On Fri, 20 Feb 2004, Matthew Morvant wrote:
> I am trying (and have been for quite some time) to repair a broken Haskell
> script.� I keep getting stuck on �Last generator in do {...} must be an
> expression�.� I am betting that this is not uncommon.� Can someone please
> help me understand?
>
> code5 :: Parser
> code5 = do
> dd <- code3
> do ddd <- code3
> do dddd <- code3
> return "ce"
>
The author appears to want this (braces and semicolons included for
clarity):
code5 = do {
dd <- code3;
ddd <- code3;
dddd <- code3;
return "ce"
}
which will assign the results of code3 3 times in succession to dd, ddd,
and ddd before returning "ce". Of course, you /could/ just write that as:
do {code3; code 3; code 3; return "ce"}
Unless I misunderstand the intent here?
> code4 :: Parser
> code4 = do
> ����������� ����������� dd <- code3
> ����������������������� do dde <- code3
> ����������������������� ����������� digit
> ����������������������������������� ddd <- many (do digit)
> ����������������������������������� q <- code5
> ����������������������������������� return (q : "ss")
>
Attempting to grok this suggests I might. Is code3 supposed to take a
parser as a parameter?
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