C++ Weekly - Ep 6 Intro To Variadic Templates

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In this episode Jason gives a brief introduction to variadic template programming. T-SHIRTS AVAILABLE!

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[planetmuman]

nm has an option '-C' which automatically demangles the C++ names.

[grahamdd]

Excellent. I explored this feature about 12 months ago but was working with legacy code since so no chance to dive back in. The code;

return { to_string(param)... };

is the part that caught my eye. (param)... those dots! :) I'll continue on with this series, its exactly whats needed to get this stuff understood (for me anyways). Watching compile time, symbol table and exe size, glaringly obvious but not something I have observed. Its now in my box of tools! :)

Thank YOU!

[raducusmir]

c++17 one-liner without lambdas:

_template<typename ... Param>_
_const auto to_string(const Param& ... param)_
_{_
_return std::vector{ (std::stringstream() << param).str() ... }; // works in MSVC v14.2 (VS 2019 v16)_
_return std::vector{ << param).str() ... }; // works in gcc/clang/MSVC_
_}_

[mytech]

Year and a half late, I could go for a 2-4 point increase in editor font. Otherwise great stuff, concise, good explanation, and nice pace.
So many other videos either run through so fast your mind is occupied just attempting to unpack the words or they go off into the weeds and waste a bunch of time on trivial aspects often barely touching on the fundamental components.

[almighty]

Very useful, glad I stumbled upon this video

[chrisminnoy]

Something that seems overlooked in the standard is when using the 'using' keyword. You can't use the ... expansion operator on the variadic list when you want to expose for example a specific function which is available in all the types of the variadic template list.

[weegreenblobbie]

Thanks for the great video. Did you know nm -C will demangle C++ for you?

[ksawery]

Thanks, very helpful, although it took me some additional reading on Stack Overflow to understand the recursion.

[arpitmaiya]

Nice explanation, can you please post a session for factory design patterns in c++ ?

[dshvets]

g++ 7.2 produces less executable size with generic lambda ...

[Blaqkmagic]

Possibly the creation of the different functor classes for the generic lambda resulted in the increased program size?

[MrVermond]

Would it be possible to use any ide, so you can see your code errors right away instead of wasting so much time to switch between vim and terminal.

[surajkukreja]

About the increase in size of exe when using generic lambdas, cud it be due to every function call having local copy of lambda object, what if we passed that lambda by reference to generic to_string.

[treyquattro]

that was good, particularly not having a canned response before you started. I find variadics and fold expressions very confusing, much more difficult to understand than C's original vararg idiom. I haven't tried this myself yet, but how does the compiler manage to return a vector of strings without apparently doing any allocations or push_backs?

[adamhunyadi]

I just revisited this old video and your series was cool back then too. Doesn't your long template perform an unnecessary copy in each recursion?

[karuneshmarch]

very good example . though i have seen this earlier but again its still cool

[BloganProgramming]

Please, tell me, what is this font you're using in this terminal? Looks awesome! I couldn't find it by myself.

[jony]

I can't believe that I wasted brain cells learning this shit early in my programming career.

[mustafakhozemadholkawala]

Very Good Video Lekin kuuch samjh nahi aya....

[alexstone]

I think newer version of nm or gcc lambdas are symbols