Hi, I'm considering using the "tuple of closures" pattern below that Araq suggested (original post) and I'm reading the closures section of the manual.
I could discover the answers to my questions empirically through profiling, but I still wouldn't know why, so I'm asking here for a 2-in-1. Thanks!
type
ITest = tuple[
setter: proc(v: int) {.closure.},
getter1: proc(): int {.closure.},
getter2: proc(): int {.closure.}]
proc getInterf(): ITest =
var shared1, shared2: int
return (setter: proc (x: int) =
shared1 = x
shared2 = x + 10,
getter1: proc (): int = result = shared1,
getter2: proc (): int = return shared2)
var i = getInterf()
i.setter(56)
echo i.getter1(), " ", i.getter2()
My intuition is that an object with methods would be more efficient, because it’s designed for exactly this, vs. closures which are much more general purpose.
As for which is better, there’s a Zen koan about that:
The venerable master Qc Na was walking with his student, Anton. Hoping to prompt the master into a discussion, Anton said “Master, I have heard that objects are a very good thing — is this true?” Qc Na looked pityingly at his student and replied, “Foolish pupil — objects are merely a poor man’s closures.”
Chastised, Anton took his leave from his master and returned to his cell, intent on studying closures. He carefully read the entire “Lambda: The Ultimate…” series of papers and its cousins, and implemented a small Scheme interpreter with a closure-based object system. He learned much, and looked forward to informing his master of his progress.
On his next walk with Qc Na, Anton attempted to impress his master by saying “Master, I have diligently studied the matter, and now understand that objects are truly a poor man’s closures.” Qc Na responded by hitting Anton with his stick, saying “When will you learn? Closures are a poor man’s object.”
At that moment, Anton became enlightened.