- for i in a do print "\t{i}"
- else if guarded_shift.has_key(t) then
- print "SHIFT/REDUCE Conflict on state {self.number} {self.name} for token {t}:"
- for i in a do print "\t{i}"
- for i in guarded_shift[t] do print "\t{i}"
+ for i in a do print "\treduce: {i}"
+ end
+ if guarded_shift.has_key(t) then
+ 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
+ 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 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
+ removed_reduces.add t
+ else
+ print "SHIFT/REDUCE Conflict on state {self.number} {self.name} for token {t}:"
+ print "\treduce: {ri}"
+ for i in guarded_shift[t] do print "\tshift: {i}"
+ removed_reduces.add t
+ end
+ end
+ end
+ for t in removed_reduces do
+ guarded_reduce.keys.remove(t)
+ t.reduces.remove(self)
+ end
+ end
+
+ # Return `i` and all other items of the state that expands, directly or indirectly, to `i`
+ fun back_expand(i: Item): Set[Item]
+ do
+ var res = new ArraySet[Item]
+ var todo = [i]
+ res.add(i)
+ while not todo.is_empty do
+ var x = todo.pop
+ if x.pos > 0 then continue
+ var p = x.alt.prod
+ for y in items do
+ if y.next != p then continue
+ if res.has(y) then continue
+ res.add(y)
+ todo.add(y)