X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FSequence.java;h=f4315182d654770e32ee45c8cc9017a3d17dda1e;hp=44b30c572bacbedd2c5257abbb29bfb26f696db3;hb=75d0fa39d405292f4b831a6d1743f2aeea01ebd4;hpb=6af13e9dda011e2416e4f0ee3cc347e8e7fcafd7 diff --git a/src/edu/berkeley/sbp/Sequence.java b/src/edu/berkeley/sbp/Sequence.java index 44b30c5..f431518 100644 --- a/src/edu/berkeley/sbp/Sequence.java +++ b/src/edu/berkeley/sbp/Sequence.java @@ -7,65 +7,73 @@ import java.util.*; import java.lang.reflect.*; import java.lang.ref.*; -/** juxtaposition; zero or more adjacent Elements; can specify a rewriting */ +/** juxtaposition; zero or more adjacent Elements; can specify a rewriting */ public abstract class Sequence extends Element implements Iterable { + protected final Element[] elements; + + final HashSet hated = new HashSet(); + + final HashSet needs = new HashSet(); + final HashSet hates = new HashSet(); + + final Position firstp; + + Atom follow = null; + // Static Constructors ////////////////////////////////////////////////////////////////////////////// abstract Sequence _clone(); Sequence dup() { Sequence ret = _clone(); - for(Sequence s : needs) { ret.needs.add(s); s.needed.add(ret); } + 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) */ - public static final Sequence empty = 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 drop(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 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 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 regionRewritingSequence(Functor tagfunctor, Element[] e, boolean[] drops) { - return new RegionRewritingSequence(tagfunctor, 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 Atom follow = null; - public final Topology follow() { return follow; } + /** 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.add(ret); 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 Iterable needs() { return needs; } - public Iterable hates() { return hates; } + /** 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; } - protected final Element[] elements; + Iterable needs() { return needs; } + Iterable hates() { return hates; } - final HashSet needed = new HashSet(); - final HashSet hated = new HashSet(); - final HashSet needs = new HashSet(); - final HashSet hates = new HashSet(); - - final Position firstp; Position firstp() { return firstp; } public Iterator iterator() { return new ArrayIterator(elements); } @@ -89,7 +97,7 @@ public abstract class Sequence extends Element implements Iterable { // 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 { private Forest zero = null; public Forest zero() { @@ -198,13 +206,12 @@ public abstract class Sequence extends Element implements Iterable { Sequence _clone() { return new Singleton(elements,idx); } } - 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, 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 Forest postReduce(Input.Region loc, Forest[] args, Position p) { for(int i=0; i { } } - // 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 sep */ - 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 sep */ - 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 sep, 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); } }