Request for a Simple Pretty Printing library
Hi, I've been using the HughesPJ pretty printing library, but I need a new combinator: wrap :: String -> Doc -> String -> Doc wrap prepend doc append = ... The semantics of this would be that the text is prepended and appended to the doc when rendered, but does not alter the pretty printing at all. The idea of this is to support printing with HTML rendering: wrap "<span class='keyword'>" (text "case") "</span>" The HughesPJ library is 1000 lines long, so will be quite a lot of work to change this to get it working properly. Is there a simpler pretty printing library, with source code available somewhere? Ideally using the same interface. Of course, if anyone knows how to make this combinator using the existing library, or using another existing library, I'd appreciate it. Thanks Neil
On Wed, Dec 13, 2006 at 08:58:25PM +0000, Neil Mitchell wrote:
I've been using the HughesPJ pretty printing library, but I need a new combinator:
wrap :: String -> Doc -> String -> Doc wrap prepend doc append = ...
The semantics of this would be that the text is prepended and appended to the doc when rendered, but does not alter the pretty printing at all. The idea of this is to support printing with HTML rendering:
wrap "<span class='keyword'>" (text "case") "</span>"
The HughesPJ library is 1000 lines long, so will be quite a lot of work to change this to get it working properly.
I am not sure it will work, but it's sufficiently easy to try. Look at the innards of HughesPJ, especially the TextBeside data constructor. Its second parameter is an Int holding the length of the text. Perhaps if you created TextBeside with your HTML markup, but with 0 length field, things would be laid out properly. Something like: wrap prepend doc append = zeroText prepend <> doc <> zeroText append zeroText s = textBeside_ (Str s) 0 Empty Best regards Tomasz
On Wed, Dec 13, 2006 at 10:31:21PM +0100, Tomasz Zielonka wrote:
I am not sure it will work, but it's sufficiently easy to try. Look at the innards of HughesPJ, especially the TextBeside data constructor. Its second parameter is an Int holding the length of the text. Perhaps if you created TextBeside with your HTML markup, but with 0 length field, things would be laid out properly.
Something like:
wrap prepend doc append = zeroText prepend <> doc <> zeroText append zeroText s = textBeside_ (Str s) 0 Empty
Of course you will have to modify the HughesPJ library, because Doc is an abstract data type. Best regards Tomasz
The Prettyprint library you can download from: http://www.cs.uu.nl/wiki/HUT/Download and is described on: http://www.cs.uu.nl/wiki/HUT/PrettyPrintingCombinators contains amongst others the following code: data Doc = Empty | Char Char -- invariant: char is not '\n' | Text !Int String -- invariant: text doesn't contain '\n' | Line !Bool -- True <=> when undone by group, do not insert a space | Cat Doc Doc | Nest !Int Doc | Union Doc Doc -- invariant: first lines of first doc longer than the first lines of the second doc | Column (Int -> Doc) | Nesting (Int -> Doc) text "" = Empty text s = Text (length s) s so if you define now: wrap l t r = Text 0 l <|> text t <|> Text 0 r you should be set and done, Doaitse Swierstra On Dec 13, 2006, at 10:31 PM, Tomasz Zielonka wrote:
On Wed, Dec 13, 2006 at 08:58:25PM +0000, Neil Mitchell wrote:
I've been using the HughesPJ pretty printing library, but I need a new combinator:
wrap :: String -> Doc -> String -> Doc wrap prepend doc append = ...
The semantics of this would be that the text is prepended and appended to the doc when rendered, but does not alter the pretty printing at all. The idea of this is to support printing with HTML rendering:
wrap "<span class='keyword'>" (text "case") "</span>"
The HughesPJ library is 1000 lines long, so will be quite a lot of work to change this to get it working properly.
I am not sure it will work, but it's sufficiently easy to try. Look at the innards of HughesPJ, especially the TextBeside data constructor. Its second parameter is an Int holding the length of the text. Perhaps if you created TextBeside with your HTML markup, but with 0 length field, things would be laid out properly.
Something like:
wrap prepend doc append = zeroText prepend <> doc <> zeroText append zeroText s = textBeside_ (Str s) 0 Empty
Best regards Tomasz _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
doaitse:
The Prettyprint library you can download from:
I've added uulib to the libraries page: http://haskell.org/haskellwiki/Libraries_and_tools/Compiler_tools#Pretty_pri... But this makes me wonder: how many other top secret utrecht libraries aren't also documented on the libraries page? No one will know to use them, if they're not on haskell.org libraries page! :) http://haskell.org/haskellwiki/Libraries_and_tools -- Don
Hi
Something like:
wrap prepend doc append = zeroText prepend <> doc <> zeroText append zeroText s = textBeside_ (Str s) 0 Empty
Thanks, that works great! Is there likely to be any support for adding this to the standard library? I'd rather not have to fork a version of HughesPJ to get this feature. Thanks Neil
participants (4)
-
Doaitse Swierstra -
dons＠cse.unsw.edu.au -
Neil Mitchell -
Tomasz Zielonka