001d620 · elk · git.iko.soy

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Provide a show instance for Patterns.

001d620evancz14 years ago

elm/src/Ast.hs+18−1

@@ -1,8 +1,11 @@

2module Ast where

4+import Data.Char (isDigit)

5+import Data.List (intercalate)

4data Pattern = PData String [Pattern] | PVar String | PAnything

7data Pattern = PData String [Pattern] | PVar String | PAnything

5− deriving (Show, Eq)

8+ deriving (Eq)

7data Expr = Number Int

10data Expr = Number Int

8 | Chr Char

11 | Chr Char

@@ -37,3 +40,17 @@ pcons h t = PData "Cons" [h,t]

37pnil = PData "Nil" []

40pnil = PData "Nil" []

38plist = foldr pcons pnil

41plist = foldr pcons pnil

39ptuple es = PData ("Tuple" ++ show (length es)) es

42ptuple es = PData ("Tuple" ++ show (length es)) es

43+

44+parens s = "(" ++ s ++ ")"

45+

46+instance Show Pattern where

47+ show (PVar x) = x

48+ show PAnything = "_"

49+ show (PData "Cons" [hd@(PData "Cons" _),tl]) =

50+ parens (show hd) ++ " : " ++ show tl

51+ show (PData "Cons" [hd,tl]) = show hd ++ " : " ++ show tl

52+ show (PData "Nil" []) = "[]"

53+ show (PData name ps) =

54+ if take 5 name == "Tuple" && all isDigit (drop 5 name) then

55+ parens . intercalate ", " $ map show ps

56+ else (if null ps then id else parens) $ unwords (name : map show ps)

elm/src/Parse/Parser.hs+1−1

@@ -54,7 +54,7 @@ parensTerm = parens $ choice

54term = choice [ numTerm, strTerm, chrTerm

55 , accessible varTerm

56 , listTerm, parensTerm ]

57− <?> "basic term (number, variable, etc.)"

57+ <?> "basic term (4, x, 'c', etc.)"

59-------- Applications --------