const_get是如何在mruby中工作的？

Question

我将mruby 1.3.0 (2017-7-4)与build_config.rb结合使用

MRuby::Build.new do |conf|
  if ENV['VisualStudioVersion'] || ENV['VSINSTALLDIR']
    toolchain :visualcpp
  else
    toolchain :gcc
  end
  enable_debug
  conf.gembox 'default'
  conf.gem :git => 'https://github.com/mattn/mruby-uv'
  conf.gem :git => 'https://github.com/mattn/mruby-http'
  conf.gem :git => 'https://github.com/iij/mruby-socket'
  conf.gem :git => 'https://github.com/luisbebop/mruby-polarssl.git'
  conf.gem :git => 'https://github.com/iij/mruby-digest'
  conf.gem :git => 'https://github.com/iij/mruby-pack'
  conf.gem :git => 'https://github.com/matsumoto-r/mruby-simplehttp.git'
  conf.gem :git => 'https://github.com/matsumotory/mruby-httprequest'
  conf.gem :git => 'https://github.com/iij/mruby-aws-s3.git'
end

MRuby::Build.new('host-debug') do |conf|
  if ENV['VisualStudioVersion'] || ENV['VSINSTALLDIR']
    toolchain :visualcpp
  else
      toolchain :gcc
  end

  enable_debug
  conf.gembox 'default'
  conf.cc.defines = %w(MRB_ENABLE_DEBUG_HOOK)
  conf.gem :core => "mruby-bin-debugger"
end

MRuby::Build.new('test') do |conf|
  if ENV['VisualStudioVersion'] || ENV['VSINSTALLDIR']
    toolchain :visualcpp
  else
    toolchain :gcc
  end
  enable_debug
  conf.enable_bintest
  conf.enable_test
  conf.gembox 'default'
end

我发现const_get方法在红宝石和红宝石中不同。在ruby (2.4.0p0)中，Class.const_get('Fixnum')返回常量Fixnum，而在mruby Class.const_get('Fixnum')中，返回错误uninitialized constant Class::Fixnum (NameError)。

然后，我尝试了另一个例子：class Hoge; end; class Hoge::Fuga; end。在红宝石中，Class.const_get('Hoge::Fuga')和Hoge.const_get('Fuga')都给出了常数Hoge::Fuga。在mruby中，只有Hoge.const_get('Fuga')才返回Hoge::Fuga。

Answer 1

mruby的Module#const_get类似于CRuby中的第二个参数(命名为inherit，用于搜索超类)。如果您使用Object.const_get(:Integer)，那么它的行为应该与您在mruby和CRuby中所期望的相同。