+// 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.*;
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<Element> {
+/** <font color=green>juxtaposition; zero or more adjacent Elements; can specify a rewriting</font> */
+public abstract class Sequence implements Iterable<Element>, SequenceOrElement {
- // Static Constructors //////////////////////////////////////////////////////////////////////////////
+ protected final Element[] elements;
+
+ boolean needed_or_hated = false;
+ boolean in_a_union = false;
+
+ final HashSet<Sequence> needs = new HashSet<Sequence>();
+ final HashSet<Sequence> hates = new HashSet<Sequence>();
+
+ // FIXME: these are ugly -- migrate into Grammar
+ HashMap<Sequence,Boolean> canNeed = new HashMap<Sequence,Boolean>();
+ HashMap<Sequence,Boolean> canKill = new HashMap<Sequence,Boolean>();
- public abstract Sequence and(Sequence s);
- public abstract Sequence not(Sequence s);
+ final Position firstp;
- private void needs(Sequence s) { s.needed.add(this); needs.add(s); }
- private void hates(Sequence s) { s.hated.add(this); hates.add(s); }
+ Atom follow = null;
- /** the empty sequence (matches the empty string) */
- public static final Sequence empty = new Sequence.Constant.Empty();
+ // Static Constructors //////////////////////////////////////////////////////////////////////////////
- /** after matching the sequence, do not add anything to the output tree */
- public static Sequence drop(Element[] e, HashSet<Sequence> and, HashSet<Sequence> not, boolean lame) { return new Constant.Drop(e, and, not, lame); }
+ /** 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 constant(Element[] e, Object o, HashSet<Sequence> and, HashSet<Sequence> not) { return new Constant(e, o, and, not); }
+ /** 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 <tt>idx</tt>th match in the output tree */
- public static Sequence singleton(Element[] e, int idx, HashSet<Sequence> and, HashSet<Sequence> not) { return new Singleton(e, idx, and, not); }
+ /** 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 <tt>e</tt> whose corresponding <tt>boolean</tt> in <tt>drops</tt> is <i>false</i> 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 <tt>e</tt> whose corresponding <tt>boolean</tt> in <tt>drops</tt>
+ * is <i>false</i> 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, HashSet<Sequence> and, HashSet<Sequence> not) {
- return new RewritingSequence(tag, e, drops, and, not); }
-
- ////////////////////////////////////////////////////////////////////////////////
+ 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 createLeft(Object head, Element[] e, boolean[] drop, boolean foster) {
+ return foster
+ ? new UnwrapLeft(e, head, drop)
+ : new RewritingSequence(head, e, drop);
+ }
- public Element noFollow = null;
- public String name = null;
- public void setName(String name) { this.name = name; }
- public final Topology noFollow() { return noFollow==null ? null : noFollow.toAtom(); }
+ /** return a new sequence identical to this one, but with a positive conjunct <tt>s</tt> */
+ 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;
+ }
- Topology toAtom() {
- if (elements.length!=1) throw new RuntimeException("cannot invoke toAtom() on a Sequence with " + elements.length + " elements: " + this);
- return elements[0].toAtom();
+ /** return a new sequence identical to this one, but with a negative conjunct <tt>s</tt> */
+ 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;
}
- protected final Element[] elements;
+ /** 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; }
+
+ ////////////////////////////////////////////////////////////////////////////////
- HashSet<Sequence> needed;
- HashSet<Sequence> hated;
- final HashSet<Sequence> needs;
- final HashSet<Sequence> hates;
- public boolean lame = false;
+ 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<Sequence> needs() { return needs; }
+ Iterable<Sequence> hates() { return hates; }
- final Position firstp;
Position firstp() { return firstp; }
+ Position lastp() { return firstp().last(); }
public Iterator<Element> iterator() { return new ArrayIterator<Element>(elements); }
- protected Sequence(Element[] elements, HashSet<Sequence> and, HashSet<Sequence> not) {
- this.needs = and==null ? new HashSet<Sequence>() : and;
- this.hates = not==null ? new HashSet<Sequence>() : not;
- if (this.needs != null)
- for(Sequence s : this.needs)
- (s.needed==null?(s.needed=new HashSet<Sequence>()):s.needed).add(this);
- if (this.hates != null)
- for(Sequence s : this.hates)
- (s.hated==null?(s.hated=new HashSet<Sequence>()):s.hated).add(this);
+ protected Sequence(Element[] elements) {
this.elements = elements;
- this.firstp = new Position(0);
+ for(int i=0; i<elements.length; i++)
+ if (elements[i]==null)
+ throw new RuntimeException("cannot have nulls in a sequence: " + this);
+ this.firstp = new Position(0, null);
}
- // DO NOT MESS WITH THE FOLLOWING LINE!!!
- private Forest.Ref epsilonForm = null;
- private boolean eps = false;
- Forest epsilonForm() {
- if (epsilonForm==null) {
- epsilonForm = new Forest.Ref();
- epsilonForm.merge(firstp().rewrite2(null));
- }
- return epsilonForm;
- }
+ abstract Forest epsilonForm(Input.Region loc, Grammar cache);
- protected abstract <T> Forest<T> postReduce(Input.Location loc, Forest<T>[] args);
+ protected abstract <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] args, Position p);
// Position //////////////////////////////////////////////////////////////////////////////
/** the imaginary position before or after an element of a sequence; corresponds to an "LR item" */
- public class Position implements IntegerMappable {
+ 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; }
/** 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 <T> Forest<T> rewrite(Input.Location loc) {
- if (this==firstp()) return epsilonForm();
- return rewrite2(loc);
- }
-
- final <T> Forest<T> rewrite2(Input.Location loc) {
+ final <T> Forest<T> rewrite(Input.Region loc, Grammar cache) {
+ if (this==firstp()) epsilonForm(loc, cache);
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) throw new Error("bad " + i);
+ if (holder[i]==null) holder[i] = ((Union)elements[i]).epsilonForm(loc, cache);
+ if (holder[i]==null) throw new Error("bad");
}
- Forest<T> ret = Sequence.this.postReduce(loc, holder);
- for(int k=0; k<pos; k++) holder[k] = null; // to help GC
- return ret;
+ return Sequence.this.postReduce(loc, holder, this);
}
public String toString() {
StringBuffer toString(StringBuffer sb) { return toString(sb, true); }
StringBuffer toString(StringBuffer sb, boolean spacing) {
for(int i=0; i<elements.length; i++) {
- sb.append(elements[i].toString());
+ sb.append(elements[i]+"");
sb.append(' ');
}
+ if (follow != null) {
+ 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;
}
static class Constant extends Sequence {
private final Object result;
- public Constant(Element[] e, Object result, HashSet<Sequence> and, HashSet<Sequence> not) { super(e, and, not); this.result = result; }
- public Sequence and(Sequence s) { Sequence ret = new Constant(elements, result, needs, hates); ret.needs(s); return ret; }
- public Sequence not(Sequence s) { Sequence ret = new Constant(elements, result, needs, hates); ret.hates(s); return ret; }
- public <T> Forest<T> postReduce(Input.Location loc, Forest<T>[] args) {
- return (Forest<T>)Forest.leaf(loc, result);
- }
- static class Drop extends Constant {
- public Drop(Element[] e, HashSet<Sequence> and, HashSet<Sequence> not, boolean lame) {
- super(e, null, and, not);
- this.lame = lame;
- }
+ 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 <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] args, Position p) {
+ return (Forest<T>)Forest.create(loc, result, null, false);
+ }
+ Forest epsilonForm(Input.Region loc, Grammar cache) {
+ return Forest.create(loc, result, null, false);
}
- static class Empty extends Sequence.Constant.Drop { public Empty() { super(new Element[] { }, null, null, false); } }
}
static class Singleton extends Sequence {
private final int idx;
- public Singleton(Element e, HashSet<Sequence> and, HashSet<Sequence> not) { this(new Element[] { e }, 0, and, not); }
- public Singleton(Element[] e, int idx, HashSet<Sequence> and, HashSet<Sequence> not) { super(e, and, not); this.idx = idx; }
- public <T> Forest<T> postReduce(Input.Location loc, Forest<T>[] args) { return (Forest<T>)Forest.singleton(loc, args[idx]); }
- public Sequence and(Sequence s) { Sequence ret = new Singleton(elements, idx, needs, hates); ret.needs(s); return ret; }
- public Sequence not(Sequence s) { Sequence ret = new Singleton(elements, idx, needs, hates); ret.hates(s); return ret; }
+ public Singleton(Element e) { this(new Element[] { e }, 0); }
+ public Singleton(Element[] e, int idx) { super(e); this.idx = idx; }
+ public <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] 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 class Unwrap extends Sequence {
+ static class Unwrap extends Sequence {
private boolean[] drops;
- public Unwrap(Element[] e, HashSet<Sequence> and, HashSet<Sequence> not) { super(e, and, not); this.drops = null; }
- public Unwrap(Element[] e, boolean[] drops, HashSet<Sequence> and, HashSet<Sequence> not) { super(e, and, not); this.drops = drops; }
- public Sequence and(Sequence s) { Sequence ret = new Unwrap(elements, drops, needs, hates); ret.needs(s); return ret; }
- public Sequence not(Sequence s) { Sequence ret = new Unwrap(elements, drops, needs, hates); ret.hates(s); return ret; }
- public <T> Forest<T> postReduce(Input.Location loc, Forest<T>[] args) {
+ private final Object 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 <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] args, Position p) {
for(int i=0; i<args.length; i++) if (args[i]==null) throw new Error();
- if (drops==null) return Forest.create(loc, null, args, true, false);
+ if (drops==null) return Forest.create(loc, (T)tag, args, true);
int count = 0;
for(int i=0; i<drops.length; i++) if (!drops[i]) count++;
Forest<T>[] args2 = new Forest[count];
int j = 0;
for(int i=0; i<args.length; i++) if (!drops[i]) args2[j++] = args[i];
- return Forest.create(loc, null, args2, true, false);
+ return Forest.create(loc, (T)tag, args2, true);
+ }
+ Forest epsilonForm(Input.Region loc, Grammar cache) {
+ return Forest.create(loc, tag, new Forest[0], false);
+ }
+ }
+
+ static class UnwrapLeft extends Sequence {
+ private boolean[] drops;
+ private final Object tag;
+ public UnwrapLeft(Element[] e, Object tag) { this(e, tag, null); }
+ public UnwrapLeft(Element[] e, Object tag, boolean[] drops) { super(e); this.drops = drops; this.tag = tag; }
+ Sequence _clone() { return new UnwrapLeft(elements, tag, drops); }
+ public <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] args, Position p) {
+ for(int i=0; i<args.length; i++) if (args[i]==null) throw new Error();
+ if (drops==null) return Forest.create(loc, (T)tag, args, false, true);
+ int count = 0;
+ for(int i=0; i<drops.length; i++) if (!drops[i]) count++;
+ Forest<T>[] args2 = new Forest[count];
+ int j = 0;
+ for(int i=0; i<args.length; i++) if (!drops[i]) args2[j++] = args[i];
+ return Forest.create(loc, (T)tag, args2, false, true);
+ }
+ 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;
- public Sequence and(Sequence s) { Sequence ret = new RewritingSequence(tag, elements, drops, needs, hates); ret.needs(s); return ret; }
- public Sequence not(Sequence s) { Sequence ret = new RewritingSequence(tag, elements, drops, needs, hates); ret.hates(s); return ret; }
- public RewritingSequence(Object tag, Element[] e, HashSet<Sequence> and, HashSet<Sequence> not) { this(tag, e, null, and, not); }
- public RewritingSequence(Object tag, Element[] e, boolean[] drops, HashSet<Sequence> and, HashSet<Sequence> not) {
- super(e, and, not);
+ 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<this.drops.length; i++) if (!this.drops[i]) count++;
}
- public <T> Forest<T> postReduce(Input.Location loc, Forest<T>[] args) {
+ public <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] args, Position p) {
Forest<T>[] args2 = new Forest[count];
int j = 0;
for(int i=0; i<args.length; i++) if (!drops[i]) args2[j++] = args[i];
- //System.out.println("reduce \""+tag+"\"");
- return Forest.create(loc, (T)tag, args2, false, false);
+ return Forest.create(loc, (T)tag, args2, false);
}
public StringBuffer toString(StringBuffer sb, boolean spacing) {
int len = sb.length();
+ if (tag != null)
+ sb.append("\""+StringUtil.escapify(tag.toString(),"\"\r\n")+"\":: ");
super.toString(sb, spacing);
len = sb.length()-len;
if (spacing) for(int i=0; i<50-len; i++) sb.append(' ');
- sb.append(" => ");
- sb.append(tag);
return sb;
}
+ Forest epsilonForm(Input.Region loc, Grammar cache) {
+ return Forest.create(loc, tag, new Forest[0], false);
+ }
}
+
}
projects / sbp.git / blobdiff