コンパイルタイム・ポリモーフィズム再び

C++ Grammar
  • Boost.Foreachが見せてくれた・・・参照
  • ADLのための関数はどうせフルネームなのだからグローバル名前空間を使えばいいということだ
  • Boost.Foreachではenumを使っているが移植性の問題かもしれない
  • 以下、eVC4, VC7, VC8, GCC3.4.4で動作確認



[]#include[] []<string>[]

[]#include[] []<boost/config.hpp>[]

[]#include[] []<pstade/print.hpp>[]


[]struct[] []pstade_overloaded[]

[]{ };[]



[]namespace[] []graphics[][] {[]
  []template[][]< [][]class[] []ShapeT[][] >[]

  []void[] []draw[][]([][]ShapeT[][]& [][]x[][])[]

[]  {[]

    []graphics_draw[][]([][]x[][], [][]pstade_overloaded[][]());[]

[]  }[]

  

[]} [][]// namespace graphics[]



[]template[][]< [][]class[] []ShapeT[][] >[]

[]void[] []graphics_draw[][]([][]ShapeT[][]&, ...)[]

[]{[]

  []pstade[][]::[][]print[][]([][]"graphics_draw default"[][]);[]

[]}[]



[]class[] []Line[]

[]{ };[]
[]inline[] []void[] []graphics_draw[][]([][]Line[][]&, [][]pstade_overloaded[][])[]

[]{[]

  []pstade[][]::[][]print[][]([][]"graphics_draw(Line&)"[][]);[]

[]}[]



[]namespace[] []crop[][] {[]
  []class[] []Circle[]

[]  { };[]
[]#if[][] !defined(BOOST_NO_ARGUMENT_DEPENDENT_LOOKUP)[]

  []inline[] []void[] []graphics_draw[][]([][]Circle[][]&, [][]pstade_overloaded[][])[]

[]  {[]

    []pstade[][]::[][]print[][]([][]"graphics_draw(Circle&)"[][]);[]

[]  }[]

[]#endif[]
[]} [][]// namespace crop[]
[]#if[][] defined(BOOST_NO_ARGUMENT_DEPENDENT_LOOKUP)[]

[]inline[] []void[] []graphics_draw[][]([][]crop[][]::[][]Circle[][]&, [][]pstade_overloaded[][])[]

[]{[]

  []pstade[][]::[][]print[][]([][]"graphics_draw(Circle&)"[][]);[]

[]}[]

[]#endif[]



[]namespace[] []never_open[][] {[]
  []template[][]< [][]class[] []CharT[][] >[]

  []class[] []Text[]

[]  { };[]

  

[]} [][]// namespace never_open[]
[]template[][]< [][]class[] []CharT[][] >[]

[]void[] []graphics_draw[][]([][]never_open[][]::[][]Text[][]<[][]CharT[][]>&, [][]pstade_overloaded[][])[]

[]{[]

  []pstade[][]::[][]print[][]([][]"graphics_draw(Text<T>&)"[][]);[]

[]}[]



[]inline[] []void[] []graphics_draw[][]([][]float[][]&, [][]pstade_overloaded[][])[]

[]{[]

  []pstade[][]::[][]print[][]([][]"graphics_draw(float&)"[][]); []

[]}[]



[]void[] []test_overloaded[][]()[]

[]{[]

  []pstade[][]::[][]print[][]([][]"overloaded..."[][]);[]
  []Line[] []l[][];[]

  []graphics[][]::[][]draw[][]([][]l[][]);[]

  

  []crop[][]::[][]Circle[] []c[][];[]

  []graphics[][]::[][]draw[][]([][]c[][]);[]

  

  []never_open[][]::[][]Text[][]<[][]char[][]> [][]t[][];[]

  []graphics[][]::[][]draw[][]([][]t[][]);[]
  []float[] []f[][];[]

  []graphics[][]::[][]draw[][]([][]f[][]);[]

  

  []std[][]::[][]string[] []s[][];[]

  []graphics[][]::[][]draw[][]([][]s[][]);[]

[]}[]
[]/* outputs...[]

[]graphics_draw(Line&)[]

[]graphics_draw(Circle&)[]

[]graphics_draw(Text<T>&)[]

[]graphics_draw(float&)[]

[]graphics_draw default[]

[]*/[]