System.Console.ANSI

ansi-terminal-0.6.2.3: Simple ANSI terminal support, with Windows compatibility

Safe Haskell | Safe
Language | Haskell98

System.Console.ANSI

Contents

- Basic data types
- Cursor movement by character
- Cursor movement by line
- Directly changing cursor position
- Clearing parts of the screen
- Scrolling the screen
- Select Graphic Rendition mode: colors and other whizzy stuff
- Cursor visibilty changes
- Changing the title
- Checking if handle supports ANSI

Description

Provides ANSI terminal support for Windows and ANSI terminal software running on a Unix-like operating system.

The ANSI escape codes are described at http://en.wikipedia.org/wiki/ANSI_escape_code and provide a rich range of functionality for terminal control, which includes:

- Colored text output, with control over both foreground and background colors
- Hiding or showing the cursor
- Moving the cursor around
- Clearing parts of the screen

The most frequently used parts of this ANSI command set are exposed with a platform independent interface by this module. Every function exported comes in three flavours:

- Vanilla: has an `IO ()` type and doesn't take a `Handle`. This just outputs the ANSI command directly on to the terminal corresponding to stdout. Commands issued like this should work as you expect on both Windows and Unix.
- Chocolate: has an `IO ()` type but takes a `Handle`. This outputs the ANSI command on the terminal corresponding to the supplied handle. Commands issued like this should also work as your expect on both Windows and Unix.
- Strawberry: has a `String` type and just consists of an escape code which can be added to any other bit of text before being output. This version of the API is often convenient to use, but due to fundamental limitations in Windows ANSI terminal support will only work on Unix. On Windows these codes will always be the empty string, so it is possible to use them portably for e.g. coloring console output on the understanding that you will only see colors if you are running on a Unix-like operating system.

Example:

    -- Set colors and write some text in those colors.
    sgrExample :: IO ()
    sgrExample = do
        setSGR [SetColor Foreground Vivid Red]
        setSGR [SetColor Background Vivid Blue]
        putStr "Red-On-Blue"
        setSGR [Reset]
        putStr "White-On-Black"

For many more examples, see the project's extensive Example.hs file.

Synopsis

- data Color
  - = Black
  - | Red
  - | Green
  - | Yellow
  - | Blue
  - | Magenta
  - | Cyan
  - | White
- data ColorIntensity
  - = Dull
  - | Vivid
- data ConsoleLayer
  - = Foreground
  - | Background
- data BlinkSpeed
  - = SlowBlink
  - | RapidBlink
  - | NoBlink
- data Underlining
  - = SingleUnderline
  - | DoubleUnderline
  - | NoUnderline
- data ConsoleIntensity
  - = BoldIntensity
  - | FaintIntensity
  - | NormalIntensity
- data SGR
  - = Reset
  - | SetConsoleIntensity ConsoleIntensity
  - | SetItalicized Bool
  - | SetUnderlining Underlining
  - | SetBlinkSpeed BlinkSpeed
  - | SetVisible Bool
  - | SetSwapForegroundBackground Bool
  - | SetColor ConsoleLayer ColorIntensity Color
- cursorUp :: Int -> IO ()
- cursorDown :: Int -> IO ()
- cursorForward :: Int -> IO ()
- cursorBackward :: Int -> IO ()
- hCursorUp :: Handle -> Int -> IO ()
- hCursorDown :: Handle -> Int -> IO ()
- hCursorForward :: Handle -> Int -> IO ()
- hCursorBackward :: Handle -> Int -> IO ()
- cursorUpCode :: Int -> String
- cursorDownCode :: Int -> String
- cursorForwardCode :: Int -> String
- cursorBackwardCode :: Int -> String
- cursorUpLine :: Int -> IO ()
- cursorDownLine :: Int -> IO ()
- hCursorUpLine :: Handle -> Int -> IO ()
- hCursorDownLine :: Handle -> Int -> IO ()
- cursorUpLineCode :: Int -> String
- cursorDownLineCode :: Int -> String
- setCursorColumn :: Int -> IO ()
- hSetCursorColumn :: Handle -> Int -> IO ()
- setCursorColumnCode :: Int -> String
- setCursorPosition :: Int -> Int -> IO ()
- hSetCursorPosition :: Handle -> Int -> Int -> IO ()
- setCursorPositionCode :: Int -> Int -> String
- clearFromCursorToScreenEnd :: IO ()
- clearFromCursorToScreenBeginning :: IO ()
- clearScreen :: IO ()
- hClearFromCursorToScreenEnd :: Handle -> IO ()
- hClearFromCursorToScreenBeginning :: Handle -> IO ()
- hClearScreen :: Handle -> IO ()
- clearFromCursorToScreenEndCode :: String
- clearFromCursorToScreenBeginningCode :: String
- clearScreenCode :: String
- clearFromCursorToLineEnd :: IO ()
- clearFromCursorToLineBeginning :: IO ()
- clearLine :: IO ()
- hClearFromCursorToLineEnd :: Handle -> IO ()
- hClearFromCursorToLineBeginning :: Handle -> IO ()
- hClearLine :: Handle -> IO ()
- clearFromCursorToLineEndCode :: String
- clearFromCursorToLineBeginningCode :: String
- clearLineCode :: String
- scrollPageUp :: Int -> IO ()
- scrollPageDown :: Int -> IO ()
- hScrollPageUp :: Handle -> Int -> IO ()
- hScrollPageDown :: Handle -> Int -> IO ()
- scrollPageUpCode :: Int -> String
- scrollPageDownCode :: Int -> String
- setSGR :: [SGR] -> IO ()
- hSetSGR :: Handle -> [SGR] -> IO ()
- setSGRCode :: [SGR] -> String
- hideCursor :: IO ()
- showCursor :: IO ()
- hHideCursor :: Handle -> IO ()
- hShowCursor :: Handle -> IO ()
- hideCursorCode :: String
- showCursorCode :: String
- setTitle :: String -> IO ()
- hSetTitle :: Handle -> String -> IO ()
- setTitleCode :: String -> String
- hSupportsANSI :: Handle -> IO Bool

# Basic data types

data Color

ANSI colors: come in various intensities, which are controlled by `ColorIntensity`

Constructors

Black |
Red |
Green |
Yellow |
Blue |
Magenta |
Cyan |
White |

Instances

Bounded Color |
Enum Color |
Eq Color |
Ord Color |
Read Color |
Show Color |
Ix Color |

data ColorIntensity

ANSI colors come in two intensities

Constructors

Dull |
Vivid |

Instances

Bounded ColorIntensity |
Enum ColorIntensity |
Eq ColorIntensity |
Ord ColorIntensity |
Read ColorIntensity |
Show ColorIntensity |
Ix ColorIntensity |

data ConsoleLayer

ANSI colors can be set on two different layers

Constructors

Foreground |
Background |

Instances

Bounded ConsoleLayer |
Enum ConsoleLayer |
Eq ConsoleLayer |
Ord ConsoleLayer |
Read ConsoleLayer |
Show ConsoleLayer |
Ix ConsoleLayer |

data BlinkSpeed

ANSI blink speeds: values other than `NoBlink` are not widely supported

Constructors

SlowBlink | Less than 150 blinks per minute
RapidBlink | More than 150 blinks per minute
NoBlink |

Instances

Bounded BlinkSpeed |
Enum BlinkSpeed |
Eq BlinkSpeed |
Ord BlinkSpeed |
Read BlinkSpeed |
Show BlinkSpeed |
Ix BlinkSpeed |

data Underlining

ANSI text underlining

Constructors

SingleUnderline |
DoubleUnderline | Not widely supported
NoUnderline |

Instances

Bounded Underlining |
Enum Underlining |
Eq Underlining |
Ord Underlining |
Read Underlining |
Show Underlining |
Ix Underlining |

data ConsoleIntensity

ANSI general console intensity: usually treated as setting the font style (e.g. `BoldIntensity` causes text to be bold)

Constructors

BoldIntensity |
FaintIntensity | Not widely supported: sometimes treated as concealing text
NormalIntensity |

Instances

Bounded ConsoleIntensity |
Enum ConsoleIntensity |
Eq ConsoleIntensity |
Ord ConsoleIntensity |
Read ConsoleIntensity |
Show ConsoleIntensity |
Ix ConsoleIntensity |

data SGR

ANSI Select Graphic Rendition command

Constructors

Reset |
SetConsoleIntensity ConsoleIntensity |
SetItalicized Bool | Not widely supported: sometimes treated as swapping foreground and background
SetUnderlining Underlining |
SetBlinkSpeed BlinkSpeed |
SetVisible Bool | Not widely supported
SetSwapForegroundBackground Bool |
SetColor ConsoleLayer ColorIntensity Color |

Instances

Eq SGR |
Ord SGR |
Read SGR |
Show SGR |

# Cursor movement by character

cursorUp

Arguments

:: Int | Number of lines or characters to move
-> IO () |

cursorDown

Arguments

:: Int | Number of lines or characters to move
-> IO () |

cursorForward

Arguments

:: Int | Number of lines or characters to move
-> IO () |

cursorBackward

Arguments

:: Int | Number of lines or characters to move
-> IO () |

hCursorUp

Arguments

:: Handle |
-> Int | Number of lines or characters to move
-> IO () |

hCursorDown

Arguments

:: Handle |
-> Int | Number of lines or characters to move
-> IO () |

hCursorForward

Arguments

:: Handle |
-> Int | Number of lines or characters to move
-> IO () |

hCursorBackward

Arguments

:: Handle |
-> Int | Number of lines or characters to move
-> IO () |

cursorUpCode

Arguments

:: Int | Number of lines or characters to move
-> String |

cursorDownCode

Arguments

:: Int | Number of lines or characters to move
-> String |

cursorForwardCode

Arguments

:: Int | Number of lines or characters to move
-> String |

cursorBackwardCode

Arguments

:: Int | Number of lines or characters to move
-> String |

# Cursor movement by line

cursorUpLine

Arguments

:: Int | Number of lines to move
-> IO () |

cursorDownLine

Arguments

:: Int | Number of lines to move
-> IO () |

hCursorUpLine

Arguments

:: Handle |
-> Int | Number of lines to move
-> IO () |

hCursorDownLine

Arguments

:: Handle |
-> Int | Number of lines to move
-> IO () |

cursorUpLineCode

Arguments

:: Int | Number of lines to move
-> String |

cursorDownLineCode

Arguments

:: Int | Number of lines to move
-> String |

# Directly changing cursor position

setCursorColumn

Arguments

:: Int | 0-based column to move to
-> IO () |

hSetCursorColumn

Arguments

:: Handle |
-> Int | 0-based column to move to
-> IO () |

setCursorColumnCode

Arguments

:: Int | 0-based column to move to
-> String |

setCursorPosition

Arguments

:: Int | 0-based row to move to
-> Int | 0-based column to move to
-> IO () |

hSetCursorPosition

Arguments

:: Handle |
-> Int | 0-based row to move to
-> Int | 0-based column to move to
-> IO () |

setCursorPositionCode

Arguments

:: Int | 0-based row to move to
-> Int | 0-based column to move to
-> String |

# Clearing parts of the screen

clearFromCursorToScreenEnd :: IO ()

clearFromCursorToScreenBeginning :: IO ()

clearScreen :: IO ()

hClearFromCursorToScreenEnd :: Handle -> IO ()

hClearFromCursorToScreenBeginning :: Handle -> IO ()

hClearScreen :: Handle -> IO ()

clearFromCursorToScreenEndCode :: String

clearFromCursorToScreenBeginningCode :: String

clearScreenCode :: String

clearFromCursorToLineEnd :: IO ()

clearFromCursorToLineBeginning :: IO ()

clearLine :: IO ()

hClearFromCursorToLineEnd :: Handle -> IO ()

hClearFromCursorToLineBeginning :: Handle -> IO ()

hClearLine :: Handle -> IO ()

clearFromCursorToLineEndCode :: String

clearFromCursorToLineBeginningCode :: String

clearLineCode :: String

# Scrolling the screen

scrollPageUp

Arguments

:: Int | Number of lines to scroll by
-> IO () |

Scroll the displayed information up or down the terminal: not widely supported

scrollPageDown

Arguments

:: Int | Number of lines to scroll by
-> IO () |

Scroll the displayed information up or down the terminal: not widely supported

hScrollPageUp

Arguments

:: Handle |
-> Int | Number of lines to scroll by
-> IO () |

Scroll the displayed information up or down the terminal: not widely supported

hScrollPageDown

Arguments

:: Handle |
-> Int | Number of lines to scroll by
-> IO () |

Scroll the displayed information up or down the terminal: not widely supported

scrollPageUpCode

Arguments

:: Int | Number of lines to scroll by
-> String |

Scroll the displayed information up or down the terminal: not widely supported

scrollPageDownCode

Arguments

:: Int | Number of lines to scroll by
-> String |

Scroll the displayed information up or down the terminal: not widely supported

# Select Graphic Rendition mode: colors and other whizzy stuff

setSGR

Arguments

:: [SGR] | Commands: these will typically be applied on top of the current console SGR mode. An empty list of commands is equivalent to the list `[Reset]`. Commands are applied left to right.
-> IO () |

Set the Select Graphic Rendition mode

hSetSGR

Arguments

:: Handle |
-> [SGR] | Commands: these will typically be applied on top of the current console SGR mode. An empty list of commands is equivalent to the list `[Reset]`. Commands are applied left to right.
-> IO () |

Set the Select Graphic Rendition mode

setSGRCode

Arguments

:: [SGR] | Commands: these will typically be applied on top of the current console SGR mode. An empty list of commands is equivalent to the list `[Reset]`. Commands are applied left to right.
-> String |

Set the Select Graphic Rendition mode

# Cursor visibilty changes

hideCursor :: IO ()

showCursor :: IO ()

hHideCursor :: Handle -> IO ()

hShowCursor :: Handle -> IO ()

hideCursorCode :: String

showCursorCode :: String

# Changing the title

setTitle

Arguments

:: String | New title
-> IO () |

Set the terminal window title

hSetTitle

Arguments

:: Handle |
-> String | New title
-> IO () |

Set the terminal window title

setTitleCode

Arguments

:: String | New title
-> String |

Set the terminal window title

Thanks to Brandon S. Allbery and Curt Sampson for pointing me in the right direction on xterm title setting on haskell-cafe. The "0" signifies that both the title and "icon" text should be set: i.e. the text for the window in the Start bar (or similar) as well as that in the actual window title. This is chosen for consistent behaviour between Unixes and Windows.

# Checking if handle supports ANSI

hSupportsANSI :: Handle -> IO Bool

Use heuristics to determine whether the functions defined in this package will work with a given handle.

The current implementation checks that the handle is a terminal, and that the `TERM` environment variable doesn't say `dumb` (whcih is what Emacs sets for its own terminal).