X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FSequence.java;h=968d78f555c968c85cba4e58192456ffb94d04cb;hb=eef891a53c43901acccac0dead16a79dbdb34c77;hp=8d6709d5f4e1d0164faacedbe0a6c60eb244ad80;hpb=e6be1f03f79b16cd410991d7e64cfa7beab6de59;p=sbp.git
diff --git a/src/edu/berkeley/sbp/Sequence.java b/src/edu/berkeley/sbp/Sequence.java
index 8d6709d..968d78f 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.*;
@@ -8,82 +10,101 @@ 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();
+ boolean needed_or_hated = false;
+ boolean in_a_union = false;
final HashSet needs = new HashSet();
final HashSet hates = new HashSet();
+ // FIXME: these are ugly -- migrate into Grammar
+ HashMap canNeed = new HashMap();
+ HashMap canKill = new HashMap();
+
final Position firstp;
Atom follow = null;
// Static Constructors //////////////////////////////////////////////////////////////////////////////
- abstract Sequence _clone();
- Sequence dup() {
- Sequence ret = _clone();
- for(Sequence s : needs) { ret.needs.add(s); }
- for(Sequence s : hates) { ret.hates.add(s); s.hated.add(ret); }
- ret.follow = follow;
- return ret;
- }
-
- /** the empty sequence (matches the empty string) */
- static final Sequence empty = new Sequence.Constant.Empty();
- public static Sequence empty() { return empty; }
+ /** create a sequence of one element */
+ public static Sequence create(Element e) { return create(new Element[] { e }, 0); }
- /** after matching the sequence, do not add anything to the output tree */
- public static Sequence drop(Element[] e) { return new Constant.Drop(e); }
+ /** 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, insert a constant into the output tree */
- public static Sequence constant(Element[] e, Object o) { return new Constant(e, o); }
-
- /** after matching the sequence, place the result of the idxth match in the output tree */
- public static Sequence singleton(Element[] e, int idx) { return new Singleton(e, idx); }
- public static Sequence singleton(Element e) { return singleton(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 rewritingSequence(Object tag, Element[] e, boolean[] drops) {
- return new RewritingSequence(tag, e, 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);
+ }
- public static Sequence regionRewritingSequence(Functor tagfunctor, Element[] e, boolean[] drops) {
- return new RegionRewritingSequence(tagfunctor, e, drops); }
+ /** return a new sequence identical to this one, but with a positive conjunct s */
+ public Sequence and(Sequence s) {
+ if (s.in_a_union)
+ throw new RuntimeException("you may not use a sequence as a conjunct if it belongs to a Union");
+ 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 andnot(Sequence s) {
+ if (s.in_a_union)
+ throw new RuntimeException("you may not use a sequence as a conjunct if it belongs to a Union");
+ Sequence ret = dup();
+ ret.hates.add(s);
+ s.needed_or_hated=true;
+ return ret;
+ }
- public Sequence and(Sequence s) { Sequence ret = dup(); ret.needs.add(s); return ret; }
- public Sequence not(Sequence s) { Sequence ret = dup(); ret.hates.add(s); s.hated.add(ret); 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; }
+ ////////////////////////////////////////////////////////////////////////////////
+
+ abstract Sequence _clone();
+ private Sequence dup() {
+ Sequence ret = _clone();
+ for(Sequence s : needs) { ret.needs.add(s); }
+ for(Sequence s : hates) { ret.hates.add(s); }
+ ret.follow = follow;
+ return ret;
+ }
+
Iterable needs() { return needs; }
Iterable hates() { return hates; }
Position firstp() { return firstp; }
+ Position lastp() { return firstp().last(); }
public Iterator iterator() { return new ArrayIterator(elements); }
protected Sequence(Element[] elements) {
this.elements = elements;
- this.firstp = new Position(0);
+ for(int i=0; i Forest postReduce(Input.Region loc, Forest[] args, Position p);
@@ -93,22 +114,26 @@ 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;
+
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);
+ if (pos > 0) throw new RuntimeException("Position.zero(): pos>0");
+ return zero = rewrite(reg);
}
-
-
+ */
final int pos;
private final Position next;
+ private final Position prev;
final Forest[] holder;
- private Position(int pos) {
+ private Position(int pos, Position prev) {
this.pos = pos;
- this.next = pos==elements.length ? null : new Position(pos+1);
+ this.next = pos==elements.length ? null : new Position(pos+1, this);
this.holder = new Forest[elements.length];
+ this.prev = prev;
}
boolean isFirst() { return pos==0; }
@@ -124,20 +149,19 @@ public abstract class Sequence extends Element implements Iterable {
/** true iff this Position is the last one in the sequence */
public boolean isLast() { return next()==null; }
+ public Position last() { return isLast() ? this : next().last(); }
+ public Position prev() { return prev; }
// Position /////////////////////////////////////////////////////////////////////////////////
- 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();
+ final Forest rewrite(Input.Region loc, Grammar cache) {
+ if (this==firstp()) epsilonForm(loc, cache);
for(int i=0; i ret = Sequence.this.postReduce(loc, holder, this);
- //for(int k=0; k {
StringBuffer toString(StringBuffer sb) { return toString(sb, true); }
StringBuffer toString(StringBuffer sb, boolean spacing) {
for(int i=0; i ");
sb.append(follow);
}
+ for(Sequence s : needs) {
+ sb.append("& ");
+ sb.append(s);
+ }
+ for(Sequence s : hates) {
+ sb.append("&~ ");
+ sb.append(s);
+ }
return sb;
}
@@ -178,18 +210,18 @@ public abstract class Sequence extends Element implements Iterable {
static class Constant extends Sequence {
private final Object result;
- public Constant(Element[] e, Object result) { super(e); this.result = result; }
+ public Constant(Element[] e, Object result) {
+ super(e);
+ if (result==null) throw new Error("constant sequences may not have result==null");
+ this.result = result;
+ }
Sequence _clone() { return new Constant(elements, result); }
public Forest postReduce(Input.Region loc, Forest[] args, Position p) {
return (Forest)Forest.create(loc, result, null, false);
}
- static class Drop extends Constant {
- Sequence _clone() { return new Drop(elements); }
- public Drop(Element[] e) { super(e, null); }
+ Forest epsilonForm(Input.Region loc, Grammar cache) {
+ return Forest.create(loc, result, null, false);
}
- static class Empty extends Sequence.Constant.Drop {
- Sequence _clone() { return new Empty(); }
- public Empty() { super(new Element[] { }); } }
}
static class Singleton extends Sequence {
@@ -198,13 +230,15 @@ public abstract class Sequence extends Element implements Iterable {
public Singleton(Element[] e, int idx) { super(e); this.idx = idx; }
public Forest postReduce(Input.Region loc, Forest[] args, Position p) { return args[idx]; }
Sequence _clone() { return new Singleton(elements,idx); }
+ Forest epsilonForm(Input.Region loc, Grammar cache) {
+ return ((Union)elements[idx]).epsilonForm(loc, cache);
+ }
}
- public static Sequence unwrap(Element[] e, Object tag, boolean[] drops) { return new Unwrap(e, tag, drops); }
static class Unwrap extends Sequence {
private boolean[] drops;
private final Object tag;
- public Unwrap(Element[] e, Object tag) { super(e); this.drops = null; this.tag = tag; }
+ public Unwrap(Element[] e, Object tag) { this(e, tag, null); }
public Unwrap(Element[] e, Object tag, boolean[] drops) { super(e); this.drops = drops; this.tag = tag; }
Sequence _clone() { return new Unwrap(elements, tag, drops); }
public Forest postReduce(Input.Region loc, Forest[] args, Position p) {
@@ -217,32 +251,20 @@ public abstract class Sequence extends Element implements Iterable {
for(int i=0; i tagf;
- public RegionRewritingSequence(Functor tagfunctor, Element[] e, boolean[] drops) {
- super(null, e, drops);
- this.tagf = tagfunctor;
- }
- public Forest postReduce(Input.Region loc, Forest[] args, Position p) {
- this.tag = tagf.invoke(loc);
- Forest ret = super.postReduce(loc, args, p);
- this.tag = null;
- return ret;
+ Forest epsilonForm(Input.Region loc, Grammar cache) {
+ return Forest.create(loc, tag, new Forest[0], false);
}
}
static class RewritingSequence extends Sequence {
- /*private*/public /*final*/ Object tag;
+ private Object tag;
private final boolean[] drops;
private int count = 0;
Sequence _clone() { return new RewritingSequence(tag, elements, drops); }
public RewritingSequence(Object tag, Element[] e) { this(tag, e, null); }
public RewritingSequence(Object tag, Element[] e, boolean[] drops) {
super(e);
+ if (tag==null) throw new Error();
this.tag = tag;
this.drops = drops == null ? new boolean[e.length] : drops;
for(int i=0; i {
Forest[] args2 = new Forest[count];
int j = 0;
for(int i=0; i {
if (spacing) for(int i=0; i<50-len; i++) sb.append(' ');
return sb;
}
+ Forest epsilonForm(Input.Region loc, Grammar cache) {
+ return Forest.create(loc, tag, new Forest[0], false);
+ }
}
}