[GHC] #1886: GHC API should preserve and provide access to comments

[GHC]

#1886: GHC API should preserve and provide access to comments
---------------------------------------------------------------+------------
 Reporter:  claus                                              |          Owner:             
     Type:  bug                                                |         Status:  new        
 Priority:  normal                                             |      Milestone:  6.10 branch
Component:  GHC API                                            |        Version:  6.9        
 Severity:  normal                                             |     Resolution:             
 Keywords:  GHC API, comments, program transformation, layout  |     Difficulty:  Unknown    
 Testcase:                                                     |   Architecture:  Unknown    
       Os:  Unknown                                            |  
---------------------------------------------------------------+------------
Comment (by Jedai):

 My proposal is to support access to a special kind of token stream
 including comments.
 As the tokens themselves aren't enough to get back to the source that
 produced them (some aesthetic details disappear), I also create a function
 to add source strings to the tokens in a stream and a function to show
 such a "rich" token stream.
 HaRe use the following model :
 get the AST and the token stream >>> modify AST &&& propagate changes to
 token stream >>> second (pretty print the token stream).

 While this model may not be as convenient as we could hope for, it works
 and the guts of this process could eventually become a package on Hackage,
 separate from HaRe.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1886#comment:6>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler