module Optimus.Pretty where
	import Flite.Syntax
	import Text.PrettyPrint.Leijen
	
	putProg :: Prog -> IO ()
	putProg = putDoc . braces . enclose line line . indent 2 . vsep . punctuate (semi <> line) . map pretty
	
	prettyProg :: Prog -> String
	prettyProg = show . braces . enclose line line . indent 2 . vsep . punctuate (semi <> line) . map pretty
	
	instance Pretty Decl where
		pretty (Func f a r) = nest 2 $ text f
							<+> hsep (map prettyArg a)
							</> char '='
							<+> pretty r
							
	instance Pretty Exp where
		pretty (App x ys) 	= hsep (pretty x : map prettyArg ys)
		pretty (Case x as)	= nest 2 (text "case" </> prettyArg x)
							</> nest 2 (text "of" </> prettyBlock prettyAlt as)
		pretty (Let bs y)	= nest 2 (text "let" </> prettyBlock prettyBind bs)
							</> nest 2 (text "in" </> prettyArg y)
		pretty (Var v)		= text v
		pretty (Fun f)		= text f
		pretty (Con c)		= text c
		pretty (Int i)		= int i
		pretty (Bottom)		= text "_|_"
	
	prettyBlock :: (a -> Doc) -> [a] -> Doc
	prettyBlock f = braces . enclose line line . vsep . punctuate semi . map f
	
	prettyAlt :: Alt -> Doc
	prettyAlt (p, x) = nest 2 $ pretty p <+> text "->" </> pretty x
	
	prettyBind :: Binding -> Doc
	prettyBind (v, x) = text v <+> text "=" <+> pretty x
	
	prettyArg :: Exp -> Doc
	prettyArg (App e []) = prettyArg e
	prettyArg e@(App _ _) = parens . pretty $ e
	prettyArg e@(Case _ _) = parens . pretty $ e
	prettyArg e@(Let _ _) = parens . pretty $ e
	prettyArg e = pretty e
	
	instance Show Decl where
		show = ('\n':) . show  . pretty
		
	instance Show Exp where
		show = ('\n':) . show . pretty