| Portability | portable (FFI) |
|---|---|
| Stability | experimental |
| Maintainer | judah.jacobson@gmail.com |
| Safe Haskell | Trustworthy |
System.Console.Terminfo.Base
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.
- data Terminal
- setupTerm :: String -> IO Terminal
- setupTermFromEnv :: IO Terminal
- data SetupTermError
- data Capability a
- getCapability :: Terminal -> Capability a -> Maybe a
- tiGetFlag :: String -> Capability Bool
- tiGuardFlag :: String -> Capability ()
- tiGetNum :: String -> Capability Int
- tiGetStr :: String -> Capability String
- tiGetOutput1 :: forall f. OutputCap f => String -> Capability f
- class OutputCap f
- class (Monoid s, OutputCap s) => TermStr s
- data TermOutput
- runTermOutput :: Terminal -> TermOutput -> IO ()
- hRunTermOutput :: Handle -> Terminal -> TermOutput -> IO ()
- termText :: String -> TermOutput
- tiGetOutput :: String -> Capability ([Int] -> LinesAffected -> TermOutput)
- type LinesAffected = Int
- class Monoid a where
- (<#>) :: Monoid m => m -> m -> m
Initialization
setupTerm :: String -> IO TerminalSource
Initialize the terminfo library to the given terminal entry.
Throws a SetupTermError if the terminfo database could not be read.
setupTermFromEnv :: IO TerminalSource
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 Source
Capabilities
getCapability :: Terminal -> Capability a -> Maybe aSource
tiGetFlag :: String -> Capability BoolSource
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 ()Source
Look up a boolean capability in the terminfo database, and fail if it's not defined.
tiGetNum :: String -> Capability IntSource
Look up a numeric capability in the terminfo database.
tiGetStr :: String -> Capability StringSource
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 fSource
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.
TermOutput
data TermOutput Source
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.
Instances
runTermOutput :: Terminal -> TermOutput -> IO ()Source
Write the terminal output to the standard output device.
hRunTermOutput :: Handle -> Terminal -> TermOutput -> IO ()Source
Write the terminal output to the terminal or file managed by the given
Handle.
termText :: String -> TermOutputSource
tiGetOutput :: String -> Capability ([Int] -> LinesAffected -> TermOutput)Source
Look up an output capability in the terminfo database.
type LinesAffected = IntSource
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
The class of monoids (types with an associative binary operation that has an identity). Instances should satisfy the following laws:
mappend mempty x = x
mappend x mempty = x
mappend x (mappend y z) = mappend (mappend x y) z
mconcat =
foldrmappend mempty
The method names refer to the monoid of lists under concatenation, but there are many other instances.
Minimal complete definition: mempty and mappend.
Some types can be viewed as a monoid in more than one way,
e.g. both addition and multiplication on numbers.
In such cases we often define newtypes and make those instances
of Monoid, e.g. Sum and Product.
Methods
Identity of mappend
An associative operation
Fold a list using the monoid.
For most types, the default definition for mconcat will be
used, but the function is included in the class definition so
that an optimized version can be provided for specific types.
Instances
| Monoid Ordering | |
| Monoid () | |
| Monoid All | |
| Monoid Any | |
| Monoid TermOutput | |
| Monoid [a] | |
| Monoid a => Monoid (Dual a) | |
| Monoid (Endo a) | |
| Num a => Monoid (Sum a) | |
| Num a => Monoid (Product a) | |
| Monoid (First a) | |
| Monoid (Last a) | |
| Monoid a => Monoid (Maybe a) | Lift a semigroup into |
| 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) |