Safe Haskell	None
Language	Haskell2010

Prednote.Comparisons

Contents

Comparisions that do not run in a context
Comparisions that run in a context
Parsing comparers

Synopsis

Comparisions that do not run in a context

compareBy Source

Arguments

:: Show a
=> Text	Description of the right-hand side
-> (a -> Ordering)	How to compare the left-hand side to the right-hand side. Return LT if the item is less than the right hand side; GT if greater; EQ if equal to the right hand side.
-> Ordering	When subjects are compared, this ordering must be the result in order for the Predbox to be True; otherwise it is False. The subject will be on the left hand side.
-> Pred a

Build a Pred that compares items. The idea is that the item on the right hand side is baked into the Pred and that the Pred compares this single right-hand side to each left-hand side item.

compare Source

Arguments

:: (Show a, Ord a)
=> a	Right-hand side
-> Ordering	When subjects are compared, this ordering must be the result in order for the Predbox to be True; otherwise it is False. The subject will be on the left hand side.
-> Pred a

Overloaded version of compareBy.

equalBy Source

Arguments

:: Show a
=> Text	Description of the right-hand side
-> (a -> Bool)	How to compare an item against the right hand side. Return `True` if the items are equal; `False` otherwise.
-> Pred a

Builds a Pred that tests items for equality.

equal Source

Arguments

:: (Eq a, Show a)
=> a	Right-hand side
-> Pred a

Overloaded version of equalBy.

compareByMaybe Source

Arguments

:: Show a
=> Text	Description of the right-hand side
-> (a -> Maybe Ordering)	How to compare an item against the right hand side. Return LT if the item is less than the right hand side; GT if greater; EQ if equal to the right hand side.
-> Ordering	When subjects are compared, this ordering must be the result in order for the Predbox to be True; otherwise it is False. The subject will be on the left hand side.
-> Pred a

Builds a Pred for items that might fail to return a comparison.

greater Source

Arguments

:: (Show a, Ord a)
=> a	Right-hand side
-> Pred a

less Source

Arguments

:: (Show a, Ord a)
=> a	Right-hand side
-> Pred a

greaterEq Source

Arguments

:: (Show a, Ord a)
=> a	Right-hand side
-> Pred a

lessEq Source

Arguments

:: (Show a, Ord a)
=> a	Right-hand side
-> Pred a

notEq Source

Arguments

:: (Show a, Eq a)
=> a	Right-hand side
-> Pred a

greaterBy Source

Arguments

:: Show a
=> Text	Description of right-hand side
-> (a -> Ordering)	How to compare an item against the right hand side. Return LT if the item is less than the right hand side; GT if greater; EQ if equal to the right hand side.
-> Pred a

lessBy Source

Arguments

:: Show a
=> Text	Description of right-hand side
-> (a -> Ordering)	How to compare an item against the right hand side. Return LT if the item is less than the right hand side; GT if greater; EQ if equal to the right hand side.
-> Pred a

greaterEqBy Source

Arguments

:: Show a
=> Text	Description of right-hand side
-> (a -> Ordering)	How to compare an item against the right hand side. Return LT if the item is less than the right hand side; GT if greater; EQ if equal to the right hand side.
-> Pred a

lessEqBy Source

Arguments

:: Show a
=> Text	Description of right-hand side
-> (a -> Ordering)	How to compare an item against the right hand side. Return LT if the item is less than the right hand side; GT if greater; EQ if equal to the right hand side.
-> Pred a

notEqBy Source

Arguments

:: Show a
=> Text	Description of right-hand side
-> (a -> Bool)	How to compare an item against the right hand side. Return `True` if equal; `False` otherwise.
-> Pred a

Comparisions that run in a context

compareByM Source

Arguments

:: (Show a, Functor f)
=> Text	Description of the right-hand side
-> (a -> f Ordering)	How to compare the left-hand side to the right-hand side. Return LT if the item is less than the right hand side; GT if greater; EQ if equal to the right hand side.
-> Ordering	When subjects are compared, this ordering must be the result in order for the Predbox to be True; otherwise it is False. The subject will be on the left hand side.
-> PredM f a

Build a Pred that compares items. The idea is that the item on the right hand side is baked into the Pred and that the Pred compares this single right-hand side to each left-hand side item.

equalByM Source

Arguments

:: (Show a, Functor f)
=> Text	Description of the right-hand side
-> (a -> f Bool)	How to compare an item against the right hand side. Return `True` if the items are equal; `False` otherwise.
-> PredM f a

Builds a Pred that tests items for equality.

compareByMaybeM Source

Arguments

:: (Functor f, Show a)
=> Text	Description of the right-hand side
-> (a -> f (Maybe Ordering))	How to compare an item against the right hand side. Return LT if the item is less than the right hand side; GT if greater; EQ if equal to the right hand side.
-> Ordering	When subjects are compared, this ordering must be the result in order for the Predbox to be True; otherwise it is False. The subject will be on the left hand side.
-> PredM f a

Builds a Pred for items that might fail to return a comparison.

greaterByM Source

Arguments

:: (Show a, Functor f)
=> Text	Description of right-hand side
-> (a -> f Ordering)	How to compare an item against the right hand side. Return LT if the item is less than the right hand side; GT if greater; EQ if equal to the right hand side.
-> PredM f a

lessByM Source

Arguments

:: (Show a, Functor f)
=> Text	Description of right-hand side
-> (a -> f Ordering)	How to compare an item against the right hand side. Return LT if the item is less than the right hand side; GT if greater; EQ if equal to the right hand side.
-> PredM f a

greaterEqByM Source

Arguments

:: (Functor f, Monad f, Show a)
=> Text	Description of right-hand side
-> (a -> f Ordering)	How to compare an item against the right hand side. Return LT if the item is less than the right hand side; GT if greater; EQ if equal to the right hand side.
-> PredM f a

lessEqByM Source

Arguments

:: (Functor f, Monad f, Show a)
=> Text	Description of right-hand side
-> (a -> f Ordering)	How to compare an item against the right hand side. Return LT if the item is less than the right hand side; GT if greater; EQ if equal to the right hand side.
-> PredM f a

notEqByM Source

Arguments

:: (Functor f, Show a)
=> Text	Description of right-hand side
-> (a -> f Bool)	How to compare an item against the right hand side. Return `True` if equal; `False` otherwise.
-> PredM f a

Parsing comparers

parseComparer Source

Arguments

:: (Monad f, Functor f)
=> Text	The string with the comparer to be parsed
-> (Ordering -> PredM f a)	A function that, when given an ordering, returns a `Pred`. Typically you will get this by partial application of `compare`, `compareBy`, or `compareByMaybe`.
-> Maybe (PredM f a)	If an invalid comparer string is given, Nothing; otherwise, the `Pred`.

Parses a string that contains text, such as >=, which indicates which comparer to use. Returns the comparer.