X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2Fmisc%2FMetaGrammar.java;h=972d3a12d8ffd8b862d0b1069decb8b3d3c28a4c;hb=eda544585c2304faa82d249c4744fd5cecbf9211;hp=33b3b1172464dd93588888c80c1473f49ccdaaaf;hpb=45d799349e635f1a99e3974e4504a43d5a7aaf33;p=sbp.git

diff --git a/src/edu/berkeley/sbp/misc/MetaGrammar.java b/src/edu/berkeley/sbp/misc/MetaGrammar.java
index 33b3b11..972d3a1 100644
--- a/src/edu/berkeley/sbp/misc/MetaGrammar.java
+++ b/src/edu/berkeley/sbp/misc/MetaGrammar.java
@@ -7,6 +7,22 @@ import java.io.*;
 
 public class MetaGrammar extends StringWalker {
 
+    /** an atom which tracks the possible tokenset of some element, provided that element can only match single-token sequences */
+    static class Infer<T extends Input> extends Atom<T> {
+        private final Element e;
+        public Infer(Element e) { this.e = e; }
+        public Topology<T> top() { return (Topology<T>)toAtom(e); }
+        public String toString() { return e.toString(); }
+    }
+
+    /** an atom which tracks the inverse of some other atom */
+    static class Invert<T extends Input> extends Atom<T> {
+        private final Atom<T> a;
+        public Invert(Atom<T> a) { this.a = a; }
+        public Topology<T> top() { return a.complement(); }
+        public String toString() { return "~"+a; }
+    }
+
     public static class Hack<T extends Input> extends Atom<T> {
         private final Atom<T> a;
         static final Topology leftright = CharRange.rightBrace.union(CharRange.leftBrace);
@@ -115,14 +131,14 @@ public class MetaGrammar extends StringWalker {
         if      ("\\n".equals(head)) return new Character('\n');
         else if ("\\r".equals(head)) return new Character('\r');
         else if ("grammar".equals(head)) { for(Tree<String> t : tree.children()) walk(t); return this; }
-        else if ("*".equals(head))   return Repeat.many0((Element)walk(tree.child(0)));
-        else if ("+".equals(head))   return Repeat.many1((Element)walk(tree.child(0)));
-        else if ("+/".equals(head))  return Repeat.many1((Element)walk(tree.child(0)), (Element)walk(tree.child(1)));
-        else if ("*/".equals(head))  return Repeat.many0((Element)walk(tree.child(0)), (Element)walk(tree.child(1)));
-        else if ("++/".equals(head)) return Repeat.maximal1((Element)walk(tree.child(0)), (Element)walk(tree.child(1)));
-        else if ("**".equals(head))  return Repeat.maximal0((Element)walk(tree.child(0)));
-        else if ("++".equals(head))  return Repeat.maximal1((Element)walk(tree.child(0)));
-        else if ("?".equals(head))   return Repeat.maybe((Element)walk(tree.child(0)));
+        else if ("*".equals(head))   return Sequence.many0((Element)walk(tree.child(0)), repeatTag());
+        else if ("+".equals(head))   return Sequence.many1((Element)walk(tree.child(0)), repeatTag());
+        else if ("+/".equals(head))  return Sequence.many1((Element)walk(tree.child(0)), (Element)walk(tree.child(1)), repeatTag());
+        else if ("*/".equals(head))  return Sequence.many0((Element)walk(tree.child(0)), (Element)walk(tree.child(1)), repeatTag());
+        else if ("++/".equals(head)) return Sequence.maximal1((Element)walk(tree.child(0)), (Element)walk(tree.child(1)), repeatTag());
+        else if ("**".equals(head))  return Sequence.maximal0((Element)walk(tree.child(0)), repeatTag());
+        else if ("++".equals(head))  return Sequence.maximal1((Element)walk(tree.child(0)), repeatTag());
+        else if ("?".equals(head))   return Sequence.maybe((Element)walk(tree.child(0)), repeatTag());
         else if ("!".equals(head))   { Element e = (Element)walk(tree.child(0)); dropAll.add(e); return e; }
         else if ("&".equals(head))   return ((Sequence)walk(tree,0)).and(sequence(walk(tree, 1), true));
         else if ("and".equals(head)) return ((Sequence)walk(tree,0)).and(sequence(walk(tree, 1), true));
@@ -153,7 +169,7 @@ public class MetaGrammar extends StringWalker {
         else if ("->".equals(head)) { PreSequence p = (PreSequence)walk(tree, 0); p.noFollow = (Element)walk(tree, 1); return p; }
         else if ("/".equals(head)) return ((PreSequence)walk(tree, 0)).sparse((Element)walk(tree, 1));
         else if (" /".equals(head)) return ((PreSequence)walk(tree, 0)).sparse((Element)walk(tree, 1));
-        else if ("~".equals(head)) return new Hack(new Atom.Invert(new Atom.Infer((Element)walk(tree, 0))));
+        else if ("~".equals(head)) return new Hack(new Invert(new Infer((Element)walk(tree, 0))));
         else if ("ps".equals(head)) return new PreSequence((Object[])walk(tree,0), null);
         else if (":".equals(head)) {
             String s = string(tree.child(0));
@@ -186,6 +202,7 @@ public class MetaGrammar extends StringWalker {
     }
 
     public Object convertLabel(String label) { return label; }
+    public Object repeatTag() { return null; }
 
     public Object walk(String tag, Object[] argo) {
         if (argo.length==0) return super.walk(tag, argo);
@@ -276,6 +293,7 @@ public class MetaGrammar extends StringWalker {
                 for(int i=0; i<o.length; i++) {
                     Object oi = o[i];
                     if (oi instanceof Keep)    {
+                        if (!unwrap && tag==null) throw new Error("cannot have labels in an untagged sequence: " + ((Keep)oi).label);
                         if (!keeping) { for(int k=0; k<i; k++) drops[k]=true; }
                         drops[i] = false;
                         keeping = true;
@@ -298,7 +316,7 @@ public class MetaGrammar extends StringWalker {
             Element[] expansion = o2;
             Sequence ret = null;
             if (dropAll || lame) ret = Sequence.drop(expansion, lame);
-            else if (unwrap)    ret = new Sequence.Unwrap(expansion, drops);
+            else if (unwrap)    ret = Sequence.unwrap(expansion, repeatTag(), drops);
             else if (keeping || tag!=null) ret = Sequence.rewritingSequence(tag, expansion, labels, drops);
             else {
                 int idx = -1;
@@ -312,7 +330,7 @@ public class MetaGrammar extends StringWalker {
             for(Sequence s : and) ret = ret.and(s);
             for(Sequence s : not) ret = ret.not(s);
             set.add(ret);
-            if (this.noFollow != null) ret.noFollow = new Atom.Invert(new Atom.Infer(this.noFollow));
+            if (this.noFollow != null) ret.noFollow = new Invert(new Infer(this.noFollow));
             return ret;
         }
     }
@@ -502,6 +520,41 @@ public class MetaGrammar extends StringWalker {
 
 
 
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         // DO NOT EDIT STUFF BELOW: IT IS AUTOMATICALLY GENERATED
 new edu.berkeley.sbp.Tree(null, "grammar", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "=", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "s", new edu.berkeley.sbp.Tree[] { })}),
         new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "psx", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "ps", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "!", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "nonTerminal", new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, null, new edu.berkeley.sbp.Tree[] { new edu.berkeley.sbp.Tree(null, "w", new edu.berkeley.sbp.Tree[] { }),
@@ -1156,3 +1209,38 @@ new edu.berkeley.sbp.Tree(null, "grammar", new edu.berkeley.sbp.Tree[] { new edu
 
 
 
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