1 // Copyright 2006 all rights reserved; see LICENSE file for BSD-style license
3 package edu.berkeley.sbp.meta;
4 import edu.berkeley.sbp.util.*;
5 import edu.berkeley.sbp.*;
6 import edu.berkeley.sbp.chr.*;
7 import edu.berkeley.sbp.misc.*;
9 import java.lang.annotation.*;
10 import java.lang.reflect.*;
13 // FIXME: deal with question-marks
15 // FIXME: put back in associativity: ^")"
17 // means that the FIRST "A" cannot match the SAME sequence in
18 // which the (A) occurs
19 // -- and add a test case
21 // FIXME: make it so that we can have multi-result nonterminals
22 // so long as they always appear under double-colons?
23 // auto-insert the unwrap?
25 // FIXME: put associativity back in
27 // FIXME: "flat" sequences (no subtrees contain "::"s?)
29 // freezing problem is related to comments in grammar files
31 /** The java classes typically used to represent a parsed grammar AST; each inner class is a type of AST node. */
32 public class GrammarBuilder {
35 * Create a grammar from a parse tree and binding resolver
37 * @param t a tree produced by parsing a grammar using the metagrammar
38 * @param s the name of the "start symbol"
39 * @param gbr a GrammarBindingResolver that resolves grammatical reductions into tree-node-heads
41 public static Union buildFromAST(Tree grammarAST, String startingNonterminal, File[] includes) {
42 return new GrammarBuilder(includes, "").buildGrammar(grammarAST, startingNonterminal);
45 public static Object illegalTag = ""; // this is the tag that should never appear in the non-dropped output FIXME
47 private final String prefix;
48 private final File[] includes;
50 //public GrammarBuilder(String path) { this(path, ""); }
51 public GrammarBuilder(File[] includes, String prefix) {
53 this.includes = includes;
56 public Union buildGrammar(Tree t, String rootNonTerminal) {
57 return ((GrammarBuilder.GrammarNode)walk(t)).build(rootNonTerminal);
60 private ElementNode epsilon = new LiteralNode("");
62 public Object[] walkChildren(Tree t) {
63 Object[] ret = new Object[t.size()];
64 for(int i=0; i<ret.length; i++) {
65 ret[i] = walk(t.child(i));
66 if (ret[i] instanceof Object[])
67 ret[i] = Reflection.lub((Object[])ret[i]);
69 return Reflection.lub(ret);
71 public String stringifyChildren(Tree t) {
72 StringBuffer sb = new StringBuffer();
73 for(int i=0; i<t.size(); i++) {
74 sb.append(t.child(i).head());
75 sb.append(stringifyChildren(t.child(i)));
79 public String unescape(Tree t) {
80 StringBuffer sb = new StringBuffer();
81 for(int i=0; i<t.size(); i++)
82 sb.append(t.child(i).head()+stringifyChildren(t.child(i)));
86 public Object walk(Tree t) {
87 String head = (String)t.head();
88 if (head.indexOf('.') != 0)
89 while(head.indexOf('.') != -1)
90 head = head.substring(head.indexOf('.')+1);
91 if (head==null) throw new RuntimeException("head is null: " + t);
92 if (head.equals("|")) return walkChildren(t);
93 if (head.equals("RHS")) return walkChildren(t);
94 if (head.equals("Grammar")) return new GrammarNode(walkChildren(t));
95 if (head.equals("(")) return new UnionNode((Seq[][])walkChildren(t.child(0)));
96 if (head.equals("Word")) return stringifyChildren(t);
97 if (head.equals("Elements")) return seq2((ElementNode[])Reflection.rebuild(walkChildren(t), ElementNode[].class));
98 if (head.equals("NonTerminalReference")) return new ReferenceNode(stringifyChildren(t.child(0)));
99 //if (head.equals(")")) return new ReferenceNode(stringifyChildren(t.child(0)));
100 if (head.equals("{")) return new XTree((Seq)walk(t.child(0)));
101 if (head.equals("::")) return tag((String)walk(t.child(0)), (Seq)walk(t.child(1)));
102 if (head.equals("++")) return plusmax((ElementNode)walk(t.child(0)));
103 if (head.equals("...")) return star(new TildeNode(new AtomNode()));
104 if (head.equals("+")) return plus((ElementNode)walk(t.child(0)));
105 if (head.equals("++/")) return plusmaxfollow((ElementNode)walk(t.child(0)), (ElementNode)walk(t.child(1)));
106 if (head.equals("+/")) return plusfollow((ElementNode)walk(t.child(0)), (ElementNode)walk(t.child(1)));
107 if (head.equals("**")) return starmax((ElementNode)walk(t.child(0)));
108 if (head.equals("*")) return star((ElementNode)walk(t.child(0)));
109 if (head.equals("**/")) return starmaxfollow((ElementNode)walk(t.child(0)), (ElementNode)walk(t.child(1)));
110 if (head.equals("*/")) return starfollow((ElementNode)walk(t.child(0)), (ElementNode)walk(t.child(1)));
111 if (head.equals("?")) return question((ElementNode)walk(t.child(0)));
112 if (head.equals("!")) return new DropNode((ElementNode)walk(t.child(0)));
113 if (head.equals("^")) return new LiteralNode((String)walk(t.child(0)), true);
114 if (head.equals("`")) {
115 ElementNode ret = (ElementNode)walk(t.child(0));
119 if (head.equals("Quoted")) return stringifyChildren(t);
120 if (head.equals("Literal")) return new LiteralNode((String)walk(t.child(0)));
121 if (head.equals("->")) return arrow((Seq)walk(t.child(0)), (ElementNode)walk(t.child(1)));
122 if (head.equals("DropNT")) return new NonTerminalNode((String)walk(t.child(0)), (Seq[][])walkChildren(t.child(1)), false, null, true);
123 if (head.equals("=") && t.size()==2) return new NonTerminalNode((String)walk(t.child(0)), (Seq[][])walk(t.child(1)), true, null, false);
124 if (head.equals("=")) return new NonTerminalNode((String)walk(t.child(0)), (Seq[][])walk(t.child(2)), true, (String)walk(t.child(1)), false);
125 if (head.equals("&")) return and2((Seq)walk(t.child(0)), (Seq)walk(t.child(1)));
126 if (head.equals("&~")) return andnot2((Seq)walk(t.child(0)), (Seq)walk(t.child(1)));
127 if (head.equals("/")) return ((Seq)walk(t.child(0))).separate((ElementNode)walk(t.child(1)));
128 if (head.equals("()")) return epsilon;
129 if (head.equals("[")) return new AtomNode((AtomNodeRange[])Reflection.rebuild(walkChildren(t), AtomNodeRange[].class));
130 if (head.equals("\\{")) return new DropNode(new AtomNode(new AtomNodeRange(CharAtom.left, CharAtom.left)));
131 if (head.equals("\\}")) return new DropNode(new AtomNode(new AtomNodeRange(CharAtom.right, CharAtom.right)));
132 if (head.equals("~")) return new TildeNode((ElementNode)walk(t.child(0)));
133 if (head.equals("Range") && t.size()==1) return new AtomNodeRange(unescape(t).charAt(0));
134 if (head.equals("Range")) return new AtomNodeRange(unescape(t).charAt(0), unescape(t).charAt(1));
135 if (head.equals("\"\"")) return "";
136 if (head.equals("\n")) return "\n";
137 if (head.equals("\r")) return "\r";
138 if (head.equals("grammar.Grammar")) return walkChildren(t);
139 if (head.equals("SubGrammar")) return GrammarBuilder.buildFromAST(t.child(0), "s", includes);
140 if (head.equals("NonTerminal"))
141 return new NonTerminalNode((String)walk(t.child(0)),
142 (Seq[][])walkChildren(t.child(1)), false, null, false);
143 if (head.equals("Colons")) {
144 String tag = (String)walk(t.child(0));
145 Seq[][] seqs = (Seq[][])walk(t.child(1));
146 for(Seq[] seq : seqs)
147 for(int i=0; i<seq.length; i++)
148 seq[i] = tag(tag, seq[i]);
149 return new NonTerminalNode(tag, seqs, false, null, false);
151 if (head.equals("TestCase"))
152 return new RegressionTests.TestCase((String)walk(t.child(0)),
153 (String)walk(t.child(1)),
154 (String[])Reflection.coerce(walkChildren(t.child(2)), String[].class),
155 (Union)walk(t.child(3)),
158 if (head.equals("#import")) {
159 String fileName = (String)stringifyChildren(t.child(0));
160 for(File f : includes) {
161 File file = new File(f.getAbsolutePath()+File.separatorChar+fileName);
162 if (!file.exists()) continue;
164 String newPrefix = t.size()<2 ? "" : ((String)walk(t.child(1))+".");
165 FileInputStream fis = new FileInputStream(file);
166 Tree tr = new CharParser(MetaGrammar.newInstance()).parse(fis).expand1();
167 return (GrammarNode)new GrammarBuilder(includes, newPrefix).walk(tr);
168 } catch (Exception e) {
169 throw new RuntimeException("while parsing " + file, e);
172 throw new RuntimeException("unable to find #include file \""+fileName+"\"");
174 throw new RuntimeException("unknown head: \"" + head + "\" => " + (head.equals("...")));
177 /** A grammar (a set of nonterminals) */
178 public class GrammarNode extends HashMap<String,NonTerminalNode> {
179 public GrammarNode(NonTerminalNode[] nonterminals) {
180 for(NonTerminalNode nt : nonterminals) {
181 if (nt==null) continue;
182 if (this.get(nt.name)!=null)
183 throw new RuntimeException("duplicate definition of nonterminal \""+nt.name+"\"");
184 this.put(nt.name, nt);
187 public GrammarNode(Object[] nt) { add(nt); }
188 private void add(Object o) {
190 else if (o instanceof Object[]) for(Object o2 : (Object[])o) add(o2);
191 else if (o instanceof NonTerminalNode) {
192 NonTerminalNode nt = (NonTerminalNode)o;
193 if (this.get(nt.name)!=null)
194 throw new RuntimeException("duplicate definition of nonterminal \""+nt.name+"\"");
195 this.put(nt.name, nt);
197 else if (o instanceof GrammarNode)
198 for(NonTerminalNode n : ((GrammarNode)o).values())
201 public String toString() {
203 for(NonTerminalNode nt : values()) ret += nt + ", ";
206 public Union build(String rootNonterminal) {
207 Context cx = new Context(this);
209 for(GrammarBuilder.NonTerminalNode nt : values())
210 if (nt.name.equals(rootNonterminal))
211 return (Union)cx.get(nt.name);
216 public class UnionNode extends ElementNode {
217 public Seq[][] sequences;
218 public String sep = null;
220 public UnionNode(Seq[][] sequences) { this(sequences, false, null); }
221 public UnionNode(Seq[][] sequences, boolean rep, String sep) {
222 this.sequences = sequences;
226 public Atom toAtom(Context cx) {
228 for(Seq[] ss : sequences)
230 ret = ret==null ? s.toAtom(cx) : (Atom)ret.union(s.toAtom(cx));
233 public Element build(Context cx, NonTerminalNode cnt, boolean dropall) {
234 return buildIntoPreallocatedUnion(cx, cnt, dropall, new Union(null, false)); }
235 public Element buildIntoPreallocatedUnion(Context cx, NonTerminalNode cnt, boolean dropall, Union u) {
238 urep = new Union(null, false);
239 urep.add(Sequence.create(new Element[0], cnt.name));
241 ? Sequence.create(new Element[] { u }, 0)
242 : Sequence.create(new Element[] { cx.get(sep), u }, 1));
244 HashSet<Sequence> bad2 = new HashSet<Sequence>();
245 for(int i=0; i<sequences.length; i++) {
246 Seq[] group = sequences[i];
247 Union u2 = new Union(null, false);
248 if (sequences.length==1) u2 = u;
249 for(int j=0; j<group.length; j++)
251 group[j].build(cx, u2, cnt, dropall);
253 Union u3 = new Union(null, false);
254 group[j].build(cx, u3, cnt, dropall);
255 Sequence s = Sequence.create(cnt.name,
256 new Element[] { u3, urep },
257 new boolean[] { false, false },
261 if (sequences.length==1) break;
262 Sequence seq = Sequence.create(u2);
263 for(Sequence s : bad2) seq = seq.andnot(s);
265 bad2.add(Sequence.create(u2));
271 public class NonTerminalNode extends UnionNode {
272 public boolean alwaysDrop;
273 public String name = null;
274 public boolean drop(Context cx) { return alwaysDrop; }
275 public NonTerminalNode(String name, Seq[][] sequences, boolean rep, String sep, boolean alwaysDrop) {
276 super(sequences, rep, sep==null?null:(prefix + sep));
277 this.name = prefix + name;
278 this.alwaysDrop = alwaysDrop;
280 public Element build(Context cx, NonTerminalNode cnt, boolean dropall) { return cx.get(name); }
284 public boolean alwaysDrop = false;
285 public boolean drop(Context cx) { return alwaysDrop; }
286 HashSet<Seq> and = new HashSet<Seq>();
287 HashSet<Seq> not = new HashSet<Seq>();
288 ElementNode[] elements;
291 public Seq(ElementNode e) { this(new ElementNode[] { e }); }
292 public Seq(ElementNode[] elements) {
293 this.elements = elements;
294 for(int i=0; i<elements.length; i++)
295 if (elements[i]==null)
296 throw new RuntimeException();
298 public Atom toAtom(Context cx) {
299 if (elements.length != 1)
300 throw new Error("you attempted to use ->, **, ++, or a similar character-class"+
301 " operator on a [potentially] multicharacter production");
302 return elements[0].toAtom(cx);
304 public Seq tag(String tag) { this.tag = tag; return this; }
305 public Seq follow(ElementNode follow) { this.follow = follow; return this; }
306 public Seq and(Seq s) { and.add(s); return this; }
307 public Seq andnot(Seq s) { not.add(s); return this; }
309 Seq ret = new Seq(elements);
316 public Seq separate(ElementNode sep) {
317 ElementNode[] elements = new ElementNode[this.elements.length * 2 - 1];
318 for(int i=0; i<this.elements.length; i++) {
319 elements[i*2] = this.elements[i];
320 if (i<this.elements.length-1)
321 elements[i*2+1] = new DropNode(sep);
323 this.elements = elements;
326 public Sequence build(Context cx, Union u, NonTerminalNode cnt, boolean dropall) {
327 Sequence ret = build0(cx, cnt, dropall);
328 for(Seq s : and) ret = ret.and(s.build(cx, null, cnt, true));
329 for(Seq s : not) ret = ret.andnot(s.build(cx, null, cnt, true));
330 if (u!=null) u.add(ret);
333 public Sequence build0(Context cx, NonTerminalNode cnt, boolean dropall) {
334 boolean[] drops = new boolean[elements.length];
335 Element[] els = new Element[elements.length];
337 for(int i=0; i<elements.length; i++) {
338 if (dropall) drops[i] = true;
339 else drops[i] = elements[i].drop(cx);
340 if (elements[i].getOwnerTag() != null)
341 tag = elements[i].getOwnerTag();
345 boolean multiNonDrop = false;
346 for(int i=0; i<drops.length; i++)
348 if (idx==-1) idx = i;
349 else multiNonDrop = true;
350 for(int i=0; i<elements.length; i++) {
351 if (!multiNonDrop && i==idx && tag!=null && elements[i] instanceof RepeatNode) {
352 els[i] = ((RepeatNode)elements[i]).build(cx, cnt, dropall, tag);
355 els[i] = elements[i].build(cx, cnt, dropall);
357 if (tag==null && multiNonDrop)
358 throw new RuntimeException("multiple non-dropped elements in sequence: " + Sequence.create(els, ""));
359 boolean lift = false;
360 if (elements.length > 0 && elements[0].lifted)
365 ? Sequence.create(els, illegalTag)
366 : Sequence.createLeft(tag, els, drops, lift);
367 else if (tag==null) ret = Sequence.create(els, idx);
368 else ret = Sequence.createLeft(tag, els, drops, lift);
371 ret = Sequence.createLeft(tag, els, drops, lift);
372 if (this.follow != null)
373 ret = ret.followedBy(this.follow.toAtom(cx));
378 public class ReferenceNode extends ElementNode {
379 public String nonTerminal;
380 public ReferenceNode() { }
381 public NonTerminalNode resolve(Context cx) {
382 NonTerminalNode ret = cx.grammar.get(nonTerminal);
383 if (ret==null) throw new RuntimeException("undefined nonterminal: " + nonTerminal);
386 public ReferenceNode(String nonTerminal) { this.nonTerminal = prefix + nonTerminal; }
387 public Atom toAtom(Context cx) { return cx.grammar.get(nonTerminal).toAtom(cx); }
388 public boolean drop(Context cx) { return resolve(cx).drop(cx); }
389 public Element build(Context cx, NonTerminalNode cnt, boolean dropall) {
390 if (!this.nonTerminal.startsWith(prefix)) nonTerminal = prefix + nonTerminal;
391 Element ret = cx.get(nonTerminal);
392 if (ret == null) throw new RuntimeException("unknown nonterminal \""+nonTerminal+"\"");
397 public class LiteralNode extends ElementNode {
398 private String string;
399 private final String thePrefix = prefix;
400 private boolean caret;
401 public LiteralNode(String string) { this(string, false); }
402 public LiteralNode(String string, boolean caret) {
403 this.string = string;
406 public String getOwnerTag() { return caret ? thePrefix+string : super.getOwnerTag(); }
407 public String toString() { return "\""+string+"\""; }
408 public boolean drop(Context cx) { return true; }
409 public Atom toAtom(Context cx) {
410 if (string.length()!=1) return super.toAtom(cx);
411 edu.berkeley.sbp.util.Range.Set set = new edu.berkeley.sbp.util.Range.Set();
412 set.add(string.charAt(0), string.charAt(0));
413 return CharAtom.set(set);
415 public Element build(Context cx, NonTerminalNode cnt, boolean dropall) { return CharAtom.string(string); }
418 public class AtomNode extends ElementNode {
419 AtomNodeRange[] ranges;
420 public AtomNode() { this(new AtomNodeRange[0]); }
421 public AtomNode(AtomNodeRange[] ranges) { this.ranges = ranges; }
422 public AtomNode(AtomNodeRange range) { this.ranges = new AtomNodeRange[] { range }; }
423 public Element build(Context cx, NonTerminalNode cnt, boolean dropall) { return toAtom(cx); }
424 public Atom toAtom(Context cx) {
425 edu.berkeley.sbp.util.Range.Set set = new edu.berkeley.sbp.util.Range.Set();
426 for(AtomNodeRange r : ranges) set.add(r.first, r.last);
427 return CharAtom.set(set);
430 public class AtomNodeRange {
433 public AtomNodeRange(char only) { first = only; last = only; }
434 public AtomNodeRange(char first, char last) { this.first = first; this.last = last; }
437 public class RepeatNode extends ElementNode {
438 public ElementNode e, sep;
439 public final boolean zero, many, max;
440 public RepeatNode(ElementNode e, ElementNode sep, boolean zero, boolean many, boolean max) {
441 this.e = e; this.sep = sep; this.zero = zero; this.many = many; this.max = max;
443 public Atom toAtom(Context cx) { return sep==null ? e.toAtom(cx) : super.toAtom(cx); }
444 public boolean drop(Context cx) { return e.drop(cx); }
445 public Element build(Context cx, NonTerminalNode cnt, boolean dropall) {
446 Element ret = build(cx, cnt, dropall, illegalTag);
447 String must = "must be tagged unless they appear within a dropped expression or their contents are dropped: ";
448 if (!dropall && !drop(cx) && !e.drop(cx))
449 if (!many) throw new RuntimeException("options (?) " + must + ret);
450 else if (zero) throw new RuntimeException("zero-or-more repetitions (*) " + must + ret);
451 else throw new RuntimeException("one-or-more repetitions (+) " + must + ret);
454 public Element build(Context cx, NonTerminalNode cnt, boolean dropall, Object repeatTag) {
456 ? Repeat.repeat(e.build(cx, null, dropall), zero, many, sep==null ? null : sep.build(cx, null, dropall), repeatTag)
458 ? Repeat.repeatMaximal(e.toAtom(cx), zero, many, repeatTag)
459 : Repeat.repeatMaximal(e.build(cx, null, dropall), zero, many, sep.toAtom(cx), repeatTag);
463 public abstract class ElementNode {
464 public boolean lifted = false;
465 public String getOwnerTag() { return null; }
466 public boolean drop(Context cx) { return false; }
467 public Atom toAtom(Context cx) { throw new Error("can't convert a " + this.getClass().getName() + " to an atom: " + this); }
468 public abstract Element build(Context cx, NonTerminalNode cnt, boolean dropall);
471 public abstract class ElementNodeWrapper extends ElementNode {
472 protected ElementNode _e;
473 public ElementNodeWrapper(ElementNode e) { this._e = e; }
474 public String getOwnerTag() { return _e.getOwnerTag(); }
475 public boolean drop(Context cx) { return _e.drop(cx); }
476 public Atom toAtom(Context cx) { return _e.toAtom(cx); }
477 public Element build(Context cx, NonTerminalNode cnt, boolean dropall) { return _e.build(cx, cnt, dropall); }
480 public class TildeNode extends ElementNodeWrapper {
481 public TildeNode(ElementNode e) { super(e); }
482 public Atom toAtom(Context cx) { return (Atom)((Topology<Character>)_e.toAtom(cx).complement()); }
483 public Element build(Context cx, NonTerminalNode cnt, boolean dropall) { return toAtom(cx); }
486 public class DropNode extends ElementNodeWrapper {
487 public DropNode(ElementNode e) { super(e); }
488 public boolean drop(Context cx) { return true; }
491 public Seq and2(Seq s, Seq a) { a.alwaysDrop = true; return s.and(a); }
492 public Seq andnot2(Seq s, Seq a) { a.alwaysDrop = true; return s.andnot(a); }
493 public Seq arrow(Seq s, ElementNode e) { return s.follow(e); }
494 public Seq tag(String tagname, Seq s) { return s.tag(tagname); }
495 public Seq seq(ElementNode[] elements) { return new Seq(elements); }
496 public Seq seq2(ElementNode[] elements) { return new Seq(elements); }
497 public ElementNode plusmax(final ElementNode e) { return new RepeatNode(e, null, false, true, true); }
498 public ElementNode plus(final ElementNode e) { return new RepeatNode(e, null, false, true, false); }
499 public ElementNode plusmaxfollow(final ElementNode e, final ElementNode sep) { return new RepeatNode(e, sep, false, true, true); }
500 public ElementNode plusfollow(final ElementNode e, final ElementNode sep) { return new RepeatNode(e, sep, false, true, false); }
501 public ElementNode starmax(final ElementNode e) { return new RepeatNode(e, null, true, true, true); }
502 public ElementNode star(final ElementNode e) { return new RepeatNode(e, null, true, true, false); }
503 public ElementNode starmaxfollow(final ElementNode e, final ElementNode sep) { return new RepeatNode(e, sep, true, true, true); }
504 public ElementNode starfollow(final ElementNode e, final ElementNode sep) { return new RepeatNode(e, sep, true, true, false); }
505 public ElementNode question(final ElementNode e) { return new RepeatNode(e, null, true, false, false); }
507 //////////////////////////////////////////////////////////////////////////////
509 public class Context {
510 public HashMap<String,Union> map = new HashMap<String,Union>();
511 public GrammarNode grammar;
512 public Context(Tree t) { }
513 public Context(GrammarNode g) { this.grammar = g; }
514 public Union build() {
516 for(NonTerminalNode nt : grammar.values()) {
517 Union u = get(nt.name);
518 if ("s".equals(nt.name))
523 public Union peek(String name) { return map.get(name); }
524 public void put(String name, Union u) { map.put(name, u); }
525 public Union get(String name) {
526 Union ret = map.get(name);
527 if (ret != null) return ret;
528 NonTerminalNode nt = grammar.get(name);
530 throw new Error("warning could not find " + name);
532 ret = new Union(name, false);
534 nt.buildIntoPreallocatedUnion(this, nt, nt.drop(this), ret);
541 public class XTree extends ElementNode {
543 public XTree(Seq seq) { this.body = seq; }
544 public Element build(Context cx, NonTerminalNode cnt, boolean dropall) {
545 Union u = new Union(null, false);
546 Sequence s = body.build(cx, u, null, dropall);
547 Union u2 = new Union(null, false);
548 u2.add(Sequence.create(new Element[] {