nitcc: improve auto-dangling

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/contrib/nitcc/src/grammar.nit b/contrib/nitcc/src/grammar.nit
index 4ecefc3..52e995c 100644 (file)
--- a/contrib/nitcc/src/grammar.nit
+++ b/contrib/nitcc/src/grammar.nit
@@ -988,31 +988,41 @@ class LRState
                                print "REDUCE/REDUCE Conflict on state {self.number} {self.name} for token {t}:"
                                for i in a do print "\treduce: {i}"
                        else if guarded_shift.has_key(t) then
-                               for ri in a.to_a do for si in guarded_shift[t] do
-                                       if lookahead(ri).has(si) then
-                                               var p = ri.alt.prod
-                                               var csi: nullable Item = null
-                                               for bsi in back_expand(si) do
-                                                       if bsi.alt.prod == p then
-                                                               csi = bsi
-                                                               break
-                                                       end
-                                               end
-                                               if csi == null then continue
-                                               print "Automatic Dangling on state {self.number} {self.name} for token {t}:"
-                                               print "\treduce: {ri}"
-                                               print "\tshift:  {si}"
-                                               if si != csi then
-                                                       print "\tcore shift: {csi}"
+                               var ri = a.first
+                               var confs = new Array[Item]
+                               var ress = new Array[String]
+                               var g = guarded_shift[t]
+                               for si in lookahead(ri) do
+                                       if si.next != t then continue
+                                       if not g.has(si) then
+                                               confs.add(si)
+                                               continue
+                                       end
+                                       var p = ri.alt.prod
+                                       var csi: nullable Item = null
+                                       for bsi in back_expand(si) do
+                                               if bsi.alt.prod == p then
+                                                       csi = bsi
+                                                       break
                                                end
-                                               a.remove(ri)
+                                       end
+                                       if csi == null then
+                                               confs.add(si)
+                                               continue
+                                       end
+                                       ress.add "\tshift:  {si}"
+                                       if si != csi then
+                                               ress.add "\tcore shift: {csi}"
                                        end
                                end
-                               if a.is_empty then
+                               if confs.is_empty then
+                                       print "Automatic Dangling on state {self.number} {self.name} for token {t}:"
+                                       print "\treduce: {ri}"
+                                       for r in ress do print r
                                        guarded_reduce.keys.remove(t)
                                else
                                        print "SHIFT/REDUCE Conflict on state {self.number} {self.name} for token {t}:"
-                                       for i in a do print "\treduce: {i}"
+                                       print "\treduce: {ri}"
                                        for i in guarded_shift[t] do print "\tshift:  {i}"
                                end
                        end