optimize pattern matching on strings

GrammaticalFramework · Aug 26, 2024 · 4282873 · 4282873
1 parent d515cfd
commit 4282873
Showing 1 changed file with 8 additions and 3 deletions.
diff --git a/src/compiler/api/GF/Compile/Compute/Concrete.hs b/src/compiler/api/GF/Compile/Compute/Concrete.hs
@@ -378,9 +378,14 @@ patternMatch v0 ((env0,ps,args0,t):eqs) = match env0 ps eqs args0
  NonExist-> patternMatch v0 eqs
  (PRep minp maxp p, v)
  -> case value2string v of
- Const s -> do let n = length s `div` (max minp 1)
- eqs <- matchRep env n minp maxp p minp maxp p ps ((env,PString []:ps,(arg:args),t) : eqs) (arg:args)
- patternMatch v0 eqs
+ Const s -> let n = length s
+ lo = min1 `max` (n-fromMaybe n max2)
+ hi = (n-min2) `min` fromMaybe n max1
+ (ds,cs) = splitAt lo s
+ in if lo <= hi
+ then do eqs <- matchStr env (p1:p2:ps) eqs (hi-lo) (reverse ds) cs args
+ patternMatch v0 eqs
+ else patternMatch v0 eqs
  RunTime -> return v0
  NonExist-> patternMatch v0 eqs
  (PChar, VStr [_]) -> match env ps eqs args