红宝石OptionParser抛出ArgumentError

Question

这是我第一次使用OptionParser，我得到了这个错误：

/Users/jay/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/mechanize-> 2.7.3/lib/mechanize/http/agent.rb:651:in resolve': absolute URL needed (not -v) (ArgumentError)from /Users/jay/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/mechanize-2.7.3/lib/mechanize/http/agent.rb:223:infetch‘from /Users/jay/.rbenv/versions/2.1.2/lib/ruby/gems/2.1.0/gems/mechanize-2.7.3/lib/mechanize.rb:440:in get' from /Users/jay/Code/linkedin-scraper/lib/myModel-scraper/profile.rb:20:ininitialize’from ./bin/myModel-scraper:6:in new' from ./bin/myModel-scraper:6:in‘

垃圾箱：

require 'rubygems'
require 'optparse'

opts = OptionParser.new do |opts|
 opts.on_tail("-v", "--version", "Show version") { puts myModel::Scraper::VERSION; exit }
 opts.parse!
end

Lib/版本：

module myModel
  module Scraper
    VERSION = '0.1.2'
  end
end

我想我做错了，有人能解释一下这里发生了什么吗？

Answer 1

我通常会写一个这样的OptionParser块：

OptionParser.new do |opts|
  opts.on_tail("-v", "--version", "Show version") { puts myModel::Scraper::VERSION; exit }
end.parse!

我可能会用on代替on_tail

opts.on("-v", "--version", "Show version") { puts myModel::Scraper::VERSION; exit }

但我理解你为什么希望它出现在帮助列表的末尾。