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<div class="moz-cite-prefix">Thanks, <br>
<br>
Now I see the last error on the main line : <br>
<br>
<div class="ide-error-span">src/Main.hs@7:28-7:39 </div>
<div class="ide-error-msg"><span>Couldn't match expected type
‘[t1] -> [a0]’ with actual type </span>
<div class="CodeMirror cm-s-default" style="font-size: 14px;">[<span
class="cm-variable">t0</span>]</div>
<span>
The function ‘[1, 2]’ is applied to one argument,
but its type </span>
<div class="CodeMirror cm-s-default" style="font-size: 14px;">[<span
class="cm-variable">t0</span>]</div>
<span> has none</span><span title="Click to show/hide extra
information" class="ide-error-collapse-btn"> …</span><span
style="display: inline;">
In the second argument of ‘($)’, namely ‘[1, 2] [3, 4]’
In the expression: print . plusplus' $ [1, 2] [3, 4]<br>
<br>
Roelof<br>
<br>
</span></div>
<br>
<br>
<br>
Alex Hammel schreef op 12-5-2015 om 20:11:<br>
</div>
<blockquote
cite="mid:CA+_xFerqXm4XYaMaSpuJN6rmLTnDbEsFesA54SLPS5K72nk5pg@mail.gmail.com"
type="cite">
<div dir="ltr">
<div>You're missing the parens around (x:yx) in the last clause.<br>
</div>
</div>
<br>
<div class="gmail_quote">On Tue, 12 May 2015 at 11:02 Roelof
Wobben <<a moz-do-not-send="true"
href="mailto:r.wobben@home.nl">r.wobben@home.nl</a>> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"> Hello, <br>
<br>
I try to re implement ++ <br>
<br>
So far I have this ; <br>
<br>
plusplus' :: [a] -> [a] -> [a]<br>
plusplus' [] (xs) = xs <br>
plusplus' [] [] = [] <br>
plusplus' (xs) [] = xs<br>
plusplus' (x:xs) yx = plusplus' xs x:yx<br>
<br>
main = print . plusplus' $ [1,2] [3,4]<br>
<br>
<br>
But I still get this error message : <br>
<br>
<div>src/Main.hs@5:23-5:37 </div>
<div><span>Couldn't match expected type </span>
<div style="font-size:14px"><span>a</span></div>
<span> with actual type </span>
<div style="font-size:14px">[<span>a</span>]</div>
<span> </span>
<div style="font-size:14px"><span>a</span></div>
<span> is a rigid type variable bound by the type
signature for plusplus' :: [a] -> [a] -> [a] at
/home/app/isolation-runner-work/projects/112825/session.207/src/src/Main.hs:1:14
Relevant
bindings include yx :: [a] (bound at
/home/app/isolation-runner-work/projects/112825/session.207/src/src/Main.hs:5:18)
xs :: [a] (bound at
/home/app/isolation-runner-work/projects/112825/session.207/src/src/Main.hs:5:14)
x :: a (bound at
/home/app/isolation-runner-work/projects/112825/session.207/src/src/Main.hs:5:12)
plusplus' :: [a] -> [a] -> [a] (bound at
/home/app/isolation-runner-work/projects/112825/session.207/src/src/Main.hs:2:1)</span><span
title="Click to show/hide extra information"> …<br>
<br>
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