[Haskell-cafe] Parser problem continued

Henning Thielemann lemming at henning-thielemann.de
Tue Mar 15 10:32:41 EST 2005


On Tue, 15 Mar 2005, Nicola Whitehead wrote:

> Curiouser and curiouser...
>
> expr :: Parser Int
> expr = do t <- term
>          do symbol "+"
>             e <- expr
>          return (t + e)
>       +++ return t
>
> solves the undefined variable problem but introduces a new 'Last 
> operator in do {...} must be an expression' error, which then disappears 
> if I explicitly return e

the nested 'do' is still there ...


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