feat: CSV rule negation

[bobobo1618]

I'm interested in hledger but really need #2054 for my use-case (certain locations for the same store fit in one purchase category, other locations in another).

I don't know a whole lot of Haskell but hopefully enough to make myself dangerous. I think this change works? The tests I added seem to pass?

[simonmichael]

Sorry for the delay @bobobo1618 . A valuable feature! In my excitement I forgot to ask for documentation. Could you suggest some wording and I'll add it.

[bobobo1618]

I had a look at the existing matcher documentation and would suggest "When a matcher is preceded by an exclamation mark (!), the matcher will be negated; only lines that don't match the original matcher will be matched."

[simonmichael]

Perfect. Thank you!

[simonmichael]

Howdy @bobobo1618 . I tried to use ! in CSV rules for the first time, in an AND-ed condition, like this:

# stripe transfers where amount is positive
if STRIPE TRANSFER
& ! %amount -

but couldn't make it work. Would you have time to check this case and show a working example, or add a test and fix ?

[bobobo1618]

Howdy @bobobo1618 . I tried to use ! in CSV rules for the first time, in an AND-ed condition, like this:

# stripe transfers where amount is positive
if STRIPE TRANSFER
& ! %amount -

but couldn't make it work. Would you have time to check this case and show a working example, or add a test and fix ?

I'd love to but I'm afraid this is beyond my Haskell abilities. Right now the logic only supports a simple prefix but this feature would require some kind of recursive logical structure and I'm not familiar enough with how to make that work.

[simonmichael]

Mentioned this limitation in the manual for now.