Created a package for s-expressions and continued refactoring the parser

src/eval/APPLY.java

@@ -7,6 +7,9 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>APPLY</code> represents the APPLY function in Lisp.

src/eval/ATOM.java

@@ -7,6 +7,10 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.Nil;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>ATOM</code> represents the ATOM function in Lisp.

src/eval/CAR.java

@@ -7,6 +7,9 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>CAR</code> represents the CAR function in Lisp.

src/eval/CDR.java

@@ -7,6 +7,9 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>CDR</code> represents the CDR function in Lisp.

src/eval/COND.java

@@ -7,6 +7,9 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.Nil;
+import sexpression.SExpression;
 
 /**
  * <code>COND</code> represents the COND form in Lisp.

src/eval/CONS.java

@@ -7,6 +7,9 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>CONS</code> represents the CONS function in Lisp.

src/eval/DEFUN.java

@@ -7,6 +7,10 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.SExpression;
+import sexpression.Symbol;
+
 import java.util.HashMap;
 
 /**

src/eval/DIVIDE.java

@@ -7,6 +7,10 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.LispNumber;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>DIVIDE</code> represents the '/' function in Lisp.

src/eval/EQ.java

@@ -7,6 +7,10 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.Nil;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>EQ</code> represents the EQ function in Lisp.

src/eval/EQUAL.java

@@ -7,6 +7,10 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.Nil;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>EQUAL</code> represents the EQUAL function in Lisp.

src/eval/EQUALSP.java

@@ -7,6 +7,11 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.LispNumber;
+import sexpression.Nil;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>EQUALSP</code> represents the '=' function in Lisp.

src/eval/EVAL.java

@@ -7,6 +7,11 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.Nil;
+import sexpression.SExpression;
+import sexpression.Symbol;
+
 import java.util.HashMap;
 
 /**

src/eval/EXIT.java

@@ -1,6 +1,9 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 public class EXIT extends LispFunction {
 

src/eval/FUNCALL.java

@@ -7,6 +7,9 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>FUNCALL</code> represents the FUNCALL function in Lisp.

src/eval/GREATERP.java

@@ -7,6 +7,11 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.LispNumber;
+import sexpression.Nil;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>GREATERP</code> represents the '&gt;' function in Lisp.

src/eval/LAMBDA.java

@@ -7,6 +7,9 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>LAMBDA</code> represents the LAMBDA form in Lisp.

src/eval/LENGTH.java

@@ -7,6 +7,10 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.LispNumber;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>LENGTH</code> represents the LENGTH function in Lisp.

src/eval/LESSP.java

@@ -7,6 +7,11 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.LispNumber;
+import sexpression.Nil;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>LESSP</code> represents the '&lt;' function in Lisp.

src/eval/LET.java

@@ -7,6 +7,9 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.Nil;
+import sexpression.SExpression;
 
 /**
  * <code>LET</code> represents the LET form in Lisp.

src/eval/LIST.java

@@ -7,6 +7,9 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.Nil;
+import sexpression.SExpression;
 
 /**
  * <code>LIST</code> represents the LIST function in Lisp.

src/eval/LISTP.java

@@ -7,6 +7,10 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.Nil;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>LISTP</code> represents the LISTP function in Lisp.

src/eval/LOAD.java

@@ -7,6 +7,12 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.LispString;
+import sexpression.Nil;
+import sexpression.SExpression;
+import sexpression.Symbol;
+
 import java.io.*;
 
 /**
@@ -64,9 +70,9 @@ public class LOAD extends LispFunction {
         }
 
         // attempt to evaluate all the S-expressions contained in the file
-        while (! parser.eof()) {
+        while (! parser.isEof()) {
             try {
-                SExpression sexpr = parser.getSExpr();
+                SExpression sexpr = parser.getNextSExpression();
 
                 EVAL.eval(sexpr);
             } catch (RuntimeException e) {

src/eval/LambdaExpression.java

@@ -7,6 +7,8 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.SExpression;
 
 /**
  * This class represents a Lisp FUNCTION in the PL-Lisp implementation.

src/eval/LispFunction.java

@@ -7,6 +7,8 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.SExpression;
 
 /**
  * A <code>LispFunction</code> is an internal representation of a built-in

src/eval/MINUS.java

@@ -7,6 +7,10 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.LispNumber;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>MINUS</code> represents the '-' function in Lisp.

src/eval/MULTIPLY.java

@@ -7,6 +7,9 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.LispNumber;
+import sexpression.SExpression;
 
 /**
  * <code>MULTIPLY</code> represents the '*' function in Lisp.

src/eval/NULL.java

@@ -7,6 +7,10 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.Nil;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>NULL</code> represents the NULL function in Lisp.

src/eval/PLUS.java

@@ -7,6 +7,9 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.LispNumber;
+import sexpression.SExpression;
 
 /**
  * <code>PLUS</code> represents the '+' function in Lisp.

src/eval/PRINT.java

@@ -7,6 +7,9 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>PRINT</code> represents the PRINT function in Lisp.

src/eval/QUOTE.java

@@ -7,6 +7,9 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>QUOTE</code> represents the QUOTE form in Lisp.

src/eval/SETF.java

@@ -7,6 +7,9 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>SETF</code> represents the SETF form in Lisp.

src/eval/SYMBOL_FUNCTION.java

@@ -7,6 +7,9 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.SExpression;
+import sexpression.Symbol;
 
 /**
  * <code>SYMBOL_FUNCTION</code> represents the SYMBOL-FUNCTION function in 

src/eval/SymbolTable.java

@@ -7,6 +7,8 @@
 package eval;
 
 import parser.*;
+import sexpression.SExpression;
+
 import java.util.HashMap;
 
 /**

src/eval/UDFunction.java

@@ -7,6 +7,10 @@
 package eval;
 
 import parser.*;
+import sexpression.Cons;
+import sexpression.SExpression;
+import sexpression.Symbol;
+
 import java.util.ArrayList;
 
 /**

src/main/LispInterpreter.java

@@ -7,6 +7,7 @@
 package main;
 
 import parser.*;
+import sexpression.SExpression;
 import eval.*;
 import error.ErrorManager;
 import error.LispException;
@@ -62,9 +63,9 @@ public class LispInterpreter {
             System.out.print(PROMPT);
         }
 
-        while (! parser.eof()) {
+        while (! parser.isEof()) {
             try {
-                SExpression sexpr = parser.getSExpr();
+                SExpression sexpr = parser.getNextSExpression();
                 String result = MessageFormat.format("{0}{1}{2}", ANSI_GREEN, EVAL.eval(sexpr), ANSI_RESET);
 
                 LispInterpreter.erasePrompt(interactive);

src/parser/LispParser.java

@@ -3,10 +3,9 @@ package parser;
 import java.io.InputStream;
 
 import error.LispException;
-import parser.MalformedSExpressionException.EofEncounteredException;
+import parser.MalformedSExpressionException.*;
-import parser.MalformedSExpressionException.StartsWithRightParenthesisException;
-import parser.MalformedSExpressionException.UnrecognizedTokenException;
 import scanner.LispScanner;
+import sexpression.*;
 import token.Eof;
 import token.Token;
 
@@ -18,37 +17,37 @@ public class LispParser {
 
     private LispScanner scanner;
     private Token nextToken;
-    private boolean nextTokenStored;
+    private boolean isNextTokenStored;
 
     public LispParser(InputStream inputStream, String fileName) {
         scanner = new LispScanner(inputStream, fileName);
         nextToken = null;
-        nextTokenStored = false;
+        isNextTokenStored = false;
     }
 
-    public boolean eof() {
+    public boolean isEof() {
-        if (!nextTokenStored) {
+        if (!isNextTokenStored)
-            try {
+            storeNextToken();
-                nextToken = scanner.getNextToken();
-                nextTokenStored = true;
-            } catch (LispException e) {
-                // this method should give the illusion of not actually reading
-                // a token, so we ignore any exceptions (they will be thrown
-                // the next time the 'getSExpr' method is called)
-
-                if (nextToken == null)
-                    return false;
-            }
-        }
 
         return nextToken instanceof Eof;
     }
 
-    public SExpression getSExpr() {
+    private void storeNextToken() {
-        if (!nextTokenStored)
+        try {
+            nextToken = scanner.getNextToken();
+            isNextTokenStored = true;
+        } catch (LispException e) {
+            // This method should give the illusion of not actually reading
+            // a token, so we ignore any exception. It will be thrown when we
+            // return the next sExpression.
+        }
+    }
+
+    public SExpression getNextSExpression() {
+        if (!isNextTokenStored)
             nextToken = scanner.getNextToken();
         else
-            nextTokenStored = false;
+            isNextTokenStored = false;
 
         return sExpr();
     }

src/sexpression/Atom.java

@@ -4,7 +4,7 @@
  * Assignment: Lisp Parser
  */
 
-package parser;
+package sexpression;
 
 /**
  * This class represents an ATOM in the PL-Lisp implementation.

src/sexpression/Cons.java

@@ -4,7 +4,7 @@
  * Assignment: Lisp Parser
  */
 
-package parser;
+package sexpression;
 
 /**
  * This class represents a Lisp CONS cell in the PL-Lisp implementation.

src/sexpression/LispNumber.java

@@ -4,7 +4,7 @@
  * Assignment: Lisp Parser
  */
 
-package parser;
+package sexpression;
 
 /**
  * This class represents a NUMBER in the PL-Lisp implementation.

src/sexpression/LispString.java

@@ -4,7 +4,7 @@
  * Assignment: Lisp Parser
  */
 
-package parser;
+package sexpression;
 
 /**
  * This class represents a STRING in the PL-Lisp implementation.

src/sexpression/Nil.java

@@ -4,7 +4,7 @@
  * Assignment: Lisp Parser
  */
 
-package parser;
+package sexpression;
 
 /**
  * This class represents NIL in the PL-Lisp implementation.

src/sexpression/SExpression.java

@@ -4,7 +4,7 @@
  * Assignment: Lisp Parser
  */
 
-package parser;
+package sexpression;
 
 /**
  * This is the base class for memory in the PL-Lisp implementation.

src/sexpression/Symbol.java

@@ -4,7 +4,7 @@
  * Assignment: Lisp Parser
  */
 
-package parser;
+package sexpression;
 
 /**
  * This class represents a SYMBOL in the PL-Lisp implementation.

test/parser/LispParserTester.java

@@ -7,6 +7,8 @@ import java.io.InputStream;
 import org.junit.Test;
 
 import error.LispException;
+import sexpression.Nil;
+import sexpression.SExpression;
 import testutils.TestUtilities;
 
 public class LispParserTester {
@@ -79,7 +81,7 @@ public class LispParserTester {
         String input = "";
         LispParser parser = createLispParser(input);
 
-        assertTrue(parser.eof());
+        assertTrue(parser.isEof());
     }
 
     @Test
@@ -87,40 +89,40 @@ public class LispParserTester {
         String input = "abc";
         LispParser parser = createLispParser(input);
 
-        assertFalse(parser.eof());
+        assertFalse(parser.isEof());
     }
 
     @Test
     public void testEofMethod_ReturnsTrueAfterSomeInput() {
         String input = "(yyz 9 9 9)";
         LispParser parser = createLispParser(input);
-        parser.getSExpr();
+        parser.getNextSExpression();
 
-        assertTrue(parser.eof());
+        assertTrue(parser.isEof());
     }
 
     @Test
     public void testEofMethod_ReturnsFalseAfterMultipleExpressions() {
         String input = "()()()";
         LispParser parser = createLispParser(input);
-        assertFalse(parser.eof());
+        assertFalse(parser.isEof());
-        parser.getSExpr();
+        parser.getNextSExpression();
-        assertFalse(parser.eof());
+        assertFalse(parser.isEof());
-        parser.getSExpr();
+        parser.getNextSExpression();
-        assertFalse(parser.eof());
+        assertFalse(parser.isEof());
     }
 
     @Test
     public void testEofMethod_ReturnsTrueAfterMultipleExpressions() {
         String input = "()()()";
         LispParser parser = createLispParser(input);
-        assertFalse(parser.eof());
+        assertFalse(parser.isEof());
-        parser.getSExpr();
+        parser.getNextSExpression();
-        assertFalse(parser.eof());
+        assertFalse(parser.isEof());
-        parser.getSExpr();
+        parser.getNextSExpression();
-        assertFalse(parser.eof());
+        assertFalse(parser.isEof());
-        parser.getSExpr();
+        parser.getNextSExpression();
-        assertTrue(parser.eof());
+        assertTrue(parser.isEof());
     }
 
     @Test
@@ -128,7 +130,7 @@ public class LispParserTester {
         String input = "()";
         LispParser parser = createLispParser(input);
 
-        assertNil(parser.getSExpr());
+        assertNil(parser.getNextSExpression());
     }
 
     @Test
@@ -136,7 +138,7 @@ public class LispParserTester {
         String input = "12";
         LispParser parser = createLispParser(input);
 
-        assertNumber(parser.getSExpr());
+        assertNumber(parser.getNextSExpression());
     }
 
     @Test
@@ -144,7 +146,7 @@ public class LispParserTester {
         String input = "identifier1";
         LispParser parser = createLispParser(input);
 
-        assertSymbol(parser.getSExpr());
+        assertSymbol(parser.getNextSExpression());
     }
 
     @Test
@@ -152,7 +154,7 @@ public class LispParserTester {
         String input = "\"string\"";
         LispParser parser = createLispParser(input);
 
-        assertString(parser.getSExpr());
+        assertString(parser.getNextSExpression());
     }
 
     @Test
@@ -160,7 +162,7 @@ public class LispParserTester {
         String input = "(1 2)";
         LispParser parser = createLispParser(input);
 
-        assertList(parser.getSExpr());
+        assertList(parser.getNextSExpression());
     }
 
     @Test
@@ -168,8 +170,8 @@ public class LispParserTester {
         String input = "'quoted";
         LispParser parser = createLispParser(input);
 
-        assertList(parser.getSExpr());
+        assertList(parser.getNextSExpression());
-        assertTrue(parser.eof());
+        assertTrue(parser.isEof());
     }
 
     @Test
@@ -177,8 +179,8 @@ public class LispParserTester {
         String input = "(defun f (x) \n (print \n (list \"x is \" x) \n ) \n )";
         LispParser parser = createLispParser(input);
 
-        assertList(parser.getSExpr());
+        assertList(parser.getNextSExpression());
-        assertTrue(parser.eof());
+        assertTrue(parser.isEof());
     }
 
     @Test
@@ -186,12 +188,12 @@ public class LispParserTester {
         String input = "(setf x 2) x \"hi\" () 29";
         LispParser parser = createLispParser(input);
 
-        assertList(parser.getSExpr());
+        assertList(parser.getNextSExpression());
-        assertSymbol(parser.getSExpr());
+        assertSymbol(parser.getNextSExpression());
-        assertString(parser.getSExpr());
+        assertString(parser.getNextSExpression());
-        assertNil(parser.getSExpr());
+        assertNil(parser.getNextSExpression());
-        assertNumber(parser.getSExpr());
+        assertNumber(parser.getNextSExpression());
-        assertTrue(parser.eof());
+        assertTrue(parser.isEof());
     }
 
     @Test
@@ -199,11 +201,11 @@ public class LispParserTester {
         String input = "()";
         LispParser parser = createLispParser(input);
 
-        parser.eof();
+        parser.isEof();
-        parser.eof();
+        parser.isEof();
 
-        assertNil(parser.getSExpr());
+        assertNil(parser.getNextSExpression());
-        assertTrue(parser.eof());
+        assertTrue(parser.isEof());
     }
 
     @Test(expected = LispException.class)
@@ -211,7 +213,7 @@ public class LispParserTester {
         String input = "[";
         LispParser parser = createLispParser(input);
 
-        parser.getSExpr();
+        parser.getNextSExpression();
     }
 
     @Test(expected = LispException.class)
@@ -219,7 +221,7 @@ public class LispParserTester {
         String input = "\"string";
         LispParser parser = createLispParser(input);
 
-        parser.getSExpr();
+        parser.getNextSExpression();
     }
 
     @Test(expected = LispException.class)
@@ -227,7 +229,7 @@ public class LispParserTester {
         String input = "(bad list";
         LispParser parser = createLispParser(input);
 
-        parser.getSExpr();
+        parser.getNextSExpression();
     }
 
     @Test(expected = LispException.class)
@@ -235,7 +237,7 @@ public class LispParserTester {
         String input = ")";
         LispParser parser = createLispParser(input);
 
-        parser.getSExpr();
+        parser.getNextSExpression();
     }
 
     @Test(expected = LispException.class)
@@ -244,27 +246,42 @@ public class LispParserTester {
         LispParser parser = createLispParser(input);
 
         try {
-            parser.eof();
+            parser.isEof();
         } catch (LispException e) {
             fail("Exception thrown too early");
         }
 
-        parser.getSExpr();
+        parser.getNextSExpression();
     }
 
     @Test(expected = LispException.class)
     public void givenBadCharacterAfterValidToken_ThrowsExceptionAtTheCorrectTime() {
-        String input = "id[]";
+        String input = "id[";
         LispParser parser = createLispParser(input);
 
         try {
-            parser.getSExpr();
+            parser.getNextSExpression();
-            parser.eof();
+            parser.isEof();
         } catch (LispException e) {
             fail("Exception thrown too early");
         }
 
-        parser.getSExpr();
+        parser.getNextSExpression();
     }
 
+    @Test
+    public void afterException_ReturnsEofCorrectly() {
+        String input = "id[";
+        LispParser parser = createLispParser(input);
+        parser.getNextSExpression();
+        parser.isEof();
+
+        try {
+            parser.getNextSExpression();
+            fail("Expected LispException");
+        } catch (LispException e) {
+        }
+        
+        assertTrue(parser.isEof());
+    }
 }