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