checkpoint
[sbp.git] / src / edu / berkeley / sbp / Parser.java
index dc6c1f6..5c399cc 100644 (file)
@@ -184,7 +184,8 @@ public abstract class Parser<T extends Token, R> {
             public boolean             canShift(Token t)           { return shifts.contains(t); }
             public Iterable<State>     getShifts(Token t)          { return shifts.get(t); }
             public boolean             isAccepting()               { return accept; }
-            public Iterable<Reduction> getReductions(Token t)      { return reductions.get(t); }
+            public Iterable<Reduction> getReductions(Token t)      { return t==null ? eofReductions : reductions.get(t); }
+            public boolean             hasReductions(Token t)      { return t==null ? eofReductions.size()>0 : reductions.has(t); }
             public Iterable<Reduction> getEofReductions()          { return eofReductions; }
             public Iterator<Position>  iterator()                  { return hs.iterator(); }
 
@@ -311,11 +312,6 @@ public abstract class Parser<T extends Token, R> {
             }
             public String toString() { return "[reduce " + position + "]"; }
 
-            public Forest reduce(GSS.Phase.Node parent, GSS.Phase.Node onlychild, Forest rex) {
-                Forest ret = reduce(parent, numPop-1, rex, onlychild, parent.phase());
-                return ret;
-            }
-
             private Forest zero = null;
             public Forest zero() {
                 if (zero != null) return zero;
@@ -323,31 +319,38 @@ public abstract class Parser<T extends Token, R> {
                 return zero = position.rewrite(null);
             }
 
+            public void reduce(GSS.Phase.Node parent) {
+                if (numPop==0) finish(parent, zero(), parent.phase());
+                else           reduce(parent, numPop-1, parent.phase());
+            }
+
+            public void reduce(GSS.Phase.Node parent, GSS.Phase.Node onlychild) {
+                if (numPop<=0) throw new Error("called wrong form of reduce()");
+                int pos = numPop-1;
+                holder[pos] = parent.pending();
+                if (pos==0) {
+                    System.arraycopy(holder, 0, position.holder, 0, holder.length);
+                    finish(onlychild, position.rewrite(parent.phase().getLocation()), parent.phase());
+                } else {
+                    reduce(onlychild, pos-1, parent.phase());
+                }
+            }
+
             // FIXME: this could be more elegant and/or cleaner and/or somewhere else
-            private Forest reduce(GSS.Phase.Node parent, int pos, Forest rex, GSS.Phase.Node onlychild, GSS.Phase target) {
-                if (pos>=0) holder[pos] = parent.pending();
+            private void reduce(GSS.Phase.Node parent, int pos, GSS.Phase target) {
+                holder[pos] = parent.pending();
                 if (pos==0) {
-                    if (rex==null) {
-                        System.arraycopy(holder, 0, position.holder, 0, holder.length);
-                        rex = position.rewrite(target.getLocation());
-                    }
-                    if (onlychild != null)
-                        reduce(onlychild, pos-1, rex, null, target);
-                    else 
-                        for(GSS.Phase.Node child : parent.parents())
-                            reduce(child, pos-1, rex, null, target);
-                } else if (pos>0) {
-                    if (onlychild != null)
-                        reduce(onlychild, pos-1, rex, null, target);
-                    else 
-                        for(GSS.Phase.Node child : parent.parents())
-                            reduce(child, pos-1, rex, null, target);
+                    System.arraycopy(holder, 0, position.holder, 0, holder.length);
+                    Forest rex = position.rewrite(target.getLocation());
+                    for(GSS.Phase.Node child : parent.parents()) finish(child, rex, target);
                 } else {
-                    State state = parent.state.gotoSetNonTerminals.get(position.owner());
-                    if (state!=null)
-                        target.newNode(parent, rex, state, numPop<=0, parent.phase());
+                    for(GSS.Phase.Node child : parent.parents()) reduce(child, pos-1, target);
                 }
-                return rex;
+            }
+            private void finish(GSS.Phase.Node parent, Forest result, GSS.Phase target) {
+                State state = parent.state.gotoSetNonTerminals.get(position.owner());
+                if (state!=null)
+                    target.newNode(parent, result, state, numPop<=0, parent.phase());
             }
         }
     }