3 ms·

An example from the article: auto f1 = std::bind(f, 2, n, _1); f1(10); // calls f(2, 5, 10); auto l1 = [ p1 = 2, p2 = n ](auto _1) { return std::invoke(f, p1

An example from the article: auto f1 = std::bind(f, 2, n, _1); f1(10); // calls f(2, 5, 10); auto l1 = [ p1 = 2, p2 = n ](auto _1) { return std::invoke(f, p1, p2, _1); }; l1(10); It seems to me std::bind is a lot cleaner syntactically.

plorkyeran 9y ago
That's a literal translation of what std::bind() is doing that no one would actually write. `[n](auto a) { return f(2, n, a); }` is a more realistic way to write that lambda.
- jlarocco 9y ago
  bind() is still the cleaner way to write it. Seeing std::bind tells me that the intention is to create a function that does nothing but call a second function with certain parameters fixed. A lambda expression is far more general, so when I see it I have to think about what it's doing. There's also a subtle implication that the author chose the more general technique for a reason. It'll raise the questions, "Why isn't this using std::bind()?", "Is there something else going on here?", etc. Off hand, I can't think of a reason why the bind would be any less efficient than the lambda.
makecheck 9y ago
And cleaner still is to not obfuscate things to this degree, no matter what syntax is involved. It certainly violates the “write once, read many times” principle: no matter how many times I look at something like this, I have to study the whole thing just to figure out what is even happening! Whereas, seeing "void g(x) { f(2, 5, x); }" is perfectly clear. It certainly violates the “premature optimization” principle: in exchange for some unproven benefit, the compiler does gymnastics to bind arguments and adds compile time instead of just paying a little more in space and runtime to define a 2nd function that calls a 1st function in a completely obvious way. It also qualifies as over-design. Even if a single binding is considered OK (and that’s a big “if”), there is every reason to expect that during normal maintenance someone will need to keep adding more. Then you have several lines of template-ese. A simple function is something that anyone can extend, whereas it’s not clear most engineers will even know how to maintain the binding version.
- solidsnack9000 9y ago
  I'm not sure how to read your comment. Are you saying not to use lambdas or closures, and just to define new functions?

plorkyeran 9y ago

That's a literal translation of what std::bind() is doing that no one would actually write. `[n](auto a) { return f(2, n, a); }` is a more realistic way to write that lambda.

jlarocco 9y ago
bind() is still the cleaner way to write it. Seeing std::bind tells me that the intention is to create a function that does nothing but call a second function with certain parameters fixed. A lambda expression is far more general, so when I see it I have to think about what it's doing. There's also a subtle implication that the author chose the more general technique for a reason. It'll raise the questions, "Why isn't this using std::bind()?", "Is there something else going on here?", etc. Off hand, I can't think of a reason why the bind would be any less efficient than the lambda.

makecheck 9y ago

And cleaner still is to not obfuscate things to this degree, no matter what syntax is involved. It certainly violates the “write once, read many times” principle: no matter how many times I look at something like this, I have to study the whole thing just to figure out what is even happening! Whereas, seeing "void g(x) { f(2, 5, x); }" is perfectly clear. It certainly violates the “premature optimization” principle: in exchange for some unproven benefit, the compiler does gymnastics to bind arguments and adds compile time instead of just paying a little more in space and runtime to define a 2nd function that calls a 1st function in a completely obvious way. It also qualifies as over-design. Even if a single binding is considered OK (and that’s a big “if”), there is every reason to expect that during normal maintenance someone will need to keep adding more. Then you have several lines of template-ese. A simple function is something that anyone can extend, whereas it’s not clear most engineers will even know how to maintain the binding version.

solidsnack9000 9y ago
I'm not sure how to read your comment. Are you saying not to use lambdas or closures, and just to define new functions?