nitcc: generate a faster DFA::trans sequence of `if`

[nit.git] / contrib / nitcc / src / autom.nit

diff --git a/contrib/nitcc/src/autom.nit b/contrib/nitcc/src/autom.nit
index 5b545b8..84df722 100644 (file)
--- a/contrib/nitcc/src/autom.nit
+++ b/contrib/nitcc/src/autom.nit
@@ -750,6 +750,13 @@ private class DFAGenerator
                                end
 
                                # Generate a sequence of `if` for the dispatch
+                               if haslast != null then
+                                       # Special case: handle up-bound first if not an error
+                                       add("\t\tif c > {last} then return dfastate_{names[haslast]}\n")
+                                       # previous become the new last case
+                                       haslast = dispatch[last]
+                                       dispatch.keys.remove(last)
+                               end
                                for c, next in dispatch do
                                        if next == null then
                                                add("\t\tif c <= {c} then return null\n")