X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FParser.java;h=db08afcd22c0afadd2671761384d5a29efcce848;hp=cbf9b479f5bfb7e7fd763c5e08a68dc03ac450a4;hb=a22c5074e705e3ffcf03e9f9d174aed8ef79fc91;hpb=c366dacc334fe2e35835164f5a37d3eebb2ca6d5

diff --git a/src/edu/berkeley/sbp/Parser.java b/src/edu/berkeley/sbp/Parser.java
index cbf9b47..db08afc 100644
--- a/src/edu/berkeley/sbp/Parser.java
+++ b/src/edu/berkeley/sbp/Parser.java
@@ -1,28 +1,27 @@
 package edu.berkeley.sbp;
 import edu.berkeley.sbp.*;
 import edu.berkeley.sbp.util.*;
-import edu.berkeley.sbp.*;
 import edu.berkeley.sbp.Sequence.Position;
-import edu.berkeley.sbp.*;
 import java.io.*;
 import java.util.*;
-import java.lang.reflect.*;
 
 /** a parser which translates streams of Tokens of type T into a Forest<R> */
 public abstract class Parser<T extends Token, R> {
 
-    public final Table pt;
+    private final Table pt;
 
     /** create a parser to parse the grammar with start symbol <tt>u</tt> */
     protected Parser(Union u)  { this.pt = new Table(u, top()); }
-    protected Parser(Table pt) { this.pt = pt; }
+    //protected Parser(Table pt) { this.pt = pt; }
 
+    /** implement this method to create the output forest corresponding to a lone shifted input token */
     public abstract Forest<R> shiftedToken(T t, Token.Location loc);
-    public abstract Topology<T> top();
 
+    /** this method must return an empty topology of the input token type */
+    public abstract Topology<T> top();
 
-    /** parse <tt>input</tt> for a exactly one unique result, throwing <tt>Ambiguous</tt> if not unique or <tt>Failed</tt> if none */
-    public Tree<R> parse1(Token.Stream<T> input) throws IOException, Failed, Ambiguous {
+    /** parse <tt>input</tt> for a exactly one unique result, throwing <tt>Ambiguous</tt> if not unique or <tt>ParseFailed</tt> if none */
+    public Tree<R> parse1(Token.Stream<T> input) throws IOException, ParseFailed, Ambiguous {
         Forest<R> ret = parse(input);
         try { return ret.expand1(); }
         catch (Ambiguous a) {
@@ -33,7 +32,7 @@ public abstract class Parser<T extends Token, R> {
     }
 
     /** parse <tt>input</tt>, using the table <tt>pt</tt> to drive the parser */
-    public Forest<R> parse(Token.Stream<T> input) throws IOException, Failed {
+    public Forest<R> parse(Token.Stream<T> input) throws IOException, ParseFailed {
         GSS gss = new GSS();
         Token.Location loc = input.getLocation();
         GSS.Phase current = gss.new Phase(null, this, null, input.next(1, 0, 0), loc, null);
@@ -53,27 +52,6 @@ public abstract class Parser<T extends Token, R> {
 
     // Exceptions //////////////////////////////////////////////////////////////////////////////
 
-    public static class Failed extends RuntimeException {
-        private final Token.Location location;
-        private final String         message;
-        public Failed() { this("", null); }
-        public Failed(String message, Token.Location loc) { this.location = loc; this.message = message; }
-        public Token.Location getLocation() { return location; }
-        public String toString() { return message/* + (location==null ? "" : (" at " + location))*/; }
-    }
-
-    public static class Ambiguous extends RuntimeException {
-        public final Forest ambiguity;
-        public Ambiguous(Forest ambiguity) { this.ambiguity = ambiguity; }
-        public String toString() {
-            StringBuffer sb = new StringBuffer();
-            sb.append("unresolved ambiguity "/*"at " + ambiguity.getLocation() + ":"*/);
-            for(Object result : ambiguity.expand(false))
-                sb.append("\n    " + result);
-            return sb.toString();
-        }
-    }
-
 
     // Table //////////////////////////////////////////////////////////////////////////////