On Mon, May 07, 2007 at 10:38:19PM +0100, Joel Reymont wrote:
Folks,
Are you using UU.PPrint [1]? Can you tell me how to print stuff like this?
{ blah blah }
I tried the following which sort of works but doesn't return the closing brace to the indentation level of the first one.
braces x = PP.braces $ linebreak <> indent 4 x
You could use braces x = PP.braces $ indent 4 (linebreak <> x) <> linebreak The tricky thing with PPrint is remembering that the current indentation level is only applied when you hit a "line", so nest doesn't affect a leading word. nest n (text "a" <> line <> doc) = text "a" <> nest (line <> doc) If you want to give the pretty printer some freedom in laying out your document, and you care about how the alternate layouts look (and why else would you be using a pretty printer), you might prefer braces x = group (PP. braces (nest 4 (linebreak <> x) <> linesbreak) That will make a one-line form like {blah, blah} rather than { blah, blah} and it lets the printer flatten a brace group whenever it fits on one line, not just if it happens to be inside an enclosing group. The trick for getting GNU braces with Text.PrettyPrint is braces x = cat [lbrace, text "", nest 4 x, rbrace] without (text "") vertical composition would overlap the indented blah with the opening brace. If you happen to be formatting C I've also worked out how to get nice argument lists out of both pretty printers. Brandon