Add initial support for --color

ShellCheck/Checker.hs

@@ -48,6 +48,7 @@ checkScript sys spec = do
     results <- checkScript (csScript spec)
     return CheckResult {
         crFilename = csFilename spec,
+        crColorOption = csColorOption spec,
         crComments = results
     }
   where

ShellCheck/Formatter/TTY.hs

@@ -46,11 +46,11 @@ colorForLevel level =
         otherwise -> 0 -- none
 
 outputError file error = do
-    color <- getColorFunc
+    color <- getColorFunc $ ColorAuto -- FIXME: should respect --color
-    hPutStrLn stderr $ color "error" $ file ++ ": " ++ error
+    hPutStrLn stderr $ color "error ZZZ" $ file ++ ": " ++ error
 
 outputResult result contents = do
-    color <- getColorFunc
+    color <- getColorFunc $ crColorOption result
     let comments = crComments result
     let fileLines = lines contents
     let lineCount = fromIntegral $ length fileLines
@@ -75,10 +75,15 @@ cuteIndent comment =
 
 code code = "SC" ++ show code
 
-getColorFunc = do
+getColorFunc colorOption = do
     term <- hIsTerminalDevice stdout
     let windows = "mingw" `isPrefixOf` os
-    return $ if term && not windows then colorComment else const id
+    let isUsableTty = term && not windows
+    let useColor = case colorOption of
+                       ColorAlways -> True
+                       ColorNever -> False
+                       ColorAuto -> isUsableTty
+    return $ if useColor then colorComment else const id
   where
     colorComment level comment =
         ansi (colorForLevel level) ++ comment ++ clear

ShellCheck/Interface.hs

@@ -34,21 +34,30 @@ data CheckSpec = CheckSpec {
     csFilename :: String,
     csScript :: String,
     csExcludedWarnings :: [Integer],
+    csColorOption :: ColorOptions,
     csShellTypeOverride :: Maybe Shell
 } deriving (Show, Eq)
 
 data CheckResult = CheckResult {
     crFilename :: String,
-    crComments :: [PositionedComment]
+    crComments :: [PositionedComment],
+    crColorOption :: ColorOptions
 } deriving (Show, Eq)
 
 emptyCheckSpec = CheckSpec {
     csFilename = "",
     csScript = "",
     csExcludedWarnings = [],
-    csShellTypeOverride = Nothing
+    csShellTypeOverride = Nothing,
+    csColorOption = ColorAuto
 }
 
+data ColorOptions =
+    ColorAuto
+    | ColorAlways
+    | ColorNever
+  deriving (Ord, Eq, Show)
+
 -- Parser input and output
 data ParseSpec = ParseSpec {
     psFilename :: String,

shellcheck.hs

@@ -59,7 +59,8 @@ instance Monoid Status where
 
 data Options = Options {
     checkSpec :: CheckSpec,
-    externalSources :: Bool
+    externalSources :: Bool,
+    color :: ColorOptions
 }
 
 defaultOptions = Options {
@@ -73,6 +74,8 @@ options = [
         (ReqArg (Flag "exclude") "CODE1,CODE2..") "exclude types of warnings",
     Option "f" ["format"]
         (ReqArg (Flag "format") "FORMAT") "output format",
+    Option "C" ["color"]
+        (ReqArg (Flag "color") "WHEN") "Set use of color (auto, always, never)",
     Option "s" ["shell"]
         (ReqArg (Flag "shell") "SHELLNAME") "Specify dialect (sh,bash,dash,ksh)",
     Option "x" ["external-sources"]
@@ -195,6 +198,13 @@ runFormatter sys format options files = do
             then NoProblems
             else SomeProblems
 
+parseColorOption colorOption =
+    case colorOption of
+        "auto" -> ColorAuto
+        "always" -> ColorAlways
+        "never" -> ColorNever
+        _ -> error $ "Bad value for --color `" ++ colorOption ++ "'"
+
 parseOption flag options =
     case flag of
         Flag "shell" str ->
@@ -224,6 +234,13 @@ parseOption flag options =
                 externalSources = True
             }
 
+        Flag "color" color ->
+            return options {
+                checkSpec = (checkSpec options) {
+                    csColorOption = parseColorOption color
+                }
+            }
+
         _ -> return options
   where
     die s = do