UI.Butcher.Monadic.Param

Parameters are arguments of your current command that are not prefixed by some flag. Typical commandline interface is something like "PROGRAM [FLAGS] INPUT". Here, FLAGS are Flags in butcher, and INPUT is a Param, in this case a String representing a path, for example.

Documentation

data Param p

param-description monoid. You probably won't need to use the constructor; mzero or any (<>) of param(Help|Default|Suggestion) works well.

Constructors

Param

Fields

• _param_default :: Maybe p
• _param_help :: Maybe Doc
• _param_suggestions :: Maybe [p]

Instances

Monoid (Param p)

Methods

mempty :: Param p

mappend :: Param p -> Param p -> Param p

mconcat :: [Param p] -> Param p

paramHelp :: Doc -> Param p

Create a Param with just a help text.

paramHelpStr :: String -> Param p

Create a Param with just a help text.

paramDefault :: p -> Param p

Create a Param with just a default value.

paramSuggestions :: [p] -> Param p

Create a Param with just a list of suggestion values.

addReadParam

Arguments

:: (Applicative f, Typeable a, Show a, Read a)

=> String

paramater name, for use in usage/help texts

-> Param a

properties

-> CmdParser f out a

Add a parameter to the CmdParser by making use of a Read instance. Take care not to use this to return Strings unless you really want that, because it will require the quotation marks and escaping as is normal for the Show/Read instances for String.

addReadParamOpt

Arguments

:: (Applicative f, Typeable a, Read a)

=> String

paramater name, for use in usage/help texts

-> Param a

properties

-> CmdParser f out (Maybe a)

Like addReadParam, but optional. I.e. if reading fails, returns Nothing.

addStringParam :: forall f out. Applicative f => String -> Param String -> CmdParser f out String

Add a parameter that matches any string of non-space characters if input String, or one full argument if input is [String]. See the Input doc for this distinction.

addStringParamOpt :: forall f out. Applicative f => String -> Param Void -> CmdParser f out (Maybe String)

Like addStringParam, but optional, I.e. succeeding with Nothing if there is no remaining input.

addRestOfInputStringParam :: forall f out. Applicative f => String -> Param Void -> CmdParser f out String

Add a parameter that consumes _all_ remaining input. Typical usecase is after a "--" as common in certain (unix?) commandline tools.