X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2Fmisc%2FDemo.java;h=d29a8f9e54301e68c74bebd991cd81c527ac8df3;hb=0eb9557f0e79be770ffaa87a36a4be7843f3d9f5;hp=b3b9f4c2dc93827faff6b927c43624d95862b839;hpb=3784457891d6a8b17429a16493cd65501e02e174;p=sbp.git

diff --git a/src/edu/berkeley/sbp/misc/Demo.java b/src/edu/berkeley/sbp/misc/Demo.java
index b3b9f4c..d29a8f9 100644
--- a/src/edu/berkeley/sbp/misc/Demo.java
+++ b/src/edu/berkeley/sbp/misc/Demo.java
@@ -17,26 +17,13 @@ public class Demo {
         Tree<String> res = new CharParser(MetaGrammar.make()).parse(new FileInputStream(s[0])).expand1();
         MetaGrammar.Meta.MetaGrammarFile mgf = m.new MetaGrammarFile(res);
         MetaGrammar.BuildContext bc = new MetaGrammar.BuildContext(mgf);
+
         Union meta = mgf.get("s").build(bc);
-        System.err.println("parsing " + s[1]);
         Tree t = new CharParser(meta).parse(new FileInputStream(s[1])).expand1();
-        System.out.println("tree:\n" + t.toPrettyString());
-
-        Reducer red = (Reducer)t.head();
-        MG.Grammar g = (MG.Grammar)red.reduce(t);
-        System.out.println(g);
-        
-        Context cx = new Context(g,m);
-        Element u = null;
-        for(MG.NonTerminal nt : g.nonterminals) {
-            Union el = (Union)cx.get(nt.name);
-            StringBuffer st = new StringBuffer();
-            el.toString(st);
-            System.err.println(st);
-            if (nt.name.equals("s")) u = el;
-        }
-        System.err.println();
 
+        Union u = Demo.make(t, "s");
+
+        System.err.println();
         System.err.println("== parsing with parsed grammar =================================================================================");
         t = new CharParser((Union)u).parse(new FileInputStream(s[1])).expand1();
         System.out.println(t.toPrettyString());
@@ -46,6 +33,15 @@ public class Demo {
         System.out.println(t.toPrettyString());
     }
 
+    public static class ReflectiveMetaPlain extends ReflectiveMeta {
+        public Object repeatTag() { return null; }
+        public Sequence tryResolveTag(String tag, String nonTerminalName, Element[] els, Object[] labels, boolean[] drops) {
+            return null; }
+        public Sequence resolveTag(String tag, String nonTerminalName, Element[] els, Object[] labels, boolean[] drops) {
+            return Sequence.rewritingSequence(tag, els, labels, drops);
+        }
+    }
+
     public static class ReflectiveMeta extends MetaGrammar.Meta {
         private final Class _cl;
         private final Class[] _inner;
@@ -53,14 +49,14 @@ public class Demo {
             this(MG.class,
                  new Class[] {
                      MG.Grammar.class,
-                     MG.NonTerminal.class,
                      MG.AnonUn.class,
                      MG.Range.class,
                      MG.El.class,
                      MG.Seq.class,
+                     MG.NonTerminal.class,
                      MG.NonTerminalReference.class,
                      MG.StringLiteral.class,
-                     MG.Tree.class,
+                     MG.XTree.class,
                      MG.CharClass.class
                  });
         }
@@ -68,49 +64,34 @@ public class Demo {
             this._cl = c;
             this._inner = inner;
         }
-        private boolean match(Method m, String s) { return match(m.getAnnotation(tag.class), null, s); }
-        private boolean match(tag t, Class c, String s) {
+        private boolean match(Method m, String s) { return match(m.getAnnotation(bind.as.class), null, s); }
+        private boolean match(bind.as t, Class c, String s) {
             if (t==null) return false;
             if (t.value().equals(s)) return true;
             if (c != null && t.equals("") && c.getSimpleName().equals(s)) return true;
             return false;
         }
+        /*
         private boolean match(nonterminal t, Class c, String s) {
             if (t==null) return false;
             if (t.value().equals(s)) return true;
             if (c != null && t.equals("") && c.getSimpleName().equals(s)) return true;
             return false;
         }
+        */
         private boolean match(Class c, String s, String nonTerminalName) {
-            if (match((tag)c.getAnnotation(tag.class), c, s)) return true;
-            if (match((nonterminal)c.getAnnotation(nonterminal.class), c, nonTerminalName)) return true;
+            if (match((bind.as)c.getAnnotation(bind.as.class), c, s)) return true;
+            //if (match((nonterminal)c.getAnnotation(bind.as.class), c, nonTerminalName)) return true;
             return false;
         }
         public boolean match(Constructor con, String s, String nonTerminalName) {
             Class c = con.getDeclaringClass();
-            if (match((tag)con.getAnnotation(tag.class), null, s)) return true;
-            if (match((nonterminal)con.getAnnotation(nonterminal.class), c, s)) return true;
+            if (match((bind.as)con.getAnnotation(bind.as.class), null, s)) return true;
+            //if (match((nonterminal)con.getAnnotation(bind.as.class), c, s)) return true;
             return false;
         }
         public Object repeatTag() {
-            return new Reducer() {
-                    public String toString() { return "[**]"; }
-                    public Object reduce(Tree t) {
-                        Object[] ret = new Object[t.numChildren()];
-                        for(int i=0; i<t.numChildren(); i++) {
-                            Tree tc = t.child(i);
-                            if (tc.head() != null && tc.head() instanceof Reducer)
-                                ret[i] = ((Reducer)tc.head()).reduce(tc);
-                            else if (tc.numChildren() == 0)
-                                ret[i] = tc.head();
-                            else {
-                                System.err.println("FIXME: don't know what to do about " + tc);
-                                ret[i] = null;
-                            }
-                        }
-                        return ret;
-                    }
-                };
+            return new Tree.ArrayBuildingTreeFunctor<Object>();
         }
         public Sequence tryResolveTag(String tag, String nonTerminalName, Element[] els, Object[] labels, boolean[] drops) {
             Production p = new Production(tag, nonTerminalName, els, labels, drops);
@@ -141,43 +122,51 @@ public class Demo {
     }
 
     
-    /**
-     *  Constructors, classes, and methods with this attribute will
-     *  match every production of the nonterminal called "value()"
-     *  that is arg-compatible.  If value() is undefined, then the
-     *  class/constructor/method name is used.
-     */ 
-    @Retention(RetentionPolicy.RUNTIME) public static @interface nonterminal { String value() default ""; }
-
-    /**
-     *  Constructors, classes, and methods with this attribute will
-     *  match every tree tagged with "value()" that is arg-compatible.
-     *  If value() is undefined, then the class/constructor/method
-     *  name is used.
-     */ 
-    @Retention(RetentionPolicy.RUNTIME) public static @interface tag         { String value() default ""; }
-
-    /**
-     *  If any parameter to a method or field in a class has a named
-     *  arg-tag, that parameter/field matches the child of the tree
-     *  which either has that label or else is a reference to a
-     *  nonterminal with the corresponding name.
-     *  
-     *  The remaining non-named arg-tags match the remaining children
-     *  of the tree in sequential order.
-     *
-     *  If any arg-tagged parameters/fields remain, the match fails.
-     *  If there were no arg-tagged parameters-fields, it is as if all
-     *  of them were non-named and arg-tagged.
-     *
-     *  A method/constructor is arg-compatible if all of its arguments
-     *  are arg-compatible.
-     *
-     *  A class is arg-compatible if all of its fields are
-     *  arg-compatible, or if one of its constructors is arg-compatible.
-     *
-     */
-    @Retention(RetentionPolicy.RUNTIME) public static @interface arg         { String value() default ""; }
+    public static class bind {    
+        /**
+         *  Constructors, classes, and methods with this attribute will
+         *  match every production of the nonterminal called "value()"
+         *  that is arg-compatible.  If value() is undefined, then the
+         *  class/constructor/method name is used.
+         */ 
+        /*
+          @Retention(RetentionPolicy.RUNTIME) public static @interface nonterminal { String value() default ""; }
+        */
+
+        @Retention(RetentionPolicy.RUNTIME) public static @interface raw { }
+
+        /**
+         *  Constructors, classes, and methods with this attribute will
+         *  match every tree tagged with "value()" that is arg-compatible.
+         *  If value() is undefined, then the class/constructor/method
+         *  name is used.
+         */ 
+
+        @Retention(RetentionPolicy.RUNTIME) public static @interface as         { String value() default ""; }
+
+
+        /**
+         *  If any parameter to a method or field in a class has a named
+         *  arg-tag, that parameter/field matches the child of the tree
+         *  which either has that label or else is a reference to a
+         *  nonterminal with the corresponding name.
+         *  
+         *  The remaining non-named arg-tags match the remaining children
+         *  of the tree in sequential order.
+         *
+         *  If any arg-tagged parameters/fields remain, the match fails.
+         *  If there were no arg-tagged parameters-fields, it is as if all
+         *  of them were non-named and arg-tagged.
+         *
+         *  A method/constructor is arg-compatible if all of its arguments
+         *  are arg-compatible.
+         *
+         *  A class is arg-compatible if all of its fields are
+         *  arg-compatible, or if one of its constructors is arg-compatible.
+         *
+         */
+        @Retention(RetentionPolicy.RUNTIME) public static @interface arg         { String value() default ""; }
+    }
 
     public static class Production {
         public String tag;
@@ -199,18 +188,26 @@ public class Demo {
     }
 
     public static abstract class Target {
-        public abstract String getName();
-        public abstract tag getTag();
-        public abstract nonterminal getNonTerminal();
         public abstract int[] buildSequence(Production p);
+        private Reflection.Bindable _bindable;
+        public Target(Reflection.Bindable b) { this._bindable = b; }
+
+        public String getName() { return _bindable.getSimpleName(); }
+        public bind.as getBindAs() { return (bind.as)_bindable.getAnnotation(bind.as.class); }
+        //public nonterminal getNonTerminal() { return (nonterminal)_bindable.getAnnotation(bind.as.class); }
+        public String toString() { return _bindable.getSimpleName(); }
+        public Object plant(Object[] fields) { return _bindable.impose(fields); }
+        public boolean isRaw() { return _bindable.isAnnotationPresent(bind.raw.class); }
+        public Object invokeRaw(Iterable<Tree<Object>> t) { return _bindable.impose(new Object[] { t }); }
+
         public boolean isCompatible(Production p) {
-            tag t = getTag();
+            bind.as t = getBindAs();
             if (t != null &&
                 (t.value().equals(p.tag) ||
-                 (t.value().equals("") && p.tag.equals(getName()))))
+                 (t.value().equals("") && getName().equals(p.tag))))
                 return buildSequence(p)!=null;
 
-            nonterminal n = getNonTerminal();
+            bind.as n = getBindAs();
             if (n != null &&
                 (n.value().equals(p.nonTerminal) ||
                  (n.value().equals("") && getName().equals(p.nonTerminal))))
@@ -218,7 +215,8 @@ public class Demo {
 
             return false;
         }
-        public int[] buildSequence(Production p, String[] names, arg[] argtags) {
+
+        public int[] buildSequence(Production p, String[] names, bind.arg[] argtags) {
             int argTagged = 0;
             for(int i=0; i<argtags.length; i++)
                 if (argtags[i] != null)
@@ -240,54 +238,54 @@ public class Demo {
             }
         }
         public Sequence makeSequence(Production p) {
-            return Sequence.rewritingSequence(new TargetReducer(p), p.elements, p.labels, p.drops);
+            return Sequence.rewritingSequence(new TargetReducer(p, buildSequence(p), "reducer-"+this),
+                                              p.elements, p.labels, p.drops);
         }
-        public abstract Object plant(Object[] fields, int[] map);
-        public class TargetReducer implements Reducer {
+
+        public class TargetReducer implements Tree.TreeFunctor<Object,Object> {
             private Production p;
             private int[] map;
-            public TargetReducer(Production p) {
+            private String name;
+            public TargetReducer(Production p, int[] map, String name) {
                 this.p = p;
-                this.map = buildSequence(p);
+                this.map = map;
+                this.name = name;
             }
-            public String toString() { return "reducer-"+Target.this; }
-            public Object reduce(Tree t) {
-                Object[] objects = new Object[t.numChildren()];
-                for(int i=0; i<t.numChildren(); i++) {
-                    Tree tc = t.child(i);
-                    if (tc.head() != null && tc.head() instanceof Reducer)
-                        objects[i] = ((Reducer)tc.head()).reduce(tc);
+            public String toString() { return name; }
+            public Object invoke(Iterable<Tree<Object>> t) {
+                if (isRaw()) return invokeRaw(t);
+                ArrayList ret = new ArrayList();
+                for(Tree tc : t) {
+                    if (tc.head() != null && tc.head() instanceof Functor)
+                        ret.add(((Tree.TreeFunctor<Object,Object>)tc.head()).invoke(tc.children()));
                     else if (tc.numChildren() == 0)
-                        objects[i] = tc.head();
+                        ret.add(tc.head());
                     else {
                         System.err.println("FIXME: don't know what to do about " + tc);
-                        objects[i] = null;
+                        ret.add(null);
                     }
                 }
                 System.err.println("input tree: " + t);
-                return plant(objects, map);
+                Object[] o = (Object[])ret.toArray(new Object[0]);
+                int max = 0;
+                for(int i=0; i<map.length; i++) max = Math.max(map[i], max);
+                Object[] o2 = new Object[max+1];
+                for(int i=0; i<o.length; i++) o2[map[i]] = o[i];
+                return plant(o2);
             }
         }
     }
 
-    public static interface Reducer {
-        public Object reduce(Tree t);
-    }
-
     public static class TargetClass extends Target {
         public final Class _class;
-        public TargetClass(Class _class) { this._class = _class; }
-        public String getName() { return _class.getSimpleName(); }
-        public tag getTag() { return (tag)_class.getAnnotation(tag.class); }
-        public nonterminal getNonTerminal() { return (nonterminal)_class.getAnnotation(nonterminal.class); }
-        public String toString() { return _class.getSimpleName(); }
+        public TargetClass(Class _class) { super(Reflection.Bindable.create(_class)); this._class = _class; }
         public int[] buildSequence(Production p) {
             Field[]  f       = _class.getDeclaredFields();
             String[] names   = new String[f.length];
-            arg[]    argtags = new arg[f.length];
+            bind.arg[]    argtags = new bind.arg[f.length];
             for(int i=0; i<f.length; i++) {
                 names[i]   = f[i].getName();
-                argtags[i] = f[i].getAnnotation(arg.class);
+                argtags[i] = f[i].getAnnotation(bind.arg.class);
             }
             int[] ret = buildSequence(p, names, argtags);
             if (ret!=null) return ret;
@@ -296,45 +294,11 @@ public class Demo {
                     return new TargetConstructor(c).buildSequence(p);
             return null;
         }
-        public Object plant(Object[] fields, int[] map) {
-            try {
-                Object ret = _class.newInstance();
-                Field[] f = _class.getFields();
-                int j = 0;
-                for(int i=0; i<f.length; i++)
-                    if (map[i] != -1) {
-                        Object tgt = Reflection.lub(fields[map[i]]);
-                        if (f[i].getType() == String.class) tgt = stringify(tgt);
-                        // FUGLY
-                        tgt = coerce(tgt, f[i].getType());
-                        System.err.println("setting a " + f[i].getType().getName() + " to " + Reflection.show(tgt));
-                        f[i].set(ret, tgt);
-                    }
-                return ret;
-            } catch (Exception e) {
-                e.printStackTrace();
-                throw new RuntimeException(e);
-            }
-        }
-    }
-
-    public static String stringify(Object o) {
-        if (o==null) return "";
-        if (!(o instanceof Object[])) return o.toString();
-        Object[] arr = (Object[])o;
-        StringBuffer ret = new StringBuffer();
-        for(int i=0; i<arr.length; i++)
-            ret.append(arr[i]);
-        return ret.toString();
     }
 
     public static class TargetConstructor extends Target {
         public final Constructor _ctor;
-        public TargetConstructor(Constructor _ctor) { this._ctor = _ctor; }
-        public String getName() { return _ctor.getName(); }
-        public tag getTag() { return (tag)_ctor.getAnnotation(tag.class); }
-        public nonterminal getNonTerminal() { return (nonterminal)_ctor.getAnnotation(nonterminal.class); }
-        public String toString() { return _ctor.getName(); }
+        public TargetConstructor(Constructor _ctor) { super(Reflection.Bindable.create(_ctor)); this._ctor = _ctor; }
         public int[] buildSequence(Production p) {
             Annotation[][] annotations = _ctor.getParameterAnnotations();
             int len = annotations.length;
@@ -347,110 +311,71 @@ public class Demo {
             }
             */
             String[] names   = new String[len];
-            arg[]    argtags = new arg[len];
+            bind.arg[]    argtags = new bind.arg[len];
             for(int i=0; i<names.length; i++)
                 for(Annotation a : annotations[i+ofs])
-                    if (a instanceof arg)
-                        argtags[i+ofs] = (arg)a;
+                    if (a instanceof bind.arg)
+                        argtags[i+ofs] = (bind.arg)a;
             return buildSequence(p, names, argtags);
         }
-        public Object plant(Object[] fields, int[] map) {
-            try {
-                Class[] argTypes = _ctor.getParameterTypes();
-                Object[] args = new Object[argTypes.length];
-                int j = 0;
-                for(int i=0; i<args.length; i++)
-                    if (map[i] != -1) {
-                        Object tgt = Reflection.lub(fields[map[i]]);
-                        if (argTypes[i] == String.class) tgt = stringify(tgt);
-                        // FUGLY
-                        tgt = coerce(tgt, argTypes[i]);
-                        System.err.println("setting a " + argTypes[i].getName() + " to " + Reflection.show(tgt));
-                        args[i] = tgt;
-                    }
-                return _ctor.newInstance(args);
-            } catch (Exception e) {
-                throw new RuntimeException(e);
-            }
-        }
     }
     public static class TargetMethod extends Target {
         public final Method _method;
-        public TargetMethod(Method _method) { this._method = _method; }
-        public String getName() { return _method.getName(); }
-        public String toString() { return _method.getName(); }
-        public tag getTag() { return (tag)_method.getAnnotation(tag.class); }
-        public nonterminal getNonTerminal() { return (nonterminal)_method.getAnnotation(nonterminal.class); }
+        public TargetMethod(Method _method) { super(Reflection.Bindable.create(_method)); this._method = _method; }
         public int[] buildSequence(Production p) {
             Annotation[][] annotations = _method.getParameterAnnotations();
             String[] names   = new String[annotations.length];
-            arg[]    argtags = new arg[annotations.length];
+            bind.arg[]    argtags = new bind.arg[annotations.length];
             for(int i=0; i<names.length; i++)
                 for(Annotation a : annotations[i])
-                    if (a instanceof arg)
-                        argtags[i] = (arg)a;
+                    if (a instanceof bind.arg)
+                        argtags[i] = (bind.arg)a;
             int[] ret = buildSequence(p, names, argtags);
             return ret;
         }
-        public Object plant(Object[] fields, int[] map) {
-            try {
-                Class[] argTypes = _method.getParameterTypes();
-                Object[] args = new Object[argTypes.length];
-                int j = 0;
-                for(int i=0; i<args.length; i++)
-                    if (map[i] != -1) {
-                        Object tgt = Reflection.lub(fields[map[i]]);
-                        if (argTypes[i] == String.class) tgt = stringify(tgt);
-                        // FUGLY
-                        tgt = coerce(tgt, argTypes[i]);
-                        System.err.println("setting a " + argTypes[i].getName() + " to " + Reflection.show(tgt));
-                        args[i] = tgt;
-                    }
-                System.err.println("invoking " + _method + " with " + Reflection.show(args));
-                return _method.invoke(null, args);
-            } catch (Exception e) {
-                throw new RuntimeException(e);
-            }
-        }
     }
 
-    public static Object coerce(Object o, Class c) {
-        if (o==null) return null;
-        if (c.isInstance(o)) return o;
-        if (c == char.class) {
-            return o.toString().charAt(0);
+    public static Union cached = null;
+    public static Union make() {
+        if (cached != null) return cached;
+        try {
+            ReflectiveMeta m = new ReflectiveMeta();
+            Tree<String> res = new CharParser(MetaGrammar.make()).parse(new FileInputStream("tests/meta.g")).expand1();
+            MetaGrammar.Meta.MetaGrammarFile mgf = m.new MetaGrammarFile(res);
+            MetaGrammar.BuildContext bc = new MetaGrammar.BuildContext(mgf);
+            Union meta = mgf.get("s").build(bc);
+            Tree t = new CharParser(meta).parse(new FileInputStream("tests/meta.g")).expand1();
+            return cached = make(t, "s");
+        } catch (Exception e) {
+            throw new RuntimeException(e);
         }
-        if (c.isArray() && (c.getComponentType().isInstance(o))) {
-            Object[] ret = (Object[])Array.newInstance(c.getComponentType(), 1);
-            ret[0] = o;
-            return ret;
-        }
-        if (o.getClass().isArray() && c.isArray()) {
-            boolean ok = true;
-            for(int i=0; i<((Object[])o).length; i++) {
-                Object ob = (((Object[])o)[i]);
-                if (ob != null) {
-                    System.err.println("no hit with " + c.getComponentType().getName() + " on " + Reflection.show(((Object[])o)[i]));
-                    ok = false;
-                }
-            }
-            if (ok) {
-                System.err.println("hit with " + c.getComponentType().getName());
-                return Array.newInstance(c.getComponentType(), ((Object[])o).length);
-            }
+    }
+    public static Union make(Tree t, String s) { return make(t, s, new ReflectiveMeta()); }
+    public static Union make(Tree t, String s, ReflectiveMeta rm) {
+        Tree.TreeFunctor<Object,Object> red = (Tree.TreeFunctor<Object,Object>)t.head();
+        MG.Grammar g = (MG.Grammar)red.invoke(t.children());
+        Context cx = new Context(g,rm);
+        Union u = null;
+        for(MG.NonTerminal nt : g.nonterminals) {
+            System.out.println(nt.name);
+            Union el = (Union)cx.get(nt.name);
+            StringBuffer st = new StringBuffer();
+            el.toString(st);
+            System.err.println(st);
+            if (nt.name.equals(s)) u = el;
         }
-        return o;
+        return u;
     }
 
     public static class MG {
-        public static @tag("grammar") class Grammar {
+        public static @bind.as("grammar") class Grammar {
             public NonTerminal get(String s) {
                 for(NonTerminal nt : nonterminals)
                     if (nt.name.equals(s))
                         return nt;
                 return null;
             }
-            public @arg("NonTerminal") NonTerminal[] nonterminals;
+            public @bind.arg("NonTerminal") NonTerminal[] nonterminals;
             public String toString() {
                 String ret = "[ ";
                 for(NonTerminal nt : nonterminals) ret += nt + ", ";
@@ -481,8 +406,8 @@ public class Demo {
         }
         public static class NonTerminal extends Un {
             public String  name = null;
-            public @nonterminal("NonTerminal") NonTerminal(@arg("Word") String name,
-                                                           @arg("RHS") Seq[][] sequences) {
+            public @bind.as("=") NonTerminal(@bind.arg("Word") String name,
+                                         @bind.arg("RHS") Seq[][] sequences) {
                 this.name = name;
                 this.sequences = sequences;
             }
@@ -490,7 +415,7 @@ public class Demo {
         }
 
         public static class AnonUn extends Un {
-            public @tag("(") AnonUn(Seq[][] sequences) {
+            public @bind.as("(") AnonUn(Seq[][] sequences) {
                 this.sequences = sequences;
             }
             public Element build(Context cx) {
@@ -500,10 +425,10 @@ public class Demo {
             }
         }
 
-        //public static @tag void range(char c) { }
+        //public static @bind.as void range(char c) { }
         public static class Range {
-            public @tag("range") Range(char only) { first = only; last = only; }
-            public @tag("-")     Range(char first, char last) { this.first = first; this.last = last; }
+            public @bind.as("range") Range(char only) { first = only; last = only; }
+            public @bind.as("-")     Range(char first, char last) { this.first = first; this.last = last; }
             public char first;
             public char last;
         }
@@ -603,31 +528,33 @@ public class Demo {
                 return ret;
             }
         }
-        public static @tag("&")   Seq  and(Seq s,         El[] elements) { return s.and(seq(elements)); }
-        public static @tag("&~")  Seq  andnot(Seq s,      El[] elements) { return s.andnot(seq(elements)); }
-        public static @tag("->")  Seq  arrow(Seq s, El e)                { return s.follow(e); }
-        public static @tag("::")  Seq  tag(String tagname, Seq s)        { return s.tag(tagname); }
-        public static @tag("/")   Seq  slash(Seq s, El e)                { return s.separate(e); }
+        public static @bind.as("&")   Seq  and(Seq s,         El[] elements) { return s.and(seq(elements)); }
+        public static @bind.as("&~")  Seq  andnot(Seq s,      El[] elements) { return s.andnot(seq(elements)); }
+        public static @bind.as("->")  Seq  arrow(Seq s, El e)                { return s.follow(e); }
+        public static @bind.as("::")  Seq  tag(String tagname, Seq s)        { return s.tag(tagname); }
+        public static @bind.as("/")   Seq  slash(Seq s, El e)                { return s.separate(e); }
 
-        public static @tag("ps")  Seq  seq(El[] elements)                { return new Seq(elements); }
-        public static @tag        Seq  psx(Seq s)                        { return s; }
-        public static @tag(":")   El   colon(String s, El e)             { return new Label(s, e); }
-        public static @tag(")")   void close(String foo)                 { throw new Error("not supported"); }
-        public static @tag("()")  El   epsilon()                         { return new Constant(Union.epsilon); }
+        public static @bind.as("ps")  Seq  seq(El[] elements)                { return new Seq(elements); }
+        public static @bind.as        Seq  psx(Seq s)                        { return s; }
+        public static @bind.as(":")   El   colon(String s, El e)             { return new Label(s, e); }
+        public static @bind.as(")")   void close(String foo)                 { throw new Error("not supported"); }
+        public static @bind.as("()")  El   epsilon()                         { return new Constant(Union.epsilon); }
 
-        public static @tag("nonTerminal") class NonTerminalReference extends El {
-            public @arg String nonTerminal;
+        public static @bind.as("nonTerminal") class NonTerminalReference extends El {
+            public @bind.arg String nonTerminal;
             public Element build(Context cx) {
                 return cx.get(nonTerminal);
             }
         }
+
         public static class StringLiteral        extends Constant {
-            public @tag("literal") StringLiteral(String string) { super(CharRange.string(string)); }
+            public @bind.as("literal") StringLiteral(String string) { super(CharRange.string(string)); }
             public boolean drop() { return true; }
         }
+
         public static                     class CharClass            extends El {
             Range[] ranges;
-            public @tag("[") CharClass(Range[] ranges) { this.ranges = ranges; }
+            public @bind.as("[") CharClass(Range[] ranges) { this.ranges = ranges; }
             public Element build(Context cx) {
                 edu.berkeley.sbp.util.Range.Set set = new edu.berkeley.sbp.util.Range.Set();
                 for(Range r : ranges)
@@ -636,8 +563,8 @@ public class Demo {
             }
         }
 
-        public static @tag("{")           class Tree                 extends El {
-            public @arg Seq body;
+        public static @bind.as("{")           class XTree                 extends El {
+            public @bind.arg Seq body;
             public Element build(Context cx) {
                 throw new Error();
             }
@@ -669,40 +596,40 @@ public class Demo {
         }
 
         // FIXME: it would be nice if we could hoist this into "Rep"
-        public static @tag("++")  El plusmax(final El e)                     { return new Rep(e, null, false, true, true); }
-        public static @tag("+")   El plus(final El e)                        { return new Rep(e, null, false, true, false); }
-        public static @tag("++/") El plusmaxfollow(final El e, final El sep) { return new Rep(e, sep,  false, true, true); }
-        public static @tag("+/")  El plusfollow(final El e, final El sep)    { return new Rep(e, sep,  false, true, false); }
-        public static @tag("**")  El starmax(final El e)                     { return new Rep(e, null, true,  true, true); }
-        public static @tag("*")   El star(final El e)                        { return new Rep(e, null, true,  true, false); }
-        public static @tag("**/") El starmaxfollow(final El e, final El sep) { return new Rep(e, sep,  true,  true, true); }
-        public static @tag("*/")  El starfollow(final El e, final El sep)    { return new Rep(e, sep,  true,  true, false); }
-        public static @tag("?")   El question(final El e)                    { return new Rep(e, null, true,  true, false); }
-
-        public static @tag("!")   El bang(final El e)                        { return new Drop(e); }
-
-        public static @tag("^")   El caret(final String s) {
+        public static @bind.as("++")  El plusmax(final El e)                     { return new Rep(e, null, false, true, true); }
+        public static @bind.as("+")   El plus(final El e)                        { return new Rep(e, null, false, true, false); }
+        public static @bind.as("++/") El plusmaxfollow(final El e, final El sep) { return new Rep(e, sep,  false, true, true); }
+        public static @bind.as("+/")  El plusfollow(final El e, final El sep)    { return new Rep(e, sep,  false, true, false); }
+        public static @bind.as("**")  El starmax(final El e)                     { return new Rep(e, null, true,  true, true); }
+        public static @bind.as("*")   El star(final El e)                        { return new Rep(e, null, true,  true, false); }
+        public static @bind.as("**/") El starmaxfollow(final El e, final El sep) { return new Rep(e, sep,  true,  true, true); }
+        public static @bind.as("*/")  El starfollow(final El e, final El sep)    { return new Rep(e, sep,  true,  true, false); }
+        public static @bind.as("?")   El question(final El e)                    { return new Rep(e, null, true,  true, false); }
+
+        public static @bind.as("!")   El bang(final El e)                        { return new Drop(e); }
+
+        public static @bind.as("^")   El caret(final String s) {
             return new Drop(new Constant(CharRange.string(s)) {
                     public String getOwnerTag() { return s; }
                 });
         }
 
-        public static @tag("~")   El tilde(final El e) {
+        public static @bind.as("~")   El tilde(final El e) {
             return new PostProcess(e) {
                     public Element postProcess(Element e) {
                         return MetaGrammar.infer((Topology<Character>)Atom.toAtom(e).complement()); 
                     } }; }
 
-        public static @tag("^^")  void doublecaret(final El e)                 { throw new Error("not implemented"); }
+        public static @bind.as("^^")  void doublecaret(final El e)                 { throw new Error("not implemented"); }
 
-        //public static @tag("(")   El subexpression(Seq[][] rhs)                { return new NonTerminal(rhs); }
+        //public static @bind.as("(")   El subexpression(Seq[][] rhs)                { return new NonTerminal(rhs); }
 
-        public static @nonterminal("Word")    String word(String s) { return s; }
-        public static @nonterminal("Quoted")  String quoted(String s) { return s; }
-        public static @nonterminal("escaped") String c(char c) { return c+""; }
-        public static @tag("\"\"")            String emptystring() { return ""; }
-        public static @tag("\n")              String retur() { return "\n"; }
-        public static @tag("\r")              String lf() { return "\r"; }
+        public static @bind.as("Word")    String word(String s) { return s; }
+        public static @bind.as("Quoted")  String quoted(String s) { return s; }
+        public static @bind.as("escaped") String c(char c) { return c+""; }
+        public static @bind.as("\"\"")    String emptystring() { return ""; }
+        public static @bind.as("\n")      String retur() { return "\n"; }
+        public static @bind.as("\r")      String lf() { return "\r"; }
 
     }
     public static class Context {
@@ -725,8 +652,8 @@ public class Demo {
         }
         public Context(Tree t, ReflectiveMeta rm) {
             this.rm = rm;
-            Reducer red = (Reducer)t.head();
-            this.grammar = (MG.Grammar)red.reduce(t);
+            Tree.TreeFunctor<Object,Object> red = (Tree.TreeFunctor<Object,Object>)t.head();
+            this.grammar = (MG.Grammar)red.invoke(t.children());
         }
         public Union peek(String name) { return map.get(name); }
         public void  put(String name, Union u) { map.put(name, u); }