[Haskell-cafe] Pretty printing a tree

[Brent Yorgey]

On Thu, May 14, 2009 at 03:58:18PM -0300, José Romildo Malaquias wrote:
> 
> Then the resulting of pretty printing the given tree would be something
> like the following:
> 
>        a
>        |
> +-------------+
> |    |        |
> b    c        d
>      |        |
>    +---+    +---+
>    |   |    |   |
>    c1  c2   d1  d2
>             |
>            d1a
> 
> There is the module Text.PrettyPrint.HughesPJ, but it lacks examples on
> how to use the pretty print combinators, and it is not well docomented.

Text.PrettyPrint.HughesPJ is actually not a good tool for this, since
it is for pretty-printing line-oriented material (i.e. source code).
I actually have a library I was developing a while ago to do the sort
of pretty-printing/layout of text that you're looking for, using a box
model similar to that of TeX, but I never released it.  Hopefully I'll
get around to polishing and releasing it this summer.

-Brent