I am learning rails and have come across the following code which I would like to use. The code in question is the answer by John F Miller (first answer) in the following link: How to render all records from a nested set into a real html tree
def tree_from_set(set) #set must be in order
buf = START_TAG(set[0])
stack = []
stack.push set[0]
set[1..-1].each do |node|
if stack.last.lft < node.lft < stack.last.rgt
if node.leaf? #(node.rgt - node.lft == 1)
buf << NODE_TAG(node)
else
buf << START_TAG(node)
stack.push(node)
end
else#
buf << END_TAG
stack.pop
retry
end
end
buf <<END_TAG
end
def START_TAG(node) #for example
"<li><p>#{node.name}</p><ul>"
end
def NODE_TAG(node)
"<li><p>#{node.name}</p></li>"
end
def END_TAG
"</li></ul>"
end
I am unsure of the following and would appreciate any guidance.
I see this will cycle through "set" assigning each item to the object "node" however I cannot determine what [1..-1] does.
set[1..-1].each do |node|
Following the logic I cannot understand the purpose of removing the last item from the array "stack"
stack.pop
It appears this command in this context is no longer supported in ruby after 1.9. I believe the intention was to return to the start of the loop and repeat.
retry
