in py, we use something like default parm so the api doesn't break.

def f(val = true)
f()

but since rust doesn't have it

one way is to separate the method

fn f( val: bool )

to

fn f() // by default true
fn f_false()

so the api doesn't break.

btw it's usually called partial function

@asukaminato0721 cc f0f2542

And if you do want to merge these api. Add https://stackoverflow.com/questions/30757914/can-i-mark-a-function-as-deprecated to them and let users to use new api :)

@dae, I find it's really hard to solve the problems mentioned in open-spaced-repetition/fsrs4anki#708, so I decided to provide an option to freeze the stability in FSRS-5 if the user has trouble with the same-day reviews. What do you think of?

Because #267 will introduce a breaking change, I decide not to use partial function.