Ruby has a set of methods to convert an object to another representation. Most of them come in explicit and implicit flavor.
| explicit | implicit |
|---|---|
to_a |
to_ary |
to_h |
to_hash |
to_s |
to_str |
to_i |
to_int |
There may be even more.
Don't name your methods like the implicit version (most prominently to_hash) but the like the explicit one.
Explicit conversion
Explicit conversion happens when requesting it, e.g. with the splat operator:
args = [1,2,3]
some_method(*args) # Ruby calls args.to_a here
Implicit conversion
Implicit conversion happens when Ruby tries to convert an object when it thinks it should:
a, b, c = args # Ruby calls args.to_ary here
# Fictional example; Ruby decomposes the block argument by calling args.to_ary
[args].each do |(x, y, z)| puts x, y, z; end
Important
You should only implement an implicit conversion method if your object already behaves like the target type.
You never create a new object in an implicit conversion method. This method should either returnselfor not be implemented at all.
Obviously, this is the reason behind this recent card about Ruby implicitly converting a hash to keyword arguments. It's not a bug, it's a feature!
Also see the linked Stackoverflow post.
