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author | Erlang/OTP <[email protected]> | 2009-11-20 14:54:40 +0000 |
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committer | Erlang/OTP <[email protected]> | 2009-11-20 14:54:40 +0000 |
commit | 84adefa331c4159d432d22840663c38f155cd4c1 (patch) | |
tree | bff9a9c66adda4df2106dfd0e5c053ab182a12bd /system/doc/extensions/funs1.erl | |
download | otp-84adefa331c4159d432d22840663c38f155cd4c1.tar.gz otp-84adefa331c4159d432d22840663c38f155cd4c1.tar.bz2 otp-84adefa331c4159d432d22840663c38f155cd4c1.zip |
The R13B03 release.OTP_R13B03
Diffstat (limited to 'system/doc/extensions/funs1.erl')
-rw-r--r-- | system/doc/extensions/funs1.erl | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/system/doc/extensions/funs1.erl b/system/doc/extensions/funs1.erl new file mode 100644 index 0000000000..b1a3e21525 --- /dev/null +++ b/system/doc/extensions/funs1.erl @@ -0,0 +1,125 @@ +-module(funs1). +-compile(export_all). +-import(lists, [reverse/1]). + +%1 +map(F, [H|T]) -> [F(H)|map(F, T)]; +map(F, []) -> []. +%1 + +%2 +foreach(F, [H|T]) -> + F(H), + foreach(F, T); +foreach(F, []) -> + ok. +%2 +% +%3 +all(Pred, [H|T]) -> + case Pred(H) of + true -> all(Pred, T); + false -> false + end; +all(Pred, []) -> + true. +%3 +%4 +any(Pred, [H|T]) -> + case Pred(H) of + true -> true; + false -> any(Pred, T) + end; +any(Pred, []) -> + false. +%4 +%5 +takewhile(Pred, [H|T]) -> + case Pred(H) of + true -> [H|takewhile(Pred, T)]; + false -> [] + end; +takewhile(Pred, []) -> + []. +%5 +%6 +dropwhile(Pred, [H|T]) -> + case Pred(H) of + true -> dropwhile(Pred, T); + false -> [H|T] + end; +dropwhile(Pred, []) -> + []. +%6 +%7 +splitlist(Pred, L) -> + splitlist(Pred, L, []). + +splitlist(Pred, [H|T], L) -> + case Pred(H) of + true -> splitlist(Pred, T, [H|L]); + false -> {reverse(L), [H|T]} + end; +splitlist(Pred, [], L) -> + {reverse(L), []}. +%7 + +flatmap(F, [Hd|Tail]) -> + F(Hd) ++ flatmap(F, Tail); +flatmap(F, []) -> []. + +%8 +foldl(F, Accu, [Hd|Tail]) -> + foldl(F, F(Hd, Accu), Tail); +foldl(F, Accu, []) -> Accu. +%8 +% +foldr(F, Accu, [Hd|Tail]) -> + F(Hd, foldr(F, Accu, Tail)); +foldr(F, Accu, []) -> Accu. +%9 +filter(F, [H|T]) -> + case F(H) of + true -> [H|filter(F, T)]; + false -> filter(F, T) + end; +filter(F, []) -> []. +%9 +%10 +mapfoldl(F, Accu0, [Hd|Tail]) -> + {R,Accu1} = F(Hd, Accu0), + {Rs,Accu2} = mapfoldl(F, Accu1, Tail), + {[R|Rs], Accu2}; +mapfoldl(F, Accu, []) -> {[], Accu}. +%10 +mapfoldr(F, Accu0, [Hd|Tail]) -> + {Rs,Accu1} = mapfoldr(F, Accu0, Tail), + {R,Accu2} = F(Hd, Accu1), + {[R|Rs],Accu2}; +mapfoldr(F, Accu, []) -> {[], Accu}. +%11 +first(Pred, [H|T]) -> + case Pred(H) of + true -> + {true, H}; + false -> + first(Pred, T) + end; +first(Pred, []) -> + false. +%11 +% +compose(F, G) -> + fun(X) -> + F(G(X)) + end. + +%20 +iterate(N, F) -> + iterate(N, N+1, F). + +iterate(Stop, Stop, _) -> + []; +iterate(N, Stop, Fun) -> + [Fun(N)|iterate(N+1, Stop, Fun)]. +%20 |