Instead of accessing the struct as an array, access it via methods. There are other places inside of this file already using this API (for example e0a5c3d2b7/lib/irb/ruby-lex.rb (L829-L830)).
This commit moves all struct array-ish calls to use their method calls instead. It is also ~1.23 faster accessing values via a method instead of as an array according to this microbenchmark:
```ruby
Elem = Struct.new(:pos, :event, :tok, :state, :message) do
def initialize(pos, event, tok, state, message = nil)
super(pos, event, tok, State.new(state), message)
end
# ...
def to_a
a = super
a.pop unless a.empty?
a
end
end
class ElemClass
attr_accessor :pos, :event, :tok, :state, :message
def initialize(pos, event, tok, state, message = nil)
@pos = pos
@event = event
@tok = tok
@state = State.new(state)
@message = message
end
def to_a
if @message
[@pos, @event, @tok, @state, @message]
else
[@pos, @event, @tok, @state]
end
end
end
# stub state class creation for now
class State; def initialize(val); end; end
```
```ruby
Benchmark.ips do |x|
x.report("struct") { struct[1] }
x.report("class ") { from_class.event }
x.compare!
end; nil
```
```
Warming up --------------------------------------
struct 1.624M i/100ms
class 1.958M i/100ms
Calculating -------------------------------------
struct 17.139M (± 2.6%) i/s - 86.077M in 5.025801s
class 21.104M (± 3.4%) i/s - 105.709M in 5.015193s
Comparison:
class : 21103826.3 i/s
struct: 17139201.5 i/s - 1.23x (± 0.00) slower
```
2b22c93533