Function lookup and calling implemented. Some SpecialForms implemented.

Special forms:
    DEFUN
    SETQ
    +
    -
    *
    /

src/edu/utexas/cs345/jdblisp/FormEntry.java

@@ -0,0 +1,9 @@
+package edu.utexas.cs345.jdblisp;
+
+/**
+ * FormEntry
+ * @author Jonathan Bernard(jdbernard@gmail.com)
+ */
+public interface FormEntry {
+    SExp call(SymbolTable table, Seq arguments) throws LispException;
+}

src/edu/utexas/cs345/jdblisp/FunctionEntry.java

@@ -4,7 +4,7 @@ package edu.utexas.cs345.jdblisp;
  * FunctionEntry
  * @author Jonathan Bernard (jdbernard@gmail.com)
  */
-public class FunctionEntry {
+public class FunctionEntry implements FormEntry {
 
     protected final Symbol[] parameters;
     protected final SExp body;

src/edu/utexas/cs345/jdblisp/Lisp.java

@@ -68,7 +68,12 @@ public class Lisp {
                 continue;
             }
 
+            try {
                 out.println(sexp.display("  "));
+                out.println(sexp.eval(globalSymbolTable));
+            } catch (LispException le) {
+                out.println(le.getLocalizedMessage());
+            }
 
             // print prompt if applicable
             if (interactive) {
@@ -77,6 +82,9 @@ public class Lisp {
             }
 
         }
+
+        out.println("\nLeaving JDB-LISP");
+        out.flush();
     }
 
 }

src/edu/utexas/cs345/jdblisp/List.java

@@ -12,7 +12,7 @@ public class List implements SExp {
     }
 
     /** {@inheritdoc}*/
-    public SymbolTable eval(SymbolTable table) throws LispException {
+    public SExp eval(SymbolTable table) throws LispException {
         // if the car of the sequence is a symbol, 
         if (seq.car instanceof Symbol) {
             // then that symbol is the name of an operator
@@ -24,10 +24,10 @@ public class List implements SExp {
             // a function form
 
             // look up in the symbol table
-            FunctionEntry functionEntry = table.lookupFunction((Symbol) seq.car);
+            FormEntry functionEntry = table.lookupFunction((Symbol) seq.car);
 
             // call function
-            return functionEntry.call(table);
+            return functionEntry.call(table, seq.cdr);
 
         }
 

src/edu/utexas/cs345/jdblisp/Num.java

@@ -8,10 +8,10 @@ import java.math.BigInteger;
  */
 public class Num implements SExp {
 
-    private Number n;
+    private BigDecimal n;
 
     public Num(String string) {
-        try { n = Short.parseShort(string); return; }
+        /*try { n = Short.parseShort(string); return; }
         catch (NumberFormatException nfe) {}
 
         try { n = Integer.parseInt(string); return; }
@@ -28,20 +28,18 @@ public class Num implements SExp {
 
         try { n = Double.parseDouble(string); return; }
         catch (NumberFormatException nfe) {}
-
+*/
         try { n = new BigDecimal(string); return; }
         catch (NumberFormatException nfe) {
-            throw new LispException("Cannot parse number: " + string);
+            assert(false);
         }
     }
 
+    public Num(BigDecimal n) { this.n = n; }
+
     /** {@inheritdoc} */
     public SExp eval(SymbolTable table) {
-        return new SymbolTable(
-            new TableEntry(
-                new Symbol("RETURN-VAL"),
-                null,
-                this));
+        return this;
     }
 
     public String display(String offset) {
@@ -52,4 +50,28 @@ public class Num implements SExp {
     public String toString() {
         return n.toString();
     }
+
+    public Num add(Num addend) {
+        return new Num(n.add(addend.n));
+    }
+
+    public Num subtract(Num subtrahend) {
+        return new Num(n.subtract(subtrahend.n));
+    }
+
+    public Num multiply(Num multiplicand) {
+        return new Num(n.multiply(multiplicand.n));
+    }
+
+    public Num divideBy(Num divisor) {
+        return new Num(n.divide(divisor.n));
+    }
+
+    public Num negate() {
+        return new Num(n.negate());
+    }
+
+    public Num abs() {
+        return new Num(n.abs());
+    }
 }

src/edu/utexas/cs345/jdblisp/SExp.java

@@ -11,7 +11,7 @@ public interface SExp {
      * @param table The SymbolTable context for this scope.
      * @return A SymbolTable containing the reutrn value.
      */
-    SymbolTable eval(SymbolTable table) throws LispException;
+    SExp eval(SymbolTable table) throws LispException;
 
     String display(String offset);
 

src/edu/utexas/cs345/jdblisp/Seq.java

@@ -25,7 +25,7 @@ public class Seq implements SExp {
     }
 
     /** {@inheritdoc}*/
-    public SymbolTable eval(SymbolTable table) {
+    public SExp eval(SymbolTable table) {
         assert(false) : "Attempted to eval() a Seq.";
         throw new UnsupportedOperationException("Attempted to eval a Seq.");
     }

src/edu/utexas/cs345/jdblisp/SpecialFormEntry.java

@@ -6,7 +6,7 @@ import java.util.ArrayList;
  * SpecialFormEntry
  * @author Jonathan Bernard (jdbernard@gmail.com)
  */
-public abstract class SpecialFormEntry extends FunctionEntry {
+public abstract class SpecialFormEntry implements FormEntry {
 
     protected Lisp environment;
 
@@ -21,7 +21,7 @@ public abstract class SpecialFormEntry extends FunctionEntry {
             public SExp call(SymbolTable symbolTable, Seq arguments) throws LispException {
 
                 Symbol functionName;
-                ArrayList<Symbol> parameters;
+                ArrayList<Symbol> parameters = new ArrayList<Symbol>();
                 SExp body;
 
                 // TODO: check to see if a function for this symbol exists
@@ -40,18 +40,17 @@ public abstract class SpecialFormEntry extends FunctionEntry {
                 arguments = arguments.cdr;
                 assert (arguments != null);
                 
-                if (!(arguments.car instanceof List))
+                //if (!(arguments.car instanceof List))
                     // TODO: error, need parameter list
 
                 // read parameters
-                parameters = new ArrayList<Symbol>();
                 Seq paramSeq = ((List) arguments.car).seq;
-                while (seq != null) {
-                    if (!(seq.car instanceof Symbol))
-                        throw new TypeException(seq.car, Symbol.class);
+                while (paramSeq != null) {
+                    if (!(paramSeq.car instanceof Symbol))
+                        throw new TypeException(paramSeq.car, Symbol.class);
 
-                    parameters.add((Symbol) seq.car);
-                    seq = seq.cdr;
+                    parameters.add((Symbol) paramSeq.car);
+                    paramSeq = paramSeq.cdr;
                 }
 
                 // third argument: function body
@@ -62,7 +61,7 @@ public abstract class SpecialFormEntry extends FunctionEntry {
                 
                 body = arguments.car;
 
-                environment.globalSymbolTable.define(functionName,
+                environment.globalSymbolTable.bind(functionName,
                     new FunctionEntry(parameters.toArray(new Symbol[]{}), body));
 
                 return functionName;
@@ -82,7 +81,7 @@ public abstract class SpecialFormEntry extends FunctionEntry {
                         arguments.length());
 
                 // first argument: Symbol for variable name
-                if (!(arguments.car instanceof Symbol))
+                //if (!(arguments.car instanceof Symbol))
                     // TODO: error: expected symbol
 
                 variableName = (Symbol) arguments.car;
@@ -92,10 +91,134 @@ public abstract class SpecialFormEntry extends FunctionEntry {
                 assert (arguments != null);
 
                 variableValue = arguments.car;
+
+                environment.globalSymbolTable.bind(variableName,
+                    new VariableEntry(variableValue));
+
+                return variableValue;
             }
         };
 
-        environment.globalSymbolTable.defin(new Symbol("DEFUN"), DEFUN);
-        environment.globalSymbolTable.defin(new Symbol("SETQ"), SETQ);
+        SpecialFormEntry SUM = new SpecialFormEntry(environment) {
+            public SExp call(SymbolTable symbolTable, Seq arguments)
+            throws LispException {
+
+                Num sum = new Num("0");
+
+                // variable number of arguments [0..inf)
+                while (arguments != null) {
+                    try {
+                        sum = sum.add((Num) arguments.car.eval(symbolTable));
+                    } catch (ClassCastException cce) {
+                        throw new TypeException(arguments.car, Num.class);
+                    }
+                }
+
+                return sum;
+            }
+        };
+
+        SpecialFormEntry DIF = new SpecialFormEntry(environment) {
+            public SExp call(SymbolTable symbolTable, Seq arguments)
+            throws LispException {
+
+                Num difference = new Num("0");
+
+                // need at least one argument
+                if (arguments == null)
+                    throw new InvalidArgumentQuantityException(1, 0);
+
+                // case: only one argument: 0 - arg
+                try {
+                    difference = difference.subtract(
+                        (Num) arguments.car.eval(symbolTable));
+                } catch (ClassCastException cce) {
+                    throw new TypeException(arguments.car, Num.class);
+                }
+
+                arguments = arguments.cdr;
+                if (arguments == null) return difference;
+
+                // case: (- x y1 ... yn)
+                difference = difference.negate();
+
+                // variable number of arguments [0..inf)
+                while (arguments != null)  {
+                    try {
+                        difference = difference.subtract(
+                            (Num) arguments.car.eval(symbolTable));
+                    } catch (ClassCastException cce) {
+                        throw new TypeException(arguments.car, Num.class);
+                    }
+                }
+
+                return difference;
+            }
+        };
+
+        SpecialFormEntry MUL = new SpecialFormEntry(environment) {
+            public SExp call(SymbolTable symbolTable, Seq arguments)
+            throws LispException {
+
+                Num product = new Num("1");
+
+                // variable number of arguments [0..inf)
+                while (arguments != null) {
+                    try {
+                        product = product.multiply(
+                            (Num) arguments.car.eval(symbolTable));
+                    } catch (ClassCastException cce) {
+                        throw new TypeException(arguments.car, Num.class);
+                    }
+                }
+
+                return product;
+            }
+        };
+
+        SpecialFormEntry DIV = new SpecialFormEntry(environment) {
+            public SExp call(SymbolTable symbolTable, Seq arguments)
+            throws LispException {
+
+                Num dividend = new Num("1");
+                Num firstArg;
+
+                if (arguments == null)
+                    throw new InvalidArgumentQuantityException(1, 0);
+
+                // case: only one argument: 1 / arg
+                try { firstArg = (Num) arguments.car.eval(symbolTable); }
+                catch (ClassCastException cce) {
+                    throw new TypeException(arguments.car, Num.class);
+                }
+
+                dividend = dividend.divideBy(firstArg);
+
+                arguments = arguments.cdr;
+                if (arguments == null) return dividend;
+
+                // case: (/ x y1 ... yn)
+                dividend = firstArg;
+
+                // variable number of arguments [0..inf)
+                while (arguments != null) {
+                    try {
+                        dividend = dividend.divideBy(
+                            (Num) arguments.car.eval(symbolTable));
+                    } catch (ClassCastException cce) {
+                        throw new TypeException(arguments.car, Num.class);
+                    }
+                }
+
+                return dividend;
+            }
+        };
+
+        environment.globalSymbolTable.bind(new Symbol("DEFUN"), DEFUN);
+        environment.globalSymbolTable.bind(new Symbol("SETQ"), SETQ);
+        environment.globalSymbolTable.bind(new Symbol("+"), SUM);
+        environment.globalSymbolTable.bind(new Symbol("-"), DIF);
+        environment.globalSymbolTable.bind(new Symbol("*"), MUL);
+        environment.globalSymbolTable.bind(new Symbol("/"), DIV);
     }
 }

src/edu/utexas/cs345/jdblisp/Str.java

@@ -12,13 +12,7 @@ public class Str implements SExp {
     }
 
     /** {@inheritdoc}*/
-    public SymbolTable eval(SymbolTable table) {
-        return new SymbolTable(
-            new TableEntry(
-                "RETURN-VAL",
-                null,
-                this));
-    }
+    public SExp eval(SymbolTable table) { return this; }
 
     public String display(String offset) {
         return offset + "Str: " + value + "\n";

src/edu/utexas/cs345/jdblisp/Symbol.java

@@ -11,7 +11,7 @@ public class Symbol implements SExp {
     }
 
     /** {@inheritdoc}*/
-    public SymbolTable eval(SymbolTable table) {
+    public SExp eval(SymbolTable table) {
         // TODO
         return null;
     }

src/edu/utexas/cs345/jdblisp/SymbolTable.java

@@ -9,7 +9,7 @@ import java.util.Map;
  */
 public class SymbolTable {
 
-    private Map<Symbol, FunctionEntry> functions = new HashMap<Symbol, FunctionEntry>();
+    private Map<Symbol, FormEntry> functions = new HashMap<Symbol, FormEntry>();
     private Map<Symbol, VariableEntry> variables = new HashMap<Symbol, VariableEntry>();
     private SymbolTable enclosingTable;
     private boolean locked = false;
@@ -23,7 +23,7 @@ public class SymbolTable {
         this.locked = locked;
     }
 
-    public Symbol bind(Symbol s, FunctionEntry f) {
+    public Symbol bind(Symbol s, FormEntry f) {
         if (functions.get(s) != null) {
             // TODO: warning: function redefinition
             // Also, check access permissions
@@ -42,8 +42,8 @@ public class SymbolTable {
         return s;
     }
 
-    public FunctionEntry lookupFunction(Symbol s) throws LispException {
-        FunctionEntry fe = functions.get(s);
+    public FormEntry lookupFunction(Symbol s) throws LispException {
+        FormEntry fe = functions.get(s);
 
         // found function definition
         if (fe != null) return fe;