Better idiom for title on an optional list?

I’m still learning Ruby, and most of the time I can find a beautiful
Ruby idiom that collapses two or more statements into one easy-to-read
(or learn) idiom, like h[key] ||= 0. My current project has a lot of
places where it emits lists if they contain any items, much like this:

unless items.empty?
puts “items\n-----”
items.each { |item| puts item }
end

My header code and list code is more complicated, and sometimes there
are lists within lists, and it all just starts to look ugly, even
split out into smaller methods. It would seem more Ruby-like if I
could fold the header into the iterator somehow – rather than what I
have now that feels like it tests the Array for items twice. Or maybe
I’m trying too hard to make it terse?

On Nov 29, 2007, at 11:25 AM, slothbear wrote:

I’m still learning Ruby, and most of the time I can find a beautiful
Ruby idiom that collapses two or more statements into one easy-to-read
(or learn) idiom, like h[key] ||= 0. My current project has a lot of
places where it emits lists if they contain any items, much like this:

unless items.empty?
puts “items\n-----”
items.each { |item| puts item }
end

puts “items”,
“-----”,
items unless items.empty?

I don’t guess that’s much better.

It does feel like it should be a separate method to me.

James Edward G. II

On Nov 29, 2007, at 10:25 AM, slothbear wrote:

My header code and list code is more complicated, and sometimes there
are lists within lists, and it all just starts to look ugly, even
split out into smaller methods. It would seem more Ruby-like if I
could fold the header into the iterator somehow – rather than what I
have now that feels like it tests the Array for items twice. Or maybe
I’m trying too hard to make it terse?

puts “list”, “----”, list unless list.empty?

  1. refactor you code so that this is ok

    require ‘yaml’

    y ‘list’ => list

    this will print and empty list. personally i think this is best
    since analysis of output is very hard when the schema keeps changing

  2. same as above, but with test

    y ‘list’ => list unless list.empty?

  3. dry it up

    def report label, list
    puts label, ‘—’, list unless list.empty?
    end

    report ‘foo’, foo

  4. create a list class and use it

    class List < ::Array
    def initialize label
    @label = label
    end

    def to_s

    end

    unfortunately this gets icky because ruby handles any subclass of
    array specically when given as an arg to puts…

regards.
a @ http://codeforpeople.com/

Thanks for the ideas. I ended up creating a separate method that
accepts a label and list as arguments. It looks pretty good and feels
pretty natural. Success! my thanks again.

sb

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