Safe Haskell	Safe-Inferred
Language	Haskell98

Data.ConfigFile.Monadic

Contents

Overview

Synopsis

type SectionSpec = String
type OptionSpec = String
data ConfigParser = ConfigParser {
- content :: CPData
- optionxform :: OptionSpec -> OptionSpec
- defaulthandler :: ConfigParser -> SectionSpec -> OptionSpec -> Either CPError String
- usedefault :: Bool
- accessfunc :: ConfigParser -> SectionSpec -> OptionSpec -> Either CPError String
}
data CPErrorData
type CPError = (CPErrorData, String)
class Get_C a where
- get :: MonadError CPError m => ConfigParser -> SectionSpec -> OptionSpec -> m a
emptyCP :: ConfigParser
sections :: ConfigParser -> [SectionSpec]
merge :: ConfigParser -> ConfigParser -> ConfigParser
to_string :: ConfigParser -> String
simpleAccess :: MonadError CPError m => SectionSpec -> OptionSpec -> ConfigParser -> m String
interpolatingAccess :: MonadError CPError m => Int -> SectionSpec -> OptionSpec -> ConfigParser -> m String
readfile :: MonadError CPError m => FilePath -> ConfigParser -> IO (m ConfigParser)
readhandle :: MonadError CPError m => Handle -> ConfigParser -> IO (m ConfigParser)
readstring :: MonadError CPError m => String -> ConfigParser -> m ConfigParser
has_section :: SectionSpec -> ConfigParser -> Bool
options :: MonadError CPError m => SectionSpec -> ConfigParser -> m [OptionSpec]
has_option :: SectionSpec -> OptionSpec -> ConfigParser -> Bool
items :: MonadError CPError m => SectionSpec -> ConfigParser -> m [(OptionSpec, String)]
set :: MonadError CPError m => SectionSpec -> OptionSpec -> String -> ConfigParser -> m ConfigParser
setshow :: (Show a, MonadError CPError m) => SectionSpec -> OptionSpec -> a -> ConfigParser -> m ConfigParser
remove_option :: MonadError CPError m => SectionSpec -> OptionSpec -> ConfigParser -> m ConfigParser
add_section :: MonadError CPError m => SectionSpec -> ConfigParser -> m ConfigParser
remove_section :: MonadError CPError m => SectionSpec -> ConfigParser -> m ConfigParser

Overview

This module reexports a slightly different version of the standard API which makes it more convenient for chaining monadically. Everywhere a ConfigParser was the first argument in a function in the standard API, it is now the last. This lets you rewrite

do let cp = emptyCP
   cp <- add_section cp "sect1"
   cp <- set cp "sect1" "opt1" "foo"
   cp <- set cp "sect1" "opt2" "bar"
   options cp "sect1"

as

return emptyCP >>=
 add_section "sect1" >>=
 set "sect1" "opt1" "foo" >>=
 set "sect1" "opt2" "bar" >>=
 options "sect1"

which may be more elegant in some cases. A future development might be to chain the ConfigParser implicitly with a state monad, which would be yet more elegant.

type SectionSpec = String Source #

Names of sections

type OptionSpec = String Source #

Names of options

data ConfigParser Source #

This is the main record that is used by ConfigFile.

Constructors

ConfigParser

Fields

content :: CPData
The data itself
optionxform :: OptionSpec -> OptionSpec
How to transform an option into a standard representation
defaulthandler :: ConfigParser -> SectionSpec -> OptionSpec -> Either CPError String
Function to look up an option, considering a default value if usedefault is True; or ignoring a default value otherwise. The option specification is assumed to be already transformed.
usedefault :: Bool
Whether or not to seek out a default action when no match is found.
accessfunc :: ConfigParser -> SectionSpec -> OptionSpec -> Either CPError String
Function that is used to perform lookups, do optional interpolation, etc. It is assumed that accessfunc will internally call defaulthandler to do the underlying lookup. The option value is not assumed to be transformed.

data CPErrorData Source #

Possible ConfigParser errors.

Instances

Instances details

Show CPErrorData Source #
Instance details Defined in Data.ConfigFile.Types Methods showsPrec :: Int -> CPErrorData -> ShowS show :: CPErrorData -> String showList :: [CPErrorData] -> ShowS
Eq CPErrorData Source #
Instance details Defined in Data.ConfigFile.Types Methods (==) :: CPErrorData -> CPErrorData -> Bool (/=) :: CPErrorData -> CPErrorData -> Bool
Ord CPErrorData Source #
Instance details Defined in Data.ConfigFile.Types Methods compare :: CPErrorData -> CPErrorData -> Ordering (<) :: CPErrorData -> CPErrorData -> Bool (<=) :: CPErrorData -> CPErrorData -> Bool (>) :: CPErrorData -> CPErrorData -> Bool (>=) :: CPErrorData -> CPErrorData -> Bool max :: CPErrorData -> CPErrorData -> CPErrorData min :: CPErrorData -> CPErrorData -> CPErrorData
Error CPError Source #
Instance details Defined in Data.ConfigFile.Types Methods noMsg :: CPError strMsg :: String -> CPError

type CPError = (CPErrorData, String) Source #

Indicates an error occurred. The String is an explanation of the location of the error.

class Get_C a where Source #

The class representing the data types that can be returned by "get".

Methods

get :: MonadError CPError m => ConfigParser -> SectionSpec -> OptionSpec -> m a Source #

Retrieves a string from the configuration file.

When used in a context where a String is expected, returns that string verbatim.

When used in a context where a Bool is expected, parses the string to a Boolean value (see logic below).

When used in a context where anything that is an instance of Read is expected, calls read to parse the item.

An error will be returned of no such option could be found or if it could not be parsed as a boolean (when returning a Bool).

When parsing to a Bool, strings are case-insentively converted as follows:

The following will produce a True value:

1
yes
on
enabled
true

The following will produce a False value:

0
no
off
disabled
false

Instances

Instances details

Get_C String Source #
Instance details Defined in Data.ConfigFile Methods get :: MonadError CPError m => ConfigParser -> SectionSpec -> OptionSpec -> m String Source #
Get_C Bool Source #
Instance details Defined in Data.ConfigFile Methods get :: MonadError CPError m => ConfigParser -> SectionSpec -> OptionSpec -> m Bool Source #
Read t => Get_C t Source #
Instance details Defined in Data.ConfigFile Methods get :: MonadError CPError m => ConfigParser -> SectionSpec -> OptionSpec -> m t Source #

emptyCP :: ConfigParser Source #

The default empty ConfigFile object.

The content contains only an empty mandatory DEFAULT section.

optionxform is set to map toLower.

usedefault is set to True.

accessfunc is set to simpleAccess.

sections :: ConfigParser -> [SectionSpec] Source #

Returns a list of sections in your configuration file. Never includes the always-present section DEFAULT.

merge :: ConfigParser -> ConfigParser -> ConfigParser Source #

Combines two ConfigParsers into one.

Any duplicate options are resolved to contain the value specified in the second parser.

The ConfigParser options in the resulting object will be set as they are in the second one passed to this function.

to_string :: ConfigParser -> String Source #

Converts the ConfigParser to a string representation that could be later re-parsed by this module or modified by a human.

Note that this does not necessarily re-create a file that was originally loaded. Things may occur in a different order, comments will be removed, etc. The conversion makes an effort to make the result human-editable, but it does not make an effort to make the result identical to the original input.

The result is, however, guaranteed to parse the same as the original input.

simpleAccess :: MonadError CPError m => SectionSpec -> OptionSpec -> ConfigParser -> m String Source #

interpolatingAccess :: MonadError CPError m => Int -> SectionSpec -> OptionSpec -> ConfigParser -> m String Source #

readfile :: MonadError CPError m => FilePath -> ConfigParser -> IO (m ConfigParser) Source #

readhandle :: MonadError CPError m => Handle -> ConfigParser -> IO (m ConfigParser) Source #

readstring :: MonadError CPError m => String -> ConfigParser -> m ConfigParser Source #

has_section :: SectionSpec -> ConfigParser -> Bool Source #

options :: MonadError CPError m => SectionSpec -> ConfigParser -> m [OptionSpec] Source #

has_option :: SectionSpec -> OptionSpec -> ConfigParser -> Bool Source #

items :: MonadError CPError m => SectionSpec -> ConfigParser -> m [(OptionSpec, String)] Source #

set :: MonadError CPError m => SectionSpec -> OptionSpec -> String -> ConfigParser -> m ConfigParser Source #

setshow :: (Show a, MonadError CPError m) => SectionSpec -> OptionSpec -> a -> ConfigParser -> m ConfigParser Source #

remove_option :: MonadError CPError m => SectionSpec -> OptionSpec -> ConfigParser -> m ConfigParser Source #

add_section :: MonadError CPError m => SectionSpec -> ConfigParser -> m ConfigParser Source #

remove_section :: MonadError CPError m => SectionSpec -> ConfigParser -> m ConfigParser Source #