logo       

Re: Bug in users manual, 6.4.2, section on pattern guards: msg#00075

lang.haskell.glasgow.bugs

Subject: Re: Bug in users manual, 6.4.2, section on pattern guards

Matthew Cox wrote:
One example given in this discussion is:

clunky env var1 var1 = case lookup env var1 of
Nothing -> fail
Just val1 -> case lookup env var2 of
Nothing -> fail
Just val2 -> val1 + val2
where
fail = val1 + val2

this needs to be fixed to:

clunky env var1 var1 = case lookup env var1 of
Nothing -> fail
Just val1 -> case lookup env var2 of
Nothing -> fail
Just val2 -> val1 + val2
where
fail = var1 + var2 <<<< (Added for emphasis)

I didn't see it myself on the first readthrough, but I was comparing structure
between two examples
and noticed the discrepency. Let's fix it for correctness' sake.

fixed; thanks.

Simon


<Prev in Thread] Current Thread [Next in Thread>
Google Custom Search

News | FAQ | advertise