Hledger.Data.TransactionModifier

A TransactionModifier is a rule that modifies certain Transactions, typically adding automated postings to them.

Documentation

transactionModifierToFunction :: TransactionModifier -> Transaction -> Transaction

Converts a TransactionModifier to a Transaction-transforming function, which applies the modification(s) specified by the TransactionModifier. Currently this means adding automated postings when certain other postings are present. The postings of the transformed transaction will reference it in the usual way (ie, txnTieKnot is called).

>>> putStr $ showTransaction $ transactionModifierToFunction (TransactionModifier "" ["pong" `post` usd 2]) nulltransaction{tpostings=["ping" `post` usd 1]}
0000/01/01
    ping           $1.00
    pong           $2.00

>>> putStr $ showTransaction $ transactionModifierToFunction (TransactionModifier "miss" ["pong" `post` usd 2]) nulltransaction{tpostings=["ping" `post` usd 1]}
0000/01/01
    ping           $1.00

>>> putStr $ showTransaction $ transactionModifierToFunction (TransactionModifier "ping" ["pong" `post` amount{amultiplier=True, aquantity=3}]) nulltransaction{tpostings=["ping" `post` usd 2]}
0000/01/01
    ping           $2.00
    pong           $6.00