2003/09/24 07:33:32
[org.ibex.core.git] / src / org / xwt / js / CompiledFunctionImpl.java
index 9d8a7f3..f118b76 100644 (file)
@@ -4,12 +4,14 @@ package org.xwt.js;
 import org.xwt.util.*;
 import java.io.*;
 
-// FIXME: could use some cleaning up
 /** a JavaScript function, compiled into bytecode */
 class CompiledFunctionImpl extends JS.Callable implements ByteCodes, Tokens {
 
     // Fields and Accessors ///////////////////////////////////////////////
 
+    /** the number of formal arguments */
+    int numFormalArgs = 0;
+
     /** the source code file that this block was drawn from */
     private String sourceName;
     public String getSourceName() throws JS.Exn { return sourceName; }
@@ -33,12 +35,16 @@ class CompiledFunctionImpl extends JS.Callable implements ByteCodes, Tokens {
     /** the scope in which this function was declared; by default this function is called in a fresh subscope of the parentScope */
     private JS.Scope parentScope;
 
-
     // Constructors ////////////////////////////////////////////////////////
 
     private CompiledFunctionImpl cloneWithNewParentScope(JS.Scope s) throws IOException {
         CompiledFunctionImpl ret = new JS.CompiledFunction(sourceName, firstLine, null, s);
-        ret.paste(this);
+        // Reuse the same op, arg, line, and size variables for the new "instance" of the function
+        // NOTE: Neither *this* function nor the new function should be modified after this call
+        ret.op = this.op;
+        ret.arg = this.arg;
+        ret.line = this.line;
+        ret.size = this.size;
         return ret;
     }
 
@@ -53,7 +59,8 @@ class CompiledFunctionImpl extends JS.Callable implements ByteCodes, Tokens {
             p.parseStatement(this, null);
             if (s == size()) break;
         }
-        add(-1, Tokens.RETURN);
+        add(-1, LITERAL, null); 
+        add(-1, RETURN);
     }
     
     public Object call(JS.Array args) throws JS.Exn { return call(args, new FunctionScope(sourceName, parentScope)); }
@@ -63,12 +70,19 @@ class CompiledFunctionImpl extends JS.Callable implements ByteCodes, Tokens {
         try {
             cx.currentCompiledFunction = (CompiledFunction)this;
             int size = cx.stack.size();
-            cx.stack.push(new CallMarker());
+            cx.stack.push(callMarker);
             cx.stack.push(args);
             eval(scope);
             Object ret = cx.stack.pop();
-            if (cx.stack.size() > size) Log.logJS(this, "warning, stack grew by " + (cx.stack.size() - size) + " elements during call");
+            if (cx.stack.size() > size)
+                // this should never happen
+                throw new Error("ERROR: stack grew by " + (cx.stack.size() - size) +
+                                " elements during call at " + sourceName + ":" + firstLine);
             return ret;
+        } catch(Error e) {
+            // Unwind the stack
+            while(cx.stack.size() > 0) if(cx.stack.pop() instanceof CallMarker) throw e;
+            throw new Error("CallMarker not found on the stack"); // should never happen
         } finally {
             cx.currentCompiledFunction = saved;
         }
@@ -78,8 +92,10 @@ class CompiledFunctionImpl extends JS.Callable implements ByteCodes, Tokens {
     // Adding and Altering Bytecodes ///////////////////////////////////////////////////
 
     int get(int pos) { return op[pos]; }
+    Object getArg(int pos) { return arg[pos]; }
     void set(int pos, int op_, Object arg_) { op[pos] = op_; arg[pos] = arg_; }
     void set(int pos, Object arg_) { arg[pos] = arg_; }
+    int pop() { size--; arg[size] = null; return op[size]; }
     void paste(CompiledFunctionImpl other) { for(int i=0; i<other.size; i++) add(other.line[i], other.op[i], other.arg[i]); }
     CompiledFunctionImpl add(int line, int op_) { return add(line, op_, null); }
     CompiledFunctionImpl add(int line, int op_, Object arg_) {
@@ -94,22 +110,37 @@ class CompiledFunctionImpl extends JS.Callable implements ByteCodes, Tokens {
         size++;
         return this;
     }
+    
+    public int getLine(int pc) {
+        if(pc < 0 || pc >= size) return -1;
+        return line[pc];
+    }
 
 
     // Invoking the Bytecode ///////////////////////////////////////////////////////
         
-    int pc = 0;
     void eval(JS.Scope s) {
         final JS.Thread cx = JS.Thread.fromJavaThread(java.lang.Thread.currentThread());
         final Vec t = cx.stack;
+        int pc;
+        int lastPC = -1;
         OUTER: for(pc=0; pc<size; pc++) {
+        try {
             String label = null;
-            cx.line = line[pc];
-            switch(op[pc]) {
+            cx.pc = lastPC = pc;
+            int curOP = op[pc];
+            Object curArg = arg[pc];
+            if(curOP == FINALLY_DONE) {
+                FinallyData fd = (FinallyData) t.pop();
+                if(fd == null) continue OUTER; // NOP
+                curOP = fd.op;
+                curArg = fd.arg;
+            }
+            switch(curOP) {
             case LITERAL: t.push(arg[pc]); break;
             case OBJECT: t.push(new JS.Obj()); break;
             case ARRAY: t.push(new JS.Array(JS.toNumber(arg[pc]).intValue())); break;
-            case DECLARE: s.declare((String)t.pop()); break;
+            case DECLARE: s.declare((String)(arg[pc]==null ? t.peek() : arg[pc])); if(arg[pc] != null) t.push(arg[pc]); break;
             case TOPSCOPE: t.push(s); break;
             case JT: if (JS.toBoolean(t.pop())) pc += JS.toNumber(arg[pc]).intValue() - 1; break;
             case JF: if (!JS.toBoolean(t.pop())) pc += JS.toNumber(arg[pc]).intValue() - 1; break;
@@ -117,8 +148,8 @@ class CompiledFunctionImpl extends JS.Callable implements ByteCodes, Tokens {
             case POP: t.pop(); break;
             case SWAP: { Object o1 = t.pop(); Object o2 = t.pop(); t.push(o1); t.push(o2); break; }
             case DUP: t.push(t.peek()); break;
-            case NEWSCOPE: /*s = new JS.Scope(s);*/ break;
-            case OLDSCOPE: /*s = s.getParentScope();*/ break;
+            case NEWSCOPE: s = new JS.Scope(s); break;
+            case OLDSCOPE: s = s.getParentScope(); break;
             case ASSERT: if (!JS.toBoolean(t.pop())) throw je("assertion failed"); break;
             case BITNOT: t.push(new Long(~JS.toLong(t.pop()))); break;
             case BANG: t.push(new Boolean(!JS.toBoolean(t.pop()))); break;
@@ -126,11 +157,10 @@ class CompiledFunctionImpl extends JS.Callable implements ByteCodes, Tokens {
             case TYPEOF: {
                 Object o = t.pop();
                 if (o == null) t.push(null);
-                else if (o instanceof org.xwt.Box) t.push("Box");
-                else if (o instanceof JS) t.push("Object");
-                else if (o instanceof String) t.push("String");
-                else if (o instanceof Number) t.push("Number");
-                else if (o.getClass().getName().startsWith("org.xwt.js.")) t.push(o.getClass().getName().substring(11));
+                else if (o instanceof JS) t.push(((JS)o).typeName());
+                else if (o instanceof String) t.push("string");
+                else if (o instanceof Number) t.push("number");
+                else if (o instanceof Boolean) t.push("boolean");
                 else t.push("unknown");
                 break;
             }
@@ -156,8 +186,7 @@ class CompiledFunctionImpl extends JS.Callable implements ByteCodes, Tokens {
 
             case LABEL: break;
             case LOOP: {
-                t.push(s);
-                t.push(new LoopMarker(pc, pc > 0 && op[pc - 1] == LABEL ? (String)arg[pc - 1] : (String)null));
+                t.push(new LoopMarker(pc, pc > 0 && op[pc - 1] == LABEL ? (String)arg[pc - 1] : (String)null,s));
                 t.push(Boolean.TRUE);
                 break;
             }
@@ -167,21 +196,31 @@ class CompiledFunctionImpl extends JS.Callable implements ByteCodes, Tokens {
                 while(t.size() > 0) {
                     Object o = t.pop();
                     if (o instanceof CallMarker) ee("break or continue not within a loop");
-                    if (o != null && o instanceof LoopMarker) {
-                        if (arg[pc] == null || arg[pc].equals(((LoopMarker)o).label)) {
+                    if (o instanceof TryMarker) {
+                        if(((TryMarker)o).finallyLoc < 0) continue; // no finally block, keep going
+                        t.push(new FinallyData(curOP, curArg));
+                        s = ((TryMarker)o).scope;
+                        pc = ((TryMarker)o).finallyLoc - 1;
+                        continue OUTER;
+                    }
+                    if (o instanceof LoopMarker) {
+                        if (curArg == null || curArg.equals(((LoopMarker)o).label)) {
                             int loopInstructionLocation = ((LoopMarker)o).location;
                             int endOfLoop = ((Integer)arg[loopInstructionLocation]).intValue() + loopInstructionLocation;
-                            s = (JS.Scope)t.pop();
-                            if (op[pc] == CONTINUE) { t.push(s); t.push(o); t.push(Boolean.FALSE); }
-                            pc = op[pc] == BREAK ? endOfLoop - 1 : loopInstructionLocation;
+                            s = ((LoopMarker)o).scope;
+                            if (curOP == CONTINUE) { t.push(o); t.push(Boolean.FALSE); }
+                            pc = curOP == BREAK ? endOfLoop - 1 : loopInstructionLocation;
                             continue OUTER;
                         }
                     }
                 }
-                throw new Error("CONTINUE/BREAK invoked but couldn't find a LoopMarker at " + sourceName + ":" + line);
+                throw new Error("CONTINUE/BREAK invoked but couldn't find a LoopMarker at " + sourceName + ":" + getLine(pc));
 
             case TRY: {
-                t.push(new TryMarker(pc + ((Integer)arg[pc]).intValue(), s));
+                int[] jmps = (int[]) arg[pc];
+                // jmps[0] is how far away the catch block is, jmps[1] is how far away the finally block is
+                // each can be < 0 if the specified block does not exist
+                t.push(new TryMarker(jmps[0] < 0 ? -1 : pc + jmps[0], jmps[1] < 0 ? -1 : pc + jmps[1],s));
                 break;
             }
 
@@ -189,7 +228,15 @@ class CompiledFunctionImpl extends JS.Callable implements ByteCodes, Tokens {
                 Object retval = t.pop();
                 while(t.size() > 0) {
                     Object o = t.pop();
-                    if (o != null && o instanceof CallMarker) {
+                    if (o instanceof TryMarker) {
+                        if(((TryMarker)o).finallyLoc < 0) continue;
+                        t.push(retval); 
+                        t.push(new FinallyData(RETURN));
+                        s = ((TryMarker)o).scope;
+                        pc = ((TryMarker)o).finallyLoc - 1;
+                        continue OUTER;
+                    }
+                    if (o instanceof CallMarker) {
                         t.push(retval);
                         return;
                     }
@@ -205,6 +252,8 @@ class CompiledFunctionImpl extends JS.Callable implements ByteCodes, Tokens {
                     throw je("tried to put a value to the " + key + " property on the null value");
                 if (!(target instanceof JS))
                     throw je("tried to put a value to the " + key + " property on a " + target.getClass().getName());
+                if (key == null)
+                    throw je("tried to assign \"" + (val==null?"(null)":val.toString()) + "\" to the null key");
                 ((JS)target).put(key, val);
                 t.push(val);
                 break;
@@ -214,7 +263,7 @@ class CompiledFunctionImpl extends JS.Callable implements ByteCodes, Tokens {
             case GET_PRESERVE: {
                 Object o, v;
                 if (op[pc] == GET) {
-                    v = t.pop();
+                    v = arg[pc] == null ? t.pop() : arg[pc];
                     o = t.pop();
                 } else {
                     v = t.pop();
@@ -223,47 +272,47 @@ class CompiledFunctionImpl extends JS.Callable implements ByteCodes, Tokens {
                 }
                 Object ret = null;
                 if (o == null) throw je("tried to get property \"" + v + "\" from the null value");
-                if (v == null) throw je("tried to get the null key from " + v);
-                if (o instanceof String) {
-                    ret = getFromString((String)o, v);
-                } else if (o instanceof Boolean) {
-                    throw je("Not Implemented: properties on Boolean objects");
-                } else if (o instanceof Number) {
-                    Log.log(this, "Not Implemented: properties on Number objects");
-                } else if (o instanceof JS) {
+                if (v == null) throw je("tried to get the null key from " + o);
+                if (o instanceof String || o instanceof Number || o instanceof Boolean)
+                    ret = Internal.getFromPrimitive(o,v);
+                else if (o instanceof JS)
                     ret = ((JS)o).get(v);
-                }
+                else 
+                    throw je("tried to get property " + v + " from a " + o.getClass().getName());
                 t.push(ret);
                 break;
             }
-                    
-            case CALL: {
+            
+            case CALLMETHOD:
+            case CALL:
+            {
                 JS.Array arguments = new JS.Array();
                 int numArgs = JS.toNumber(arg[pc]).intValue();
                 arguments.setSize(numArgs);
                 for(int j=numArgs - 1; j >= 0; j--) arguments.setElementAt(t.pop(), j);
-                JS.Callable f = (JS.Callable)t.pop();
-                if (f == null) throw je("attempted to call null");
-                try {
-                    t.push(f.call(arguments));
-                    break;
-                } catch (JS.Exn e) {
-                    t.push(e);
+                Object o = t.pop();
+                if(o == null) throw je("attempted to call null");
+                Object ret;
+                if(op[pc] == CALLMETHOD) {
+                    Object method = o;
+                    o = t.pop();
+                    if(o instanceof String || o instanceof Number || o instanceof Boolean)
+                        ret = Internal.callMethodOnPrimitive(o,method,arguments);
+                    else if(o instanceof JS)
+                        ret = ((JS)o).callMethod(method,arguments,false);
+                    else
+                        throw new JS.Exn("Tried to call a method on an object that isn't a JS object");
+                } else {                   
+                    ret = ((JS.Callable)o).call(arguments);
                 }
+                t.push(ret);
+                break;
             }
             // fall through if exception was thrown
             case THROW: {
-                Object exn = t.pop();
-                while(t.size() > 0) {
-                    Object o = t.pop();
-                    if (o instanceof TryMarker) {
-                        t.push(exn);
-                        pc = ((TryMarker)o).location - 1;
-                        s = ((TryMarker)o).scope;
-                        continue OUTER;
-                    }
-                }
-                throw new JS.Exn(exn);
+                Object o = t.pop();
+                if(o instanceof JS.Exn) throw (JS.Exn)o;
+                throw new JS.Exn(o);
             }
 
             case INC: case DEC: {
@@ -276,26 +325,78 @@ class CompiledFunctionImpl extends JS.Callable implements ByteCodes, Tokens {
                 t.push(isPrefix ? val : num);
                 break;
             }
+            
+            case ASSIGN_SUB: case ASSIGN_ADD: {
+                Object val = t.pop();
+                Object old = t.pop();
+                Object key = t.pop();
+                Object obj = t.peek();
+                if (val instanceof CompiledFunction) {
+                    if (obj instanceof JS.Scope) {
+                        JS.Scope parent = (JS.Scope)obj;
+                        while(parent.getParentScope() != null) parent = parent.getParentScope();
+                        if (parent instanceof org.xwt.Box) {
+                            if (curOP == ASSIGN_ADD) {
+                                ((org.xwt.Box)parent).addTrap(key, val);
+                            } else {
+                                ((org.xwt.Box)parent).delTrap(key, val);
+                            }
+                            // skip over the "normal" implementation of +=/-=
+                            pc += ((Integer)arg[pc]).intValue() - 1;
+                            break;
+                        }
+                    }
+                }
+                // use the "normal" implementation
+                t.push(key);
+                t.push(old);
+                t.push(arg);
+                break;
+            }
+
+            case ADD: {
+                int count = ((Number)arg[pc]).intValue();
+                if(count < 2) throw new Error("this should never happen");
+                if(count == 2) {
+                    // common case
+                    Object right = t.pop();
+                    Object left = t.pop();
+                    if(left instanceof String || right instanceof String) t.push(JS.toString(left).concat(JS.toString(right)));
+                    else t.push(new Double(JS.toDouble(left) + JS.toDouble(right)));
+                } else {
+                    Object[] args = new Object[count];
+                    while(--count >= 0) args[count] = t.pop();
+                    if(args[0] instanceof String) {
+                        StringBuffer sb = new StringBuffer(64);
+                        for(int i=0;i<args.length;i++) sb.append(JS.toString(args[i]));
+                        t.push(sb.toString());
+                    } else {
+                        int numStrings = 0;
+                        for(int i=0;i<args.length;i++) if(args[i] instanceof String) numStrings++;
+                        if(numStrings == 0) {
+                            double d = 0.0;
+                            for(int i=0;i<args.length;i++) d += JS.toDouble(args[i]);
+                            t.push(new Double(d));
+                        } else {
+                            double d=0.0;
+                            int i=0;
+                            do {
+                                d += JS.toDouble(args[i++]);
+                            } while(!(args[i] instanceof String));
+                            StringBuffer sb = new StringBuffer(64);
+                            sb.append(JS.toString(new Double(d)));
+                            while(i < args.length) sb.append(JS.toString(args[i++]));
+                            t.push(sb.toString());
+                        }
+                    }
+                }
+                break;
+            }
 
             default: {
                 Object right = t.pop();
                 Object left = t.pop();
                 switch(op[pc]) {
-
-                case 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(JS.toDouble(l) + JS.toDouble(r))); break;
-                }
                         
                 case BITOR: t.push(new Long(JS.toLong(left) | JS.toLong(right))); break;
                 case BITXOR: t.push(new Long(JS.toLong(left) ^ JS.toLong(right))); break;
@@ -331,6 +432,7 @@ class CompiledFunctionImpl extends JS.Callable implements ByteCodes, Tokens {
                     boolean ret;
                     if (l == null) { Object tmp = r; r = l; l = tmp; }
                     if (l == null && r == null) ret = true;
+                    else if (r == null) ret = false; // l != null, so its false
                     else if (l instanceof Boolean) ret = new Boolean(JS.toBoolean(r)).equals(l);
                     else if (l instanceof Number) ret = JS.toNumber(r).doubleValue() == JS.toNumber(l).doubleValue();
                     else if (l instanceof String) ret = r != null && l.equals(r.toString());
@@ -341,87 +443,120 @@ class CompiledFunctionImpl extends JS.Callable implements ByteCodes, Tokens {
                 default: throw new Error("unknown opcode " + op[pc]);
                 } }
             }
-        }
-    }
-
-
-    // Helpers for Number, String, and Boolean ////////////////////////////////////////
-
-    private static Object getFromString(final String o, final Object v) {
-        if (v.equals("length")) return new Integer(((String)o).length());
-        else if (v.equals("substring")) return new JS.Callable() {
-                public Object call(JS.Array args) {
-                    if (args.length() == 1) return ((String)o).substring(JS.toNumber(args.elementAt(0)).intValue());
-                    else if (args.length() == 2) return ((String)o).substring(JS.toNumber(args.elementAt(0)).intValue(),
-                                                                              JS.toNumber(args.elementAt(1)).intValue());
-                    else throw new JS.Exn("String.substring() can only take one or two arguments");
+        } catch(JS.Exn e) {
+            while(t.size() > 0) {
+                Object o = t.pop();
+                if (o instanceof CatchMarker || o instanceof TryMarker) {
+                    boolean inCatch = o instanceof CatchMarker;
+                    if(inCatch) {
+                        o = t.pop();
+                        if(((TryMarker)o).finallyLoc < 0) continue; // no finally block, keep going
+                    }
+                    if(!inCatch && ((TryMarker)o).catchLoc >= 0) {
+                        // run the catch block, this will implicitly run the finally block, if it exists
+                        t.push(o);
+                        t.push(catchMarker);
+                        t.push(e.getObject());
+                        s = ((TryMarker)o).scope;
+                        pc = ((TryMarker)o).catchLoc - 1;
+                        continue OUTER;
+                    } else {
+                        t.push(e);
+                        t.push(new FinallyData(THROW));
+                        s = ((TryMarker)o).scope;
+                        pc = ((TryMarker)o).finallyLoc - 1;
+                        continue OUTER;
+                    }
                 }
-            };
-        else if (v.equals("toLowerCase")) return new JS.Callable() {
-                public Object call(JS.Array args) {
-                    return ((String)o).toLowerCase();
-                } };
-        else if (v.equals("toUpperCase")) return new JS.Callable() {
-                public Object call(JS.Array args) {
-                    return ((String)o).toString().toUpperCase();
-                } };
-        else if (v.equals("charAt")) return new JS.Callable() {
-                public Object call(JS.Array args) {
-                    return ((String)o).charAt(JS.toNumber(args.elementAt(0)).intValue()) + "";
-                } };
-        else if (v.equals("lastIndexOf")) return new JS.Callable() {
-                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.Callable() {
-                public Object call(JS.Array args) {
-                    if (args.length() != 1) return null;
-                    return new Integer(((String)o).indexOf(args.elementAt(0).toString()));
-                } };
-        throw new JS.Exn("Not Implemented: propery " + v + " on String objects");
+                // no handler found within this func
+                if(o instanceof CallMarker) throw e;
+            }
+            throw new Error("couldn't find a Try or Call Marker!");
+        } // end try/catch
+        } // end for
+        // this should never happen, we will ALWAYS have a RETURN at the end of the func
+        throw new Error("Just fell out of CompiledFunction::eval() loop. Last PC was " + lastPC);
     }
 
+    // Debugging //////////////////////////////////////////////////////////////////////
+
+    public String toString() {
+        StringBuffer sb = new StringBuffer(1024);
+        sb.append("\n" + sourceName + ": " + firstLine + "\n");
+        for (int i=0; i < size; i++) {
+            sb.append(i);
+            sb.append(": ");
+            if (op[i] < 0)
+                sb.append(bytecodeToString[-op[i]]);
+            else
+                sb.append(codeToString[op[i]]);
+            sb.append(" ");
+            sb.append(arg[i] == null ? "(no arg)" : arg[i]);
+            if((op[i] == JF || op[i] == JT || op[i] == JMP) && arg[i] != null && arg[i] instanceof Number) {
+                sb.append(" jump to ").append(i+((Number) arg[i]).intValue());
+            } else  if(op[i] == TRY) {
+                int[] jmps = (int[]) arg[i];
+                sb.append(" catch: ").append(jmps[0] < 0 ? "No catch block" : ""+(i+jmps[0]));
+                sb.append(" finally: ").append(jmps[1] < 0 ? "No finally block" : ""+(i+jmps[1]));
+            }
+            sb.append("\n");
+        }
+        return sb.toString();
+    } 
 
     // Exception Stuff ////////////////////////////////////////////////////////////////
 
     static class EvaluatorException extends RuntimeException { public EvaluatorException(String s) { super(s); } }
-    EvaluatorException ee(String s) { throw new EvaluatorException(sourceName + ":" + line[pc] + " " + s); }
-    JS.Exn je(String s) { throw new JS.Exn(sourceName + ":" + line[pc] + " " + s); }
+    EvaluatorException ee(String s) { throw new EvaluatorException(sourceName + ":" + JS.Thread.currentJSThread().getLine() + " " + s); }
+    JS.Exn je(String s) { throw new JS.Exn(sourceName + ":" + JS.Thread.currentJSThread().getLine() + " " + s); }
 
 
     // FunctionScope /////////////////////////////////////////////////////////////////
 
-    private class FunctionScope extends JS.Scope {
+    private static class FunctionScope extends JS.Scope {
         String sourceName;
         public FunctionScope(String sourceName, Scope parentScope) { super(parentScope); this.sourceName = sourceName; }
         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);
-        }
     }
 
 
     // Markers //////////////////////////////////////////////////////////////////////
 
     public static class CallMarker { public CallMarker() { } }
+    private static CallMarker callMarker = new CallMarker();
+    
+    public static class CatchMarker { public CatchMarker() { } }
+    private static CatchMarker catchMarker = new CatchMarker();
+    
     public static class LoopMarker {
         public int location;
         public String label;
-        public LoopMarker(int location, String label) {
+        public JS.Scope scope;
+        public LoopMarker(int location, String label, JS.Scope scope) {
             this.location = location;
             this.label = label;
+            this.scope = scope;
         }
     }
     public static class TryMarker {
-        public int location;
+        public int catchLoc;
+        public int finallyLoc;
         public JS.Scope scope;
-        public TryMarker(int location, JS.Scope scope) {
-            this.location = location;
+        public TryMarker(int catchLoc, int finallyLoc, JS.Scope scope) {
+            this.catchLoc = catchLoc;
+            this.finallyLoc = finallyLoc;
             this.scope = scope;
         }
     }
+    public static class FinallyData {
+        public int op;
+        public Object arg;
+        public FinallyData(int op, Object arg) { this.op = op; this.arg = arg; }
+        public FinallyData(int op) { this(op,null); }
+    }
+}
 
+/** this class exists solely to work around a GCJ bug */
+abstract class JSCallable extends JS.Callable {
+        public abstract Object call(JS.Array args) throws JS.Exn;
 }