-- code for generating a list of attributes and a list of
-- local variables as comments in the generated file

imports
{
import List  (intersect, (\\))
import qualified UU.DData.Map as Map(toList) 
}


ATTR Productions Production Alternatives Alternative Rules Rule [ o_pretty:{Bool} | | ]

SEM Grammar
  | Grammar     loc.o_pretty = attrInfo @lhs.options

SEM Production
  | Production  loc.comment = let syn'     = map toString (Map.toList @syn)
                                  inh'     = map toString (Map.toList @inh)
                                  toString (a,t) = (getName a, case t of (NT nt) -> getName nt; Haskell t -> t)
                                  chnn     = inh' `intersect` syn'
                                  inhn     = inh' \\ chnn
                                  synn     = syn' \\ chnn
                              in Comment . unlines $
                                 [ replicate 3 ' ' ++ "inherited attributes:"
                                 , unlines . map ((replicate 6 ' ')++) .
                                       map (\(x,y) -> x ++ replicate ((20 - length x) `max` 0) ' ' ++ " : " ++ y) $ inhn
                                 , replicate 3 ' ' ++ "chained attributes:"
                                 , unlines . map ((replicate 6 ' ')++) .
                                       map (\(x,y) -> x ++ replicate ((20 - length x) `max` 0) ' ' ++ " : " ++ y) $ chnn
                                 , replicate 3 ' ' ++ "synthesised attributes:"
                                 , unlines . map ((replicate 6 ' ')++) .
                                       map (\(x,y) -> x ++ replicate ((20 - length x) `max` 0) ' ' ++ " : " ++ y) $ synn
                                 ]
                
SEM Alternatives [ || comments : {Decls} ] 
  | Cons lhs.comments = @hd.comment : @tl.comments
  | Nil  lhs.comments = []

SEM Alternative [ || comment : {Decl} ] 
  | Alternative lhs.comment = Comment . unlines $
                                 [ replicate 3 ' ' ++ "local variables for " ++ getName @lhs.nt ++ "." ++ getName @con ++ ":"
                                 , unlines . map ((replicate 6 ' ')++) $ map getName @rules.locVars
                                 ]

-- copied from DefaultRules, double computation :-(

ATTR Rules Rule Patterns Pattern [ | | locVars USE {++} {[]}:{[Name]} ]

SEM Pattern
  | Alias    lhs.locVars   = if @field == _LOC 
                                then [@attr]
                                else []