Percent Literals

• Use %Q{} for single-line strings which require both interpolation and embedded double-quotes. For multi-line strings, prefer heredocs. ^[link]

  # bad:  no interpolation needed
  %Q{<div class="text">Some text</div>}
  # should be '<div class="text">Some text</div>'
  
  # bad:  no double-quotes
  %Q{This is #{quality} style}
  # should be "This is #{quality} style"
  
  # bad:  multiple lines
  %Q{<div>\n<span class="big">#{exclamation}</span>\n</div>}
  # should be a heredoc.
  
  # good:  requires interpolation, has quotes, single line
  %Q{<tr><td class="name">#{name}</td>}
  

• Avoid %q unless you have a string with both ' and " in it. Regular string literals are more readable and should be preferred unless a lot of characters would have to be escaped in them. ^[link]

  # bad
  name = %q{Bruce Wayne}
  time = %q{8 o'clock}
  question = %q{"What did you say?"}
  
  # good
  name = "Bruce Wayne"
  time = "8 o'clock"
  question = '"What did you say?"'
  quote = %q{<p class='quote'>"What did you say?"</p>}
  

• Use %r only for regular expressions matching at least one '/' character. ^[link]

  # bad
  %r{\s+}
  
  # good
  %r{^/(.*)$}
  %r{^/blog/2011/(.*)$}
  

• Avoid the use of %x unless you're going to invoke a command with backquotes in it(which is rather unlikely). ^[link]

  # bad
  date = %x{date}
  
  # good
  date = `date`
  echo = %x{echo `date`}
  

• Avoid the use of %s. It seems that the community has decided :"some string" is the preferred way to create a symbol with spaces in it. ^[link]