Allow adding causes to lexer and parser exceptions

Not used by SableCC-generated code (yet?), but may be used by other code
that modifies lexer/parser exceptions.

src/main/java/org/sablecc/sablecc/lexer/LexerException.java

@@ -9,14 +9,19 @@ public class LexerException extends Exception
     private final int pos;
     private final String realMsg;
 
-    public LexerException(int line, int pos, String message)
+    public LexerException(int line, int pos, String message, Throwable cause)
     {
-        super("[" + line + "," + pos + "] " + message);
+        super("[" + line + "," + pos + "] " + message, cause);
         this.line = line;
         this.pos = pos;
         this.realMsg = message;
     }
 
+    public LexerException(int line, int pos, String message)
+    {
+        this(line, pos, message, null);
+    }
+
     public LexerException(String message)
     {
         this(0, 0, message);

src/main/java/org/sablecc/sablecc/parser/ParserException.java

@@ -10,13 +10,18 @@ public class ParserException extends Exception
     private final Token token;
     private final String realMsg;
 
-    public ParserException(Token token, String message)
+    public ParserException(Token token, String message, Throwable cause)
     {
-        super("[" + token.getLine() + "," + token.getPos() + "] " + message);
+        super("[" + token.getLine() + "," + token.getPos() + "] " + message, cause);
         this.token = token;
         this.realMsg = message;
     }
 
+    public ParserException(Token token, String message)
+    {
+        this(token, message, (Throwable)null);
+    }
+
     /**
      * @deprecated Use {@link #ParserException(Token, String)} instead.
      *     The token position info is now added automatically to the message.

src/main/resources/org/sablecc/sablecc/lexer.txt

@@ -17,14 +17,19 @@ public class LexerException extends Exception
     private final int pos;
     private final String realMsg;
 
-    public LexerException(int line, int pos, String message)
+    public LexerException(int line, int pos, String message, Throwable cause)
     {
-        super("[" + line + "," + pos + "] " + message);
+        super("[" + line + "," + pos + "] " + message, cause);
         this.line = line;
         this.pos = pos;
         this.realMsg = message;
     }
 
+    public LexerException(int line, int pos, String message)
+    {
+        this(line, pos, message, null);
+    }
+
     public LexerException(String message)
     {
         this(0, 0, message);

src/main/resources/org/sablecc/sablecc/parser.txt

@@ -512,13 +512,18 @@ public class ParserException extends Exception
     private final Token token;
     private final String realMsg;
 
-    public ParserException(Token token, String message)
+    public ParserException(Token token, String message, Throwable cause)
     {
-        super("[" + token.getLine() + "," + token.getPos() + "] " + message);
+        super("[" + token.getLine() + "," + token.getPos() + "] " + message, cause);
         this.token = token;
         this.realMsg = message;
     }
 
+    public ParserException(Token token, String message)
+    {
+        this(token, message, (Throwable)null);
+    }
+
     /**
      * @deprecated Use {@link #ParserException(Token, String)} instead.
      *     The token position info is now added automatically to the message.