On Wednesday, 14 May 2014 at 22:32:01 UTC, Jonathan M Davis via
Digitalmars-d-learn wrote:
Yeah, much as Andrei would hate to hear it (enforce was his
idea, and he quite
likes the idiom), the fact that lazy is so inefficient makes it
so that it's
arguably bad practice to use it in high performance code. We
really need to
find a way to make it so that lazy is optimized properly so
that we _can_
safely use enforce, but for now, it's not a good idea unless
the code that
you're working on can afford the performance hit.
Honestly, in general, I'd avoid most anything which uses lazy
(e.g. that's why
I'd use explict try-catch blocks rather than use
std.exception.assumeWontThrow - like enforce, it's a nice idea,
but it's too
expensive at this point).
- Jonathan M Davis
On the topic of lazy, why *is* it so slow, exactly? I thought it
was just shorthand for taking a function that evaluates the
expression, and wrapping said expression in that function at the
call site. That is, I thought that:
int doSomething(lazy int n)
{
return n();
}
Was more or less equivalent to:
int doSomething(int function(int) n)
{
return n();
}
