checkpoint

[sbp.git] / src / edu / berkeley / sbp / misc / MetaGrammar.java

diff --git a/src/edu/berkeley/sbp/misc/MetaGrammar.java b/src/edu/berkeley/sbp/misc/MetaGrammar.java
index 687d2d8..889e2bc 100644 (file)
--- a/src/edu/berkeley/sbp/misc/MetaGrammar.java
+++ b/src/edu/berkeley/sbp/misc/MetaGrammar.java
@@ -31,9 +31,16 @@ public class MetaGrammar extends ReflectiveWalker {
     private HashMap<String,Union> nt;
     private int anon = 0;
     private String startSymbol;
+    private boolean strings;
 
-    public MetaGrammar() { this("s"); }
-    public MetaGrammar(String s) { done(s); }
+    private Element  set(Range.Set r) { if (strings) throw new Error(); return CharToken.set(r); }
+    private Element  string(String s) { return strings ? StringToken.string(s) : CharToken.string(s); }
+    private Atom     leftBrace()      { return strings ? StringToken.leftBrace : CharToken.leftBrace; }
+    private Atom     rightBrace()     { return strings ? StringToken.rightBrace : CharToken.rightBrace; }
+
+    public MetaGrammar() { this("s", false); }
+    public MetaGrammar(String s) { this(s, false); }
+    public MetaGrammar(String s, boolean strings) { this.strings = strings; done(s); }
     public Union done() { return done("s"); }
     public Union done(String str) {
         Union ret = g;
@@ -55,7 +62,7 @@ public class MetaGrammar extends ReflectiveWalker {
     public Element     _rightparen_(Object e)                                         { return SELF; }
     public Element     _bang_(Element r)                                              { return r; }
     public Object      _caret_(String s)                                              { return new MyLift(s); }
-    public Object      _leftparen__rightparen_()                                      { return epsilon; }
+    public Object      _leftparen__rightparen_(Object o)                              { return epsilon; }
     public Union       nonTerminal(String s)                                          { return nonTerminal(s, null, false, false); }
     public Union       _colon__colon__equals_(String s, PreSequence[][] p)            { return nonTerminal(s, p, false, false); }
     public Union       _bang__colon__colon__equals_(String s, PreSequence[][] p)      { return nonTerminal(s, p, false, true); }
@@ -82,13 +89,24 @@ public class MetaGrammar extends ReflectiveWalker {
     }
 
     public Object   _backslash__leftbrace_(String s)      { return SELF; }
-    public Object   _leftbrace_(String s)                 { return SELF; }
-    public Object   _plus_(final Element r) { return Repeat.many1(r); }
+    public Object   _leftbrace_(PreSequence p) {
+        return nonTerminal("braced"+(anon++),
+                           new PreSequence[][] {
+                               new PreSequence[] {
+                                   new PreSequence(leftBrace()),
+                                   p,
+                                   new PreSequence(rightBrace())
+                               }
+                           },
+                           false,
+                           false);
+    }
 
-    public PreSequence rewrite(Object[] o)                                            { return new PreSequence(o, null); }
-    public PreSequence _equals__greater_(Object[] o, String s)                        { return new PreSequence(o, s); }
+    public Object   _plus_(final Element r)                    { return Repeat.many1(r); }
+    public PreSequence rewrite(Object[] o)                     { return new PreSequence(o, null); }
+    public PreSequence _equals__greater_(Object[] o, String s) { return new PreSequence(o, s); }
     public PreSequence seq(Object[] o, Object sep, String tag) { return new PreSequence(sep==null ? o : _slash_(o, sep), tag); }
-    public Object[] seq(Object[] o) { return o; }
+    public Object[] seq(Object[] o)                            { return o; }
     public Object[] _slash_(Object[] o, Object sep) {
         if (o.length <= 1) return o;
         Object[] ret = new Object[o.length * 2 - 1];
@@ -110,7 +128,7 @@ public class MetaGrammar extends ReflectiveWalker {
     public MetaGrammar grammar(Object o, Union[] u, Object x) { return this; }
     public char    _backslash_n() { return '\n'; }
     public char    _backslash_r() { return '\r'; }
-    public Object    literal(String s) { return new MyDrop(CharToken.string(s)); }
+    public Object    literal(String s) { return new MyDrop(string(s)); }
     public Range     _minus_(char a, char b) { return new Range(a, b); }
     public Range     range(char a)         { return new Range(a, a); }
     public Element   _leftbracket_       (Range[] rr) { return ranges(true, rr); }
@@ -121,19 +139,19 @@ public class MetaGrammar extends ReflectiveWalker {
             for(Range r : rr)
                 if (positive) ret.add(r);
                 else          ret.remove(r);
-        return CharToken.set(ret);
+        return set(ret);
     }
 
-    public static class MyLift {
+    public class MyLift {
         public final String s;
         public MyLift(String s) { this.s = s; }
     }
-    public static class MyDrop {
+    public class MyDrop {
         public final Object o;
         public MyDrop(Object o) { this.o = o; }
     }
 
-    public static class PreSequence {
+    public class PreSequence {
         public PreSequence not(Sequence s) { not.add(s); return this; }
         public PreSequence and(Sequence s) { and.add(s); return this; }
         public final HashSet<Sequence> and  = new HashSet<Sequence>();
@@ -141,6 +159,8 @@ public class MetaGrammar extends ReflectiveWalker {
         public /*final*/ String tag;
         public final Object[] o;
 
+        public PreSequence(Object o) { this(new Object[] { o }, null); }
+        public PreSequence(Object[] o) { this(o, null); }
         public PreSequence(Object[] o, String tag) { this.o = o; this.tag = tag; }
         boolean[] drops = null;
         public Union    buildUnion() {
@@ -154,6 +174,7 @@ public class MetaGrammar extends ReflectiveWalker {
             for(Sequence s : not) u.add(s);
             HashSet<Sequence> set = new HashSet<Sequence>();
             Element[] o2 = o==null ? new Element[0] : new Element[o.length];
+            int nonDrop = 0;
             if (o != null) {
                 drops = new boolean[o.length];
                 int j = 0;
@@ -162,10 +183,11 @@ public class MetaGrammar extends ReflectiveWalker {
                     if (oi instanceof MyDrop)      { oi = ((MyDrop)oi).o; drops[j] = true; }
 
                     if (oi==SELF)                    o2[j] = u.new Subset("(("+u+"))", set);
-                    else if (oi instanceof MyLift) { o2[j] = CharToken.string(tag = ((MyLift)oi).s); drops[j] = true; }
+                    else if (oi instanceof MyLift) { o2[j] = string(tag = ((MyLift)oi).s); drops[j] = o.length>1; }
                     else                             o2[j] = (Element)oi;
 
                     if (MetaGrammar.dropAll.contains(o2[j])) drops[j] = true;
+                    nonDrop += drops[j] ? 0 : 1;
                     o2[j] = o2[j];
                     j++;
                 }