Add support for double literals

src/Expr.hs

@@ -16,6 +16,7 @@ import           Text.Parsec.Text  (Parser)
 -- >>> :set -XOverloadedStrings
 
 data Expr = IntLiteral Integer
+          | DoubleLiteral Double
           | StringLiteral Text
           | FunctionCall { fcName :: Text, fcArgs :: [Expr] }
           deriving (Show, Eq)
@@ -27,14 +28,28 @@ instance IsString Expr where
       (Left err) -> error $ show err
       (Right e)  -> e
 
+
 expr :: Parser Expr
 expr = literal <|> functionCall
 
+
 literal :: Parser Expr
 literal = number <|> stringLiteral
 
+
 number :: Parser Expr
-number = IntLiteral . read <$> many1 digit
+number = do
+  integer <- many1 digit
+  optionalDot <- optionMaybe (char '.')
+  case optionalDot of
+    Nothing  -> pure $ IntLiteral (read integer)
+    (Just _) -> do
+      fractional <- many digit
+      let
+        value :: Double
+        value = read $ integer <> "." <> fractional
+      pure $ DoubleLiteral value
+
 
 stringLiteral :: Parser Expr
 stringLiteral = do
@@ -64,12 +79,14 @@ ident = do
   pure $ T.pack (firstChar : next)
 
 
-
 -- | Parse an expression
 --
 -- >>> parseExpr "20"
 -- Right (IntLiteral 20)
 --
+-- >>> parseExpr "20.3"
+-- Right (DoubleLiteral 20.3)
+--
 -- >>> parseExpr "uuid4"
 -- Right (FunctionCall {fcName = "uuid4", fcArgs = []})
 --

src/Fake.hs

@@ -78,8 +78,8 @@ randomInt lower upper = do
 
 -- | Generate a random double
 --
--- >>> exec "randomDouble(1, 3)"
--- Number 1.1555807501666868
+-- >>> exec "randomDouble(1.5, 3)"
+-- Number 1.6166855626250152
 randomDouble :: Expr -> Expr -> State Value
 randomDouble lower upper = do
   lower' <- A.asDouble <$> eval lower
@@ -162,6 +162,7 @@ fromFile fileName = do
 eval :: Expr -> State Value
 eval (IntLiteral x)    = pure $ Number $ fromInteger x
 eval (StringLiteral x) = pure $ String x
+eval (DoubleLiteral x) = pure $ Number $ S.fromFloatDigits x
 eval (FunctionCall "uuid4" []) = String . UUID.toText <$> withStdGen random
 eval (FunctionCall "uuid1" []) = String . UUID.toText <$> uuid1
 eval (FunctionCall "randomInt" [lower, upper]) = randomInt lower upper