X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FSequence.java;h=f4315182d654770e32ee45c8cc9017a3d17dda1e;hp=5ee8433431ef5d25137fead50bdb7a8debedd86a;hb=75d0fa39d405292f4b831a6d1743f2aeea01ebd4;hpb=0e17670bcfa7b0fe8eb3a2cac81f4b080a09fc98 diff --git a/src/edu/berkeley/sbp/Sequence.java b/src/edu/berkeley/sbp/Sequence.java index 5ee8433..f431518 100644 --- a/src/edu/berkeley/sbp/Sequence.java +++ b/src/edu/berkeley/sbp/Sequence.java @@ -19,8 +19,7 @@ public abstract class Sequence extends Element implements Iterable { final Position firstp; - public Atom follow = null; - public final Topology follow() { return follow; } + Atom follow = null; // Static Constructors ////////////////////////////////////////////////////////////////////////////// @@ -33,39 +32,47 @@ public abstract class Sequence extends Element implements Iterable { 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); + } //////////////////////////////////////////////////////////////////////////////// + /** 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; } + + /** 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; } + + Iterable needs() { return needs; } + Iterable hates() { return hates; } Position firstp() { return firstp; } @@ -90,7 +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() { @@ -199,13 +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); } }