calculator (empty) → 0.1.2.2
raw patch · 8 files changed
+626/−0 lines, 8 filesdep +QuickCheckdep +basedep +haskelinesetup-changed
Dependencies added: QuickCheck, base, haskeline, parsec
Files
- LICENSE +339/−0
- Setup.hs +2/−0
- calculator.cabal +46/−0
- src/Calculator/Evaluator.hs +40/−0
- src/Calculator/Parser.hs +85/−0
- src/Main.hs +21/−0
- src/Model/Arithmetic.hs +41/−0
- tests/Arithmetic.hs +52/−0
+ LICENSE view
@@ -0,0 +1,339 @@+ GNU GENERAL PUBLIC LICENSE+ Version 2, June 1991++ Copyright (C) 1989, 1991 Free Software Foundation, Inc.,+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA+ Everyone is permitted to copy and distribute verbatim copies+ of this license document, but changing it is not allowed.++ Preamble++ The licenses for most software are designed to take away your+freedom to share and change it. By contrast, the GNU General Public+License is intended to guarantee your freedom to share and change free+software--to make sure the software is free for all its users. This+General Public License applies to most of the Free Software+Foundation's software and to any other program whose authors commit to+using it. (Some other Free Software Foundation software is covered by+the GNU Lesser General Public License instead.) You can apply it to+your programs, too.++ When we speak of free software, we are referring to freedom, not+price. 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+ Setup.hs view
@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain
+ calculator.cabal view
@@ -0,0 +1,46 @@+name: calculator+version: 0.1.2.2+synopsis: A calculator that operates on string inputs+description: A calculator repl that processes mathematical expressions.+ Does basic arithmetic, and provides pre-defined basic mathematical functions.+ Aims to provide variable bindings and function bindings in the future.+homepage: https://github.com/sumitsahrawat/calculator+license: GPL-2+license-file: LICENSE+author: Sumit Sahrawat+maintainer: sumit.sahrawat.apm13@itbhu.ac.in+-- copyright: +category: Math+build-type: Simple+-- extra-source-files: +cabal-version: >=1.10++executable calculator+ main-is: Main.hs+ other-modules: Calculator.Evaluator+ , Calculator.Parser+ -- other-extensions: + build-depends: QuickCheck >= 2.7.6 && <2.7.7+ , base >=4.7 && <4.8+ , haskeline >=0.7.1.0 && <0.7.2.0+ , parsec >=3.1.7 && <3.2+ hs-source-dirs: src/+ ghc-options: -Wall+ default-language: Haskell2010++test-suite model-test-arithmetic+ type: exitcode-stdio-1.0+ main-is: Arithmetic.hs+ other-modules: Calculator.Evaluator+ , Calculator.Parser+ , Model.Arithmetic+ hs-source-dirs: tests/ src/+ build-depends: QuickCheck >= 2.7.6 && <2.7.7+ , base >=4.7 && <4.8+ , parsec >=3.1.7 && <3.2+ ghc-options: -Wall+ default-language: Haskell2010++source-repository head+ type: git+ location: https://github.com/sumitsahrawat/calculator.git
+ src/Calculator/Evaluator.hs view
@@ -0,0 +1,40 @@+module Calculator.Evaluator (eval) where++import Calculator.Parser (parseExpr)+import Calculator.Primitives++import Control.Applicative ((<$>), (<*))+import Data.Function (on)+import Text.ParserCombinators.Parsec (ParseError, eof, parse)++evaluate :: Expr -> Expr+evaluate e@(Constant _) = e+evaluate e@(InvalidError _) = e+evaluate (UnOp (UnaryOp op) e) = Constant . op . fromConst $ evaluate e+evaluate (BinOp (expr, rest)) = process expr rest+evaluate (Function "" e) = evaluate e+evaluate (Function f e) =+ let func = lookup f dispatch :: Maybe (Number -> Number)+ val = fromConst $ evaluate e+ in case func of+ Nothing -> InvalidError $ "Unknown function " ++ show f+ Just g -> Constant $ g val+evaluate _ = InvalidError evalFaliure++process :: Expr -> [(Operator, Expr)] -> Expr+process expr rest = evaluate $ foldl evalPart expr rest++evalPart :: Expr -> (Operator, Expr) -> Expr+evalPart e1 ((BinaryOp op), e2) =+ let val1 = evaluate e1+ val2 = evaluate e2+ in if isConst val1 && isConst val2+ then Constant $ (op `on` fromConst) val1 val2+ else case (val1, val2) of+ (e@(InvalidError _), _) -> e+ (_, e@(InvalidError _)) -> e+ (_, _) -> InvalidError evalFaliure+evalPart _ _ = InvalidError evalFaliure++eval :: String -> Either ParseError Expr+eval s = evaluate <$> parse (parseExpr <* eof) s s
+ src/Calculator/Parser.hs view
@@ -0,0 +1,85 @@+module Calculator.Parser (parseExpr) where++import Calculator.Primitives++import Control.Applicative ((<$>))+import Control.Monad (liftM2)+import Text.ParserCombinators.Parsec++-- expr -> term ( "+-" term )*++parseExpr :: Parser Expr+parseExpr = do+ term <- parseTerm+ rest <- parseRestExpr+ if null rest+ then return term+ else return $ BinOp (term, rest)++parseRestExpr :: Parser [(Operator, Expr)]+parseRestExpr = many $ do+ oper <- oneOf "+-"+ let (Just op) = lookup oper binaryOps+ expr <- parseTerm+ return (op, expr)++-- term -> fact ( "*/" fact )*++parseTerm :: Parser Expr+parseTerm = do+ fact <- parseFact+ rest <- parseRestTerm+ if null rest+ then return fact+ else return $ BinOp (fact, rest)++parseRestTerm :: Parser [(Operator, Expr)]+parseRestTerm = many $ do+ oper <- oneOf "*/"+ let (Just op) = lookup oper binaryOps+ expr <- parseFact+ return (op, expr)++-- fact -> val ( "^" fact )?+-- Right recursion for right associativity++constEq :: Expr -> Expr -> Bool+constEq (Constant x) (Constant y) = x == y+constEq _ _ = False++parseFact :: Parser Expr+parseFact = do+ val <- parseVal+ pow <- parsePower+ if constEq (Constant 1) (snd pow)+ then return val+ else return $ BinOp (val, [pow])++parsePower :: Parser (Operator, Expr)+parsePower = let (Just op) = lookup '^' binaryOps+ in option (op, Constant 1) $ do+ _ <- char '^'+ fact <- parseFact+ return (op, fact)++-- val -> func? ( expr ) | number+-- Parentheses can be seen as function calls++parseVal :: Parser Expr+parseVal = parseFunction <|> parseNumber++parseFunction :: Parser Expr+parseFunction = do+ fname <- option "" (many letter)+ _ <- char '('+ e <- parseExpr+ _ <- char ')'+ return $ Function fname e++parseNumber :: Parser Expr+parseNumber = Constant . read <$> do+ dec <- many1 digit+ flt <- option "" (liftM2 (:) (char '.') (many1 digit))+ if null flt+ then return dec+ else return $ dec ++ flt
+ src/Main.hs view
@@ -0,0 +1,21 @@+module Main where++import Calculator.Evaluator (eval)+import Calculator.Primitives (result)++import System.Console.Haskeline++type Repl a = InputT IO a++process :: String -> Repl ()+process input = outputStrLn $ result $ eval input++repl :: Repl ()+repl = do+ input <- getInputLine "calc> "+ case input of+ Nothing -> return ()+ Just inp -> process inp >> repl++main :: IO ()+main = runInputT defaultSettings repl
+ src/Model/Arithmetic.hs view
@@ -0,0 +1,41 @@+module Model.Arithmetic (modelEval) where++import Calculator.Primitives (Number)++import Control.Applicative ((<*))+import Text.ParserCombinators.Parsec+import Text.ParserCombinators.Parsec.Expr++modelEval :: String -> Either ParseError Number+modelEval = parse (expr <* eof) "expression"++expr :: Parser Number+expr = buildExpressionParser table factor <?> "Expression"++table :: [[ Operator Char st Number ]]+table = [ [ op "^" (**) AssocRight ]+ , [ op "*" (*) AssocLeft, op "/" (/) AssocLeft ]+ , [ op "+" (+) AssocLeft, op "-" (-) AssocLeft ]+ ]+ where op s f = Infix (string s >> return f)++parseFactor :: Parser Number+parseFactor = do+ _ <- char '('+ x <- expr+ _ <- char ')'+ return x++factor :: Parser Number+factor = parseFactor <|> number <?> "Simple expression"++number :: Parser Number+number = fmap read $ do+ ch <- many1 digit+ de <- option "" $ do+ dot <- char '.'+ flt <- many1 digit+ return $ dot : flt+ return $ if null de+ then ch+ else ch ++ de
+ tests/Arithmetic.hs view
@@ -0,0 +1,52 @@+module Main where++import Calculator.Evaluator (eval)+import Calculator.Primitives (Number)+import Model.Arithmetic++import Data.Function (on)+import Control.Monad+import Control.Applicative ((<$>))+import System.Exit (exitSuccess, exitFailure)+import Test.QuickCheck++newtype ExprString = ExprString { unwrapExprString :: String }++instance Show ExprString where+ show (ExprString s) = s++instance Arbitrary ExprString where+ arbitrary = ExprString <$> genExprString++operators :: [Char]+operators = "+-*/^"++genOp :: Gen Char+genOp = elements operators++genArg :: Gen String+genArg = show . abs <$> (arbitrary :: Gen Number)++genExprString :: Gen String+genExprString = liftM concat .+ liftM2 (:) genArg .+ listOf $ liftM2 (:) genOp genArg++-- Converts to string so that NaN == NaN evaluates to true+equal :: Either a Number -> Either a Number -> Bool+equal (Right x) (Right y) = on (==) show x y+equal (Left _) (Left _) = True+equal _ _ = False++prop_model :: ExprString -> Bool+prop_model xs = (calcResult `equal` modelResult)+ where expr = unwrapExprString xs+ calcResult = eval expr+ modelResult = modelEval expr++main :: IO ()+main = do+ status <- quickCheckWithResult stdArgs { maxSuccess = 2500 } prop_model+ case status of+ (Success _ _ _) -> exitSuccess+ _ -> exitFailure