+// 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;
- abstract Sequence _clone();
- Sequence dup() {
- Sequence ret = _clone();
- for(Sequence s : needs) { ret.needs.add(s); s.needed.add(ret); }
- for(Sequence s : hates) { ret.hates.add(s); s.hated.add(ret); }
- ret.follow = follow;
- ret.lame = lame;
- return ret;
- }
+ 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>();
+
+ final Position firstp;
+
+ 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, boolean lame) { return new Constant.Drop(e, 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) { 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 <tt>idx</tt>th 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 <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) {
- 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 createLeft(Object head, Element[] e, boolean[] drop, boolean foster) {
+ return foster
+ ? new UnwrapLeft(e, head, drop)
+ : new RewritingSequence(head, e, drop);
+ }
- public Element follow = null;
- public final Topology follow() { return follow==null ? null : Atom.toAtom(follow); }
+ /** 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 Atom.toAtom(elements[0]);
+ /** 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;
}
- public Sequence and(Sequence s) { Sequence ret = dup(); ret.needs.add(s); s.needed.add(ret); 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 <tt>a</tt> */
+ public Sequence followedBy(Atom a) { Sequence ret = dup(); ret.follow = a; return ret; }
- protected final Element[] elements;
+ ////////////////////////////////////////////////////////////////////////////////
- final HashSet<Sequence> needed = new HashSet<Sequence>();
- final HashSet<Sequence> hated = new HashSet<Sequence>();
- final HashSet<Sequence> needs = new HashSet<Sequence>();
- final HashSet<Sequence> hates = new HashSet<Sequence>();
- 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) {
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;
- Forest epsilonForm() {
- if (epsilonForm!=null) return epsilonForm;
- epsilonForm = new Forest.Ref();
- epsilonForm.merge(firstp().rewrite(null, false));
- return epsilonForm;
- }
+ abstract Forest epsilonForm(Input.Region loc, Grammar cache);
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.Region loc) { return rewrite(loc, true); }
- private final <T> Forest<T> rewrite(Input.Region loc, boolean epsilonCheck) {
- if (epsilonCheck && this==firstp()) return epsilonForm();
+ 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, this);
- //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) { 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 <T> Forest<T> postReduce(Input.Region loc, Forest<T>[] args, Position p) {
- return (Forest<T>)Forest.leaf(loc, result, p);
+ return (Forest<T>)Forest.create(loc, result, null, false);
}
- static class Drop extends Constant {
- Sequence _clone() { return new Drop(elements, lame); }
- public Drop(Element[] e, boolean lame) {
- super(e, null);
- this.lame = lame;
- }
+ 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[] { }, false); } }
}
static class Singleton extends Sequence {
private final int idx;
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 (Forest<T>)Forest.singleton(loc, args[idx], p); }
+ 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 Unwrap 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, drops); }
+ 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, (T)tag, args, true, false, p);
+ 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, (T)tag, args2, true, false, p);
+ 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;
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++;
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, p);
+ return Forest.create(loc, (T)tag, args2, false);
}
public StringBuffer toString(StringBuffer sb, boolean spacing) {
int len = sb.length();
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);
+ }
}
- // Repeat //////////////////////////////////////////////////////////////////////////////
-
- /** repeat zero or one times */
- public static Element maybe(Element e) { return new Repeat(e, true, false, null, null); }
- public static Element maybe(Element e, Object tag) { return new Repeat(e, true, false, null, tag); }
- /** repeat zero or more times */
- public static Element many0(Element e) { return new Repeat(e, true, true, null, null); }
- public static Element many0(Element e, Object tag) { return new Repeat(e, true, true, null, tag); }
- /** repeat zero or more times, separated by <tt>sep</tt> */
- public static Element many0(Element e, Element sep) { return new Repeat(e, true, true, sep, null); }
- public static Element many0(Element e, Element sep, Object tag) { return new Repeat(e, true, true, sep, tag); }
- /** repeat one or more times */
- public static Element many1(Element e) { return new Repeat(e, false, true, null, null); }
- public static Element many1(Element e, Object tag) { return new Repeat(e, false, true, null, tag); }
- /** repeat one or more times, separated by <tt>sep</tt> */
- public static Element many1(Element e, Element sep) { return new Repeat(e, false, true, sep, null); }
- public static Element many1(Element e, Element sep, Object tag) { return new Repeat(e, false, true, sep, tag); }
-
- /** repeat zero or more times, matching a maximal sequence of atoms */
- public static Element maximal0(Atom e) { return new Repeat.Maximal(e, true, true, null); }
- public static Element maximal0(Atom e, Object tag) { return new Repeat.Maximal(e, true, true, tag); }
- /** repeat one or more times, matching a maximal sequence of atoms */
- public static Element maximal1(Atom e) { return new Repeat.Maximal(e, false, true, null); }
- public static Element maximal1(Atom e, Object tag) { return new Repeat.Maximal(e, false, true, tag); }
- /** repeat one or more times, separated by an atom <tt>sep</tt>, matching a maximal sequence */
- public static Element maximal1(Element e, Atom sep) { return new Repeat.Maximal(e, false, true, sep, null); }
- public static Element maximal1(Element e, Atom sep, Object tag) { return new Repeat.Maximal(e, false, true, sep, tag); }
-
- public static Element repeatMaximal(Atom e, boolean zero, boolean many, Object tag) {
- return new Repeat.Maximal(e, zero, many, tag); }
- public static Element repeatMaximal(Element e, boolean zero, boolean many, Atom sep, Object tag) {
- return new Repeat.Maximal(e, zero, many, sep, tag); }
- public static Element repeat(Element e, boolean zero, boolean many, Object tag) {
- return new Repeat(e, zero, many, tag); }
- public static Element repeat(Element e, boolean zero, boolean many, Element sep, Object tag) {
- return new Repeat(e, zero, many, sep, tag); }
}
projects / sbp.git / blobdiff