|
![](/i/fill.gif) |
On 12-3-2009 15:22, Invisible wrote:
> OK, so does anybody know the trick to taking a parse tree such as
>
> (2*(5^2))+((8*6)^(x-1)))
>
> and printing it out *without* several billion brackets?
>
> Printing it with brackets as above, or with no brackets at all, is quite
> trivial:
>
> output expr = case expr of
> Operator n x y = "(" ++ output x ++ n ++ output y ++ ")"
> Variable n = n
> Constant v = show v
> ...
>
> But how do you "decide" when the brackets can or can't be omitted?
Why not in (reverse) polish, no brackets at all
Post a reply to this message
|
![](/i/fill.gif) |