Add function to join arguments/array into a string

Example usage:

    mkjson "x=join('', join(replicate(randomInt(40, 48), randomInt(1, 9))), '.', join(replicate(2, randomInt(1, 9))))"

README.md

@@ -85,6 +85,8 @@ You may also want to read this [introduction and sample use case][1].
  - object(key, value [, ...])
  - fromFile(fileName)
  - fromRegex(pattern)
+ - join(sep, val1, [, ...])
+ - join(array)
 
 
 ## Installation

src/Aeson.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE OverloadedStrings #-}
 
 module Aeson (
   asInt,
@@ -65,7 +66,12 @@ asArray o         = Left $ "Expected an array, but received: " <> show o
 --
 -- >>> asText (Number 10.3)
 -- Right "10.3"
+--
+-- >>> asText (Number 4)
+-- Right "4"
 asText :: Value -> Either String T.Text
 asText (String t) = Right t
-asText (Number n) = Right . T.pack $ show n
+asText (Number n) = Right $ case (S.toBoundedInteger n :: Maybe Int) of
+  Nothing -> T.pack $ show n
+  Just int -> T.pack $ show int
 asText o          = Left $ "Expected a string, but received: " <> show o

src/Fake.hs

@@ -54,6 +54,7 @@ import qualified Text.Regex.TDFA.ReadRegex as R
 import Prelude hiding (lines, replicate)
 import Data.Aeson.Key (fromText)
 import Data.Aeson.Types (Pair)
+import qualified Data.Either as V
 
 
 -- $setup
@@ -154,6 +155,44 @@ oneOfArray arr = do
   pure $ arr' V.! idx
 
 
+-- | Join argument expressions into a string.
+--
+-- If there is more than one argument the first first argument is used as separator.
+-- If there is a single argument and it is an array, the array is concattenated.
+--
+-- >>> exec "join(['Hello', 'World'])"
+-- String "HelloWorld"
+--
+-- >>> exec "join('-', 'Hello', 'World')"
+-- String "Hello-World"
+--
+-- >>> exec "join('foo')"
+-- String "foo"
+--
+-- >>> exec "join([1, 2, 3])"
+-- String "123"
+--
+-- >>> exec "join()"
+-- String ""
+joinArgs :: [Expr] -> Fake Value
+joinArgs [] = pure $ String ""
+joinArgs [arg] = do
+  val <- eval arg
+  pure $ case val of
+    (String _) -> val
+    (Array arr') -> do
+      let strings = V.rights . V.toList $ fmap A.asText arr'
+          text = T.intercalate "" strings
+      String text
+    _ -> error $ "Expected a string or array, but received: " <> show val
+joinArgs (x:xs) = do
+  sep <- Except.liftEither . A.asText =<< eval x
+  values <- mapM eval xs
+  let strings = V.rights $ fmap A.asText values
+      text = T.intercalate sep strings
+  pure $ String text
+
+
 -- | Select one random argument
 --
 -- >>> exec "oneOf(37, 42, 21)"
@@ -443,6 +482,7 @@ eval (Fn "randomDateTime" [lower, upper]) = do
   upper' <- rightToMaybe . A.asText <$> eval upper
   randomDateTime lower' upper'
 eval (Fn "array" args) = Array . V.fromList <$> mapM eval args
+eval (Fn "join" args) = joinArgs args
 eval (Fn "oneOf" [arg]) = oneOfArray arg
 eval (Fn "oneOf" args) = oneOfArgs args
 eval (Fn "replicate" [num, expr]) = replicate num expr

stack.yaml

@@ -1,5 +1,5 @@
 ---
-resolver: lts-22.13
+resolver: lts-22.29
 
 packages:
   - .

stack.yaml.lock

@@ -6,7 +6,7 @@
 packages: []
 snapshots:
 - completed:
-    sha256: 6f0bea3ba5b07360f25bc886e8cff8d847767557a492a6f7f6dcb06e3cc79ee9
-    size: 712905
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/22/13.yaml
-  original: lts-22.13
+    sha256: 98fe98dae6f42f9b4405e5467f62f57df2896c57b742a09772688c900c722510
+    size: 719579
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/22/29.yaml
+  original: lts-22.29