- // Expr //////////////////////////////////////////////////////////////////////
-
- public static final Object NO_ARG = new Object();
-
- class ByteCode extends Expr {
-
- // This class interprets a small forthlike bytecode language
- // we use to represent JavaScript. It's a stack machine.
-
- // Each instruction is an opcode and a literal. Any operation
- // that accesses the top of the stack and does not have a
- // mandatory literal can be performed on a literal instead of
- // the top of the stack.
-
- // opcodes:
- public static final byte arithmetic = -1; // -- arithmetic operators from parser
- public static final byte LITERAL = -2; // < String | Number | null > -- push a literal onto the stack
- public static final byte ARRAY = -3; // < size > -- create a new array of size <size>
- public static final byte OBJECT = -4; // -- push an empty object onto the stack
- public static final byte FUNCTION = -5; // < bytecode_block > -- push a new instance of a function with the given bytecode
- public static final byte DECLARE = -6; // < name > -- declare <name> in the current scope
- public static final byte THIS = -7; // -- push the topmost non-transparent scope onto the stack
- public static final byte GET = -8; // -- get stack[0] from stack[1]
- public static final byte GET_PRESERVE = -80; // -- get stack[0] from stack[1]
- public static final byte PUT = -9; // -- put stack[1] to key stack[0] on stack[2]; leaves object on the stack
- public static final byte JT = -13; // < relative_address > -- pop the stack; if true, jump to <relative_address>
- public static final byte JF = -21; // < relative_address > -- pop the stack; if false, jump to <relative_address>
- public static final byte JMP = -22; // < relative_address > -- jump to <relative_address>
- static public final byte POP = -14; // -- discard the top element on the stack
-
- public static final byte CALL = -15; // < numargs > -- call stack[0] with the topmost <numargs> values as arguments
-
- public static final byte PUSHKEYS = -19; // -- ??
- public static final byte EXPR = -20; // -- transitional
- public static final byte SWAP = -23; // -- transitional
- public static final byte SCOPE = -30; // -- transitional
- public static final byte LOOP = -40; // -- transitional
- public static final byte DUP = -50; // -- transitional
- public static final byte LABEL = -60; // -- transitional
-
- int[] op = new int[10];
- Object[] arg = new Object[10];
- int size = 0;
-
- public ByteCode(int line) { super(line, "foo"); }
- public ByteCode(int line, int op_, Object arg_) { this(line); add(op_, arg_); }
-
- public int size() { return size; }
- public void set(int pos, int op_, Object arg_) { op[pos] = op_; arg[pos] = arg_; }
- public ByteCode add(int op_, Object arg_) {
- if (size == op.length - 1) {
- int[] op2 = new int[op.length * 2]; System.arraycopy(op, 0, op2, 0, op.length); op = op2;
- Object[] arg2 = new Object[op.length * 2]; System.arraycopy(arg, 0, arg2, 0, arg.length); arg = arg2;
- }
- op[size] = op_;
- arg[size] = arg_;
- size++;
- return this;
- }
-
- public Object eval(final JS.Scope s) throws ControlTransferException, JS.Exn {
- return eval(s, new Parser.Thread());
- }
- public Object eval(final JS.Scope s, Parser.Thread t) throws ControlTransferException {
- for(int i=0; i<size; i++)
- switch(op[i]) {
- case LABEL: break; // FIXME
- case LITERAL: t.push(arg[i]); break;
- case OBJECT: t.push(new JS.Obj()); break;
- case ARRAY: t.push(new JS.Array(toNumber(arg[i]).intValue())); break;
- case DECLARE: s.declare(arg[i] == NO_ARG ? (String)t.pop() : (String)arg[i]); break;
- case THIS: t.push(s); break; // FIXME: transparents
- case JT: if (toBoolean(t.pop())) i += toNumber(arg[i]).intValue() - 1; break;
- case JF: if (!toBoolean(t.pop())) i += toNumber(arg[i]).intValue() - 1; break;
- case JMP: i += toNumber(arg[i]).intValue() - 1; break;
- case POP: t.pop(); break;
- case SWAP: t.swap(); break;
- case DUP: t.push(t.peek()); break;
- case NOP: break;
- case EXPR: t.push(((Expr)arg[i]).eval(s)); break;
- case SCOPE: t.push(((ByteCode)arg[i]).eval(new JS.Scope(s), t)); break;
-
- case ASSERT: if (!toBoolean(t.pop())) throw new EvaluatorException("assertion failed"); break;
- case RETURN: throw new ReturnException(t.pop());
- case THROW: throw new JS.Exn(t.pop());
-
- case TRY: break;
- case INSTANCEOF: break;
- case TYPEOF: break;
- case PUSHKEYS: {
- Object o = t.peek();
- Object[] keys = ((JS)o).keys();
- JS.Array a = new JS.Array();
- a.setSize(keys.length);
- for(int j=0; j<keys.length; j++) a.setElementAt(keys[j], j);
- t.push(a);
- break;
- }
-
- case Lexer.BITNOT: t.push(new Long(~toLong(t.pop()))); break;
- case Lexer.BANG: t.push(new Boolean(!toBoolean(t.pop()))); break;
-
- case Lexer.BREAK: {
- // FIXME: make sure this can only appear in proper places
- return Boolean.FALSE;
- }
- case Lexer.CONTINUE: {
- // FIXME: make sure this can only appear in proper places
- return Boolean.TRUE;
- }
- case LOOP: {
- ByteCode loop = (ByteCode)arg[i];
- Parser.Thread t2 = new Parser.Thread();
- t2.push(Boolean.TRUE);
- while (true) {
- Boolean result;
- try {
- result = (Boolean)loop.eval(new JS.Scope(s), t2);
- } catch (ContinueException c) {
- result = Boolean.TRUE;
- } catch (BreakException b) {
- result = Boolean.FALSE;
- }
- if (result == Boolean.FALSE) break;
- t2 = new Parser.Thread();
- t2.push(Boolean.FALSE);
- }
- break;
- }
-
- case PUT: {
- Object val = arg[i] == NO_ARG ? t.pop() : arg[i];
- Object key = t.pop();
- ((JS)t.peek()).put(key, val);
- t.push(val);
- break;
- }
-
- case GET: {
- Object v = arg[i] == NO_ARG ? t.pop() : arg[i];
- Object o = t.pop();
- t.push(doGet(o, v));
- break;
- }
-
- case GET_PRESERVE: {
- Object v = t.pop();
- Object o = t.peek();
- t.push(v);
- t.push(doGet(o, v));
- break;
- }
-
- case CALL: {
- JS.Array arguments = new JS.Array();
- int numArgs = toNumber(arg[i]).intValue();
- arguments.setSize(numArgs);
- for(int j=numArgs - 1; j >= 0; j--) arguments.setElementAt(t.pop(), j);
- JS.Function f = (JS.Function)t.pop();
- if (f == null) throw new JS.Exn(new EvaluatorException("attempted to call null"));
- t.push(f.call(arguments));
- break;
- }
-
- case FUNCTION: {
- final ByteCode myBytes = (ByteCode)arg[i];
- t.push(new JS.Function() {
- public String toString() { return sourceName + ":" + line; }
- public String getSourceName() throws JS.Exn { return sourceName; }
- public Object _call(final JS.Array args) throws JS.Exn {
- Function save = JS.getCurrentFunction();
- JS.currentFunction.put(java.lang.Thread.currentThread(), this);
- JS.Scope scope = new JS.Scope(s) {
- // FIXME
- public String getSourceName() { return sourceName; }
- public Object get(Object key) throws JS.Exn {
- if (key.equals("trapee")) return org.xwt.Trap.currentTrapee();
- else if (key.equals("cascade")) return org.xwt.Trap.cascadeFunction;
- return super.get(key);
- }
- };
- Parser.Thread t0 = new Parser.Thread();
- t0.push(args);
- try {
- return myBytes.eval(scope, t0);
- } catch (ReturnException r) {
- return r.retval;
- } catch (ControlTransferException c) {
- throw new EvaluatorException("error, ControlTransferException tried to leave a function: " + c);
- } finally {
- if (save == null) JS.currentFunction.remove(java.lang.Thread.currentThread());
- else JS.currentFunction.put(java.lang.Thread.currentThread(), save);
- }
- }
- });
- break;
- }
-
- case Lexer.INC: case Lexer.DEC: {
- boolean isPrefix = toBoolean(arg[i]);
- Object key = t.pop();
- JS obj = (JS)t.pop();
- Number num = toNumber(obj.get(key));
- Number val = new Double(op[i] == Lexer.INC ? num.doubleValue() + 1.0 : num.doubleValue() - 1.0);
- obj.put(key, val);
- t.push(isPrefix ? val : num);
- break;
- }
-
- default: {
- Object right = t.pop();
- Object left = t.pop();
- switch(op[i]) {
-
- case Lexer.BITOR: t.push(new Long(toLong(left) | toLong(right))); break;
- case Lexer.BITXOR: t.push(new Long(toLong(left) ^ toLong(right))); break;
- case Lexer.BITAND: t.push(new Long(toLong(left) & toLong(right))); break;
-
- case Lexer.ADD: {
- Object l = left;
- Object r = right;
- if (l instanceof String || r instanceof String) {
- if (l == null) l = "null";
- if (r == null) r = "null";
- if (l instanceof Number && ((Number)l).doubleValue() == ((Number)l).longValue())
- l = new Long(((Number)l).longValue());
- if (r instanceof Number && ((Number)r).doubleValue() == ((Number)r).longValue())
- r = new Long(((Number)r).longValue());
- t.push(l.toString() + r.toString()); break;
- }
- t.push(new Double(toDouble(l) + toDouble(r))); break;
- }
-
- case Lexer.SUB: t.push(new Double(toDouble(left) - toDouble(right))); break;
- case Lexer.MUL: t.push(new Double(toDouble(left) * toDouble(right))); break;
- case Lexer.DIV: t.push(new Double(toDouble(left) / toDouble(right))); break;
- case Lexer.MOD: t.push(new Double(toDouble(left) % toDouble(right))); break;
-
- case Lexer.LSH: t.push(new Long(toLong(left) << toLong(right))); break;
- case Lexer.RSH: t.push(new Long(toLong(left) >> toLong(right))); break;
- case Lexer.URSH: t.push(new Long(toLong(left) >>> toLong(right))); break;
-
- // FIXME: these need to work on strings
- case Lexer.LT: t.push(toDouble(left) < toDouble(right) ? Boolean.TRUE : Boolean.FALSE); break;
- case Lexer.LE: t.push(toDouble(left) <= toDouble(right) ? Boolean.TRUE : Boolean.FALSE); break;
- case Lexer.GT: t.push(toDouble(left) > toDouble(right) ? Boolean.TRUE : Boolean.FALSE); break;
- case Lexer.GE: t.push(toDouble(left) >= toDouble(right) ? Boolean.TRUE : Boolean.FALSE); break;
-
- case Lexer.EQ:
- case Lexer.NE: {
- // FIXME: should use Javascript coercion-equality rules
- Object l = left;
- Object r = right;
- boolean ret;
- if (l == null) { Object tmp = r; r = l; l = tmp; }
- if (l == null && r == null) ret = true;
- else if (l instanceof Boolean) ret = new Boolean(toBoolean(r)).equals(l);
- else if (l instanceof Number) ret = toNumber(r).doubleValue() == toNumber(l).doubleValue();
- else if (l instanceof String) ret = r != null && l.equals(r.toString());
- else ret = l.equals(r);
- t.push(new Boolean(op[i] == Lexer.EQ ? ret : !ret)); break;
- }
-
- default: throw new Error("unknown opcode " + op[i]);
- } }
- }
- if (t.size() != 1) {
- throw new EvaluatorException("eval() terminated with " + t.size() + " elements on the stack; one expected");
- }
- return t.pop();
- }
-
- public Object doGet(final Object o, final Object v) {
- if (o == null) throw new EvaluatorException("tried to get property \"" + v + "\" from the null value");
- if (o instanceof String) {
- if (v.equals("length")) return new Integer(((String)o).length());
- else if (v.equals("substring")) return new JS.Function() {
- public Object _call(JS.Array args) {
- if (args.length() == 1) return ((String)o).substring(toNumber(args.elementAt(0)).intValue());
- else if (args.length() == 2) return ((String)o).substring(toNumber(args.elementAt(0)).intValue(),
- toNumber(args.elementAt(1)).intValue());
- else throw new Error("String.substring() can only take one or two arguments");
- }
- };
- else if (v.equals("toLowerCase")) return new JS.Function() {
- public Object _call(JS.Array args) {
- return ((String)o).toLowerCase();
- } };
- else if (v.equals("toUpperCase")) return new JS.Function() {
- public Object _call(JS.Array args) {
- return ((String)o).toString().toUpperCase();
- } };
- else if (v.equals("charAt")) return new JS.Function() {
- public Object _call(JS.Array args) {
- return ((String)o).charAt(toNumber(args.elementAt(0)).intValue()) + "";
- } };
- else if (v.equals("lastIndexOf")) return new JS.Function() {
- public Object _call(JS.Array args) {
- if (args.length() != 1) return null;
- return new Integer(((String)o).lastIndexOf(args.elementAt(0).toString()));
- } };
- else if (v.equals("indexOf")) return new JS.Function() {
- public Object _call(JS.Array args) {
- if (args.length() != 1) return null;
- return new Integer(((String)o).indexOf(args.elementAt(0).toString()));
- } };
- throw new Error("Not Implemented: propery " + v + " on String objects");
- } else if (o instanceof Boolean) {
- throw new Error("Not Implemented: properties on Boolean objects");
- } else if (o instanceof Number) {
- Log.log(this, "Not Implemented: properties on Number objects");
- return null;
- //throw new Error("Not Implemented: properties on Number objects");
- } else if (o instanceof JS) {
- return ((JS)o).get(v);
- }
- return null;
- }
- }
-
- class Thread {
- public Object[] os = new Object[256];
- private int size = 0;
- public void push(Object o) {
- os[size++] = o;
- }
- public Object pop() { return os[--size]; }
- public Object peek() { return os[size - 1]; }
- public void swap() { Object temp = os[size - 1]; os[size - 1] = os[size - 2]; os[size - 2] = temp; }
- public int size() { return size; }
- }
-
- class ExprList extends Expr {
- Vec v = new Vec();
- public ExprList(int curLine, int code) { super(curLine, code); }
- public void add(Expr e) { v.addElement(e); }
- public int numExprs() { return v.size(); }
- public int size() { return v.size(); }
- public Expr elementAt(int i) { return (Expr)v.elementAt(i); }
- public Object eval(final JS.Scope s) throws ControlTransferException, JS.Exn {
- switch(code) {
- case LC: {
- // Block
- JS.Scope scope = new JS.Scope(s);
- for(int i=0; i<v.size(); i++) ((Expr)v.elementAt(i)).eval(scope);
- return null;
- }
- case Lexer.LB: {
- // Array ctor
- JS.Array ret = new JS.Array();
- for(int i=0; i<numExprs(); i++) ret.addElement(elementAt(i).eval(s));
- return ret;
- }
- case Lexer.RC: {
- // Object ctor
- JS.Obj ret = new JS.Obj();
- for(int i=0; i<numExprs(); i++) {
- Expr e = elementAt(i);
- Object key = e.left.string;
- Object val = e.right.eval(s);
- ret.put(key, val);
- }
- return ret;
- }
- case Lexer.WHILE:
- case Lexer.DO:
- try {
- boolean first = true;
- Object bogus = null;
- ExprList list = this;
- Expr whileExpr = list.elementAt(0);
- Expr bodyExpr = list.elementAt(1);
- Expr incExpr = list.elementAt(2);
- for(;(first && code == Lexer.DO) || toBoolean(whileExpr.eval(s)); bogus = incExpr.eval(s)) {
- first = false;
- try {
- bodyExpr.eval(s);
- } catch (ContinueException c) {
- if (c.label == null || c.label.equals(string)) continue;
- } catch (BreakException b) {
- if (b.label == null || b.label.equals(string)) return null;
- throw (BreakException)b.fillInStackTrace();
- }
- }
- } catch (BreakException e) {
- if (e.label != null && !e.label.equals(string)) throw e;
- }
- return null;
- case Lexer.VAR:
- for(int i=0; i<size(); i++) {
- Expr e = elementAt(i);
- s.declare(e.left.string);
- if (e.right != null) e.right.eval(s);
- }
- return null;
- default: throw new Error("augh!");
- }
- }
- }
-