OptEnvConf.Setting

Documentation

data Setting a

A setting for parsing and documenting a single value.

Constructors

Setting

Fields

• settingDasheds :: ![Dashed]

  Which dashed values are required for parsing

  No dashed values means this is an argument.

• settingReaders :: ![Reader a]

  Which readers should be tried to parse a value from a string

• settingTryArgument :: !Bool

  Whether the readers should be used to parsed arguments

• settingSwitchValue :: !(Maybe a)

  What value to parse when the switch exists.

  Nothing means this is not a switch.

• settingTryOption :: !Bool

  Whether the dasheds should be tried together with the readers as options.

• settingEnvVars :: !(Maybe (NonEmpty String))

  Which env vars can be read.

• settingConfigVals :: !(Maybe (NonEmpty (NonEmpty String, DecodingCodec a)))

  Which and how to parse config values

• settingDefaultValue :: !(Maybe (a, String))

  Default value, if none of the above find the setting.

• settingExamples :: ![String]

  Example values

• settingHidden :: !Bool

  Whether to hide docs

• settingMetavar :: !(Maybe Metavar)

  Which metavar should be show in documentation

• settingHelp :: !(Maybe String)

Builders

help :: String -> Builder a

Document a setting

Multiple helps concatenate help on new lines.

metavar :: String -> Builder a

Document an option or env var.

Multiple metavars override eachother.

argument :: Builder a

Try to parse an argument.

You'll also need to add a reader.

Multiple arguments are redundant.

option :: Builder a

Try to parse an argument.

You'll also need to add a reader, at least one long or short, and a metavar.

Multiple options are redundant.

switch :: a -> Builder a

Try to parse a switch, activate the given value when succesful

You'll also need to add at least one long or short.

Multiple switchs override eachother.

reader :: Reader a -> Builder a

Declare how to parse an argument, option, or environment variable.

str :: IsString s => Reader s

Read a string as-is.

This is the reader you will want to use for reading a String.

This is different from auto for strings because Read wants to parse quotes when parsing Strings.

auto :: Read a => Reader a

Read via the Read instance

You cannot use this for bare strings, because Read for strings parses quotes.

long :: String -> Builder a

Try to parse this long option or switch.

long "foo" corresponds to --foo

Notes: * Parsing options with an empty name in the long is not supported. * Parsing options with an '=' sign in the long is not supported.

Multiple longs will be tried in order. Empty longs will be ignored.

short :: Char -> Builder a

Try to parse this short option or switch.

short f corresponds to -f

Notes: * Parsing options with short - is not supported.

Multiple shorts will be tried in order.

env :: String -> Builder a

Try to parse an environment variable.

You'll also need to add a reader and a metavar.

Multiple envs will be tried in order.

conf :: HasCodec a => String -> Builder a

Try to parse a configuration value at the given key.

Multiple confs will be tried in order.

confWith :: String -> ValueCodec void a -> Builder a

Like conf but with a custom Codec for parsing the value.

confWith' :: String -> ValueCodec void (Maybe a) -> Builder a

Like confWith but allows interpreting Null as a value other than "Not found".

name :: HasCodec a => String -> Builder a

Short-hand function for option, long, env, and conf at the same time.

Multiple names will be tried in order.

value :: Show a => a -> Builder a

Set the default value

Multiple values override eachother.

API Note: default is not a valid identifier in Haskell. I'd also have preferred default instead.

valueWithShown :: a -> String -> Builder a

Set the default value, along with a shown version of it.

example :: String -> Builder a

Provide an example value for documentation.

The example is provided as a literal string.

If you use reader auto, you'll want to use shownExample instead.

shownExample :: Show a => a -> Builder a

Use Show to show an example.

This only makes sense if you use reader auto.

hidden :: Builder a

Don't show this setting in documentation

Multiple hiddens are redundant.

newtype Builder a

Builder for a Setting

Constructors

Builder

Fields

• unBuilder :: Setting a -> Setting a

Instances

Monoid (Builder f)

Defined in OptEnvConf.Setting

Methods

mempty :: Builder f

mappend :: Builder f -> Builder f -> Builder f

mconcat :: [Builder f] -> Builder f

Semigroup (Builder f)

Defined in OptEnvConf.Setting

Methods

(<>) :: Builder f -> Builder f -> Builder f

sconcat :: NonEmpty (Builder f) -> Builder f

stimes :: Integral b => b -> Builder f -> Builder f

Internal

showSettingABit :: Setting a -> ShowS

Show a Setting as much as possible, for debugging

completeBuilder :: Builder a -> Setting a

Complete a Builder into a Setting

emptySetting :: Setting a

A mempty Setting to build up a setting from.

data DecodingCodec a

Constructors

forall void. DecodingCodec (ValueCodec void (Maybe a))

type Metavar = String

type Help = String