First, a statement switch can use the arrow syntax with an expression that
throw an expression.
switch(x) {
case 10 -> 42;
default -> throw new AssertionError(); // there is no curly braces needed
here
}
but lambdas do not allow throw as an expression.
This is not coherent, i think, we should fill that hole by allowing throw
expression with no curly braces in lambdas (like we already allow function
calls that return void in a lambda).
General warning: let's be careful with "for consistency" arguments; in a
language as complex and which has been maintained over 20+ years like
Java, you will always find inconsistencies, and the cure may be worse
than the disease. (If "for consistency" is the best argument one can
think of for a given idea, that's a sign that it's probably not such a
strong idea.)
For example, the same "for consistency" argument could lead you down the
slippery slope of allowing throw everywhere an expression is allowed,
such as
m(throw e) // never calls m()
or
for (int i = throw e; i++; i<j) { ... }
which I think is farther than we'd want to go. But, I think you are
making an argument for a narrower form of consistency, which is
"consistency after the arrow", as both constructs here attempt to
provide a streamlined single-consequent, no-brace form?
(Note that we could also "restore consistency" by requiring the braces
on the switch.)
That said, lambdas of the form
() -> throw e;
do seem pretty harmless.
A question that have came twice at the end of my both talks about the
expression switch is: why there is not arrow syntax for the
try-catch/try-finally/try-with-resources ?
(This is, in fact, an illustration of the general silliness of most "for
consistency" arguments :)
I agree, this is a poor direction to go down.
