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by enedil
1960 days ago
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The variables used in the expressions might not be in scope (in fact they usually aren't). Also, I'm rather sure that's how it works in C++ (which by accident copies arguments instead of leaving a reference, but the single time default argument evaluation holds). |
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That's solved easily enough by evaluating the expression in the scope where it was defined (again that's what other languages do).
> Also, I'm rather sure that's how it works in C++
Default arguments in C++ work as I described: If you define `void f(int arg = g(x)) {}`, then calling `f()` n times will call `g` n times as well (using the `x` that was in scope when `f` was defined) - and if you never call `f`, `g` isn't called either.
An example demonstrating this: https://ideone.com/vs26Oq