On Wednesday, 24 February 2021 at 06:18:02 UTC, H. S. Teoh wrote:
Usually it's when there's a decision that needs to be made at
compile-time (or desirable to be made at compile-time for
whatever reason). For example, if there are two very different
branches of code that should run depending on the value of
parameter, and user code is expected to want only one or the
other code path, so fixing the code path at compile-time may be
advantageous.
D's operator overloading is one example of this. It takes a
compile-time string containing the operator, which lets the
implementor choose whether to implement multiple operator
overloads separately, or grouped together in a common
implementation. E.g.:
Thank you for the additional clarification with a new example.
Compile-time parameters are indeed a powerful tool.
