[Sending this from another account, so I’m sorry if this double-posts.]
With all the responses I got here, I figured it out. Thanks to all of
you.
I’ll put the relevant source here and what I did, just in case this
helps
others.
===============
First, a bit of explanation. I have a Step class. I also have a StepList
class. (This is similar to the Song and SongList class in the Pickaxe
book.)
The idea is that when a new step is created, I do so like this:
$stepList.append(Step.new(firstStep, thisStep, thisFilter))
So here are the classes:
class Step
attr_reader :point1, :point2, :filter
def initialize(point1, point2, filter=nil)
@point1 = point1
@point2 = point2
@filter = filter
end
end
class StepList
def initialize
@guides = Array.new
end
def append(thisGuide)
@guides.push(thisGuide)
self
end
def filter(thisGuide)
@guides.find { |guide| thisGuide == guide.filter }
end
def
@guides[index] if index.kind_of?(Integer)
end
def each
@guides.find { |guide| guide.filter }
end
end
Then I have $stepList referencing a StepList object. When I have added
all
the steps and just do a print of $stepList, I get this:
#<StepList:0x2f37954 @guides=[#<Step:0x2a9ad10 @filter=“first after
202G_OrdAdd,203G_OrdUp
dateFirst”, @point2=“203G_OrdUpdate”, @point1=“202G_OrdAdd”>,
#<Step:0x2a99e88 @filter=“la
st,203G_OrdUpdateLast”, @point2=“203G_OrdUpdate”,
@point1=“202G_OrdAdd”>,
#<Step:0x2a96a94
@filter=“last,203G_OrdUpdateLast”, @point2=“203G_OrdUpdate”,
@point1=“203G_OrdUpdate”>]>
So what I wanted to do is filter through all the Step objects that are
in
the StepList and then check if they have a filter set.
So here was the logic I had:
$stepList.each { |thisFilter|
puts thisFilter
}
What my hope was is that the “each” method of my StepList class would
return
me the filters. And it did – if I changed my method like this:
def each
@guides.find { |guide| puts guide.filter }
end
(or if I used “yield” as some had suggested). With the puts or yield in
place, I saw this when the code for the $stepList.each is run:
first after 202G_OrdAdd,203G_OrdUpdateFirst
last,203G_OrdUpdateLast
last,203G_OrdUpdateLast
Those are definitely the filters. So what I was hoping was that each of
those would, in turn, get sent to thisFilter in my each loop. That
appeared
to not happen. If I changed the ‘each’ method to a ‘selection’ method
(Paul’s idea), I got this if I had yield in place in the method:
./classes.rb:118:in `selection’: no block given (LocalJumpError)
However, if I did not have yield in place, I got this:
undefined method `each’ for #Step:0x2a9a98c
That seemed to make sense since I needed an ‘each’ method for my Step
class.
So I added this ‘each’ method to the Step class:
def each
yield @filter
end
That seems to do the trick perfectly.
