Toml.FromValue.ParseTable

This module provides utilities for matching key-value pairs out of tables while building up application-specific values.

It will help generate warnings for unused keys, help select between multiple possible keys, and emit location-specific error messages when keys are unavailable.

This module provides the ParseTable implementation, but most of the basic functionality is exported directly from Toml.FromValue.

Base interface

data ParseTable a

A Matcher that tracks a current set of unmatched key-value pairs from a table.

Use optKey and reqKey to extract keys.

Use getTable and setTable to override the table and implement other primitives.

Instances

MonadFail ParseTable

Implemented in terms of fail on Matcher

Defined in Toml.FromValue.ParseTable

Methods

fail :: String -> ParseTable a

Alternative ParseTable

Defined in Toml.FromValue.ParseTable

Methods

empty :: ParseTable a

(<|>) :: ParseTable a -> ParseTable a -> ParseTable a

some :: ParseTable a -> ParseTable [a]

many :: ParseTable a -> ParseTable [a]

Applicative ParseTable

Defined in Toml.FromValue.ParseTable

Methods

pure :: a -> ParseTable a

(<*>) :: ParseTable (a -> b) -> ParseTable a -> ParseTable b

liftA2 :: (a -> b -> c) -> ParseTable a -> ParseTable b -> ParseTable c

(*>) :: ParseTable a -> ParseTable b -> ParseTable b

(<*) :: ParseTable a -> ParseTable b -> ParseTable a

Functor ParseTable

Defined in Toml.FromValue.ParseTable

Methods

fmap :: (a -> b) -> ParseTable a -> ParseTable b

(<$) :: a -> ParseTable b -> ParseTable a

Monad ParseTable

Defined in Toml.FromValue.ParseTable

Methods

(>>=) :: ParseTable a -> (a -> ParseTable b) -> ParseTable b

(>>) :: ParseTable a -> ParseTable b -> ParseTable b

return :: a -> ParseTable a

MonadPlus ParseTable

Defined in Toml.FromValue.ParseTable

Methods

mzero :: ParseTable a

mplus :: ParseTable a -> ParseTable a -> ParseTable a

data KeyAlt a

Key and value matching function

Since: 1.2.0.0

Constructors

Key String (Value -> Matcher a)

pick alternative based on key match

Else (Matcher a)

default case when no previous cases matched

pickKey :: [KeyAlt a] -> ParseTable a

Take the first option from a list of table keys and matcher functions. This operation will commit to the first table key that matches. If the associated matcher fails, only that error will be propagated and the other alternatives will not be matched.

If no keys match, an error message is generated explaining which keys would have been accepted.

This is provided as an alternative to chaining multiple reqKey cases together with (<|>) because that will generate one error message for each unmatched alternative as well as the error associate with the matched alternative.

Since: 1.2.0.0

runParseTable :: ParseTable a -> Table -> Matcher a

Run a ParseTable computation with a given starting Table. Unused tables will generate a warning. To change this behavior getTable and setTable can be used to discard or generate error messages.

Primitives

liftMatcher :: Matcher a -> ParseTable a

Lift a matcher into the current table parsing context.

warnTable :: String -> ParseTable ()

Emit a warning at the current location.

setTable :: Table -> ParseTable ()

Replace the remaining portion of the table being matched.

getTable :: ParseTable Table

Return the remaining portion of the table being matched.