Add Node#type? to reduce complexity of checking against multiple node types

[dvandersluis]

There are a lot of places in rubocop in which we check if a node is one of multiple node types. This allows those checks to be refactored to be less complex.

node.call_type? || node.const_type? || node.lvar_type?

# can become
node.type?(:call, :const, :lvar)

This covers both the standard node type predicates, as well as the meta predicates for multiple node types (ie. call_type? for send and csend).

If Node#string_type? in #328 is accepted, I'll add that in here as well.

[dvandersluis]

@marcandre any idea how I can simplify this?

[marcandre]

Yes, you could make a map precise type => group type (e.g. true: :boolean, float: :numeric) and do

return true if types.include?(@type)
group_type = SPECIFIC_TO_GROUP[@type]
return group_type != nil && types.include?(group_type)

[marcandre]

We could even use that constant to define boolean_type?, numeric_type?, etc.

[dvandersluis]

Awesome, thank you! ❤️

[dvandersluis]

I've added a prior commit to redefine argument_type?, boolean_type?, etc. in terms of a hash of groups, and then used it to refactor type?.

[marcandre]

I'd make this constant private

[marcandre]

I wouldn't refer to the constant in the doc but instead explain it, say:

Suggested change

	# Allows specific single node types, as well as `TYPE_GROUP` keys to
	# Allows specific single node types, as well as "grouped" types (e.g. `:boolean` for `:true` or `:false`)

[dvandersluis]

Good call! Updated.

[marcandre]

Great stuff, thanks!

[marcandre]

Let's see if we get other feedback on string_type? and I'll make a release shortly after