X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FSequence.java;h=a029274a0a01f7cbe48db426e645c1def564e64a;hp=b67f8a7b81c30762a42496255d76f8e6f29a7b0c;hb=0620c2d97d6df986d74dbe13160afb1435096431;hpb=111166986ad83b54d0cae5c03c2304d23e332f29

diff --git a/src/edu/berkeley/sbp/Sequence.java b/src/edu/berkeley/sbp/Sequence.java
index b67f8a7..a029274 100644
--- a/src/edu/berkeley/sbp/Sequence.java
+++ b/src/edu/berkeley/sbp/Sequence.java
@@ -1,3 +1,5 @@
+// Copyright 2006 all rights reserved; see LICENSE file for BSD-style license
+
 package edu.berkeley.sbp;
 import edu.berkeley.sbp.util.*;
 import edu.berkeley.sbp.*;
@@ -8,11 +10,16 @@ import java.lang.reflect.*;
 import java.lang.ref.*;
 
 /** <font color=green>juxtaposition; zero or more adjacent Elements; can specify a rewriting</font> */
-public abstract class Sequence /*extends Element*/ implements Iterable<Element>, SequenceOrElement {
+public abstract class Sequence implements Iterable<Element>, SequenceOrElement {
 
     protected final Element[] elements;
 
-    final HashSet<Sequence> hated  = new HashSet<Sequence>();
+    public boolean needed_or_hated = false;
+
+    public HashMap<Sequence,Boolean> canNeed = new HashMap<Sequence,Boolean>();
+    public HashMap<Sequence,Boolean> canKill = new HashMap<Sequence,Boolean>();
+
+    final HashSet<Sequence> hated   = new HashSet<Sequence>();
 
     final HashSet<Sequence> needs  = new HashSet<Sequence>();
     final HashSet<Sequence> hates  = new HashSet<Sequence>();
@@ -63,14 +70,20 @@ public abstract class Sequence /*extends Element*/ implements Iterable<Element>,
     ////////////////////////////////////////////////////////////////////////////////
 
     /** return a new sequence identical to this one, but with a positive conjunct <tt>s</tt> */
-    public Sequence and(Sequence s) { Sequence ret = dup(); ret.needs.add(s); return ret; }
+    public Sequence and(Sequence s) { Sequence ret = dup(); ret.needs.add(s); s.needed_or_hated=true; return ret; }
 
     /** return a new sequence identical to this one, but with a negative conjunct <tt>s</tt> */
-    public Sequence not(Sequence s) { Sequence ret = dup(); ret.hates.add(s); s.hated.add(ret); return ret; }
+    public Sequence andnot(Sequence s) { Sequence ret = dup(); ret.hates.add(s); s.hated.add(ret); s.needed_or_hated=true; return ret; }
 
     /** return a new sequence identical to this one, but with a follow-set restricted to <tt>a</tt> */
     public Sequence followedBy(Atom a) { Sequence ret = dup(); ret.follow = a; return ret; }
 
+    boolean hatesAny(Iterable<Sequence> it) {
+        if (hates.isEmpty()) return false;
+        for(Sequence s : it) if (hates.contains(s)) return true;
+        return false;
+    }
+
     Iterable<Sequence> needs() { return needs; }
     Iterable<Sequence> hates() { return hates; }
 
@@ -84,10 +97,10 @@ public abstract class Sequence /*extends Element*/ implements Iterable<Element>,
 
     // DO NOT MESS WITH THE FOLLOWING LINE!!!
     private Forest.Many epsilonForm = null;
-    Forest epsilonForm() {
+    Forest epsilonForm(Input.Region loc) {
         if (epsilonForm!=null) return epsilonForm;
         epsilonForm = new Forest.Many();
-        epsilonForm.merge(firstp().rewrite(null, false));
+        epsilonForm.merge(firstp().rewrite(loc, false));
         return epsilonForm;
     }
 
@@ -99,11 +112,25 @@ public abstract class Sequence /*extends Element*/ implements Iterable<Element>,
     /** the imaginary position before or after an element of a sequence; corresponds to an "LR item" */
     class Position implements IntegerMappable {
 
+        public int ord = -1;
+        public int compareTo(Position p, Walk.Cache cache) {
+            Position position = this;
+            Position rposition = p;
+            int ret = 0;
+            if (Reduction.canKill(cache, position, rposition) &&
+                Reduction.canKill(cache, rposition, position)) throw new Error();
+            if      (Reduction.canKill(cache, position,   rposition)) ret =  1;
+            else if (Reduction.canKill(cache, rposition, position)) ret = -1;
+            if      (Reduction.canNeed(cache, position,   rposition)) ret =  1;
+            else if (Reduction.canNeed(cache, rposition, position)) ret = -1;
+            return ret;
+        }
+
         private Forest zero = null;
-        public Forest zero() {
+        public Forest zero(Input.Region reg) {
             if (zero != null) return zero;
             if (pos > 0) throw new Error();
-            return zero = rewrite(null);
+            return zero = rewrite(reg);
         }
 
 
@@ -135,10 +162,10 @@ public abstract class Sequence /*extends Element*/ implements Iterable<Element>,
 
         final <T> Forest<T> rewrite(Input.Region loc) { return rewrite(loc, true); }
         private final <T> Forest<T> rewrite(Input.Region loc, boolean epsilonCheck) {
-            if (epsilonCheck && this==firstp()) return epsilonForm();
+            if (epsilonCheck && this==firstp()) return epsilonForm(loc);
             for(int i=0; i<pos; i++) if (holder[i]==null) throw new Error("realbad " + i);
             for(int i=pos; i<elements.length; i++) {
-                if (holder[i]==null) holder[i] = elements[i].epsilonForm();
+                if (holder[i]==null) holder[i] = elements[i].epsilonForm(loc);
                 if (holder[i]==null) throw new Error("bad " + i);
             }
             Forest<T> ret = Sequence.this.postReduce(loc, holder, this);
@@ -176,6 +203,14 @@ public abstract class Sequence /*extends Element*/ implements Iterable<Element>,
             sb.append("-> ");
             sb.append(follow);
         }
+        for(Sequence s : needs) {
+            sb.append("& ");
+            sb.append(s);
+        }
+        for(Sequence s : hates) {
+            sb.append("&~ ");
+            sb.append(s);
+        }
         return sb;
     }