On Monday, 28 April 2025 at 04:59:24 UTC, Orion wrote:
At the compiler level, enum lambda is represented as a literal.
But how is alias represented? As an expression?
A lambda is basically syntax sugar for a local function
declaration. So when you write this:
fun((float x) => 0.5 + x);
...the compiler replaces it internally with code that looks like
this:
auto __lambda(float x) => 0.5 + x;
fun(&__lambda);
When the lambda is generic, the compiler generates a template
function instead of a regular function:
// Before:
range.map!(x => 0.5 + x);
// After:
auto __lambda(T)(T x) => 0.5 + x;
range.map!(__lambda);
So, when you use `alias` to give a name to a lambda, what you are
really doing is giving a name to this internal function or
template that the compiler replaces the lambda with.
Of course, at that point, you might as well just write a named
function directly:
// Instead of this:
alias m = (float x) => 0.5 + x;
// You can just write this:
auto m(float x) => 0.5 + x;
