terminfo-0.3.2.5: Haskell bindings to the terminfo library.

Portabilityportable (FFI)
Stabilityexperimental
Maintainerjudah.jacobson@gmail.com
Safe HaskellTrustworthy

System.Console.Terminfo.Base

Contents

Description

This module provides a low-level interface to the C functions of the terminfo library.

NOTE: Since this library is built on top of the curses interface, it is not thread-safe.

Synopsis

Initialization

data Terminal

setupTerm :: String -> IO Terminal

Initialize the terminfo library to the given terminal entry.

Throws a SetupTermError if the terminfo database could not be read.

setupTermFromEnv :: IO Terminal

Initialize the terminfo library, using the TERM environmental variable. If TERM is not set, we use the generic, minimal entry dumb.

Throws a SetupTermError if the terminfo database could not be read.

data SetupTermError

Instances

Show SetupTermError 
Typeable SetupTermError 
Exception SetupTermError 

Capabilities

data Capability a

A feature or operation which a Terminal may define.

Instances

Monad Capability 
Functor Capability 
MonadPlus Capability 

getCapability :: Terminal -> Capability a -> Maybe a

tiGetFlag :: String -> Capability Bool

Look up a boolean capability in the terminfo database.

Unlike tiGuardFlag, this capability never fails; it returns False if the capability is absent or set to false, and returns True otherwise.

tiGuardFlag :: String -> Capability ()

Look up a boolean capability in the terminfo database, and fail if it's not defined.

tiGetNum :: String -> Capability Int

Look up a numeric capability in the terminfo database.

tiGetStr :: String -> Capability String

Deprecated: use tiGetOutput instead.

Look up a string capability in the terminfo database. NOTE: This function is deprecated; use tiGetOutput1 instead.

Output

Terminfo contains many string capabilities for special effects. For example, the cuu1 capability moves the cursor up one line; on ANSI terminals this is accomplished by printing the control sequence "\ESC[A". However, some older terminals also require "padding", or short pauses, after certain commands. For example, when TERM=vt100 the cuu1 capability is "\ESC[A$<2>", which instructs terminfo to pause for two milliseconds after outputting the control sequence.

The TermOutput monoid abstracts away all padding and control sequence output. Unfortunately, that datatype is difficult to integrate into existing String-based APIs such as pretty-printers. Thus, as a workaround, tiGetOutput1 also lets us access the control sequences as Strings. The one caveat is that it will not allow you to access padded control sequences as Strings. For example:

 > t <- setupTerm "vt100"
 > isJust (getCapability t (tiGetOutput1 "cuu1") :: Maybe String)
 False
 > isJust (getCapability t (tiGetOutput1 "cuu1") :: Maybe TermOutput)
 True

String capabilities will work with software-based terminal types such as xterm and linux. However, you should use TermOutput if compatibility with older terminals is important. Additionally, the visualBell capability which flashes the screen usually produces its effect with a padding directive, so it will only work with TermOutput.

tiGetOutput1 :: forall f. OutputCap f => String -> Capability f

Look up an output capability which takes a fixed number of parameters (for example, Int -> Int -> TermOutput).

For capabilities which may contain variable-length padding, use tiGetOutput instead.

class OutputCap f

Instances

OutputCap TermOutput 
OutputCap [Char] 
(Enum p, OutputCap f) => OutputCap (p -> f) 

class (Monoid s, OutputCap s) => TermStr s

Instances

TermOutput

data TermOutput

An action which sends output to the terminal. That output may mix plain text with control characters and escape sequences, along with delays (called "padding") required by some older terminals.

runTermOutput :: Terminal -> TermOutput -> IO ()

Write the terminal output to the standard output device.

hRunTermOutput :: Handle -> Terminal -> TermOutput -> IO ()

Write the terminal output to the terminal or file managed by the given Handle.

termText :: String -> TermOutput

tiGetOutput :: String -> Capability ([Int] -> LinesAffected -> TermOutput)

Look up an output capability in the terminfo database.

type LinesAffected = Int

A parameter to specify the number of lines affected. Some capabilities (e.g., clear and dch1) use this parameter on some terminals to compute variable-length padding.

Monoid functions

class Monoid a where

Methods

mempty :: a

mappend :: a -> a -> a

mconcat :: [a] -> a

Instances

Monoid Ordering 
Monoid () 
Monoid Any 
Monoid All 
Monoid TermOutput 
Monoid [a] 
Monoid a => Monoid (Maybe a) 
Num a => Monoid (Sum a) 
Num a => Monoid (Product a) 
Monoid (Last a) 
Monoid (First a) 
Monoid (Endo a) 
Monoid a => Monoid (Dual a) 
Monoid b => Monoid (a -> b) 
(Monoid a, Monoid b) => Monoid (a, b) 
(Monoid a, Monoid b, Monoid c) => Monoid (a, b, c) 
(Monoid a, Monoid b, Monoid c, Monoid d) => Monoid (a, b, c, d) 
(Monoid a, Monoid b, Monoid c, Monoid d, Monoid e) => Monoid (a, b, c, d, e) 

(<#>) :: Monoid m => m -> m -> m

An operator version of mappend.