Replace deprecated binder2nd and binder1st #1287
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binder2nd generates error in c++17 Replace by lambdas when possible and with std::function when the type is required. decltype(lambda) does not work, so we bind the lambda to a std::function. Other option is to use std::bind and std::placeholders, but it is harder to read the code IMO. FIX DGtal-team#1221
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Thanks ! In fact, we can make a There is still one |
| using ValuePredicate = std::function<bool(Image::Value)>; | ||
| ValuePredicate equalTo1 = [](Image::Value&& v) | ||
| { | ||
| return std::forward<Image::Value>(v) == 1; |
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You can also simply pass v by const-ref and test v == 1. In fact, using && here forbids lvalue parameters, like in the code
const auto fn = [] ( int&& v ) { return v == 1; };
int a = 3;
bool dummy = fn(a);
Here, since the std::function signature specifies a pass-by-value parameter, it doesn't fail.
Therefore, I also suggest to use a std::function<bool(Image::Value const&)>.
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Ahh, makes sense, still rusty with std::forward usage. I will change it in 12 hours
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Good points, I will polish it tomorrow morning, thanks! |
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(tagged as 0.9.4) |
Use std::bind instead of lambdas in examples.
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I have changed the signature of std::function as @rolanddenis suggested. Replaced binder1st with std::function, and its instantiation, using std::bind1st, with a std::bind and std::placeholder. |
phcerdan
changed the title
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Thanks ! |
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thanks @phcerdan & @rolanddenis Merging.. |
binder2nd generates error in c++17
Replace by lambdas when possible and with std::function when the type is
required.
decltype(lambda) does not work, so we bind the lambda to a std::function.
Other option also used is std::bind and std::placeholders.
FIX #1221
Checklist
cmakemode (otherwise, Travis C.I. will fail).