supplant the old interface, which relied on the Num typeclass.
MixedAmount did not have a very good Num instance. The only functions
which were defined were fromInteger, (+), and negate. Furthermore, it
was not law-abiding, as 0 + a /= a in general. Replacements for used
functions are:
0 -> nullmixedamt / mempty
(+) -> maPlus / (<>)
(-) -> maMinus
negate -> maNegate
sum -> maSum
sumStrict -> maSum
Also creates some new constructors for MixedAmount:
mixedAmount :: Amount -> MixedAmount
maAddAmount :: MixedAmount -> Amount -> MixedAmount
maAddAmounts :: MixedAmount -> [Amount] -> MixedAmount
Add Semigroup and Monoid instances for MixedAmount.
Ideally we would remove the Num instance entirely.
The only change needed have nullmixedamt/mempty substitute for
0 without problems was to not squash prices in
mixedAmount(Looks|Is)Zero. This is correct behaviour in any case.
This means committing a bunch more generated files, but it's probably
worthwhile, so we can have both rich hyperlinked/styled command docs
and clean readable command help.
These commands now detect the account types declared by account directives.
Whenever such declarations are not present, built-in regular expressions
are used, as before.
This was added in 2012, I guess to prevent CPP breaking on some
needed and I don't want to do this everywhere; we'll just remember
to not put CPP-like content in quasi-quoted blocks.
Income, liability and equity balances, which until now we have
always displayed as negative numbers, are now shown as normally positive
by these reports.
Negative numbers now indicate a contra-balance (eg an overdrawn
checking account), a net loss, a negative net worth, etc.
This makes these reports more like conventional financial statements,
and easier to read and share with normal people.
Compound balance commands like these can now be aware of normal account
balance sign, and sort negative balances accordingly.
This also adds utility-ht as a dependency, only for the uncurry function
right now but it looks potentially useful to have.
