+++ /dev/null
-// Copyright 2006 all rights reserved; see LICENSE file for BSD-style license
-
-package edu.berkeley.sbp;
-import edu.berkeley.sbp.*;
-import edu.berkeley.sbp.util.*;
-import edu.berkeley.sbp.Sequence.Position;
-import java.io.*;
-import java.util.*;
-import java.lang.reflect.*;
-import java.lang.ref.*;
-
-/** a traversal of the grammar performed by mapping from SequenceOrElements to a lattice and computing the resulting LUB */
-abstract class Walk<T> {
- protected HashSet<SequenceOrElement> acc = new HashSet<SequenceOrElement>();
- protected abstract T bottom(SequenceOrElement e);
-
- protected final Cache c;
- public Walk() { this(null); }
- public Walk(Cache c) { this.c = c; }
-
- public T walkSequence(Sequence s) {
- T ret = bottom(s);
- for(Position p = s.firstp(); p!=null && !p.isLast(); p = p.next())
- ret = sequence(s, ret, walk(p.element()));
- return ret;
- }
-
- public T walkAtom(Atom r) { return walk(r); }
- public T union(Union u, T a, T b) { return bottom(u); }
- public T sequence(Sequence s, T a, T b) { return bottom(s); }
- protected T walk(SequenceOrElement e) {
- if (acc.contains(e)) return bottom(e);
- acc.add(e);
- return walk2(e);
- }
-
- protected T walk2(SequenceOrElement e) {
- if (e instanceof Atom) return walkAtom((Atom)e);
- else if (e instanceof Sequence) return walkSequence((Sequence)e);
- else if (e instanceof Union) {
- T ret = bottom(e);
- for(Sequence s : (Union)e)
- ret = union((Union)e, ret, walk(s));
- return ret;
- } else {
- throw new Error("unknown element of class " + e.getClass().getName() + ": " + e);
- }
- }
-
- static class YieldSet extends Walk<HashSet<SequenceOrElement>> {
- private final SequenceOrElement e;
- public final HashSet<SequenceOrElement> walk() { return walk(e); }
- public YieldSet(SequenceOrElement e, Cache c) { super(c); this.e = e; }
- public HashSet<SequenceOrElement> bottom(SequenceOrElement e) { return acc; }
- public HashSet<SequenceOrElement> walkSequence(Sequence seq) { return bottom(seq); }
- public HashSet<SequenceOrElement> walkAtom(Atom r) {
- c.atoms.put(e, c.atoms.get(e)==null ? r : c.atoms.get(e).union(r));
- return super.walkAtom(r);
- }
- protected HashSet<SequenceOrElement> walk2(SequenceOrElement e) {
- HashSet<SequenceOrElement> ret = super.walk2(e);
- if (e instanceof Union)
- for(Sequence s : (Union)e) {
- for(Sequence ss : s.needs()) ret = union((Union)e, ret, walk(ss));
- for(Sequence ss : s.hates()) ret = union((Union)e, ret, walk(ss));
- }
- return ret;
- }
- }
-
- static class YieldSet2 extends Walk<HashSet<SequenceOrElement>> {
- private final SequenceOrElement e;
- public final HashSet<SequenceOrElement> walk() { return walk(e); }
- public YieldSet2(SequenceOrElement e, Cache c) { super(c); this.e = e; }
- public HashSet<SequenceOrElement> bottom(SequenceOrElement e) { return acc; }
- public HashSet<SequenceOrElement> walkSequence(Sequence seq) { return bottom(seq); }
- public HashSet<SequenceOrElement> walkAtom(Atom r) {
- c.atoms.put(e, c.atoms.get(e)==null ? r : c.atoms.get(e).union(r));
- return super.walkAtom(r);
- }
- }
-
- static class EquivalentTo extends Walk<HashSet<Sequence>> {
- private final Sequence s;
- private final HashSet<Sequence> eq = new HashSet<Sequence>();
- public final HashSet<Sequence> walk() { return walk(s); }
- public EquivalentTo(Sequence e, Cache c) {
- super(c); this.s = e;
- }
- public HashSet<Sequence> bottom(SequenceOrElement e) { return eq; }
- public HashSet<Sequence> walkSequence(Sequence seq) {
- eq.add(seq);
- Position p = seq.firstp();
- for(; !p.isLast(); p = p.next()) {
- if (!p.isLast() && isRightNullable(p.next()))
- walk(p.element());
- if (!c.possiblyEpsilon(p.element())) break;
- }
- return eq;
- }
- public HashSet<Sequence> walkAtom(Atom r) {
- return eq;
- }
- private boolean isRightNullable(Position p) {
- if (p.isLast()) return true;
- if (!c.possiblyEpsilon(p.element())) return false;
- return isRightNullable(p.next());
- }
- }
-
-
- // Boolean //////////////////////////////////////////////////////////////////////////////
-
- static class PossiblyEpsilon extends Walk<Boolean> {
- public Boolean walkAtom(Atom r) { return false; }
- public Boolean sequence(Sequence s, Boolean a, Boolean b) { return new Boolean(a && b); }
- public Boolean union(Union u, Boolean a, Boolean b) { return new Boolean(a || b); }
- public Boolean bottom(SequenceOrElement e) { return (e instanceof Union) ? false : true; }
- private HashMap<SequenceOrElement,Boolean> hm = new HashMap<SequenceOrElement,Boolean>();
- protected Boolean walk(SequenceOrElement e) {
- if (hm.get(e) != null) return hm.get(e);
- hm.put(e, false);
- Boolean ret = walk2(e);
- hm.put(e, ret);
- return ret;
- }
- }
-
- static class EpsilonFollowSet extends Walk<Atom> {
- Atom all;
- Atom empty;
- public EpsilonFollowSet(Atom a, Atom empty, Cache c) {
- super(c);
- this.all = all;
- this.empty = empty;
- }
- public Atom walkAtom(Atom r) { return all; }
- public Atom walkSequence(Sequence s) {
- if (s.follow==null) return all;
- return s.follow;
- }
- public Atom sequence(Sequence s, Atom a, Atom b) {
- throw new RuntimeException();
- }
- public Atom union(Union u, Atom a, Atom b) {
- /*
- if (a==null) return b;
- if (b==null) return a;
- */
- if (a==null || b==null) return all;
- return (Atom)a.union(b);
- }
- public Atom bottom(SequenceOrElement e) {
- return (e instanceof Union) ? empty : all;
- }
- }
-
- // Input-Set //////////////////////////////////////////////////////////////////////////////
-
- static abstract class WalkTokenSet<Tok extends Input> extends Walk<Topology<Tok>> {
- public Topology<Tok> cs;
- public WalkTokenSet(Topology<Tok> cs) { this.cs = cs; }
- public WalkTokenSet(Topology<Tok> cs, Cache c) { super(c); this.cs = cs; }
- public Topology<Tok> bottom(SequenceOrElement e) { return cs; }
- public Topology<Tok> walkAtom(Atom r) { cs = cs.union(r.getTokenTopology()); return cs; }
- }
-
- // feature: intersect with "first" set of all positive conjuncts
- static class First<Tok extends Input> extends WalkTokenSet<Tok> {
- public First(Topology<Tok> cs, Walk.Cache cache) { super(cs, cache); }
- public Topology<Tok> walkSequence(Sequence seq) {
- for(Position p = seq.firstp(); p!=null && !p.isLast(); p = p.next()) {
- walk(p.element());
- if (!c.possiblyEpsilon(p.element())) break;
- }
- return cs;
- }
- }
-
- static class Follow<Tok extends Input> extends WalkTokenSet<Tok> {
- private final SequenceOrElement me;
- private final HashSet<SequenceOrElement> all;
- private boolean eof = false;
- public boolean includesEof() { return eof; }
- public Follow(Topology<Tok> cs, SequenceOrElement me, HashSet<SequenceOrElement> all, Cache c) {
- super(cs, c); this.me = me; this.all = all; }
- public Topology<Tok> bottom(SequenceOrElement e) { return cs; }
- public Topology<Tok> walkSequence(Sequence seq) { return cs; }
- public Topology<Tok> walkAtom(Atom r) { return walk((SequenceOrElement)r); }
- public Topology<Tok> walk(SequenceOrElement e) {
- if (acc.contains(e)) return bottom(e);
- acc.add(e);
-
- if (c != null) {
- Topology<Tok> cached = (Topology<Tok>)c.follow.get(e);
- if (cached != null) {
- cs = cs.union(cached);
- eof |= c.eof.get(e);
- return cs;
- }
- }
-
- Topology<Tok> cso = cs;
- boolean eofo = eof;
- eof = c.eof.get(e) != null && c.eof.get(e).booleanValue();
- cs = cso.empty();
-
- for(SequenceOrElement x : all) {
- boolean matched = false;
- if (!(x instanceof Sequence)) continue;
- Sequence a = (Sequence)x;
- Position mp = null;
- for(Position pos = a.firstp(); pos != null && !pos.isLast(); pos = pos.next()) {
- if (matched) cs = cs.union(c.first(pos.element(), cs.empty()));
- if (pos.isLast()) { matched = (matched && c.possiblyEpsilon(pos.element())); continue; }
- boolean good = false;
- if (e instanceof Atom) {
- Topology top = c.atoms.get(pos.element());
- if (top==null) continue;
- if (!(top.containsAll(((Atom)e)))) continue;
- } else {
- if (c.ys.contains(pos.element(),e)) good = true;
- }
- if (good) {
- mp = pos;
- matched = true;
- }
- }
- if (matched) walk(a);
- }
-
- if (e instanceof Sequence) {
- Sequence s = (Sequence)e;
- if (s.follow != null) cs = cs.intersect(s.follow.getTokenTopology());
- }
-
- if (c != null && e==me) {
- c.follow.put(e, cs);
- c.eof.put(e, eof);
- }
-
- cso = cso.union(cs);
- cs = cso;
- eofo |= eof;
- eof = eofo;
-
- return cs;
- }
- }
-
- static class Cache {
- public final HashMap<SequenceOrElement,Boolean> possiblyEpsilon = new HashMap<SequenceOrElement,Boolean>();
- public HashMap<SequenceOrElement,Boolean> eof = new HashMap<SequenceOrElement,Boolean>();
- public HashMap<SequenceOrElement,Topology> follow = new HashMap<SequenceOrElement,Topology>();
- public HashMapBag<SequenceOrElement,SequenceOrElement> ys = new HashMapBag<SequenceOrElement,SequenceOrElement>();
- public HashMapBag<SequenceOrElement,SequenceOrElement> ys2 = new HashMapBag<SequenceOrElement,SequenceOrElement>();
- public HashMap<SequenceOrElement,Topology> atoms = new HashMap<SequenceOrElement,Topology>();
- public <Tok extends Input> Topology<Tok> first(SequenceOrElement e, Topology<Tok> empty) {
- return new Walk.First<Tok>(empty, this).walk(e);
- }
- final boolean possiblyEpsilon(SequenceOrElement e) {
- Walk.Cache cache = this;
- Boolean ret = possiblyEpsilon.get(e);
- if (ret != null) return ret.booleanValue();
- ret = new Walk.PossiblyEpsilon().walk(e) ? Boolean.TRUE : Boolean.FALSE;
- possiblyEpsilon.put(e, ret);
- return ret;
- }
- }
-}
projects / sbp.git / blobdiff