Haspara.Accounting.Side

This module provides definitions for and functions to work with Debit/Credit dichotomy which is essential to double-entry bookkeeping.

In our concept, we refer to this dichotomy as Side (materialized via Side sum-type) which is either Debit (materialized via SideDebit nullary data constructor) or Dredit (materialized via SideCredit nullary data constructor).

This module provides FromJSON and ToJSON instances for Side as well. Following accounting conventions, we chose the JSON value for Debit as "db", and for Credit as "cr".

Documentation

data Side

Data definition for encoding the debit/credit indicator.

Constructors

SideDebit

SideCredit

Instances

Eq Side

Defined in Haspara.Accounting.Side

Methods

(==) :: Side -> Side -> Bool

(/=) :: Side -> Side -> Bool

Ord Side

Defined in Haspara.Accounting.Side

Methods

compare :: Side -> Side -> Ordering

(<) :: Side -> Side -> Bool

(<=) :: Side -> Side -> Bool

(>) :: Side -> Side -> Bool

(>=) :: Side -> Side -> Bool

max :: Side -> Side -> Side

min :: Side -> Side -> Side

Show Side

Defined in Haspara.Accounting.Side

Methods

showsPrec :: Int -> Side -> ShowS

show :: Side -> String

showList :: [Side] -> ShowS

ToJSON Side

ToJSON instance for Side.

>>> Aeson.encode SideDebit
"\"db\""
>>> Aeson.encode SideCredit
"\"cr\""
>>> Aeson.decode (Aeson.encode SideDebit) == Just SideDebit
True
>>> Aeson.decode (Aeson.encode SideCredit) == Just SideCredit
True

Defined in Haspara.Accounting.Side

Methods

toJSON :: Side -> Value

toEncoding :: Side -> Encoding

toJSONList :: [Side] -> Value

toEncodingList :: [Side] -> Encoding

FromJSON Side

FromJSON instance for Side.

>>> Aeson.eitherDecode "\"db\"" :: Either String Side
Right SideDebit
>>> Aeson.eitherDecode "\"cr\"" :: Either String Side
Right SideCredit
>>> Aeson.eitherDecode "\"hebele\"" :: Either String Side
Left "Error in $: Unkown side indicator: \"hebele\". Expecting one of \"db\" or \"cr\""

Defined in Haspara.Accounting.Side

Methods

parseJSON :: Value -> Parser Side

parseJSONList :: Value -> Parser [Side]

otherSide :: Side -> Side

Gives the other side.

>>> otherSide SideDebit
SideCredit
>>> otherSide SideCredit
SideDebit

sideByAccountKind :: KnownNat precision => AccountKind -> Quantity precision -> Side

Computes the Side by the given AccountKind and the sign of the given Quantity.

The sign of the Quantity is indeed a proxy for whether the event of the Quantity is an increment (+1) or decrement (-1) event.

0 quantities are considered to originate from an increment event. So far, this seems to be a safe assumption that gives us totality in the context of this function.

Note the following mapping as a guide:

Kind of account	Debit	Credit
Asset	Increase	Decrease
Liability	Decrease	Increase
Equity/Capital	Decrease	Increase
Income/Revenue	Decrease	Increase
ExpenseCostDividend	Increase	Decrease

>>> :set -XDataKinds
>>> import Haspara.Quantity
>>> let decrement = mkQuantity (-0.42) :: Quantity 2
>>> let nocrement = mkQuantity 0 :: Quantity 2
>>> let increment = mkQuantity 0.42 :: Quantity 2
>>> fmap (sideByAccountKind AccountKindAsset) [decrement, nocrement, increment]
[SideCredit,SideDebit,SideDebit]
>>> fmap (sideByAccountKind AccountKindLiability) [decrement, nocrement, increment]
[SideDebit,SideCredit,SideCredit]
>>> fmap (sideByAccountKind AccountKindEquity) [decrement, nocrement, increment]
[SideDebit,SideCredit,SideCredit]
>>> fmap (sideByAccountKind AccountKindRevenue) [decrement, nocrement, increment]
[SideDebit,SideCredit,SideCredit]
>>> fmap (sideByAccountKind AccountKindExpense) [decrement, nocrement, increment]
[SideCredit,SideDebit,SideDebit]

normalSideByAccountKind :: AccountKind -> Side

Returns the "normal" side for a given AccountKind.

Note the following mapping as a guide:

Kind of Account	Normal Balance	Negative Balance
Asset	Debit	Credit
Liability	Credit	Debit
Equity	Credit	Debit
Revenue	Credit	Debit
Expense	Debit	Credit