| Safe Haskell | None |
|---|---|
| Language | Haskell98 |
System.Console.Docopt
Contents
Description
Example:
{-# LANGUAGE QuasiQuotes #-}
module Main where
import Control.Monad (when)
import Data.Char (toUpper)
import System.Environment (getArgs)
import System.Console.Docopt
patterns :: Docopt
patterns = [docopt|
docopt-sample version 0.1.0
Usage:
docopt-sample cat <file>
docopt-sample echo [--caps] <string>
Options:
-c, --caps Caps-lock the echoed argument
|]
getArgOrExit = getArgOrExitWith patterns
main :: IO ()
main = do
args <- parseArgsOrExit patterns =<< getArgs
when (args `isPresent` (command "cat")) $ do
file <- args `getArgOrExit` (argument "file")
putStr =<< readFile file
when (args `isPresent` (command "echo")) $ do
let charTransform = if args `isPresent` (longOption "caps")
then toUpper
else id
string <- args `getArgOrExit` (argument "string")
putStrLn $ map charTransform string
- docopt :: QuasiQuoter
- docoptFile :: QuasiQuoter
- parseArgs :: Docopt -> [String] -> Either ParseError Arguments
- parseArgsOrExit :: Docopt -> [String] -> IO Arguments
- data ParseError :: *
- data Docopt
- usage :: Docopt -> String
- exitWithUsage :: Docopt -> IO a
- exitWithUsageMessage :: Docopt -> String -> IO a
- data Option
- type Arguments = Map Option ArgValue
- isPresent :: Arguments -> Option -> Bool
- notPresent :: Arguments -> Option -> Bool
- getArg :: Arguments -> Option -> Maybe String
- getArgOrExitWith :: Docopt -> Arguments -> Option -> IO String
- getArgWithDefault :: Arguments -> String -> Option -> String
- getAllArgs :: Arguments -> Option -> [String]
- getArgCount :: Arguments -> Option -> Int
- command :: String -> Option
- argument :: String -> Option
- shortOption :: Char -> Option
- longOption :: String -> Option
- getAllArgsM :: Monad m => Arguments -> Option -> m [String]
- notPresentM :: Monad m => Arguments -> Option -> m Bool
- isPresentM :: Monad m => Arguments -> Option -> m Bool
- getFirstArg :: Monad m => Arguments -> Option -> m String
QuasiQuoter usage parsers
docopt :: QuasiQuoter #
A QuasiQuoter which parses a usage string and returns a
Docopt.
Example usage:
patterns :: Docopt patterns = [docopt| docopt-sample version 0.1.0 Usage: docopt-sample cat <file> docopt-sample echo [--caps] <string> Options: -c, --caps Caps-lock the echoed argument |]
For help with the docopt usage format, see the readme on github.
Same as docopt, but parses the given file instead of a literal
string.
Example:
patterns :: Docopt patterns = [docoptFile|USAGE|]
where USAGE is the name of a file which contains the usage
string (relative to the directory from which ghc is invoked).
Command line arguments parsers
parseArgsOrExit :: Docopt -> [String] -> IO Arguments #
Same as parseArgs, but exitWithUsage on parse failure. E.g.
args <- parseArgsOrExit patterns =<< getArgs
Re-exported from Parsec
data ParseError :: * #
The abstract data type ParseError represents parse errors. It
provides the source position (SourcePos) of the error
and a list of error messages (Message). A ParseError
can be returned by the function parse. ParseError is an
instance of the Show and Eq classes.
Instances
Parsed usage string
exitWithUsage :: Docopt -> IO a #
Exit after printing usage text.
exitWithUsageMessage :: Docopt -> String -> IO a #
Exit after printing a custom message followed by usage text. Intended for convenience when more context can be given about what went wrong.
Argument lookup
A named leaf node of the usage pattern tree
type Arguments = Map Option ArgValue #
Maps each Option to all of the valued parsed from the command line (in order of last to first, if multiple values encountered)
Query functions
isPresent :: Arguments -> Option -> Bool #
True if an option was present at all in an invocation.
Useful with longOptions and shortOptions, and in conjunction with when.
notPresent :: Arguments -> Option -> Bool #
getArgOrExitWith :: Docopt -> Arguments -> Option -> IO String #
Same as getArg, but exitWithUsage if Nothing.
As in getArg, if your usage pattern required the option, getArgOrExitWith will not exit.
getAllArgs :: Arguments -> Option -> [String] #
Returns all occurrences of a repeatable option, e.g. <file>....
getArgCount :: Arguments -> Option -> Int #
Return the number of occurrences of an option in an invocation.
Useful with repeatable flags, e.g. [ -v | -vv | -vvv].
Option constructors
For Usage: prog cmd, ask for command "cmd".
For Usage: prog - or Usage: prog [-], ask for command "-". Same for --.
argument :: String -> Option #
For Usage: prog <file>, ask for argument "file".
Note: A Usage: prog --output=<file> is not matched by argument "file". See longOption.
shortOption :: Char -> Option #
For Usage: prog -h, ask for shortOption 'h'.
For Usage: prog -o=<file>, ask for shortOption 'o'.
longOption :: String -> Option #
For Usage: prog --version, ask for longOption "version".
For Usage: prog --output=<file>, ask for longOption "output".
Deprecated
getAllArgsM :: Monad m => Arguments -> Option -> m [String] #
Deprecated: Monadic query functions will soon be removed
notPresentM :: Monad m => Arguments -> Option -> m Bool #
Deprecated: Monadic query functions will soon be removed
isPresentM :: Monad m => Arguments -> Option -> m Bool #
Deprecated: Monadic query functions will soon be removed
getFirstArg :: Monad m => Arguments -> Option -> m String #
Deprecated: Use getAllArgs instead