文章分类 -  Ruby

摘要：Ryan Davis’sRuby QuickRefsays (without explanation):Don’t rescue Exception. EVER. or I will stab you.Why not? What’s the right thing to do?Exceptionis the root of Ruby's exception hierarchy, so when yourescue Exceptionyou rescue fromeverything, including subclasses such asSyntaxError,LoadError, 阅读全文

摘要：It is important to understand the place of StandardError in the hierarchy of ruby exceptions:class TestException1 < StandardErrorend class TestException2 < Exceptionend begin begin raise TestException1 rescue puts $!.class.name end begin raise TestException2 rescue puts $!.class.na... 阅读全文

摘要：While learning Ruby I've come across the "=>" operator on occasion. Usually I see it in the form of:symbol => valueand itseemsto be used frequently when passing values to functions. What exactly is that operator called? What does it do/mean? Is it built into Ruby or is it somethi 阅读全文

摘要：def procBuilder(message)Proc.new{ puts message;return}enddef test puts "entering method" p = procBuilder("entering proc") p.call puts "exit method"endtestBy design, this is to throw a LocalJumpError, but I don't rightly understand why. If I had to guess what this di 阅读全文

摘要：Instance variables begin with an at sign (@) and can be referenced only within class methods. They differ from local variables in that they don't exist within any particular scope. Instead, a similar variable table is stored for each instance of a class. Instance variables live within a class in 阅读全文

摘要：原文：http://ionrails.com/2009/09/19/ruby_require-vs-load-vs-include-vs-extend/Require：require方法让你加载一个库，并且只加载一次，如果你多次加载会返回false。只有当你要加载的库位于一个分离的文件中时才有必要使用require。使用时不需要加扩展名，一般放在文件的最前面： require ‘test_library’Load：load用来多次加载一个库，你必须指定扩展名： load ‘test_library.rb’Include:当你的库加载之后，你可以在你的类定义中包含一个module，让module 阅读全文