Re: [boost] flyweight - gsoc idea - multikey-value flyweight

Subject: Re: [boost] flyweight - gsoc idea - multikey-value flyweight
From: Joaquin M LópezMuñoz (joaquin_at_[hidden])
Date: 2016-02-16 10:00:28

Vicente J. Botet Escriba <vicente.botet <at> wanadoo.fr> writes:

> 
> Le 15/02/2016 07:51, Joaquin M LópezMuñoz a écrit :
> > Vicente J. Botet Escriba <vicente.botet <at> wanadoo.fr> writes:
> >
> >> Hi Joaquin,
> >>
> >> I have a use case where I have several keys to the same flyweight.
>
> [...]
>
> Let say you are writing an application that manage with some entities. 
> You have two kind of operator that use a specific protocol and each 
> protocol identify these entities using a key MOi. Suppose that you 
> application use a library that has an interface that use different keys 
> to identify these same entities, because it is using an internal 
> protocol. You want also to have some CLI for debugging purposes that 
> uses strings to identify theÍ…µ”•¹Ñ¥Ñ¥•Ì¸(ø€(ø±°Ñ¡•Í”­•ǻ…É”¥Í½µ½ÉÁ¡¥ŒÍ¼å½Ô…¸µ½Ù”™É½´½¹”­•äÑ¼Ñ¡”½Ñ¡•È€(øÕÍ¥¹œ„ÍÁ•¥™¥Œ…±½É¥Ñ¡µl¸¸¹t()=,°±•ÐÌÍ­•Ñ Ñ¡•Í”¥‘•…̸1•ÐÌÍ…ä((€­•äÄõ¥¹Ð(€­•äÈõ¡…È(€Ù…±Õ”õÍѐèéÍÑÉ¥¹œ()…¹Ý”Ý…¹ÐÑ¼µ¥¹¥µ¥é”½¹Ù•ÉÍ¥½¸™É½´­•å¤Ñ¼­•å¨…¹½¹ÍÑÉՍѥ½¸)½˜Ù…±Õ•Ì°‰•…ÕÍ”Ñ¡•äÉ”…±°•áÁ•¹Í¥Ù”½Á•É…Ñ¥½¹Ì€¡¹½Ð¥¸Ñ¡¥Ì)Á…ÉÑ¥Õ±…ȁ…Í”°‰ÕЁå½Ô•ÐÑ¡”¥‘•„¤¸]”µ…­”Ñ¡”½¹Ù•ÉÑ¥¹œ™Õ¹Ñ¥½¹Ì)½ÕÑÁÕЁѼÑ¡”½¹Í½±”Ñ¼­••ÀÑÉ…¬½˜¥˜½Ý¡•¸Ñ¡•äÉ”…±±•è((€€€¡…ȁ­•äÉ}™É½µ}­•äÄ¡¥¹Ð¤¤(€€€ì(€€€€€Íѐè鍽ÕÐðð‰­•äÉ}™É½µ}­•äÅq¸ˆì(€€€€€É•ÑÕɸÍÑ…Ñ¥}…ÍÐñ¡…Èø¡¤¤ì(€€€ô(€€€€€€€€(€€€¥¹Ð­•äÅ}™É½µ}­•äÈ¡¡…ȁŒ¤(€€€ì(€€€€€Íѐè鍽ÕÐðð‰­•äÅ}™É½µ}­•äÉq¸ˆì(€€€€€É•ÑÕɸÍÑ…Ñ¥}…ÍÐñ¥¹Ðø¡Œ¤ì(€€€ô(€€€€(€€€ÍѐèéÍÑÉ¥¹œÙ…±Õ•}™É½µ}­•äÄ¡¥¹Ð¢°¢7FC£¦6÷WCÃÂ'fÇVUög&öÕö¶W“Æâ#°¢&WGW&â&ö÷7C£¦ÆW†–6Åö67CÇ7FC£§7G&–æs→“°¢ТÛÛœÝ[[Y[	ˆJXÛÛœÝÜ™]\›ˆKšÙ^LNßBˆNˆˆ\Ú[™ÈÙ^LWÙ›]ÙZYÚY›]ÙZYÚÙ^Wݘ[YO[[[Y[[[Y[ÚÙ^LOŽÂ‚˜]›ÝÈÙHØ[È\ÙHÙ^Lˆ\ÈÙ[ˆÛ™HØ^HÈœš[™ÈÙ^Lˆ[HØÙ[™HÚ[H™Y™\œš[™ÈÈHØ[YH[]Y\È\ÈÚ]Ù^LH
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And we want to go a step further so that flyweights created with key1
interoperate with those created with key2 --that is, we want both kinds
of objects to be realizations of the same type:

    struct multi_flyweight:boost::variant<key1_flyweight,key2_flyweight>
    {
      using super=boost::variant<key1_flyweight,key2_flyweight>;
      
      multi_flyweight(int i):super{key1_flyweight{i}}{}
      multi_flyweight(char c):super{key2_flyweight{c}}{}
      multi_flyweight(const element& e):super{key1_flyweight{e}}{}
      
      const element& get()const
      {
        return boost::apply_visitor(
          [](const auto& f)->decltype(auto){return f.get();},
          *this);
      }
      
      operator const element&()const{ret¸Ñ¡¥Ì´ù•Ð ¤íô(€€€ôì((€€€‰½½°½Á•É…ѽÈôô¡½¹ÍЁµÕ±Ñ¥}™±åÝ•¥¡Ð˜à±½¹ÍЁµÕ±Ñ¥}™±åÝ•¥¡Ð˜ä¤(€€€ì(€€€€€É•ÑÕɸ€™à¹•Ð ¤ôô™ä¹•Ð ¤ì(€€€ô()±°½˜Ñ¡¥Ì…±±½Ý́ṌѼ‘¼((€€€¥¹Ðµ…¥¸ ¤(€€€ì(€€€€€µÕ±Ñ¥}™±åÝ•¥¡Ð˜ÅìÄÈÑôì(€€€€€µÕ±Ñ¥}™±åÝ•¥¡Ð˜É퍡…ÉìÄÈÑõôì(€€€€€µÕ±Ñ¥}™±åÝ•¥¡Ð˜Íí˜È¹•Ð ¥ôì(€€€€€µÕ±Ñ¥}™±åÝ•¥¡Ð˜Ñí˜Åôì(€€€€€€(€€€€€Íѐè鍽ÕÐðñ˜Ä¹•Ð ¤¹Ù…±Õ”ðð‰q¸ˆì(€€€€€Íѐè鍽ÕÐðñ˜È¹•Ð ¤¹Ù…±Õ”ðð‰q¸ˆì(€€€€€Íѐè鍽ÕÐðñ˜Ì¹•Ð ¤¹Ù…±Õ”ðð‰q¸ˆì(€€€€€Íѐè鍽ÕÐðñ˜Ð¹•Ð ¤¹Ù…±Õ”ðð‰q¸ˆì(€€€€€Íѐè鍽ÕÐðð¡˜Äôõ˜È¤ðð‰q¸ˆì(€€€€€Íѐè鍽ÕÐðð¡˜Èôõ˜Ì¤ðð‰q¸ˆì(€€€€€Íѐè鍽ÕÐðð¡˜Ìôõ˜Ð¤ðð‰q¸ˆì(€€€ô()Ý¥Ñ ½ÕÑÁÕÐ((€€€­•äÉ}™É½µ}­•äÄ(€€€Ù…±Õ•}™É½µ}­•äÄ(€€€€ÄÈÐ(€€€€ÄÈÐ(€€€€ÄÈÐ(€€€€ÄÈÐ(€€€€Ä(€€€€Ä(€€€€Ä()Ý¡¥ •™™•Ñ¥Ù•±äÍ¡½Ý́ѡ…Ё­•ä…¹Ù…±Õ”É•…Ñ¥½¸¥Ìµ¥¹¥µ¥é•°…¹F†R&W7VÇF–ær6VÖçF–72—2v†BvRvW&RgFW"â–÷R6âÆ’v—F‚¦6ö×ÆWFRW†×ÆR@ ¦‡GG¢òö6öÆ—'Rç7F6¶VBÖ7&öö¶VBæ6öÒöófF#&3SScC36f#0 ¤FöW2F†—2&ö6‚–÷W"W6R66Sò6öÖRö–çG3  ¢¢F†—26â&RV6–Ç’vVæW&Æ—¦VBFòâ¶W—2v—F‚6öÖRÖWF&öw&ÖÖ–ærࢢæ÷FRF†BvR†fVâwB6†ævVBF†R–çFW&æÇ2öb&ö÷7BäfÇ—vV–v‡BFð§W6R6öÖWF†–ærÆ–¶R×VÇF’Ö¶W’f7F÷'’‡v†–6‚—2&ö&&Ç’v†B–÷P¦†B–âÖ–æB’â–ç7FVBÂF†—2—2ÆÂFöæRöâF÷öbF†RW†—7F–ærÆ–'&'’À§v†–6‚†2F†Rö'f–÷W2G&v&6²†Ööær÷F†W'2’F†@§6—¦Vöb†×VÇF•öfÇ—vV–v‡B“ÓÓ"§6—¦Vöb‡fö–B¢’Âv†W&R6—¦Vöb†fÇ—vV–v‡B’—0§G—–6ÆÇ’6—¦Vöb‡fö–B¢’âv†WF†W"F†—2—266WF&ÆR÷"æ÷BFWVæG0§&VÆÇ’öâF†RW6R66W2Â’vB6’ࢢ&Ww&—F–ærF†—2–âF†RÖ÷7BVff–6–VçBv’F‡&÷Vv‚×VÇF’Ö¶W’f7F÷&–W0¢†Æ–¶VÇ’\ÙYÛˆ›ÛÜÝ“][R[™^
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