4 ms·

Ask HN: Any tool to look C++ interpretation template form syntax to substitution

8 points by mardiyah 4y ago

Is there please, any tool to have/look c++ interpretation from a template form syntax to its expansion/substitution before it really gets compiled to object/binary ?

AlbertoGP 4y ago
I seem to remember having used some GCC options to look at the expanded templates years ago, but I’m not certain about the details and my impression was that it did not help much. Trying to verify that I found this tool called Templator that apparently does it in a nice graphical way: https://www.cevelop.com/#templator https://www.cevelop.com/#templator The license is restrictive but you can download it for free: https://www.cevelop.com/license/ https://www.cevelop.com/license/
- sargstuff 4y ago
  clang+ & g++ options for asm & psuedo c/c++ : https://stackoverflow.com/questions/4448094/can-we-see-the-template-instantiated-code-by-c-compiler https://stackoverflow.com/questions/4448094/can-we-see-the-t...
  - sargstuff 4y ago
    Compiler Explorer shows template, expanded template & equivalent assembler. https://godbolt.org/ https://godbolt.org/
    - sargstuff 4y ago
      Untested / unverified approaches: Seems thee's an emacs "expand the C++ template" concept: demystifycpp https://github.com/chriskmanx/demystifycpp https://github.com/chriskmanx/demystifycpp etbrain's ide package(s) support gcc cpp directives, so in theory should be able to expand a c++ template in cpp fashion in similar manner as regular code blocks. https://www.jetbrains.com https://www.jetbrains.com
      - sargstuff 4y ago
        arc [1] / racket implimentation of demystifycpp might be able to provide something 'usable'/presentable at the command line and/or as a straight up web browser html file. [1] : https://arclanguage.github.io/ https://arclanguage.github.io/
tlb 4y ago
Try https://cppinsights.io https://cppinsights.io. For example, go to https://cppinsights.io/s/8401262a https://cppinsights.io/s/8401262a and click the play button at the top left. If you're doing something more complex, you might need metashell. See http://metashell.org/manual/how_to/index.html#see-what-templates-are-instantiated-by-a-certain-normal-c-expression http://metashell.org/manual/how_to/index.html#see-what-templ.... But you have to really, deeply, love C++ to get much out of it.
- sargstuff 4y ago
  Metashell & Templator provide a graphical way to display/walk through templight "template code" debugging. https://github.com/mikael-s-persson/templight https://github.com/mikael-s-persson/templight templar : https://github.com/schulmar/Templar/wiki/HowTo https://github.com/schulmar/Templar/wiki/HowTo metashell gui front end : https://kandi.openweaver.com/c++/RangelReale/msgui https://kandi.openweaver.com/c++/RangelReale/msgui
dswilkerson 4y ago
We wrote a C++ front-end from scratch that is quite de-constructed. For example, it will show you the parse tree before type disambiguation. You can visit the templates, or the templates instantiated. It has not been maintained for a while, but here it is: main page: http://dsw.users.sonic.net/oink/index.html http://dsw.users.sonic.net/oink/index.html github repo: https://github.com/dsw/oink-stack/ https://github.com/dsw/oink-stack/

8 points by mardiyah 4y ago

Is there please, any tool to have/look c++ interpretation from a template form syntax to its expansion/substitution before it really gets compiled to object/binary ?

AlbertoGP 4y ago

I seem to remember having used some GCC options to look at the expanded templates years ago, but I’m not certain about the details and my impression was that it did not help much. Trying to verify that I found this tool called Templator that apparently does it in a nice graphical way: https://www.cevelop.com/#templator https://www.cevelop.com/#templator The license is restrictive but you can download it for free: https://www.cevelop.com/license/ https://www.cevelop.com/license/

sargstuff 4y ago
clang+ & g++ options for asm & psuedo c/c++ : https://stackoverflow.com/questions/4448094/can-we-see-the-template-instantiated-code-by-c-compiler https://stackoverflow.com/questions/4448094/can-we-see-the-t...
- sargstuff 4y ago
  Compiler Explorer shows template, expanded template & equivalent assembler. https://godbolt.org/ https://godbolt.org/
  - sargstuff 4y ago
    Untested / unverified approaches: Seems thee's an emacs "expand the C++ template" concept: demystifycpp https://github.com/chriskmanx/demystifycpp https://github.com/chriskmanx/demystifycpp etbrain's ide package(s) support gcc cpp directives, so in theory should be able to expand a c++ template in cpp fashion in similar manner as regular code blocks. https://www.jetbrains.com https://www.jetbrains.com
    - sargstuff 4y ago
      arc [1] / racket implimentation of demystifycpp might be able to provide something 'usable'/presentable at the command line and/or as a straight up web browser html file. [1] : https://arclanguage.github.io/ https://arclanguage.github.io/

tlb 4y ago

Try https://cppinsights.io https://cppinsights.io. For example, go to https://cppinsights.io/s/8401262a https://cppinsights.io/s/8401262a and click the play button at the top left. If you're doing something more complex, you might need metashell. See http://metashell.org/manual/how_to/index.html#see-what-templates-are-instantiated-by-a-certain-normal-c-expression http://metashell.org/manual/how_to/index.html#see-what-templ.... But you have to really, deeply, love C++ to get much out of it.

sargstuff 4y ago
Metashell & Templator provide a graphical way to display/walk through templight "template code" debugging. https://github.com/mikael-s-persson/templight https://github.com/mikael-s-persson/templight templar : https://github.com/schulmar/Templar/wiki/HowTo https://github.com/schulmar/Templar/wiki/HowTo metashell gui front end : https://kandi.openweaver.com/c++/RangelReale/msgui https://kandi.openweaver.com/c++/RangelReale/msgui

dswilkerson 4y ago

We wrote a C++ front-end from scratch that is quite de-constructed. For example, it will show you the parse tree before type disambiguation. You can visit the templates, or the templates instantiated. It has not been maintained for a while, but here it is: main page: http://dsw.users.sonic.net/oink/index.html http://dsw.users.sonic.net/oink/index.html github repo: https://github.com/dsw/oink-stack/ https://github.com/dsw/oink-stack/