From b3b610d65969bcd5325bdba70f9e9c9e03cc83b3 Mon Sep 17 00:00:00 2001
From: adam <adam@megacz.com>
Date: Sun, 27 May 2007 16:29:15 -0400
Subject: [PATCH] lots of misc cleanups to GrammarAST

darcs-hash:20070527202915-5007d-f093deca58721692fc7987bb2aa2222939922d39.gz
---
 src/edu/berkeley/sbp/meta/GrammarAST.java |  181 ++++++++++++++++++-----------
 1 file changed, 114 insertions(+), 67 deletions(-)

diff --git a/src/edu/berkeley/sbp/meta/GrammarAST.java b/src/edu/berkeley/sbp/meta/GrammarAST.java
index 19f12a3..fc76a00 100644
--- a/src/edu/berkeley/sbp/meta/GrammarAST.java
+++ b/src/edu/berkeley/sbp/meta/GrammarAST.java
@@ -27,7 +27,9 @@ 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;
@@ -52,7 +54,7 @@ public class GrammarAST {
         }
         return Reflection.lub(ret);
     }
-    public String stringifyChildren(Tree t) {
+    private String stringifyChildren(Tree t) {
         StringBuffer sb = new StringBuffer();
         for(int i=0; i<t.size(); i++) {
             sb.append(t.child(i).head());
@@ -60,14 +62,17 @@ public class GrammarAST {
         }
         return sb.toString();
     }
-    public String unescape(Tree t) {
+    private String unescape(Tree t) {
         StringBuffer sb = new StringBuffer();
         for(int i=0; i<t.size(); i++)
             sb.append(t.child(i).head()+stringifyChildren(t.child(i)));
         return sb.toString();
     }
 
-    public Object walk(Tree t) {
+    private ElementNode walkElement(Tree t) { return (ElementNode)walk(t); }
+    private String      walkString(Tree t) { return (String)walk(t); }
+    private Seq         walkSeq(Tree t) { return (Seq)walk(t); }
+    private Object walk(Tree t) {
         String head = (String)t.head();
         while(head.indexOf('.') > 0)
             head = head.substring(head.indexOf('.')+1);
@@ -77,7 +82,7 @@ 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)));
@@ -124,16 +129,16 @@ public class GrammarAST {
         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("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<seq.length; i++)
-                    seq[i] = tag(tag, seq[i]);
+                    seq[i] = seq[i].tag(tag);
             return new NonTerminalNode(tag, seqs, false, null, false);
         }
         if (head.equals("TestCase"))
@@ -149,10 +154,10 @@ public class GrammarAST {
                 File file = new File(f.getAbsolutePath()+File.separatorChar+fileName);
                 if (!file.exists()) continue;
                 try {
-                    String newPrefix = t.size()<2 ? "" : ((String)walk(t.child(1))+".");
+                    String newPrefix = t.size()<2 ? "" : (walkString(t.child(1))+".");
                     FileInputStream fis = new FileInputStream(file);
                     Tree tr = new CharParser(MetaGrammar.newInstance()).parse(fis).expand1();
-                    return (GrammarNode)new GrammarBuilder(includes, newPrefix).walk(tr);
+                    return (GrammarNode)new GrammarAST(includes, newPrefix).walk(tr);
                 } catch (Exception e) {
                     throw new RuntimeException("while parsing " + file, e);
                 }
@@ -161,6 +166,7 @@ public class GrammarAST {
         }
         throw new RuntimeException("unknown head: \"" + head + "\" => " + (head.equals("...")));
     }
+
     
     // Nodes //////////////////////////////////////////////////////////////////////////////
 
@@ -203,16 +209,24 @@ public class GrammarAST {
         }
     }
 
-    public class UnionNode extends ElementNode {
+    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 +240,7 @@ 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 +259,7 @@ 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 +272,7 @@ 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 +284,49 @@ 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<elements.length; i++)
+                if (!elements[i].drop(cx))
+                    return false;
+            return true;
+        }
         HashSet<Seq> and = new HashSet<Seq>();
         HashSet<Seq> not = new HashSet<Seq>();
         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<elements.length; i++)
+        public Seq(ElementNode[] elements) { this(elements, true); }
+        public Seq(ElementNode[] el, boolean check) {
+            this.elements = new ElementNode[el.length];
+            System.arraycopy(el, 0, elements, 0, el.length);
+            for(int i=0; i<elements.length; i++) {
                 if (elements[i]==null)
                     throw new RuntimeException();
+                elements[i].ownerSeq = this;
+            }
+            // FIXME: this whole mechanism is sketchy
+            if (check)
+                for(int i=0; i<elements.length; i++) {
+                    if ((elements[i] instanceof ReferenceNode) && ((ReferenceNode)elements[i]).parenthesized) {
+                        ReferenceNode rn = (ReferenceNode)elements[i];
+                        ElementNode replace = null;
+                        for(int j=0; j<elements.length; j++) {
+                            if (!(elements[j] instanceof ReferenceNode)) continue;
+                            ReferenceNode rn2 = (ReferenceNode)elements[j];
+                            if (rn2.nonTerminal.equals(rn.nonTerminal) && !rn2.parenthesized) {
+                                if (replace == null) {
+                                    replace = new UnionNode(new Seq(rn2).andnot(new Seq(elements, false)));
+                                }
+                                elements[j] = replace;
+                            }
+                        }
+                    }
+                }
         }
         public Atom toAtom(Context cx) {
             if (elements.length != 1)
@@ -295,14 +338,6 @@ public class GrammarAST {
         public Seq follow(ElementNode follow) { this.follow = follow; return this; }
         public Seq and(Seq s) { and.add(s); return this; }
         public Seq andnot(Seq s) { not.add(s); return this; }
-        public Seq dup() {
-            Seq ret = new Seq(elements);
-            ret.and.addAll(and);
-            ret.not.addAll(not);
-            ret.follow = follow;
-            ret.tag = tag;
-            return ret;
-        }
         public Seq separate(ElementNode sep) {
             ElementNode[] elements = new ElementNode[this.elements.length * 2 - 1];
             for(int i=0; i<this.elements.length; i++) {
@@ -365,26 +400,38 @@ public class GrammarAST {
         }
     }
 
-    public class ReferenceNode extends ElementNode {
+    private class ReferenceNode extends ElementNode {
         public String nonTerminal;
+        public boolean parenthesized;
         public ReferenceNode() { }
+        public ReferenceNode(String nonTerminal) { this(nonTerminal, false); }
+        public ReferenceNode(String nonTerminal, boolean parenthesized) {
+            this.nonTerminal = nonTerminal.indexOf('.')==-1 ? (prefix + nonTerminal) : nonTerminal;
+            this.parenthesized = parenthesized;
+        }
         public NonTerminalNode resolve(Context cx) {
             NonTerminalNode ret = cx.grammar.get(nonTerminal);
             if (ret==null) throw new RuntimeException("undefined nonterminal: " + nonTerminal);
             return ret;
         }
-        public ReferenceNode(String nonTerminal) { this.nonTerminal = prefix + nonTerminal; }
-        public Atom toAtom(Context cx) { return cx.grammar.get(nonTerminal).toAtom(cx); }
+        public Atom toAtom(Context cx) {
+            ElementNode ret = cx.grammar.get(nonTerminal);
+            if (ret == null) throw new RuntimeException("unknown nonterminal \""+nonTerminal+"\"");
+            return ret.toAtom(cx);
+        }
         public boolean drop(Context cx) { return resolve(cx).drop(cx); }
         public Element build(Context cx, NonTerminalNode cnt, boolean dropall) {
-            if (!this.nonTerminal.startsWith(prefix)) nonTerminal = prefix + nonTerminal;
+            /*
+            if (!this.nonTerminal.startsWith(prefix))
+                nonTerminal = prefix + nonTerminal;
+            */
             Element ret = cx.get(nonTerminal);
             if (ret == null) throw new RuntimeException("unknown nonterminal \""+nonTerminal+"\"");
             return ret;
         }
     }
 
-    public class LiteralNode extends ElementNode {
+    private class LiteralNode extends ElementNode {
         private String string;
         private final String thePrefix = prefix;
         private boolean caret;
@@ -398,33 +445,27 @@ public class GrammarAST {
         public boolean drop(Context cx) { return true; }
         public Atom toAtom(Context cx) {
             if (string.length()!=1) return super.toAtom(cx);
-            edu.berkeley.sbp.util.Range.Set set = new edu.berkeley.sbp.util.Range.Set();
+            Range.Set set = new Range.Set();
             set.add(string.charAt(0), string.charAt(0));
             return CharAtom.set(set);
         }
         public Element build(Context cx, NonTerminalNode cnt, boolean dropall) { return CharAtom.string(string); }
     }
 
-    public class AtomNode extends ElementNode {
-        AtomNodeRange[] ranges;
-        public AtomNode() { this(new AtomNodeRange[0]); }
-        public AtomNode(AtomNodeRange[] ranges) { this.ranges = ranges; }
-        public AtomNode(AtomNodeRange range) { this.ranges = new AtomNodeRange[] { range }; }
+    private class AtomNode extends ElementNode {
+        char[][] ranges;
+        public AtomNode() { this(new char[0][]); }
+        public AtomNode(char[][] ranges) { this.ranges = ranges; }
+        public AtomNode(char[] range) { this.ranges = new char[][] { range }; }
         public Element build(Context cx, NonTerminalNode cnt, boolean dropall) { return toAtom(cx); }
         public Atom toAtom(Context cx) {
-            edu.berkeley.sbp.util.Range.Set set = new edu.berkeley.sbp.util.Range.Set();
-            for(AtomNodeRange r : ranges) set.add(r.first, r.last);
+            Range.Set set = new Range.Set();
+            for(char[] r : ranges) set.add(r[0], r[1]);
             return CharAtom.set(set);
         }
     }
-    public class AtomNodeRange {
-        public char first;
-        public char last;
-        public AtomNodeRange(char only) { first = only; last = only; }
-        public AtomNodeRange(char first, char last) { this.first = first; this.last = last; }
-    }
 
-    public class RepeatNode extends ElementNode {
+    private class RepeatNode extends ElementNode {
         public ElementNode e, sep;
         public final boolean zero, many, max;
         public RepeatNode(ElementNode e, ElementNode sep, boolean zero, boolean many, boolean max) {
@@ -450,15 +491,17 @@ public class GrammarAST {
         }
     }
 
-    public abstract class ElementNode {
+    private abstract class ElementNode {
         public boolean lifted = false;
+        public Seq ownerSeq = null;
         public String getOwnerTag() { return 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);
     }
 
-    public abstract class ElementNodeWrapper extends ElementNode {
+    private abstract class ElementNodeWrapper extends ElementNode {
         protected ElementNode _e;
         public ElementNodeWrapper(ElementNode e) { this._e = e; }
         public String getOwnerTag() { return _e.getOwnerTag(); }
@@ -467,32 +510,36 @@ public class GrammarAST {
         public Element build(Context cx, NonTerminalNode cnt, boolean dropall) { return _e.build(cx, cnt, dropall); }
     }
 
-    public class TildeNode extends ElementNodeWrapper {
+    private class TildeNode extends ElementNodeWrapper {
         public TildeNode(ElementNode e) { super(e); }
         public Atom toAtom(Context cx) { return (Atom)((Topology<Character>)_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); }
+    // FIXME: doesn't this require a tag?
+    private class BracedNode extends ElementNode {
+        public Seq body;
+        public BracedNode(Seq seq) { this.body = seq; }
+        public Element build(Context cx, NonTerminalNode cnt, boolean dropall) {
+            Union u = new Union(null, false);
+            Sequence s = body.build(cx, u, null, dropall);
+            Union u2 = new Union(null, false);
+            u2.add(Sequence.create(new Element[] {
+                CharAtom.leftBrace,
+                u,
+                CharAtom.rightBrace
+            }, 1));
+            return u2;
+        }
+    }
+
+    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); }
 
     //////////////////////////////////////////////////////////////////////////////
 
-- 
1.7.10.4