LiveCode Builder Language

Replace concept of 'undefined' with 'nothing'

• The use of the keyword 'undefined' is now deprecated, 'nothing' should be used instead.
  • Use 'returns nothing' to indicate a handler which returns no value.
  • Use 'nothing' to indicate no value when manipulating optionally type variables
• The 'is defined', 'is undefined', 'is not defined', 'is not undefined' syntax is now deprecated, 'is' and 'is not' should be used with 'nothing' instead
  • Use <expr> is nothing and <expr> is not nothing to test whether an expression has a value or not
  • The phrase <left> is <right> will now return true if <left> and <right> are both nothing
  • The phrase <left> is not <right> will now return true if one of <left> or <right> are nothing (but not both).