X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2Fmeta%2FGrammarAST.java;h=05c7b39dc7394dac4cc448b59f5a6dbc70f76422;hp=19f12a32981f5882b51f208b0219372c46d8b53e;hb=013262fd96a3dfc4c2cd7a0ba320dd7981ce678c;hpb=584cef55d8811e3215858fde22e708d2a3d1cf70
diff --git a/src/edu/berkeley/sbp/meta/GrammarAST.java b/src/edu/berkeley/sbp/meta/GrammarAST.java
index 19f12a3..05c7b39 100644
--- a/src/edu/berkeley/sbp/meta/GrammarAST.java
+++ b/src/edu/berkeley/sbp/meta/GrammarAST.java
@@ -1,4 +1,4 @@
-// Copyright 2006 all rights reserved; see LICENSE file for BSD-style license
+// Copyright 2006-2007 all rights reserved; see LICENSE file for BSD-style license
package edu.berkeley.sbp.meta;
import edu.berkeley.sbp.util.*;
@@ -17,6 +17,14 @@ import java.io.*;
public class GrammarAST {
/**
+ * Returns a Union representing the metagrammar (meta.g); the Tree produced by
+ * parsing with this Union should be provided to buildFromAST
+ */
+ public static Union getMetaGrammar() {
+ return MetaGrammar.newInstance();
+ }
+
+ /**
* Create a grammar from a parse tree and binding resolver
*
* @param t a tree produced by parsing a grammar using the metagrammar
@@ -27,7 +35,9 @@ public class GrammarAST {
return new GrammarAST(includes, "").buildGrammar(grammarAST, startingNonterminal);
}
- public static Object illegalTag = ""; // this is the tag that should never appear in the non-dropped output FIXME
+ private static Object illegalTag = ""; // this is the tag that should never appear in the non-dropped output FIXME
+
+ // Instance //////////////////////////////////////////////////////////////////////////////
private final String prefix;
private final File[] includes;
@@ -40,19 +50,18 @@ public class GrammarAST {
// Methods //////////////////////////////////////////////////////////////////////////////
private Union buildGrammar(Tree t, String rootNonTerminal) {
- return ((GrammarAST.GrammarNode)walk(t)).build(rootNonTerminal);
+ Object o = walk(t);
+ if (o instanceof Union) return (Union)o;
+ return ((GrammarAST.GrammarNode)o).build(rootNonTerminal);
}
- public Object[] walkChildren(Tree t) {
+ private Object[] walkChildren(Tree t) {
Object[] ret = new Object[t.size()];
- for(int i=0; i 0)
head = head.substring(head.indexOf('.')+1);
@@ -77,10 +89,9 @@ public class GrammarAST {
if (head.equals("Grammar")) return new GrammarNode(walkChildren(t));
if (head.equals("(")) return new UnionNode((Seq[][])walkChildren(t.child(0)));
if (head.equals("Word")) return stringifyChildren(t);
- if (head.equals("Elements")) return seq2((ElementNode[])Reflection.rebuild(walkChildren(t), ElementNode[].class));
+ if (head.equals("Elements")) return new Seq((ElementNode[])Reflection.rebuild(walkChildren(t), ElementNode[].class));
if (head.equals("NonTerminalReference")) return new ReferenceNode(stringifyChildren(t.child(0)));
if (head.equals(")")) return new ReferenceNode(stringifyChildren(t.child(0)), true);
- if (head.equals("{")) return new BracedNode(walkSeq(t.child(0)));
if (head.equals("::")) return walkSeq(t.child(1)).tag(walkString(t.child(0)));
if (head.equals("...")) return new DropNode(new RepeatNode(new TildeNode(new AtomNode()), null, true, true, false));
@@ -103,8 +114,8 @@ public class GrammarAST {
if (head.equals("DropNT")) return new NonTerminalNode(walkString(t.child(0)), (Seq[][])walkChildren(t.child(1)), false, null, true);
if (head.equals("=")) return new NonTerminalNode(walkString(t.child(0)), (Seq[][])walk(t.child(2)),
true, t.size()==2 ? null : walkString(t.child(1)), false);
- if (head.equals("&")) return and2(walkSeq(t.child(0)), walkSeq(t.child(1)));
- if (head.equals("&~")) return andnot2(walkSeq(t.child(0)), walkSeq(t.child(1)));
+ if (head.equals("&")) return walkSeq(t.child(0)).and(walkSeq(t.child(1)));
+ if (head.equals("&~")) return walkSeq(t.child(0)).andnot(walkSeq(t.child(1)));
if (head.equals("/")) return (walkSeq(t.child(0))).separate(walkElement(t.child(1)));
if (head.equals("()")) return new LiteralNode("");
if (head.equals("[")) return new AtomNode((char[][])Reflection.rebuild(walkChildren(t), char[][].class));
@@ -114,45 +125,37 @@ public class GrammarAST {
if (head.equals("<<")) return new DropNode(new AtomNode(new char[] { CharAtom.right, CharAtom.right }));
if (head.equals("~")) return new TildeNode(walkElement(t.child(0)));
if (head.equals("~~")) return new Seq(new RepeatNode(new TildeNode(new AtomNode()), null, true, true, false)).andnot(walkSeq(t.child(0)));
- if (head.equals("Range") && t.size()==2 && ">".equals(t.child(0).head()))
- return new char[] { CharAtom.left, CharAtom.left };
- if (head.equals("Range") && t.size()==2 && "<".equals(t.child(0).head()))
- return new char[] { CharAtom.right, CharAtom.right };
- if (head.equals("Range") && t.size()==1) return new char[] { unescape(t).charAt(0), unescape(t).charAt(0) };
- if (head.equals("Range")) return new char[] { unescape(t).charAt(0), unescape(t).charAt(1) };
+ if (head.equals("Range")) {
+ if (t.size()==2 && ">".equals(t.child(0).head())) return new char[] { CharAtom.left, CharAtom.left };
+ if (t.size()==2 && "<".equals(t.child(0).head())) return new char[] { CharAtom.right, CharAtom.right };
+ if (t.size()==1) return new char[] { unescape(t).charAt(0), unescape(t).charAt(0) };
+ return new char[] { unescape(t).charAt(0), unescape(t).charAt(1) };
+ }
if (head.equals("\"\"")) return "";
- if (head.equals("\n")) return "\n";
- if (head.equals("\r")) return "\r";
- if (head.equals("grammar.Grammar")) return walkChildren(t);
- if (head.equals("SubGrammar")) return GrammarBuilder.buildFromAST(t.child(0), "s", includes);
+ if (head.equals("\n")) return "\n";
+ if (head.equals("\r")) return "\r";
+ if (head.equals("SubGrammar")) return GrammarAST.buildFromAST(t.child(0), "s", includes);
if (head.equals("NonTerminal"))
- return new NonTerminalNode((String)walk(t.child(0)),
+ return new NonTerminalNode(walkString(t.child(0)),
(Seq[][])walkChildren(t.child(1)), false, null, false);
if (head.equals("Colons")) {
- String tag = (String)walk(t.child(0));
+ String tag = walkString(t.child(0));
Seq[][] seqs = (Seq[][])walk(t.child(1));
for(Seq[] seq : seqs)
for(int i=0; i " + (head.equals("...")));
}
+
// Nodes //////////////////////////////////////////////////////////////////////////////
@@ -203,16 +207,33 @@ public class GrammarAST {
}
}
- public class UnionNode extends ElementNode {
+ private abstract class ElementNode {
+ public boolean lifted = false;
+ public Seq ownerSeq = null;
+ public ElementNode lifted() { this.lifted = true; return this; }
+ public boolean drop(Context cx) { return false; }
+ public Atom toAtom(Context cx) { throw new Error("can't convert a " + this.getClass().getName() + " to an atom: " + this); }
+ public abstract Element build(Context cx, NonTerminalNode cnt, boolean dropall);
+ }
+
+ private class UnionNode extends ElementNode {
public Seq[][] sequences;
public String sep = null;
public boolean rep;
+ public UnionNode(Seq seq) { this(new Seq[][] { new Seq[] { seq } }); }
public UnionNode(Seq[][] sequences) { this(sequences, false, null); }
public UnionNode(Seq[][] sequences, boolean rep, String sep) {
this.sequences = sequences;
this.rep = rep;
this.sep = sep;
}
+ public boolean drop(Context cx) {
+ for(Seq[] seqs : sequences)
+ for(Seq seq : seqs)
+ if (!seq.drop(cx))
+ return false;
+ return true;
+ }
public Atom toAtom(Context cx) {
Atom ret = null;
for(Seq[] ss : sequences)
@@ -226,7 +247,7 @@ public class GrammarAST {
Union urep = null;
if (rep) {
urep = new Union(null, false);
- urep.add(Sequence.create(new Element[0], cnt.name));
+ urep.add(Sequence.create(cnt.name, new Element[0]));
urep.add(sep==null
? Sequence.create(new Element[] { u }, 0)
: Sequence.create(new Element[] { cx.get(sep), u }, 1));
@@ -245,7 +266,7 @@ public class GrammarAST {
Sequence s = Sequence.create(cnt.name,
new Element[] { u3, urep },
new boolean[] { false, false },
- true);
+ new boolean[] { false, true});
u2.add(s);
}
if (sequences.length==1) break;
@@ -258,7 +279,7 @@ public class GrammarAST {
}
}
- public class NonTerminalNode extends UnionNode {
+ private class NonTerminalNode extends UnionNode {
public boolean alwaysDrop;
public String name = null;
public boolean drop(Context cx) { return alwaysDrop; }
@@ -270,20 +291,49 @@ public class GrammarAST {
public Element build(Context cx, NonTerminalNode cnt, boolean dropall) { return cx.get(name); }
}
- public class Seq {
+ private class Seq {
public boolean alwaysDrop = false;
- public boolean drop(Context cx) { return alwaysDrop; }
+ public boolean drop(Context cx) {
+ if (alwaysDrop) return true;
+ if (tag!=null) return false;
+ for(int i=0; i and = new HashSet();
HashSet not = new HashSet();
ElementNode[] elements;
ElementNode follow;
String tag = null;
public Seq(ElementNode e) { this(new ElementNode[] { e }); }
- public Seq(ElementNode[] elements) {
- this.elements = elements;
- for(int i=0; i)_e.toAtom(cx).complement()); }
public Element build(Context cx, NonTerminalNode cnt, boolean dropall) { return toAtom(cx); }
}
- public class DropNode extends ElementNodeWrapper {
+ private class DropNode extends ElementNodeWrapper {
public DropNode(ElementNode e) { super(e); }
public boolean drop(Context cx) { return true; }
}
- public Seq and2(Seq s, Seq a) { a.alwaysDrop = true; return s.and(a); }
- public Seq andnot2(Seq s, Seq a) { a.alwaysDrop = true; return s.andnot(a); }
- public Seq arrow(Seq s, ElementNode e) { return s.follow(e); }
- public Seq tag(String tagname, Seq s) { return s.tag(tagname); }
- public Seq seq(ElementNode[] elements) { return new Seq(elements); }
- public Seq seq2(ElementNode[] elements) { return new Seq(elements); }
- public ElementNode plusmax(final ElementNode e) { return new RepeatNode(e, null, false, true, true); }
- public ElementNode plus(final ElementNode e) { return new RepeatNode(e, null, false, true, false); }
- public ElementNode plusmaxfollow(final ElementNode e, final ElementNode sep) { return new RepeatNode(e, sep, false, true, true); }
- public ElementNode plusfollow(final ElementNode e, final ElementNode sep) { return new RepeatNode(e, sep, false, true, false); }
- public ElementNode starmax(final ElementNode e) { return new RepeatNode(e, null, true, true, true); }
- public ElementNode star(final ElementNode e) { return new RepeatNode(e, null, true, true, false); }
- public ElementNode starmaxfollow(final ElementNode e, final ElementNode sep) { return new RepeatNode(e, sep, true, true, true); }
- public ElementNode starfollow(final ElementNode e, final ElementNode sep) { return new RepeatNode(e, sep, true, true, false); }
- public ElementNode question(final ElementNode e) { return new RepeatNode(e, null, true, false, false); }
-
//////////////////////////////////////////////////////////////////////////////
public class Context {