tests

man/kvs_stream.htm

@@ -60,47 +60,35 @@
 <h3>EXAMPLE</h3>
 
 <figure><code>
- create_destroy() ->
+-module(kvs_stream).
+-compile(export_all).
+
+check() ->
     Cur = new(),
+    take(-1,down(top(Cur))),
     [A,B,C,D] = [ kvs:next_id(person,1)
              || _ <- lists:seq(1,4) ],
-    S  = kvs_stream:save(
-         kvs_stream:add(#person{id=A},
-         kvs_stream:down(
-         kvs_stream:add(#person{id=B},
-         kvs_stream:up(
-         kvs_stream:add(#person{id=C},
-         kvs_stream:down(
-         kvs_stream:add(#person{id=D},
-         kvs_stream:up(
-         kvs_stream:new()))))))))),
-    Y  = kvs_stream:remove(B,
-         kvs_stream:remove(D,
-         kvs_stream:remove(A,
-         kvs_stream:remove(C,S)))),
-    [] = kvs_stream:take(-1,
-         kvs_stream:down(
-         kvs_stream:top(Y))).
+    R = save(add(top,#person{id=A},
+             add(bot,#person{id=B},
+             add(top,#person{id=C},
+             add(bot,#person{id=D}, Cur ))))),
+    X = take(-1,down(top(R))),
+    Y = take(-1,up(bot(R))),
+    X = lists:reverse(Y),
+    L = length(X).
 
  > kvs_stream:check().
- ok
+ 4
 
  > kvs:all(cur).
- [{cur,8,[],0,[],[]},
-  {cur,4,[],0,[],[]},
-  {cur,9,{person,21,23,[],[],[],[],[],[]},0,21,22},
-  {cur,6,{person,13,15,[],[],[],[],[],[]},0,13,14},
-  {cur,5,{person,9,11,[],[],[],[],[],[]},0,9,10}]
-
-> kvs_stream:take(-1,
-  kvs_stream:down(
-  kvs_stream:top(
-  kvs_stream:seek(24,
-  kvs:get(cur,9))))).
-[{person,22,[],24,[],[],[],[],[]},
- {person,24,22,23,[],[],[],[],[]},
- {person,23,24,21,[],[],[],[],[]},
- {person,21,23,[],[],[],[],[],[]}]
+ [{cur,1,{person,1,3,[],[],[],[],[],[]},0,1,2}]
+
+ > kvs_stream:take(-1,
+   kvs_stream:top(kvs:get(cur,1))).
+[{person,2,[],4,[],[],[],[],[]},
+ {person,4,2,3,[],[],[],[],[]},
+ {person,3,4,1,[],[],[],[],[]},
+ {person,1,3,[],[],[],[],[],[]}]
 
 </code></figure>
     </section>
@@ -114,17 +102,17 @@
 
 <h4>save(#cur{}) -> #cur{}.</h4>
 
-<p>Saves cursor to database.<?p>
+<p>Saves the cursor to database.<?p>
 
 <h4>load() -> #ok{data::#cur{}} | #error{}.</h4>
 
-<p>Gets a curson from database.</p>
+<p>Gets a cursor from database.</p>
 
-<h4>next(#cur{}) -> #cur{}.</h4>
+<h4>next(#cur{}) -> #cur{} | #error{}.</h4>
 
 <p>Moves cursor to next. Consume data top down.</p>
 
-<h4>prev(#cur{}) -> #cur{}.</h4>
+<h4>prev(#cur{}) -> #cur{} | #error{}.</h4>
 
 <p>Moves cursor to prev. Consume data bottom up.</p>
 
@@ -133,11 +121,11 @@
 <p>Moves cursor to record by its id.
    If cursor has no cached value then function returns error.</p>
 
-<h4>top(#cur{}) -> #cur{}.</h4>
+<h4>top(#cur{}) -> #cur{} | #error{}.</h4>
 
 <p>Moves cursor to top of the list.</p>
 
-<h4>bot(#cur{}) -> #cur{}.</h4>
+<h4>bot(#cur{}) -> #cur{} | #error{}.</h4>
 
 <p>Moves cursor to bottom of the list.</p>
 

src/kvs_stream.erl

@@ -7,8 +7,12 @@
 % PUBLIC
 
 new() -> #cur{id=kvs:next_id(cur,1)}.
+top({ok,#cur{}=C})    -> top(C);
+top({error,X})        -> {error,X};
 top(#cur{top=[]}=C)   -> C#cur{val=[]};
 top(#cur{top=T}=C)    -> seek(T,C).
+bot({ok,#cur{}=C})    -> bot(C);
+bot({error,X})        -> {error,X};
 bot(#cur{bot=[]}=C)   -> C#cur{val=[]};
 bot(#cur{bot=B}=C)    -> seek(B,C).
 add(M,#cur{dir=D}=C)  -> add(dir(D),M,C).
@@ -18,6 +22,8 @@ next(#cur{val=[]}=C)  -> {error,[]};
 next(#cur{val=B}=C)   -> lookup(kvs:get(tab(B),en(B)),C).
 prev(#cur{val=[]}=C)  -> {error,[]};
 prev(#cur{val=B}=C)   -> lookup(kvs:get(tab(B),ep(B)),C).
+take(N,{ok,#cur{}}=C) -> take(N,C);
+take(N,{error,X})     -> {error,X};
 take(N,#cur{dir=D}=C) -> take(acc(D),N,C,[]).
 
 seek(I,  {ok,#cur{}=C})  -> seek(I,C);
@@ -62,9 +68,8 @@ fix(M,X)    -> fix(kvs:get(M,X)).
 fix({ok,O}) -> O;
 fix(_)      -> [].
 
-lookup({ok,R},C) -> C#cur{val=R};
-lookup(X,C)      -> X.
-
+lookup({ok,R},C)          -> C#cur{val=R};
+lookup({error,X},C)       -> {error,X}.
 take(_,_,{error,_},R)     -> lists:flatten(R);
 take(_,0,_,R)             -> lists:flatten(R);
 take(A,N,#cur{val=B}=C,R) -> take(A,N-1,?MODULE:A(C),[B|R]).