Copyright	(c) Eric Mertens 2023
License	ISC
Maintainer	emertens@gmail.com
Safe Haskell	Safe-Inferred
Language	Haskell2010

Toml.FromValue.Matcher

Contents

Types
Operations
Scope helpers

Description

This type helps to build up computations that can validate a TOML value and compute some application-specific representation.

It supports warning messages which can be used to deprecate old configuration options and to detect unused table keys.

It supports tracking multiple error messages when you have more than one decoding option and all of them have failed.

Use prettyMatchMessage for an easy way to make human readable strings from matcher outputs.

Synopsis

data Matcher a
data Result e a
- = Failure [e]
- | Success [e] a
data MatchMessage = MatchMessage {
- matchPath :: [Scope]
- matchMessage :: String
}
runMatcher :: Matcher a -> Result MatchMessage a
withScope :: Scope -> Matcher a -> Matcher a
getScope :: Matcher [Scope]
warning :: String -> Matcher ()
data Scope
- = ScopeIndex Int
- | ScopeKey String
inKey :: String -> Matcher a -> Matcher a
inIndex :: Int -> Matcher a -> Matcher a

Types

data Matcher a Source #

Computations that result in a Result and which track a list of nested contexts to assist in generating warnings and error messages.

Use withScope to run a Matcher in a new, nested scope.

Instances

Instances details

MonadFail Matcher Source #	Fail with an error message annotated to the current location.
Instance details Defined in Toml.FromValue.Matcher Methods fail :: String -> Matcher a #
Alternative Matcher Source #
Instance details Defined in Toml.FromValue.Matcher Methods empty :: Matcher a # (<\|>) :: Matcher a -> Matcher a -> Matcher a # some :: Matcher a -> Matcher [a] # many :: Matcher a -> Matcher [a] #
Applicative Matcher Source #
Instance details Defined in Toml.FromValue.Matcher Methods pure :: a -> Matcher a # (<>) :: Matcher (a -> b) -> Matcher a -> Matcher b # liftA2 :: (a -> b -> c) -> Matcher a -> Matcher b -> Matcher c # (>) :: Matcher a -> Matcher b -> Matcher b # (<*) :: Matcher a -> Matcher b -> Matcher a #
Functor Matcher Source #
Instance details Defined in Toml.FromValue.Matcher Methods fmap :: (a -> b) -> Matcher a -> Matcher b # (<$) :: a -> Matcher b -> Matcher a #
Monad Matcher Source #
Instance details Defined in Toml.FromValue.Matcher Methods (>>=) :: Matcher a -> (a -> Matcher b) -> Matcher b # (>>) :: Matcher a -> Matcher b -> Matcher b # return :: a -> Matcher a #
MonadPlus Matcher Source #
Instance details Defined in Toml.FromValue.Matcher Methods mzero :: Matcher a # mplus :: Matcher a -> Matcher a -> Matcher a #

data Result e a Source #

Computation outcome with error and warning messages. Multiple error messages can occur when multiple alternatives all fail. Resolving any one of the error messages could allow the computation to succeed.

Since: 1.3.0.0

Constructors

Failure [e]	error messages
Success [e] a	warning messages and result

Instances

Instances details

(Read e, Read a) => Read (Result e a) Source #	Default instance
Instance details Defined in Toml.FromValue.Matcher Methods readsPrec :: Int -> ReadS (Result e a) # readList :: ReadS [Result e a] # readPrec :: ReadPrec (Result e a) # readListPrec :: ReadPrec [Result e a] #
(Show e, Show a) => Show (Result e a) Source #	Default instance
Instance details Defined in Toml.FromValue.Matcher Methods showsPrec :: Int -> Result e a -> ShowS # show :: Result e a -> String # showList :: [Result e a] -> ShowS #
(Eq e, Eq a) => Eq (Result e a) Source #	Default instance
Instance details Defined in Toml.FromValue.Matcher Methods (==) :: Result e a -> Result e a -> Bool # (/=) :: Result e a -> Result e a -> Bool #
(Ord e, Ord a) => Ord (Result e a) Source #	Default instance
Instance details Defined in Toml.FromValue.Matcher Methods compare :: Result e a -> Result e a -> Ordering # (<) :: Result e a -> Result e a -> Bool # (<=) :: Result e a -> Result e a -> Bool # (>) :: Result e a -> Result e a -> Bool # (>=) :: Result e a -> Result e a -> Bool # max :: Result e a -> Result e a -> Result e a # min :: Result e a -> Result e a -> Result e a #

data MatchMessage Source #

A message emitted while matching a TOML value. The message is paired with the path to the value that was in focus when the message was generated. These message get used for both warnings and errors.

Since: 1.3.0.0

Constructors

MatchMessage
Fields matchPath :: [Scope] path to message location matchMessage :: String error and warning message body

Instances

Instances details

Read MatchMessage Source #	Default instance
Instance details Defined in Toml.FromValue.Matcher Methods readsPrec :: Int -> ReadS MatchMessage # readList :: ReadS [MatchMessage] # readPrec :: ReadPrec MatchMessage # readListPrec :: ReadPrec [MatchMessage] #
Show MatchMessage Source #	Default instance
Instance details Defined in Toml.FromValue.Matcher Methods showsPrec :: Int -> MatchMessage -> ShowS # show :: MatchMessage -> String # showList :: [MatchMessage] -> ShowS #
Eq MatchMessage Source #	Default instance
Instance details Defined in Toml.FromValue.Matcher Methods (==) :: MatchMessage -> MatchMessage -> Bool # (/=) :: MatchMessage -> MatchMessage -> Bool #
Ord MatchMessage Source #	Default instance
Instance details Defined in Toml.FromValue.Matcher Methods compare :: MatchMessage -> MatchMessage -> Ordering # (<) :: MatchMessage -> MatchMessage -> Bool # (<=) :: MatchMessage -> MatchMessage -> Bool # (>) :: MatchMessage -> MatchMessage -> Bool # (>=) :: MatchMessage -> MatchMessage -> Bool # max :: MatchMessage -> MatchMessage -> MatchMessage # min :: MatchMessage -> MatchMessage -> MatchMessage #

Operations

runMatcher :: Matcher a -> Result MatchMessage a Source #

Run a Matcher with an empty scope.

Since: 1.3.0.0

withScope :: Scope -> Matcher a -> Matcher a Source #

Run a Matcher with a locally extended scope.

Since: 1.3.0.0

getScope :: Matcher [Scope] Source #

Get the current list of scopes.

Since: 1.3.0.0

warning :: String -> Matcher () Source #

Emit a warning mentioning the current scope.

Scope helpers

data Scope Source #

Scopes for TOML message.

Since: 1.3.0.0

Constructors

ScopeIndex Int	zero-based array index
ScopeKey String	key in a table

Instances

Instances details

Read Scope Source #	Default instance
Instance details Defined in Toml.FromValue.Matcher Methods readsPrec :: Int -> ReadS Scope # readList :: ReadS [Scope] # readPrec :: ReadPrec Scope # readListPrec :: ReadPrec [Scope] #
Show Scope Source #	Default instance
Instance details Defined in Toml.FromValue.Matcher Methods showsPrec :: Int -> Scope -> ShowS # show :: Scope -> String # showList :: [Scope] -> ShowS #
Eq Scope Source #	Default instance
Instance details Defined in Toml.FromValue.Matcher Methods (==) :: Scope -> Scope -> Bool # (/=) :: Scope -> Scope -> Bool #
Ord Scope Source #	Default instance
Instance details Defined in Toml.FromValue.Matcher Methods compare :: Scope -> Scope -> Ordering # (<) :: Scope -> Scope -> Bool # (<=) :: Scope -> Scope -> Bool # (>) :: Scope -> Scope -> Bool # (>=) :: Scope -> Scope -> Bool # max :: Scope -> Scope -> Scope # min :: Scope -> Scope -> Scope #

inKey :: String -> Matcher a -> Matcher a Source #

Update the scope with the message corresponding to a table key

Since: 1.3.0.0

inIndex :: Int -> Matcher a -> Matcher a Source #

Update the scope with the message corresponding to an array index

Since: 1.3.0.0