Exceptions are for dealing with the pamount field, which is really just
dealing with an unnormalised list of amounts.
This creates an API for dealing with MixedAmount, so we never have to
access the internals outside of Hledger.Data.Amount.
Also remove a comment, since it looks like #1207 has been resolved.
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.
aquantity.
Journal entries still require a positive @@ price, but now the sign is
set after parsing, rather than when converting in amountToCost.
The reason for this change is that, if we're going to perform arithmetic
on Amount with TotalCost, then the presence of aquantity=0 means that
amountToCost would render the total cost as 0, because signum 0 == 0.
This makes journal entries like the following impossible to balance:
2000-01-01
a 0 @@ 10 A
b -10 A
simplifySign now covers a few more sign combinations that might arise.
And in particular, it strips a standalone sign with no number,
which simplifies sign flipping with amount-in/amount-out.
Error messages for these four are now a bit fancier and more
consistent. But not yet optimised for machine readability.
Cf #1436.
Added to hledger-lib: chomp1, linesPrepend[2].
Command-line account aliases now also affect transactions read
from these formats (not just journal format).
lib: journalApplyAliases, transactionApplyAliases, postingApplyAliases
helpers have been added.
Journal keeps a new piece of parsing state, a decimal mark character,
which can optionally be set to force the number format expected by all
amount parsers.
