Haskell: Variable not in scope : <p>I have a code as:</p>

<pre><code>main = interact $ show . maxsubseq . map read . words

maxsubseq :: (Ord a,Num a) =&gt; [a] -&gt; (a,[a])
maxsubseq = snd . foldl f ((0,[]),(0,[])) where 
f ((h1,h2),sofar) x = (a,b) where
a = max (0,[]) (h1 + x ,h2 ++ [x]) 
b = max sofar a
</code></pre>

<p>But I am getting error:</p>

<pre><code>maxSub.hs:6:17: error: Variable not in scope: h1

maxSub.hs:6:22: error: Variable not in scope: x

maxSub.hs:6:25: error: Variable not in scope: h2 :: [t1]

maxSub.hs:6:32: error: Variable not in scope: x

maxSub.hs:7:9: error: Variable not in scope: sofar :: (t, [t1])
</code></pre>

<p>Not able to figure out why??</p>

<p>Any ideas??</p>

<p>Thanks.</p>
