Hi, for the book i need the pattern matching engine now rather than
later... doh! I'm working in my dev branch. Won't affect 3.1.2. I
have cool examples for book. E.g., I want to distribute a scalar
multiply across a vector on way down tree and then repeatedly apply
simplifications to subtrees on way back up. With filter=true in tree
grammar you can do:
vmult options {strategy=downup; order=between;}
: ^('*' INT ^(VEC (e+=.)+)) -> ^(VEC ^('*' INT $e)+)
;
mult0 //options {strategy=downup; order=downup}
: ^('*' a=. b=INT {$b.int==0}?) -> $b // x*0 -> 0
;
Test run:
$ cat t1
x = 4 * [0, 5*0, 3]
$ java Test < t1
Original tree: (= x (* 4 (VEC 0 (* 5 0) 3)))
(* 4 (VEC 0 (* 5 0) 3)) -> (VEC (* 4 0) (* 4 (* 5 0)) (* 4 3))
(* 4 0) -> 0
(* 5 0) -> 0
(* 4 0) -> 0
Simplified tree: (= x (VEC 0 0 (* 4 3)))
$
saaaweeet. No code gen changes that I can tell; amazing. Using
existing options to set superClass etc... More later.
Kay: guess what you're helping me with when you arrive in December! ;)
Ter
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