escape: remove too agressive JSON escaping (#248)

Criterion/Report.hs

@@ -119,8 +119,14 @@ report reports = do
 -- (should only affect old versions of IE).
 --
 -- The following characters are replaced with their unicode escape sequnces
--- (\uXXXX) <, >, &, +, \0, \n, \r, ' (single quote), /, \, \x2028 (line
--- separator) and \x2029 (paragraph separator)
+-- (\uXXXX):
+-- <, >, &, +, \x2028 (line separator), and \x2029 (paragraph
+-- separator)
+--
+-- Other characters are such as \\ (backslash) and \n (newline) are not escaped
+-- here as the JSON serializer @encodeToLazyText@ already escapes them when
+-- they occur inside JSON strings and they cause no issues with respect to HTML
+-- safety when used outside of strings in the JSON-encoded payload.
 escapeJSON :: Char -> TL.Text
 escapeJSON '<'      = "\\u003c" -- ban closing of the script tag by making </ impossible
 escapeJSON '>'      = "\\u003e" -- encode tags with unicode escape sequences
@@ -129,11 +135,6 @@ escapeJSON '\x2029' = "\\u2029" -- paragraph separator
 escapeJSON '&'      = "\\u0026" -- avoid HTML entities
 escapeJSON '+'      = "\\u002b" -- + can be used in UTF-7 escape sequences
 escapeJSON '\0'     = "\\u0000" -- make null characters explicit
-escapeJSON '\n'     = "\\u000a" -- for good measure also escape newlines
-escapeJSON '\r'     = "\\u000d" -- , carriage returns
-escapeJSON '\''     = "\\u0027" -- , single quotes
-escapeJSON '/'      = "\\u002f" -- , slashes
-escapeJSON '\\'     = "\\u005c" -- , and backslashes
 escapeJSON c        = TL.singleton c
 
 -- | Format a series of 'Report' values using the given Mustache template.

examples/Quotes.hs

@@ -0,0 +1,12 @@
+module Main where
+
+import Criterion
+import Criterion.Main
+
+main :: IO ()
+main = defaultMain
+    [ env (return ()) $
+       \ ~() -> bgroup "\"oops\"" [bench "dummy" $ nf id ()]
+    , env (return ()) $
+       \ ~() -> bgroup "'oops'" [bench "dummy" $ nf id ()]
+    ]

examples/criterion-examples.cabal

@@ -112,6 +112,15 @@ executable extensible-cli
     criterion,
     optparse-applicative
 
+executable quotes
+  main-is: Quotes.hs
+
+  default-language: Haskell2010
+  ghc-options: -Wall -rtsopts
+  build-depends:
+    base == 4.*,
+    criterion
+
 -- Cannot uncomment due to https://github.com/haskell/cabal/issues/1725
 --
 -- executable judy