git.iko.soy/vty
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vty/src/Graphics/Vty/Terminal.hs
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1-- Copyright 2009 Corey O'Connor
2-- * Graphics.Vty.Terminal: This instantiates an abtract interface to the terminal interface
3-- based on the TERM and COLORTERM environment variables.
4-- * Graphics.Vty.Terminal.Generic: Defines the generic interface all terminals need to implement.
5-- * Graphics.Vty.Terminal.TerminfoBased: Defines a terminal instance that uses terminfo for all
6-- control strings.
7-- - No attempt is made to change the character set to UTF-8 for these terminals. I don't
8-- know a way to reliably determine if that is required or how to do so.
9-- * Graphics.Vty.Terminal.XTermColor: This module contains an interface suitable for
10-- xterm-like terminals. These are the terminals where TERM == xterm. This does use terminfo
11-- for as many control codes as possible. H: This should derive functionality from the
12-- TerminfoBased terminal.
13--
14--
15{-# LANGUAGE ScopedTypeVariables #-}
16{-# LANGUAGE GADTs #-}
17module Graphics.Vty.Terminal ( module Graphics.Vty.Terminal
18 , Terminal(..)
19 , TerminalHandle(..)
20 , DisplayHandle(..)
21 , output_picture
22 , display_context
23 )
24 where
27import Graphics.Vty.Terminal.Generic
28import Graphics.Vty.Terminal.MacOSX as MacOSX
29import Graphics.Vty.Terminal.XTermColor as XTermColor
30import Graphics.Vty.Terminal.TerminfoBased as TerminfoBased
32import Control.Exception ( SomeException, try )
33import Data.Either
34import Data.List ( isPrefixOf )
35import Data.Word
37import System.Environment
39-- | Returns a TerminalHandle (an abstract Terminal instance) for the current terminal.
40--
41-- The specific Terminal implementation used is hidden from the API user. All terminal
42-- implementations are assumed to perform more, or less, the same. Currently all implementations use
43-- terminfo for at least some terminal specific information. This is why platforms without terminfo
44-- are not supported. However, as mentioned before, any specifics about it being based on terminfo
45-- are hidden from the API user. If a terminal implementation is developed for a terminal for a
46-- platform without terminfo support then Vty should work as expected on that terminal.
47--
48-- Selection of a terminal is done as follows:
49--
50-- * If TERM == xterm
51-- then the terminal might be one of the Mac OS X .app terminals. Check if that might be
52-- the case and use MacOSX if so.
53-- otherwise use XTermColor.
54--
55-- * for any other TERM value TerminfoBased is used.
56--
57--
58-- The terminal has to be determined dynamically at runtime. To satisfy this requirement all
59-- terminals instances are lifted into an abstract terminal handle via existential qualification.
60-- This implies that the only equations that can used are those in the terminal class.
61--
62-- To differentiate between Mac OS X terminals this uses the TERM_PROGRAM environment variable.
63-- However, an xterm started by Terminal or iTerm *also* has TERM_PROGRAM defined since the
64-- environment variable is not reset/cleared by xterm. However a Terminal.app or iTerm.app started
65-- from an xterm under X11 on mac os x will likely be done via open. Since this does not propogate
66-- environment variables (I think?) this assumes that XTERM_VERSION will never be set for a true
67-- Terminal.app or iTerm.app session.
68--
69-- todo: add an implementation for windows that does not depend on terminfo. Should be installable
70-- with only what is provided in the haskell platform.
71--
72-- todo: The Terminal interface does not provide any input support.
73terminal_handle :: IO TerminalHandle
74terminal_handle = do
75 term_type <- getEnv "TERM"
76 t <- if "xterm" `isPrefixOf` term_type
77 then do
78 maybe_terminal_app <- get_env "TERM_PROGRAM"
79 case maybe_terminal_app of
80 Nothing
81 -> XTermColor.terminal_instance term_type >>= new_terminal_handle
82 Just v | v == "Apple_Terminal" || v == "iTerm.app"
83 -> do
84 maybe_xterm <- get_env "XTERM_VERSION"
85 case maybe_xterm of
86 Nothing -> MacOSX.terminal_instance >>= new_terminal_handle
87 Just _ -> XTermColor.terminal_instance term_type >>= new_terminal_handle
88 -- Assume any other terminal that sets TERM_PROGRAM to not be an OS X terminal.app
89 -- like terminal?
90 _ -> XTermColor.terminal_instance term_type >>= new_terminal_handle
91 -- Not an xterm-like terminal. try for generic terminfo.
92 else TerminfoBased.terminal_instance term_type >>= new_terminal_handle
93 return t
94 where
95 get_env var = do
96 mv <- try $ getEnv var
97 case mv of
98 Left (_e :: SomeException) -> return $ Nothing
99 Right v -> return $ Just v
101-- | Sets the cursor position to the given output column and row.
102--
103-- This is not necessarially the same as the character position with the same coordinates.
104-- Characters can be a variable number of columns in width.
105--
106-- Currently, the only way to set the cursor position to a given character coordinate is to specify
107-- the coordinate in the Picture instance provided to output_picture or refresh.
108set_cursor_pos :: TerminalHandle -> Word -> Word -> IO ()
109set_cursor_pos t x y = do
110 bounds <- display_bounds t
111 d <- display_context t bounds
112 marshall_to_terminal t (move_cursor_required_bytes d x y) (serialize_move_cursor d x y)
114-- | Hides the cursor
115hide_cursor :: TerminalHandle -> IO ()
116hide_cursor t = do
117 bounds <- display_bounds t
118 d <- display_context t bounds
119 marshall_to_terminal t (hide_cursor_required_bytes d) (serialize_hide_cursor d)
121-- | Shows the cursor
122show_cursor :: TerminalHandle -> IO ()
123show_cursor t = do
124 bounds <- display_bounds t
125 d <- display_context t bounds
126 marshall_to_terminal t (show_cursor_required_bytes d) (serialize_show_cursor d)