: *** unexpected "[" expecting word character, "::", "=", ":=", "::=", ";" or "}" at <interactive> line 1, column 52` [download] Update: This works though `pugs> sub fib (Int $n) { state @seen; return 1 if $n < 2; @seen[$n] / +/= fib($n-1) + fib($n-2); }; undef pugs> say fib 4; 5 undef pugs> say fib 8; 34 undef pugs> say fib 800; 1121023813016570197539221312040081070329432498024398917379911096096424 +176870242714672419719090010009284331740160122026805305229708722215290 +03044406006693244742562963426 undef` [download] Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal? "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice.	[reply] [d/l] [select]
Re^5: How will you use state declared variables in Perl6? by TimToady (Parson) on Nov 06, 2006 at 06:18 UTC
You must be running an older pugs. In fact, the current (working) version in the pugs repository (r14657) now reads: `sub fib (UInt $n) { (state $seen = [0,1,1]).[$n] //= fib($n-1) + fib($n-2); }` [download] It would also work as `state @seen = 0,1,1` except there's a bug with initializing state variables using a list that causes it to reinitialize every time instead of just the first time, which, while it lets it run, kinda defeats the memoization...	[reply] [d/l]


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