On 05/07/2018 05:35 PM, Paul Backus wrote:
Personally, I consider [pattern matching] an essential
feature--arguably *the* essential feature--
After having used Nemerle, I tend to agree.
I haven't gotten around to using this yet, but I did take a look at the
source and was blown away by how small and simple it is. Kudos!
Oh, and I love that it's much easier to remember how to spell than
"Algebraic" :)
That said, it would be really nice if D made it possible for a tool like
this to support more things being defined in-line. For example, in
Nemerle, it's possible to define a binary tree like this:
---------------------------------
// Mainly from:
// https://github.com/rsdn/nemerle/wiki/Grok-Variants-and-matching
variant Tree {
| Node {
left : Tree;
elem : int;
right : Tree;
}
| EmptyLeaf
}
---------------------------------
But AFAIK, in D, each part would have to be defined separately, making
the overall structure less clear:
---------------------------------
struct Node {
Tree* left;
int elem;
Tree* right;
}
struct EmptyLeaf {}
alias Tree = SumType!(Node, EmptyLeaf);
---------------------------------
Of course, that's not your lib's fault, just an unfortunate limitation of D.
