造了一个 beancount 的插件用于复杂的 balance check

[skies457]

项目地址在 https://github.com/w1ndy/beancount_balexpr

给 balance 添加了四则运算，方便检验信用卡余额（本月账单+未出账单+分期金额=目前总欠款）

plugin "beancount_balexpr.balexpr"
1990-01-01 open Assets:A
1990-01-01 open Assets:B
1990-01-01 open Equity:OpenBalance
1991-01-01 pad Assets:A Equity:OpenBalance
1991-01-01 pad Assets:B Equity:OpenBalance
1991-01-02 balance Assets:A 213.00 USD
1991-01-02 balance Assets:B 264.00 USD
1991-01-03 custom "balexpr" "200.00+300.00" 500.00 USD
1991-01-03 custom "balexpr" "Assets:A+Assets:B" 477.00 USD
1991-01-03 custom "balexpr" "Assets:A+200.00" 413.00 USD
1991-01-03 custom "balexpr" "Assets:B*(Assets:A+200.00)" 109032.00 USD
1991-01-03 custom "balexpr" "Assets:A-Assets:B" -51.00 USD
1991-01-03 custom "balexpr" "Assets:A*Assets:B" 56232.00 USD
1991-01-03 custom "balexpr" "Assets:A/Assets:B" 0.81 USD
1991-01-03 custom "balexpr" "Assets:A+Assets:A*Assets:B" 56445.00 USD
1991-01-03 custom "balexpr" "(Assets:A+Assets:A)*Assets:B" 112464.00 USD