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Lazy: fetch deep values only when you need to
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# Example: Lazy.new(lambda { |id| API::HackerNews.item(id) }, 0) | |
class Lazy | |
attr_reader :value | |
def initialize(function:, value:) | |
@function = function | |
@value = value | |
@cached = nil | |
@is_cached = false | |
end | |
def method_missing(method, *args, &block) | |
cached.send(method, *args, &block) | |
end | |
def cached | |
unless @cached | |
@cached = @function.call(value) | |
@is_cached = true | |
end | |
@cached | |
end | |
def cached? | |
@is_cached | |
end | |
def to_s | |
value.to_s | |
end | |
def inspect | |
"#<Lazy @value=#{value.inspect} cached?=#{cached?.inspect}>" | |
end | |
end |
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