X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FSequence.java;h=a029274a0a01f7cbe48db426e645c1def564e64a;hp=bb0ba4815a6212744ae9c0c27efed77172548ff3;hb=0620c2d97d6df986d74dbe13160afb1435096431;hpb=4378d20232cd88fb2a57edc5a5114f952ab58a18
diff --git a/src/edu/berkeley/sbp/Sequence.java b/src/edu/berkeley/sbp/Sequence.java
index bb0ba48..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.*;
/** juxtaposition; zero or more adjacent Elements; can specify a rewriting */
-public abstract class Sequence extends Element implements Iterable {
+public abstract class Sequence implements Iterable, SequenceOrElement {
protected final Element[] elements;
- final HashSet hated = new HashSet();
+ public boolean needed_or_hated = false;
+
+ public HashMap canNeed = new HashMap();
+ public HashMap canKill = new HashMap();
+
+ final HashSet hated = new HashSet();
final HashSet needs = new HashSet();
final HashSet hates = new HashSet();
@@ -32,42 +39,51 @@ public abstract class Sequence extends Element implements Iterable {
return ret;
}
- /** the empty sequence (matches the empty string) */
- public static Sequence newEmptySequence() { return new Sequence.Constant.Empty(); }
+ /** create an empty sequence (matches the empty string) */
+ public static Sequence create() { return new Sequence.Constant.Empty(); }
- /** after matching the sequence, do not add anything to the output tree */
- public static Sequence newDropSequence(Element[] e) { return new Constant.Drop(e); }
+ /** create a sequence of one element */
+ public static Sequence create(Element e) { return create(new Element[] { e }, 0); }
- /** after matching the sequence, insert a constant into the output tree */
- public static Sequence newConstantSequence(Element[] e, Object o) { return new Constant(e, o); }
+ /** create a sequence which drops the result of all but one of its element */
+ public static Sequence create(Element[] e, int which) { return new Singleton(e, which); }
- /** after matching the sequence, place the result of the idxth match in the output tree */
- public static Sequence newSingletonSequence(Element[] e, int idx) { return new Singleton(e, idx); }
- public static Sequence newSingletonSequence(Element e) { return newSingletonSequence(new Element[] { e }, 0); }
+ /** create a sequence which always evaluates to a constant result */
+ public static Sequence create(Element[] e, Object result) { return new Constant(e, result); }
/**
- * after matching the sequence, create the specified output tree
- * @param tag the tag for the output tree
- * @param e the elements to match
- * @param drops only elements of e whose corresponding boolean in drops
- * is false will be included in the output tree
+ * create a sequence (general form)
+ * @param head the head of the output tree
+ * @param e the elements to match
+ * @param drop only elements of e whose corresponding boolean in drops
+ * is false will be included in the output tree
+ * @param foster if true, all children of the last child (ie
+ * grandchildren) are promoted to children of this
+ * node; this is very useful for matching repetitions
**/
- public static Sequence newRewritingSequence(Object tag, Element[] e, boolean[] drops) {
- return new RewritingSequence(tag, e, drops); }
-
- public static Sequence newUnwrapSequence(Element[] e, Object tag, boolean[] drops) { return new Unwrap(e, tag, drops); }
+ public static Sequence create(Object head, Element[] e, boolean[] drop, boolean foster) {
+ return foster
+ ? new Unwrap(e, head, drop)
+ : new RewritingSequence(head, e, drop);
+ }
////////////////////////////////////////////////////////////////////////////////
/** return a new sequence identical to this one, but with a positive conjunct s */
- 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 s */
- 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 a */
public Sequence followedBy(Atom a) { Sequence ret = dup(); ret.follow = a; return ret; }
+ boolean hatesAny(Iterable it) {
+ if (hates.isEmpty()) return false;
+ for(Sequence s : it) if (hates.contains(s)) return true;
+ return false;
+ }
+
Iterable needs() { return needs; }
Iterable hates() { return hates; }
@@ -81,10 +97,10 @@ public abstract class Sequence extends Element implements Iterable {
// 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;
}
@@ -96,11 +112,25 @@ public abstract class Sequence extends Element implements Iterable {
/** 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);
}
@@ -132,10 +162,10 @@ public abstract class Sequence extends Element implements Iterable {
final Forest rewrite(Input.Region loc) { return rewrite(loc, true); }
private final Forest rewrite(Input.Region loc, boolean epsilonCheck) {
- if (epsilonCheck && this==firstp()) return epsilonForm();
+ if (epsilonCheck && this==firstp()) return epsilonForm(loc);
for(int i=0; i ret = Sequence.this.postReduce(loc, holder, this);
@@ -173,6 +203,14 @@ public abstract class Sequence extends Element implements Iterable {
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;
}