Question

我将mruby 1.3.0 (2017-7-4)与build_config.rb：

一起使用

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

然后，我尝试了另一个例子：class Hoge; end; class Hoge::Fuga; end。在ruby中，Class.const_get('Hoge::Fuga')和Hoge.const_get('Fuga')都会给出常量Hoge::Fuga。在mruby中，只有Hoge.const_get('Fuga')返回Hoge::Fuga。

Answer 1

mruby的inherit就像第二个参数（在{名} false中搜索超类）{J}中的Object.const_get(:Integer)一样。如果你使用DECLARE @Student TABLE(StudentId CHAR(1), SubCode VARCHAR(2),SubName VARCHAR(10)) INSERT INTO @Student VALUES('1','M1','Math') INSERT INTO @Student VALUES('1','S1','Science') INSERT INTO @Student VALUES('1','E1','English') INSERT INTO @Student VALUES('2','H1','History') INSERT INTO @Student VALUES('2','G2','Geography') INSERT INTO @Student VALUES('4','M1','Math') SELECT CASE WHEN D.RN=1 THEN D.StudentId ELSE '' END StudentId ,D.SubCode,D.SubName FROM( SELECT * ,ROW_NUMBER() OVER(PARTITION BY StudentId ORDER BY StudentId)RN FROM @Student )D ORDER BY D.StudentID, D.RN，它的行为应该与你在mruby和CRuby中的预期相同。

const_get如何在mruby中工作？

1 个答案: