X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=src%2Forg%2Fxwt%2Fjs%2FJS.java;h=ba83b01dcc72b80256dd069d8683a8d751e6ca93;hb=4444c6057bb0cee5d2ae5a55b3045fd8eb790295;hp=c05388145a79f663296d9390a974554fb771c384;hpb=56387d062db4aca0510daa34579aa139570bac87;p=org.ibex.core.git

diff --git a/src/org/xwt/js/JS.java b/src/org/xwt/js/JS.java
index c053881..ba83b01 100644
--- a/src/org/xwt/js/JS.java
+++ b/src/org/xwt/js/JS.java
@@ -1,203 +1,270 @@
-// Copyright 2002 Adam Megacz, see the COPYING file for licensing [GPL] 
+// Copyright 2003 Adam Megacz, see the COPYING file for licensing [GPL] 
 
 package org.xwt.js; 
 import org.xwt.util.*; 
+import org.xwt.*; 
 import java.io.*;
 import java.util.*;
 
-/** The public API for the JS engine */
-// FEATURE: try using mutable, recycled 'Num' objects
+/**
+ *  The public API for the JS engine.  JS itself is actually a class
+ *  implementing the absolute minimal amount of functionality for an
+ *  Object which can be manipulated by JavaScript code.  The static
+ *  methods, fields, and inner classes of JS define the publicly
+ *  visible API for the XWT JavaScript engine; code outside this
+ *  package should never depend on anything not defined in this file.
+ */
 public abstract class JS { 
 
-    // Static Methods //////////////////////////////////////////////////////////////////////
+    // Public Helper Methods //////////////////////////////////////////////////////////////////////
 
-    public static Function getCurrentFunction() {
-	return (Function)currentFunction.get(Thread.currentThread());
-    }
-    public static String getCurrentFunctionSourceName() {
-	return getCurrentFunctionSourceName(Thread.currentThread());
-    }
-    public static String getCurrentFunctionSourceName(Thread t) {
-	Function f = (Function)currentFunction.get(t);
-	if (f == null) return "null";
-	return f.getSourceName();
-    }
-    public static String getFileAndLine() {
-	return "unknown:??";
+    /** parse and compile a function */
+    public static Function parse(String sourceName, int firstLine, Reader sourceCode) throws IOException {
+        return new Function(sourceName, firstLine, sourceCode, null);
     }
 
+    /** coerce an object to a Boolean */
     public static boolean toBoolean(Object o) {
-	if (o == null) return false;
-	if (o instanceof Boolean) return ((Boolean)o).booleanValue();
-	if (o instanceof Number) return o.equals(new Integer(0));
-	return true;
+        if (o == null) return false;
+        if (o instanceof Boolean) return ((Boolean)o).booleanValue();
+        if (o instanceof Long) return ((Long)o).longValue() != 0;
+        if (o instanceof Integer) return ((Integer)o).intValue() != 0;
+        if (o instanceof Number) {
+            double d = ((Number) o).doubleValue();
+            // NOTE: d == d is a test for NaN. It should be faster than Double.isNaN()
+            return d != 0.0 && d == d;
+        }
+        if (o instanceof String) return ((String)o).length() != 0;
+        return true;
     }
+
+    /** coerce an object to a Long */
     public static long toLong(Object o) { return toNumber(o).longValue(); }
+
+    /** coerce an object to an Int */
+    public static int toInt(Object o) { return toNumber(o).intValue(); }
+
+    /** coerce an object to a Double */
     public static double toDouble(Object o) { return toNumber(o).doubleValue(); }
+
+    /** coerce an object to a Number */
     public static Number toNumber(Object o) {
-	if (o == null) return new Long(0);
-	if (o instanceof Number) return ((Number)o);
-	if (o instanceof String) try { return new Double((String)o); } catch (NumberFormatException e) { return new Double(0); }
-	if (o instanceof Boolean) return ((Boolean)o).booleanValue() ? new Long(1) : new Long(0);
-	if (o instanceof JS) return ((JS)o).coerceToNumber();
-	// FIXME
-	throw new Error("toNumber() got object of type " + o.getClass().getName());
-    }
+        if (o == null) return new Long(0);
+        if (o instanceof Number) return ((Number)o);
 
+        // NOTE: There are about 3 pages of rules in ecma262 about string to number conversions
+        //       We aren't even close to following all those rules.  We probably never will be.
+        if (o instanceof String)
+            try { return new Double((String)o); } catch (NumberFormatException e) { return new Double(Double.NaN); }
+        if (o instanceof Boolean) return ((Boolean)o).booleanValue() ? new Long(1) : new Long(0);
+        if (o instanceof JS) return ((JS)o).coerceToNumber();
+        throw new Error("toNumber() got object of type " + o.getClass().getName() + " which we don't know how to handle");
+    }
+    
+    /** coerce an object to a String */
+    public static String toString(Object o) {
+        if(o == null) return "null";
+        if(o instanceof String) return (String) o;
+        if(o instanceof Integer || o instanceof Long || o instanceof Boolean) return o.toString();
+        if(o instanceof JS) return ((JS)o).coerceToString();
+        if(o instanceof Double || o instanceof Float) {
+            double d = ((Number)o).doubleValue();
+            if((int)d == d) return Integer.toString((int)d);
+            return o.toString();
+        }
+        return o.toString();
+    }
+    
     // Instance Methods ////////////////////////////////////////////////////////////////////
  
     public abstract Object get(Object key) throws JS.Exn; 
-    public abstract void put(Object key, Object val) throws JS.Exn; 
+    public abstract Object put(Object key, Object val) throws JS.Exn; 
     public abstract Object[] keys(); 
-
-    public Number coerceToNumber() { throw new Error("you cannot coerce a " + this.getClass().getName() + " into a Number"); }
-    public String coerceToString() { throw new Error("you cannot coerce a " + this.getClass().getName() + " into a String"); }
-    public boolean coerceToBoolean() { throw new Error("you cannot coerce a " + this.getClass().getName() + " into a Boolean"); }
+    public Object callMethod(Object method, Array args, boolean checkOnly) throws JS.Exn {
+	if (checkOnly) return Boolean.FALSE;
+	Object o = get(method);
+	if (o instanceof JS.Callable) return ((JS.Callable)o).call(args);
+        else if (o == null) throw new JS.Exn("Attempted to call non-existent method: " + method);
+        else throw new JS.Exn("Attempted to call a non-function: " +method);
+    }
+    
+    public Number coerceToNumber() { throw new JS.Exn("tried to coerce a JavaScript object to a Number"); }
+    public String coerceToString() { throw new JS.Exn("tried to coerce a JavaScript object to a String"); }
+    public boolean coerceToBoolean() { throw new JS.Exn("tried to coerce a JavaScript object to a Boolean"); }
+    public String typeName() { return "object"; }
 
 
-    // Subclasses /////////////////////////////////////////////////////////////////////////
+    // Inner Classes /////////////////////////////////////////////////////////////////////////
 
+    /** A sensible implementation of the abstract methods in the JS class */
     public static class Obj extends JS {
-	private Hash entries = new Hash();
-	private boolean sealed = false;
-	public Obj() { this(false); }
-	public Obj(boolean sealed) { this.sealed = sealed; }
-	public void setSeal(boolean sealed) { this.sealed = sealed; }
-	public Object get(Object key) { return entries.get(key); }
-	public void put(Object key, Object val) { if (!sealed) entries.put(key, val); }
-	public Object[] keys() { return(entries.keys()); }
+        private Hash entries = null;
+        private boolean sealed = false;
+        public Obj() { this(false); }
+        public Obj(boolean sealed) { this.sealed = sealed; }
+        public void setSeal(boolean sealed) { this.sealed = sealed; }      ///< a sealed object cannot have its properties modified
+        public Object put(Object key, Object val) { put2(key, null, val); return null; }
+        protected void put2(Object key, Object key2, Object val) {
+            if (sealed) return;
+            if (entries == null) entries = new Hash();
+            entries.put(key, key2, val); }
+        public Object[] keys() { return entries == null ? new Object[0] : entries.keys(); }
+        public Object get(Object key) { return get(key, null); }
+        protected Object get(Object key, Object key2) {
+            if (entries == null) return null;
+            if(key2 == null && callMethod((String)key, null, true) == Boolean.TRUE)
+                return new Internal.CallableStub(this, key);
+            return entries.get(key, key2);
+        }
     }
 
+    /** An exception which can be thrown and caught by JavaScript code */
     public static class Exn extends RuntimeException { 
-	private Object js = null; 
-	public Exn(Object js) { this.js = js; } 
-	public String toString() { return "JS.Exn: " + js.toString(); }
-	public String getMessage() { return toString(); }
-	public Object getObject() { return js; } 
+        private Object js = null; 
+        public Exn(Object js) { this.js = js; } 
+        public String toString() { return "JS.Exn: " + js; }
+        public String getMessage() { return toString(); }
+        public Object getObject() { return js; } 
     } 
 
-    public static class Array extends Obj {
-	private Vec vec = new Vec();
-	public Array() { }
-	public Array(int size) { vec.setSize(size); }
-	private static int intVal(Object o) {
-	    if (o instanceof Number) {
-		int intVal = ((Number)o).intValue();
-		if (intVal == ((Number)o).doubleValue()) return intVal;
-		return Integer.MIN_VALUE;
-	    }
-	    if (!(o instanceof String)) return Integer.MIN_VALUE;
-	    String s = (String)o;
-	    for(int i=0; i<s.length(); i++) if (s.charAt(i) < '0' || s.charAt(i) > '9') return Integer.MIN_VALUE;
-	    return Integer.parseInt(s);
-	}
-	public Object get(Object key) throws JS.Exn {
-	    // FIXME: HACK!
-	    if (key.equals("cascade")) return org.xwt.Trap.cascadeFunction;
-	    if (key.equals("trapee")) return org.xwt.Trap.currentTrapee();
-	    if (key.equals("length")) return new Long(vec.size());
-	    int i = intVal(key);
-	    if (i == Integer.MIN_VALUE) return super.get(key);
-	    try {
-		return vec.elementAt(i);
-	    } catch (ArrayIndexOutOfBoundsException e) {
-		throw new JS.Exn(e.getMessage());
-	    }
-	}
-	public void put(Object key, Object val) {
-	    if (key.equals("length")) vec.setSize(toNumber(val).intValue());
-	    int i = intVal(key);
-	    if (i == Integer.MIN_VALUE) super.put(key, val);
-	    else {
-		if (i >= vec.size()) vec.setSize(i+1);
-		vec.setElementAt(val, i);
-	    }
-	}
-	public Object[] keys() {
-	    Object[] sup = super.keys();
-	    Object[] ret = new Object[vec.size() + 1 + sup.length];
-	    System.arraycopy(sup, 0, ret, vec.size(), sup.length);
-	    for(int i=0; i<vec.size(); i++) ret[i] = new Integer(i);
-	    ret[vec.size()] = "length";
-	    return ret;
-	}
-	public void setSize(int i) { vec.setSize(i); }
-	public int length() { return vec.size(); }
-	public Object elementAt(int i) { return vec.elementAt(i); }
-	public void addElement(Object o) { vec.addElement(o); }
-	public void setElementAt(Object o, int i) { vec.setElementAt(o, i); }
+    /** The publicly-visible face of JavaScript Array objects */
+    public static class Array extends ArrayImpl {
+        public Array() { }
+        public Array(int size) { super(size); }
+        public void setSize(int i) { super.setSize(i); }
+        public int length() { return super.length(); }
+        public Object elementAt(int i) { return super.elementAt(i); }
+        public void addElement(Object o) { super.addElement(o); }
+        public void setElementAt(Object o, int i) { super.setElementAt(o, i); }
+        public Object get(Object key) { return super._get(key); }
+        public Object put(Object key, Object val) { super._put(key, val); return null; }
     }
 
-    public static Hashtable currentFunction = new Hashtable();
-    public static abstract class Function extends Obj {
-	public abstract Object _call(JS.Array args) throws JS.Exn;
-	public String getSourceName() throws JS.Exn { return "unknown"; }
-	public final Object call(JS.Array args) throws JS.Exn { return _call(args); }
+    /** Any object which becomes part of the scope chain must support this interface */ 
+    public static class Scope extends ScopeImpl { 
+        public Scope(Scope parentScope) { this(parentScope, false); }
+        public Scope(Scope parentScope, boolean sealed) { super(parentScope, sealed); }
+        public boolean isTransparent() { return super.isTransparent(); }   //< transparent scopes are not returned by THIS
+        public boolean has(Object key) { return super.has(key); }
+        public Object get(Object key) { return super._get(key); }
+        public Object put(Object key, Object val) { super._put(key, val); return null; }
+        public void declare(String s) { super.declare(s); }
+    } 
+
+    /** the result of a graft */
+    public static class Graft extends JS {
+        private JS graftee;
+        private Object replaced_key;
+        private Object replaced_val;
+        public Graft(JS graftee, Object key, Object val) {
+            if (graftee instanceof Array) throw new JS.Exn("can't graft onto Arrays (yet)");
+            if (graftee instanceof Callable) throw new JS.Exn("can't graft onto Callables (yet)");
+            if (graftee instanceof Scope) throw new JS.Exn("can't graft onto Scopes (yet)");
+            this.graftee = graftee;
+            replaced_key = key;
+            replaced_val = val;
+        }
+        public boolean equals(Object o) { return (this == o || graftee.equals(o)); }
+        public int hashCode() { return graftee.hashCode(); }
+        public Object get(Object key) { return replaced_key.equals(key) ? replaced_val : graftee.get(key); }
+        public Object put(Object key, Object val) { graftee.put(key, val); return null; }
+        public Object callMethod(Object method, Array args, boolean checkOnly) throws JS.Exn {
+            if (!replaced_key.equals(method)) return graftee.callMethod(method, args, checkOnly);
+            if (replaced_val instanceof Callable) return checkOnly ? Boolean.TRUE : ((Callable)replaced_val).call(args);
+            if (checkOnly) return Boolean.FALSE;
+            throw new JS.Exn("attempt to call non-function");
+        }
+        public Number coerceToNumber() { return graftee.coerceToNumber(); }
+        public String coerceToString() { return graftee.coerceToString(); }
+        public boolean coerceToBoolean() { return graftee.coerceToBoolean(); }
+        public String typeName() { return graftee.typeName(); }
+        public Object[] keys() {
+            Object[] ret = graftee.keys();
+            for(int i=0; i<ret.length; i++) if (replaced_key.equals(ret[i])) return ret;
+            Object[] ret2 = new Object[ret.length + 1];
+            System.arraycopy(ret, 0, ret2, 0, ret.length);
+            ret2[ret2.length - 1] = replaced_key;
+            return ret2;
+        }
     }
 
-    public static class Script extends Function {
-	Vector e = null;
-	private Script(Vector e) { this.e = e; }
-	public String getSourceName() throws JS.Exn { return ((ForthBlock)e.elementAt(0)).sourceName; }
-	public Object _call(JS.Array args) throws JS.Exn {
-	    Scope rootScope = (Scope)args.elementAt(0);
-	    Function saved = (Function)currentFunction.get(Thread.currentThread());
-	    currentFunction.put(Thread.currentThread(), this);
-	    try {
-		for(int i=0; i<e.size(); i++)
-		    ((ForthBlock)e.elementAt(i)).eval(rootScope);
-	    } catch (ForthBlock.ReturnException e) {
-		// ignore
-	    } catch (ForthBlock.ControlTransferException e) {
-		throw new JS.Exn("block threw a ControlTransferException: " + e);
-	    } finally {
-		if (saved == null) currentFunction.remove(Thread.currentThread());
-		else currentFunction.put(Thread.currentThread(), saved);
-	    }
-	    return null;
-	}
-	public static Script parse(Reader r, String sourceName, int line) throws IOException {
-	    Parser p = new Parser(r, sourceName, line);
-	    try {
-		Vector exprs = new Vector();
-		while(true) {
-		    ForthBlock ret = p.parseStatement(false);
-		    if (ret == null) break;
-		    exprs.addElement(ret);
-		}
-		return new Script(exprs);
-	    } catch (Exception e) {
-		if (Log.on) Log.log(Parser.class, e);
-		return null;
-	    }
-	}
+    /** anything that is callable with the () operator and wasn't compiled from JS code */
+    public static abstract class Callable extends JS.Obj {
+        public abstract Object call(JS.Array args) throws JS.Exn;
     }
 
-    /** Any object which becomes part of the scope chain must support this interface */ 
-    public static class Scope extends Obj { 
-	private Scope parentScope;
-	private static Object NULL = new Object();
-	public Scope(Scope parentScope) { this(parentScope, false); }
-	public Scope(Scope parentScope, boolean sealed) { super(sealed); this.parentScope = parentScope; }
-	public Scope getParentScope() { return parentScope; }
-
-	// transparent scopes are not returned by THIS
-	public boolean isTransparent() { return false; }
-
-	public boolean has(Object key) { return super.get(key) != null; }
-	public Object get(Object key) {
-	    if (!has(key)) return parentScope == null ? null : getParentScope().get(key);
-	    Object ret = super.get(key); return ret == NULL ? null : ret;
-	}
-	public void put(Object key, Object val) {
-	    if (!has(key) && parentScope != null) getParentScope().put(key, val);
-	    else super.put(key, val == null ? NULL : val);
-	}
-	public Object[] keys() { throw new Error("you can't enumerate the properties of a Scope"); }
-	public void declare(String s) { if (isTransparent()) getParentScope().declare(s); else super.put(s, NULL);}
-    } 
+    /** a scope that is populated with js objects and functions normally found in the global scope */
+    public static class GlobalScope extends GlobalScopeImpl {
+        public GlobalScope() { this(null); }
+        public GlobalScope(JS.Scope parent) { super(parent); }
+    }
+
+    public static class TailCall {
+        Function func = null;
+        JS.Array args = null;
+        public TailCall() { }
+        public TailCall set(Function func) { this.func = func; this.args = new JS.Array(); return this; }
+        public TailCall set(Function func, JS.Array args) { this.func = func; this.args = args; return this; }
+    }
  
+    /** encapsulates the state of a JavaScript "thread" (ie stack) */
+    public static class Context {
+
+
+        // Statics //////////////////////////////////////////////////////////////////////
+
+        /**
+         *  Return this from call/get/put in order to make the interpreter pause.  The interpreter will expect a value
+         *  (the return from the call or the get) to be pushed onto the stack when it is resumed.
+         */
+        public static Object pause = new Object();
+
+        private int getLine_() { return current().f == null ? -1 : (pc < 0 || pc >= f.size) ? -1 : f.line[pc]; }
+        public static int getLine() { return current().getLine_(); }
+        public static String getSourceName() { return current().f == null ? null : current().f.sourceName; } 
+
+        /** fetches the currently-executing javascript function */
+        public static JS.Context current() { return (JS.Context)threadToContext.get(Thread.currentThread()); }
+        private static Hashtable threadToContext = new Hashtable();
+
 
+        // Instance members and methods //////////////////////////////////////////////////////////////////////
+
+        /** the currently-executing Function */
+        Function f = null;
+
+        /** the currently-executing scope */
+        public Scope scope = null;  // FIXME: do we really need this?  the function should contain this info
+
+        /** the object stack */
+        Vec stack = new Vec();
+
+        /** the program counter */
+        int pc = 0;
+
+        public Context(Function function, Scope scope) {
+            if (scope == null) scope = new Scope(function.parentScope);
+            stack.push(new Function.CallMarker(this));
+            stack.push(new JS.Array());
+            this.f = function;
+            this.scope = scope;
+        }
+
+        public Object resume() { return resume(null); }
+        public Object resume(Object o) {
+            Thread t = Thread.currentThread();
+            Context old = (Context)threadToContext.get(t);
+            try {
+                threadToContext.put(t, this);
+                stack.push(o);
+                return Function.eval(this);
+            } finally {
+                if (old == null) threadToContext.remove(t);
+                else threadToContext.put(t, old);
+            }
+        }
+
+    }
 }