Copyright	Copyright (C) 2023 Yoo Chung
License	GPL-3.0-or-later
Maintainer	dev@chungyc.org
Safe Haskell	Safe-Inferred
Language	GHC2021

Problems.Monads

Description

Supporting definitions for monad problems.

Synopsis

data Operator
- = Negate
- | Add
- | Subtract
- | Multiply
- | Divide
- | Modulo
data Element
- = Operator Operator
- | Operand Integer
parsePostfix :: String -> [Element]

Documentation

data Operator Source #

Encodes an operator for a mathematical expression.

Constructors

Negate	Encodes negation. Equivalent to an unary minus. Unary operator.
Add	Encodes duplication. Makes another copy of its operand. Unary operator.
Subtract	Encodes subtraction. Binary operator.
Multiply	Encodes multiplication. Binary operator.
Divide	Encodes division. Equivalent to `div`. Binary operator.
Modulo	Encodes a modulo operator. Equivalent to `mod`. Binary operator.

Instances

Instances details

Bounded Operator Source #
Instance details Defined in Problems.Monads Methods minBound :: Operator # maxBound :: Operator #
Enum Operator Source #
Instance details Defined in Problems.Monads Methods succ :: Operator -> Operator # pred :: Operator -> Operator # toEnum :: Int -> Operator # fromEnum :: Operator -> Int # enumFrom :: Operator -> [Operator] # enumFromThen :: Operator -> Operator -> [Operator] # enumFromTo :: Operator -> Operator -> [Operator] # enumFromThenTo :: Operator -> Operator -> Operator -> [Operator] #
Show Operator Source #
Instance details Defined in Problems.Monads Methods showsPrec :: Int -> Operator -> ShowS # show :: Operator -> String # showList :: [Operator] -> ShowS #
Eq Operator Source #
Instance details Defined in Problems.Monads Methods (==) :: Operator -> Operator -> Bool # (/=) :: Operator -> Operator -> Bool #

data Element Source #

A single element within a mathematical expression. A list of these elements comprises an expression in postfix notation.

Constructors

Operator Operator
Operand Integer

Instances

Instances details

Show Element Source #
Instance details Defined in Problems.Monads Methods showsPrec :: Int -> Element -> ShowS # show :: Element -> String # showList :: [Element] -> ShowS #
Eq Element Source #
Instance details Defined in Problems.Monads Methods (==) :: Element -> Element -> Bool # (/=) :: Element -> Element -> Bool #

parsePostfix :: String -> [Element] Source #

Parses a string containing a mathematical expression in postfix notation. This can make it easier to write down an expression in a more conventional form.

For example,

>>> parsePostfix "3 4 2 - *"
[Operand 3,Operand 4,Operand 2,Operator Subtract,Operator Multiply]

The operators are encoded as follows:

Operator	String
`Negate`	`"negate"`
`Add`	`"+"`
`Subtract`	`"-"`
`Multiply`	`"*"`
`Divide`	`"/"`
`Modulo`	`"%"`