Maintainer | judah.jacobson@gmail.com |
---|---|
Stability | experimental |
Portability | portable (FFI) |
Safe Haskell | Trustworthy |
Language | Haskell2010 |
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 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.
Capabilities
data Capability a #
A feature or operation which a Terminal
may define.
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 String
s. 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.
hasOkPadding, outputCap
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
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 =
foldr
mappend mempty
The method names refer to the monoid of lists under concatenation, but there are many other instances.
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 newtype
s and make those instances
of Monoid
, e.g. Sum
and Product
.
Identity of mappend
mappend :: a -> a -> a Source #
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.
Monoid Ordering | Since: 2.1 |
Monoid () | Since: 2.1 |
Monoid TermOutput # | |
Monoid [a] | Since: 2.1 |
Monoid a => Monoid (Maybe a) | Lift a semigroup into Since: 2.1 |
Monoid a => Monoid (IO a) | Since: 4.9.0.0 |
(Ord a, Bounded a) => Monoid (Min a) | Since: 4.9.0.0 |
(Ord a, Bounded a) => Monoid (Max a) | Since: 4.9.0.0 |
Monoid m => Monoid (WrappedMonoid m) | Since: 4.9.0.0 |
Semigroup a => Monoid (Option a) | Since: 4.9.0.0 |
Monoid b => Monoid (a -> b) | Since: 2.1 |
(Monoid a, Monoid b) => Monoid (a, b) | Since: 2.1 |
(Monoid a, Monoid b, Monoid c) => Monoid (a, b, c) | Since: 2.1 |
(Monoid a, Monoid b, Monoid c, Monoid d) => Monoid (a, b, c, d) | Since: 2.1 |
(Monoid a, Monoid b, Monoid c, Monoid d, Monoid e) => Monoid (a, b, c, d, e) | Since: 2.1 |