forked from GitHub/gf-core
165 lines
4.6 KiB
Haskell
165 lines
4.6 KiB
Haskell
module PrintCFG where
|
|
|
|
-- pretty-printer generated by the BNF converter
|
|
|
|
import AbsCFG
|
|
import Char
|
|
|
|
-- the top-level printing method
|
|
printTree :: Print a => a -> String
|
|
printTree = render . prt 0
|
|
|
|
type Doc = [ShowS] -> [ShowS]
|
|
|
|
doc :: ShowS -> Doc
|
|
doc = (:)
|
|
|
|
-- seriously hacked spacing
|
|
render :: Doc -> String
|
|
render d = rend 0 (map ($ "") $ d []) "" where
|
|
rend i ss = case ss of
|
|
";" :ts -> showString ";" . new i . rend i ts
|
|
-- H removed a bunch of cases here
|
|
"]":".":ts -> showString "]" . space "." . rend i ts -- H
|
|
t:t' :ts | noSpace t' -> showString t . showString t' . rend i ts -- H
|
|
t :ts | noSpace t -> showString t . rend i ts -- H
|
|
t :ts -> space t . rend i ts
|
|
_ -> id
|
|
new i = showChar '\n' . replicateS (2*i) (showChar ' ') . dropWhile isSpace
|
|
space t = showString t . (\s -> if null s then "" else (' ':s))
|
|
noSpace t = t `elem` ["[","]","{","}",",","/",":",".","!"] -- H
|
|
|
|
parenth :: Doc -> Doc
|
|
parenth ss = doc (showChar '(') . ss . doc (showChar ')')
|
|
|
|
concatS :: [ShowS] -> ShowS
|
|
concatS = foldr (.) id
|
|
|
|
concatD :: [Doc] -> Doc
|
|
concatD = foldr (.) id
|
|
|
|
replicateS :: Int -> ShowS -> ShowS
|
|
replicateS n f = concatS (replicate n f)
|
|
|
|
-- the printer class does the job
|
|
class Print a where
|
|
prt :: Int -> a -> Doc
|
|
prtList :: [a] -> Doc
|
|
prtList = concatD . map (prt 0)
|
|
|
|
instance Print a => Print [a] where
|
|
prt _ = prtList
|
|
|
|
instance Print Char where
|
|
prt _ s = doc (showChar '\'' . mkEsc '\'' s . showChar '\'')
|
|
prtList s = doc (showChar '"' . concatS (map (mkEsc '"') s) . showChar '"')
|
|
|
|
mkEsc :: Char -> Char -> ShowS
|
|
mkEsc q s = case s of
|
|
_ | s == q -> showChar '\\' . showChar s
|
|
'\\'-> showString "\\\\"
|
|
'\n' -> showString "\\n"
|
|
'\t' -> showString "\\t"
|
|
_ -> showChar s
|
|
|
|
prPrec :: Int -> Int -> Doc -> Doc
|
|
prPrec i j = if j<i then parenth else id
|
|
|
|
|
|
instance Print Integer where
|
|
prt _ x = doc (shows x)
|
|
prtList es = case es of
|
|
[] -> (concatD [])
|
|
[x] -> (concatD [prt 0 x])
|
|
x:xs -> (concatD [prt 0 x , doc (showString ",") , prt 0 xs])
|
|
|
|
|
|
instance Print Double where
|
|
prt _ x = doc (shows x)
|
|
|
|
|
|
instance Print Ident where
|
|
prt _ (Ident i) = doc (showString i)
|
|
|
|
|
|
|
|
instance Print Grammars where
|
|
prt i e = case e of
|
|
Grammars grammars -> prPrec i 0 (concatD [prt 0 grammars])
|
|
|
|
|
|
instance Print Grammar where
|
|
prt i e = case e of
|
|
Grammar id flags rules -> prPrec i 0 (concatD [doc (showString "grammar") , prt 0 id , prt 0 flags , prt 0 rules , doc (showString "end") , doc (showString "grammar")])
|
|
|
|
prtList es = case es of
|
|
[] -> (concatD [])
|
|
x:xs -> (concatD [prt 0 x , prt 0 xs])
|
|
|
|
instance Print Flag where
|
|
prt i e = case e of
|
|
StartCat category -> prPrec i 0 (concatD [doc (showString "startcat") , prt 0 category])
|
|
|
|
prtList es = case es of
|
|
[] -> (concatD [])
|
|
x:xs -> (concatD [prt 0 x , doc (showString ";") , prt 0 xs])
|
|
|
|
instance Print Rule where
|
|
prt i e = case e of
|
|
Rule id name profile category symbols -> prPrec i 0 (concatD [prt 0 id , doc (showString ":") , prt 0 name , prt 0 profile , doc (showString ".") , prt 0 category , doc (showString "->") , prt 0 symbols])
|
|
|
|
prtList es = case es of
|
|
[] -> (concatD [])
|
|
x:xs -> (concatD [prt 0 x , doc (showString ";") , prt 0 xs])
|
|
|
|
instance Print Profile where
|
|
prt i e = case e of
|
|
Profile intss -> prPrec i 0 (concatD [doc (showString "[") , prt 0 intss , doc (showString "]")])
|
|
|
|
|
|
instance Print Ints where
|
|
prt i e = case e of
|
|
Ints ns -> prPrec i 0 (concatD [doc (showString "[") , prt 0 ns , doc (showString "]")])
|
|
|
|
prtList es = case es of
|
|
[] -> (concatD [])
|
|
[x] -> (concatD [prt 0 x])
|
|
x:xs -> (concatD [prt 0 x , doc (showString ",") , prt 0 xs])
|
|
|
|
instance Print Symbol where
|
|
prt i e = case e of
|
|
CatS category -> prPrec i 0 (concatD [prt 0 category])
|
|
TermS str -> prPrec i 0 (concatD [prt 0 str])
|
|
|
|
prtList es = case es of
|
|
[] -> (concatD [])
|
|
x:xs -> (concatD [prt 0 x , prt 0 xs])
|
|
|
|
instance Print Name where
|
|
prt i e = case e of
|
|
Name identparams category -> prPrec i 0 (concatD [prt 0 identparams , prt 0 category])
|
|
|
|
|
|
instance Print Category where
|
|
prt i e = case e of
|
|
Category identparam id params -> prPrec i 0 (concatD [prt 0 identparam , doc (showString ".") , prt 0 id , prt 0 params])
|
|
|
|
|
|
instance Print IdentParam where
|
|
prt i e = case e of
|
|
IdentParam id params -> prPrec i 0 (concatD [prt 0 id , doc (showString "{") , prt 0 params , doc (showString "}")])
|
|
|
|
prtList es = case es of
|
|
[] -> (concatD [])
|
|
x:xs -> (concatD [prt 0 x , doc (showString "/") , prt 0 xs])
|
|
|
|
instance Print Param where
|
|
prt i e = case e of
|
|
Param id -> prPrec i 0 (concatD [doc (showString "!") , prt 0 id])
|
|
|
|
prtList es = case es of
|
|
[] -> (concatD [])
|
|
x:xs -> (concatD [prt 0 x , prt 0 xs])
|
|
|
|
|