Write You a Haskell Stephen Diehl

Recommendations

Info

initParseState :: ParseState initParseState = ParseState 0 defaultOps addOperator :: FixitySpec -> Parsec s ParseState () addOperator fixdecl = do modifyState $ \st -> st { fixities = fixdecl : (fixities st) } e initial state will consist of the default arithmetic and list operators defined with the same specification as the <strong>Haskell</strong> specification. defaultOps :: [FixitySpec] defaultOps = [ FixitySpec (Infix L 4) ”>” , FixitySpec (Infix L 4) ” Int fixityPrec (FixitySpec (Infix _ n) _) = n fixityPrec (FixitySpec _ _) = 0 toParser (FixitySpec ass tok) = case ass of Infix L _ -> infixOp tok (op (Name tok)) Ex.AssocLeft Infix R _ -> infixOp tok (op (Name tok)) Ex.AssocRight Infix N _ -> infixOp tok (op (Name tok)) Ex.AssocNone mkTable ops = map (map toParser) $ groupBy ((==) ‘on‘ fixityPrec) $ reverse $ sortBy (compare ‘on‘ fixityPrec) $ ops Now when parsing a infix operator declarations we simply do a state operation and add the operator to the parser state so that all subsequent definitions. is differs from <strong>Haskell</strong> slightly in that operators must be defined before their usage in a module. 140
fixityspec :: Parser FixitySpec fixityspec = do fix
Page 1 and 2:
Write You a Haskell Building a mode
Page 3 and 4:
Contents Introduction 6 Goals . . .
Page 5 and 6:
Evaluation . . . . . . . . . . . .
Page 7 and 8:
Syntax Errors . . . . . . . . . . .
Page 9 and 10:
• containers • unordered-contai
Page 11 and 12:
File ””, line 1, in TypeError:
Page 13 and 14:
] TokenSym ”x”, TokenAdd, Token
Page 15 and 16:
f: mov res, arg add res, 1 ret defi
Page 17 and 18:
Datatypes Constructors for datatype
Page 19 and 20:
length :: [a] -> Int length [] = 0
Page 21 and 22:
Higher-Kinded Types e “type of ty
Page 23 and 24:
eturn a >>= f = f a Law 2 m >>= ret
Page 25 and 26:
data PlatonicSolid = Tetrahedron |
Page 27 and 28:
foo :: Stack () foo = Stack $ do pu
Page 29 and 30:
, bar :: Int } deriving (Show) comp
Page 31 and 32:
class IsString a where fromString :
Page 33 and 34:
Parsing Parser Combinators For pars
Page 35 and 36:
instance Monad Parser where return
Page 37 and 38:
natural :: Parser Integer natural =
Page 39 and 40:
print $ eval $ run a Now we can try
Page 41 and 42:
module Syntax where data Expr = Tr
Page 43 and 44:
cannot proceed because the reductio
Page 45 and 46:
later into native CPU instructions
Page 47 and 48:
λx.e ere are several syntactical c
Page 49 and 50:
type Name = String data Expr = Var
Page 51 and 52:
Eta-expansion (λx.ex)e ′ β →
Page 53 and 54:
Y = SSK(S(K(SS(S(SSK))))K) In a unt
Page 55 and 56:
parensIf :: Bool -> Doc -> Doc pare
Page 57 and 58:
In this notation, the expression ab
Page 59 and 60:
In all the languages which we will
Page 61 and 62:
eval1 expr = case expr of Succ t ->
Page 63 and 64:
TNat -> return TNat _ -> throwError
Page 65 and 66:
• T-Var Variables are simply pull
Page 67 and 68:
t1 throwError $ Mismatch t2 a ty -
Page 69 and 70:
Full Source • Typed Arithmetic
Page 71 and 72:
1. Evaluate f to λy.e 2. Evaluate
Page 73 and 74:
e 1 → e ′ 1 e 1 e 2 → e ′ 1
Page 75 and 76:
case we will use a GADT to embed a
Page 77 and 78:
AppP (AppP (VarP f) (VarP x)) (AppP
Page 79 and 80:
e prim function will simply perform
Page 81 and 82:
ere is nothing more practical than
Page 83 and 84:
As before let rec expressions will
Page 85 and 86:
Γ, x : τ = (Γ\x) ∪ {x : τ} Op
Page 87 and 88:
where s’ = foldr Map.delete s as
Page 89 and 90:
s2 Type -> Infer Subst bind a t |
Page 91 and 92: infer :: TypeEnv -> Expr -> Infer (
Page 93 and 94: App e1 e2 -> do tv
Page 95 and 96: -- | Unify two types uni :: Type ->
Page 97 and 98: unifies t (TVar v) = v ‘bind‘ t
Page 99 and 100: Interpreter Our evaluator will oper
Page 101 and 102: Our language can be compiled into a
Page 103 and 104: exec True contents -- :type command
Page 105 and 106: let rec fib n = if (n == 0) then 0
Page 107 and 108: • Higher order functions • Para
Page 109 and 110: • e PHOAS, the type-erased Core i
Page 111 and 112: If the ProtoHaskell compiler is inv
Page 113 and 114: infixl 6 + infixl 7 * f = 1 + 2 * 3
Page 115 and 116: -- Desugared f x = case x of Just _
Page 117 and 118: data Kind = KStar | KArr Kind Kind
Page 119 and 120: TypeError) -- | Inference state dat
Page 121 and 122: e expression or Expr type is the co
Page 123 and 124: data qname [var] where [tydecl] dat
Page 125 and 126: Typeclass Declarations Typeclass de
Page 127 and 128: Syntax Name Kind Description (,) Pa
Page 129 and 130: So for instance if we have three AS
Page 131 and 132: -- **Begin Haskell Syntax** { {-# O
Page 133 and 134: tokens :- -- Whitespace insensitive
Page 135 and 136: Expr : let VAR ’=’ Expr in Expr
Page 137 and 138: data Type = TVar Loc TVar | TCon Lo
Page 139 and 140: -- Start of layout ( Column: 0 ) fi
Page 141: Extensible Operators Haskell famous
show all

Write You a Haskell Stephen Diehl

Create successful ePaper yourself

Delete template?

Save as template?