On Wednesday, 9 July 2014 at 07:10:09 UTC, Jacob Carlborg wrote:
On 09/07/14 00:21, bearophile wrote:
9. Built-in tuples usable in all the most important situations
(with a
syntax that doesn't kill possible future improvements of the
switch
statement to perform basic pattern matching on structs that
have an
optional method named "unapply").
I think it would be possible to implement pattern matching in
library code. Something like this:
match!(value,
(int t) => ifInt(),
(char t) => ifChar(),
() => noOtherMatch()
);
Destructing a type could look something like this:
match(value,
(type!(Foo), int a, int b) => doSomething(), // match if
value is of type Foo and extract it
(int a, int b) => doSomething() // match anything that can
be destructed to two ints
);
The syntax is not so pretty but I think it would be possible.
As far as I know, there's no reason we can't add pattern matching
to switch or final switch or both. There's no ambiguity because
right now it's not possible to switch on structs or classes. See
Kenji's DIP32 for syntax for tuples that could be leveraged.
