[ruby-cvs:58807] ko1:r51659 (trunk): * vm_opts.h, iseq.c, iseq.h: add compile option to force frozen

[ko1 at ruby-lang.org]

ko1	2015-08-22 05:47:53 +0900 (Sat, 22 Aug 2015)

  New Revision: 51659

  http://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=51659

  Log:
    * vm_opts.h, iseq.c, iseq.h: add compile option to force frozen
      string literals.
      [Feature #11473]
      This addition is not specification change, but to try frozen
      string literal world discussed on [Feature #11473].
      You can try frozen string literal world using this magical line:
        RubyVM::InstructionSequence.compile_option =
          {frozen_string_literal: true}
      Note that this is a global compilation option, so that you need to
      compile another script like that:
        p 'foo'.frozen? #=> false
        RubyVM::InstructionSequence.compile_option =
          {frozen_string_literal: true}
        p 'foo'.frozen? #=> false, because this line is already compiled.
        p eval("'foo'.frozen?") #=> true
      Details:
        * String literals are deduped by rb_fstring().
        * Dynamic string literals ("...#{xyz}...") is now only frozen,
          not deduped. Maybe you have other ideas.
      Now, please do not use this option on your productions :)
      Of course, current specification can be changed.
    * compile.c: ditto.
    * test/ruby/test_iseq.rb: add a test.

  Modified files:
    trunk/ChangeLog
    trunk/compile.c
    trunk/iseq.c
    trunk/iseq.h
    trunk/test/ruby/test_iseq.rb
    trunk/vm_opts.h