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    <p>What you implemented (rather, what you think you implemented) is a function that works only on lists of <code>Integer</code>s, what the assignment wants you to do is create one that works on lists of all types provided they are equality-comparable (so that your function will also work on lists of booleans or strings). You probably don't have to change a lot: Try removing the explicit type signatures from your code and ask <code>ghci</code> about the type that it would infer from your code (<code>:l yourfile.hs</code> and then <code>:t deleteAll_list_comp</code>). Unless you use arithmetic operations or similar things, you will most likely find that your functions already work for all <code>Eq a</code>.</p> <p>As a simpler example that may explain the concept: Let's say we want to write a function <code>isequal</code> that checks for equality (slightly useless, but hey):</p> <pre><code>isequal :: Integer -&gt; Integer -&gt; Bool isequal a b = (a == b) </code></pre> <p>This is a perfectly fine definition of <code>isequal</code>, but the type constraints that I have manually put on it are way stronger than they have to. In fact, in the absence of the manual type signature, ghci infers:</p> <pre><code>Prelude&gt; :t isequal isequal :: Eq a =&gt; a -&gt; a -&gt; Bool </code></pre> <p>which tells us that the function will work for all input types, as long as they are <code>deriving Eq</code>, which means nothing more than having a proper <code>==</code> relation defined on them.</p> <hr> <p>There is still a problem with your <code>_rec</code> function though, since it should do the same thing as your <code>_comp</code> function, the type signatures should match.</p>
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    1. COThanks very much, yeah I finally understand the difference in the parameters being established and realize that I actually made this mistake in my first assignment as well. The teacher isn't a very clear lecturer and all his examples in class showed the parameters going from a to a stricter primitive. Thanks for the clarification. I did still run into errors though, most likely due to my lack of knowledge of Haskell, if you are willing to take a look at my simple methods :)
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