Weekday

Description

A simple demonstration on how to map to and from a bounded, enumerated data type.

In this example we use the weekdays names as our type to iterate across.

The makeWeekday code is rather weak as any word where the first 3 letters map to a weekday is valid for conversion.

Other Examples

This example shows how use Weekday from an enumeration:

>>> toEnum 0 :: WeekDay
Mon

Synopsis

Documentation

Abbreviated days of the week from Mon (Monday) to Sun (Sunday).

Constructors

Instances details

Arbitrary Weekday Source #	Provide a random instance of a `Weekday`. This is for ease of use in property testing. `>>>` `generate arbitrary :: IO Weekday`Wed
Instance details Defined in Weekday Methods arbitrary :: Gen Weekday # shrink :: Weekday -> [Weekday] #
Bounded Weekday Source #
Instance details Defined in Weekday Methods minBound :: Weekday # maxBound :: Weekday #
Enum Weekday Source #
Instance details Defined in Weekday Methods succ :: Weekday -> Weekday # pred :: Weekday -> Weekday # toEnum :: Int -> Weekday # fromEnum :: Weekday -> Int # enumFrom :: Weekday -> [Weekday] # enumFromThen :: Weekday -> Weekday -> [Weekday] # enumFromTo :: Weekday -> Weekday -> [Weekday] # enumFromThenTo :: Weekday -> Weekday -> Weekday -> [Weekday] #
Read Weekday Source #
Instance details Defined in Weekday Methods readsPrec :: Int -> ReadS Weekday # readList :: ReadS [Weekday] # readPrec :: ReadPrec Weekday # readListPrec :: ReadPrec [Weekday] #
Show Weekday Source #
Instance details Defined in Weekday Methods showsPrec :: Int -> Weekday -> ShowS # show :: Weekday -> String # showList :: [Weekday] -> ShowS #
Eq Weekday Source #
Instance details Defined in Weekday Methods (==) :: Weekday -> Weekday -> Bool # (/=) :: Weekday -> Weekday -> Bool #

Read a Weekday from a String.

Some string to Weekday examples:

>>> makeWeekday "tHU"
Just Thu

>>> makeWeekday "sun"
Just Sun

>>> makeWeekday "Bad"
Nothing

Any string bigger than 3 characters also fails: >>> makeWeekday Mond Nothing

List all days of the week.

>>> fullWeek
[Mon,Tue,Wed,Thu,Fri,Sat,Sun]

Return title case of string.

>>> capitalise "monday"
"Monday"

>>> null (capitalise "")
True