"Ramaswamy, Vivek" <vivek.ramasw...@fmr.com> writes:
> Hello All~
>
> I have been reading the book ?Haskell for real programmers? and am presently
> on
> chapter 03.
>
> There was a small program demonstrated by the author on ?let?. The problem is
> that when I cut and paste authors code into eclipse, the program works fine,
> where as when I write my own copy of the program I am getting an error. I
> figured out that when I remove the function any one function lend or bend, the
> file compiles and runs fine.
>
> My question is why does the Haskell compiler complains, in the case 2
> functions
> with the same signature and logic, even though their names are different.
>
> module Lending where
>
> {-- snippet lend --}
>
> lend amount balance = let reserve = 100
>
> newBalance = balance - amount
>
> in if balance < reserve
>
> then Nothing
>
> else Just newBalance
>
> {-- /snippet lend --}
>
> bend amount balance = let reserver = 100
>
> newBalance=balance-amount
The problem is here ^^^^
each element in a let clause should be indented to the same level, that
is
let foo = bar
baz = qux
is legal. foo and baz are both defined. But
let foo = bar
baz = qux
is not legal, the compiler thinks baz = qux is part of the statement
`foo = bar`, like `foo = bar baz = qux`. Also
let foo = bar
baz = qux
is not legal, since the compiler thinks the let clause is over and
expects the keyword `in`
>
> in if balance < reserver
>
> then Nothing
>
> else Just newBalance
>
> Regards
>
> -Vivek Ramaswamy-
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