Differences From Artifact [5b2c3c452aca5b18]:
- File
sample/fib.pmy
- 2010-11-24 12:14:00 - part of checkin [3ae09b8cbf] on branch trunk - changed if-then-else syntax (user: kinaba) [annotate]
To Artifact [4438bc82733dcb16]:
- File
sample/fib.pmy
- 2010-11-27 11:46:26 - part of checkin [203e4cb208] on branch trunk - fixed automatic memoization bug (whole part of the contexts are now used as the memo key) (user: kinaba) [annotate]
> 1 # Standard Fibonacci function
1 def fib(x) 2 def fib(x)
2 { 3 {
3 if x<2 then 1 else fib(x-1) + fib(x-2) 4 if x<2 then 1 else fib(x-1) + fib(x-2)
4 }; 5 };
5 6
6 let upto = fun(n, f){ 7 let upto = fun(n, f){
7 if n > 0: upto(n-1,f); 8 if n > 0: upto(n-1,f);
8 f(n) 9 f(n)
9 }; 10 };
10 11
11 var compose = fun(f,g){ fun(x){f(g(x))} }; 12 var compose = fun(f,g){ fun(x){f(g(x))} };
12 var "<<" = compose; 13 var "<<" = compose;
13 14
14 upto(16, print<<fib); | 15 upto(18, print<<fib);
> 16
> 17
> 18 ######################################
> 19 # Omake. Feel the automatic memoization!
> 20
> 21 # Set up a mirror layer (do-the-same-thing layer) of @value
> 22 @@m(x){x};
> 23 @m "+" (x,y) { @value(@m(x)+@m(y)) };
> 24 @m "-" (x,y) { @value(@m(x)-@m(y)) };
> 25 @m "<" (x,y) { @value(@m(x)<@m(y)) };
> 26 @m "if" (c,t,e) { @value(if @m(c) then @m(t()) else @m(e())) };
> 27
> 28 # Helper function to call fib in layer @m
> 29 def fibm(x @value) { @m(fib(@value(x))) };
> 30
> 31 # User defined layers are automatically memoized.
> 32 # So this is much faster.
> 33 upto(18, print<<fibm);