Finished initial version of AbstractSyntax

build.xml

@@ -41,7 +41,9 @@
         <javac
             srcdir="${src.dir}"
             destdir="${build.dir}"
-            classpathref="javac.path"/>
+            classpathref="javac.path"
+            debug="on"
+            debuglevel="source,vars,lines"/>
 
     </target>
 

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

@@ -1,11 +1,81 @@
 package edu.utexas.cs345.jdblisp;
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.PrintWriter;
+import java.util.Scanner;
+
+import edu.utexas.cs345.jdblisp.parser.Parser;
+import edu.utexas.cs345.jdblisp.parser.ParseException;
+
 /**
  * @author Jonathan Bernard (jdbernard@gmail.com)
  */
 public class Lisp {
 
-    public static void main(String[] args) {
+    private Parser parser;
+    private SymbolTable globalSymbolTable;
+    private boolean interactive = true;
 
+    public Lisp() {
+        this(true);
+    }
+
+    public Lisp(boolean interactive) {
+        this.interactive = interactive;
+        Parser parser = new Parser(new ByteArrayInputStream(new byte[]{}));
+    }
+
+    public static void main(String[] args) {
+        Lisp lisp = new Lisp();
+        lisp.repl(System.in, System.out);
+        globalSymbolTable = SpecialForms.createSymbolTable();
+    }
+
+    public void repl(InputStream is, OutputStream os) {
+
+        // wrap input and output in more friendly objects
+        Scanner in = new Scanner(is);
+        PrintWriter out = new PrintWriter(os);
+
+        // print prompt if applicable
+        if (interactive) {
+            out.print("> ");
+            out.flush();
+        }
+
+        // read each line of input
+        while(in.hasNextLine()) {
+
+            // get line
+            String line = in.nextLine();
+
+            // stuff it into an input buffer for the parser
+            ByteArrayInputStream bin = new ByteArrayInputStream(line.getBytes());
+
+            // re-init the parser with the new stream
+            parser.ReInit(bin);
+
+            // parse the line
+            SExp sexp;
+            try { sexp = parser.sexp(); }
+            catch (ParseException pe) {
+                // TODO
+                out.println(pe.getLocalizedMessage());
+                continue;
+            }
+
+            out.println(sexp.display("  "));
+            out.println(sexp.eval(globalSymbolTable).car.body);
+
+            // print prompt if applicable
+            if (interactive) {
+                out.print("> ");
+                out.flush();
+            }
+
+        }
     }
 
 }

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

@@ -0,0 +1,15 @@
+package edu.utexas.cs345.jdblisp;
+
+/**
+ * LispException
+ */
+public class LispException extends Exception {
+
+    public LispException(String message) {
+        this(message, null);
+    }
+
+    public LispException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

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

@@ -0,0 +1,58 @@
+package edu.utexas.cs345.jdblisp;
+
+/**
+ * @author Jonathan Bernard (jdbernard@gmail.com)
+ */
+public class List implements SExp {
+    public final Seq seq;
+
+    public List(Seq seq) {
+        this.seq = seq;
+    }
+
+    /** {@inheritdoc}*/
+    public SymbolTable 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
+            // Depending on the funciton binding of the operator in the
+            // current lexical environment the form is either:
+            // a special form
+            // a macro form or
+            // a function form
+
+            // look up in the symbol table
+            TableEntry functionEntry = table.findFunction((Symbol) seq.car);
+
+            // check parameter length
+            if (functionEntry.parameters.length != seq.cdr.length())
+                throw new LispException("Invalid number of parameters: "
+                    + seq.cdr.length());
+
+            // create a new SymbolTable and bind arguments to parameters
+            SymbolTable newTable = table;
+            Seq nextArg = seq.cdr;
+            for (Symbol parameter : functionEntry.parameters) {
+                TableEntry newEntry = new TableEntry(parameter, null, nextArg.car);
+                newTable = new SymbolTable(newEntry, newTable);
+                nextArg = nextArg.cdr;
+            }
+
+            // call function
+            return functionEntry.body.eval(newTable);
+
+        }
+
+        return null;
+    }
+
+    public String display(String offset) {
+        StringBuilder sb = new StringBuilder();
+        sb.append(offset);
+        sb.append("List: \n");
+        if (seq == null) sb.append(offset + "  NIL\n");
+        else sb.append(seq.display(offset + "  "));
+        return sb.toString();
+    }
+
+}

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

@@ -0,0 +1,54 @@
+package edu.utexas.cs345.jdblisp;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+
+/**
+ * @author Jonathan Bernard (jdbernard@gmail.com)
+ */
+public class Num implements SExp {
+
+    private Number n;
+
+    public Num(String string) {
+        try { n = Short.parseShort(string); return; }
+        catch (NumberFormatException nfe) {}
+
+        try { n = Integer.parseInt(string); return; }
+        catch (NumberFormatException nfe) {}
+
+        try { n = Long.parseLong(string); return; }
+        catch (NumberFormatException nfe) {}
+
+        try { n = new BigInteger(string); return; }
+        catch (NumberFormatException nfe) {}
+
+        try { n = Float.parseFloat(string); return; }
+        catch (NumberFormatException nfe) {}
+
+        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);
+        }
+    }
+
+    /** {@inheritdoc} */
+    public SymbolTable eval(SymbolTable table) {
+        return new SymbolTable(
+            new TableEntry(
+                new Symbol("RETURN-VAL"),
+                null,
+                this));
+    }
+
+    public String display(String offset) {
+        return offset + "Num: " + n.toString() + "\n";
+    }
+
+    public String toString() {
+        return n.toString();
+    }
+}

src/edu/utexas/cs345/jdblisp/Parser.jj

@@ -8,7 +8,7 @@ options {
 PARSER_BEGIN(Parser)
 package edu.utexas.cs345.jdblisp.parser;
 
-import edu.utexas.cs345.jdblisp.data.*;
+import edu.utexas.cs345.jdblisp.*;
 public class Parser {
 
 }
@@ -44,9 +44,9 @@ TOKEN : /* LITERALS & SYMBOLS */
 SExp sexp():
 {	SExp s = null; Token t;
 }
-{     t = <SYMB> { return new Symbol(t); }
+{     t = <SYMB> { return new Symbol(t.image.toUpperCase()); }
-    | t = <STRG> { return new Str(t); }
+    | t = <STRG> { return new Str(t.image); }
-    | t = <NUMB> { return new Num(t); }
+    | t = <NUMB> { return new Num(t.image); }
     | s = list() { return s; }     
 }
 
@@ -56,7 +56,7 @@ SExp sexp():
 List list(): 
 {	Seq s;
 }
-{ <LPAREN>  s = seq() <RPAREN> { return (s == null) ? null : new List(s); }    
+{ <LPAREN>  s = seq() <RPAREN> { return new List(s); }    
 }
 
 /**

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

@@ -0,0 +1,18 @@
+package edu.utexas.cs345.jdblisp;
+
+/**
+ * SExp
+ * @author Jonathan Bernard (jdbernard@gmail.com)
+ */
+public interface SExp {
+
+    /**
+     * Evaluate this SExp within the context of the given SymbolTable.
+     * @param table The SymbolTable context for this scope.
+     * @return A SymbolTable containing the reutrn value.
+     */
+    SymbolTable eval(SymbolTable table) throws LispException;
+
+    String display(String offset);
+
+}

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

@@ -0,0 +1,49 @@
+package edu.utexas.cs345.jdblisp;
+
+/**
+ * Seq
+ * @author Jonathan Bernard (jdbernard@gmail.com)
+ */
+public class Seq implements SExp {
+
+    public final SExp car;
+    public final Seq cdr;
+
+    public Seq(SExp car, Seq cdr) {
+        assert (car != null);
+        this.car = car;
+        this.cdr = cdr;
+    }
+
+    public Seq(SExp... elements) {
+        int idx = elements.length;
+        Seq last = null;
+        while (idx > 1) last = new Seq(elements[--idx], last);
+
+        this.car = elements[0];
+        this.cdr = last;
+    }
+
+    /** {@inheritdoc}*/
+    public SymbolTable eval(SymbolTable table) {
+        assert(false) : "Attempted to eval() a Seq.";
+        throw new UnsupportedOperationException("Attempted to eval a Seq.");
+    }
+
+    public int length() {
+        if (cdr == null) return 1;
+        return 1 + cdr.length();
+    }
+
+    public String display(String offset) {
+        StringBuilder sb = new StringBuilder();
+        sb.append(offset);
+        sb.append("Seq: \n");
+        
+        sb.append(car.display(offset + "  "));
+
+        if (cdr != null) sb.append(cdr.display(offset));
+
+        return sb.toString();
+    }
+}

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

@@ -0,0 +1,30 @@
+package edu.utexas.cs345.jdblisp;
+
+/**
+ * @author Jonathan Bernard (jdbernard@gmail.com)
+ */
+public class Str implements SExp {
+
+    public final String value;
+
+    public Str(String value) {
+        this.value = value;
+    }
+
+    /** {@inheritdoc}*/
+    public SymbolTable eval(SymbolTable table) {
+        return new SymbolTable(
+            new TableEntry(
+                "RETURN-VAL",
+                null,
+                this));
+    }
+
+    public String display(String offset) {
+        return offset + "Str: " + value + "\n";
+    }
+
+    public String toString() {
+        return value;
+    }
+}

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

@@ -1,4 +1,5 @@
-package edu.utexas.cs345.jdblisp.data;
+package edu.utexas.cs345.jdblisp;
+
 /**
  * @author Jonathan Bernard (jdbernard@gmail.com)
  */
@@ -9,8 +10,13 @@ public class Symbol implements SExp {
         this.name = name;
     }
 
-    public SExp eval(SExp sexp, SymbolTable table) {
+    /** {@inheritdoc}*/
+    public SymbolTable eval(SymbolTable table) {
         // TODO
         return null;
     }
+
+    public String display(String offset) {
+        return offset + "Symbol: " + name + "\n";
+    }
 }

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

@@ -1,17 +0,0 @@
-package edu.utexas.cs345.jdblisp.data;
-/**
- * @author Jonathan Bernard (jdbernard@gmail.com)
- */
-public class List implements SExp {
-    public final Seq<SExp> seq;
-
-    public List(Seq<SExp> seq) {
-        this.seq = seq;
-    }
-
-    public SExp eval(SExp sexp, SymbolTable table) {
-        // TODO
-        return null;
-    }
-
-}

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

@@ -1,16 +0,0 @@
-package edu.utexas.cs345.jdblisp.data;
-/**
- * @author Jonathan Bernard (jdbernard@gmail.com)
- */
-public class Num implements SExp {
-
-    public Num(String n) {
-        // TODO
-    }
-
-    public SExp eval(SExp sexp, SymbolTable table) {
-        // TODO
-        return null;
-    }
-
-}

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

@@ -1,9 +0,0 @@
-package edu.utexas.cs345.jdblisp.data;
-/**
- * SExp
- * @author Jonathan Bernard (jdbernard@gmail.com)
- */
-public interface SExp {
-
-    SymbolTable eval(SExp sexp, SymbolTable table);
-}

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

@@ -1,29 +0,0 @@
-package edu.utexas.cs345.jdblisp.data;
-/**
- * Seq
- * @author Jonathan Bernard (jdbernard@gmail.com)
- */
-public class Seq<T extends SExp> implements SExp {
-
-    public final T car;
-    public final Seq<T> cdr;
-
-    public Seq(T car, Seq<T> cdr) {
-        this.car = car;
-        this.cdr = cdr;
-    }
-
-    public Seq(T... elements) {
-        int idx = elements.length;
-        Seq last = null;
-        while (idx > 1) last = new Seq(elements[--idx], last);
-
-        this.car = elements[0];
-        this.cdr = last;
-    }
-
-    public SExp eval(SExp sexp, SymbolTable table) {
-        // TODO
-        return null;
-    }
-}

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

@@ -1,11 +0,0 @@
-package edu.utexas.cs345.jdblisp.data;
-/**
- * @author Jonathan Bernard (jdbernard@gmail.com)
- */
-public class Str implements SExp {
-
-    public SExp eval(SExp sexp, SymbolTable table) {
-        // TODO
-        return null;
-    }
-}

src/edu/utexas/cs345/jdblisp/parser/Parser.java

@@ -1,7 +1,7 @@
 /* Generated By:JavaCC: Do not edit this line. Parser.java */
 package edu.utexas.cs345.jdblisp.parser;
 
-import edu.utexas.cs345.jdblisp.data.*;
+import edu.utexas.cs345.jdblisp.*;
 public class Parser implements ParserConstants {
 
 /**
@@ -12,15 +12,15 @@ public class Parser implements ParserConstants {
     switch ((jj_ntk==-1)?jj_ntk():jj_ntk) {
     case SYMB:
       t = jj_consume_token(SYMB);
-                   {if (true) return new Symbol(t);}
+                   {if (true) return new Symbol(t.image.toUpperCase());}
       break;
     case STRG:
       t = jj_consume_token(STRG);
-                   {if (true) return new Str(t);}
+                   {if (true) return new Str(t.image);}
       break;
     case NUMB:
       t = jj_consume_token(NUMB);
-                   {if (true) return new Num(t);}
+                   {if (true) return new Num(t.image);}
       break;
     case LPAREN:
       s = list();
@@ -42,7 +42,7 @@ public class Parser implements ParserConstants {
     jj_consume_token(LPAREN);
     s = seq();
     jj_consume_token(RPAREN);
-                                 {if (true) return (s == null) ? null : new List(s);}
+                                 {if (true) return new List(s);}
     throw new Error("Missing return statement in function");
   }
 

src/edu/utexas/cs345/jdblisp/parser/ParserTokenManager.java

@@ -1,6 +1,6 @@
 /* Generated By:JavaCC: Do not edit this line. ParserTokenManager.java */
 package edu.utexas.cs345.jdblisp.parser;
-import edu.utexas.cs345.jdblisp.data.*;
+import edu.utexas.cs345.jdblisp.*;
 
 /** Token Manager. */
 public class ParserTokenManager implements ParserConstants