package org.xwt.js;
import org.xwt.util.*;
+import org.xwt.*;
import java.io.*;
import java.util.*;
/**
- * The public API for the JS engine; JS itself is actually a class
- * implementing the minimal amount of functionality for an Object
- * which can be manipulated by JavaScript code.
+ * 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.
*/
-public abstract class JS {
+public class JS {
+ // Public Helper Methods //////////////////////////////////////////////////////////////////////
- // Static Methods //////////////////////////////////////////////////////////////////////
-
- private static Hashtable currentFunction = new Hashtable();
- public static Function getCurrentFunction() { return (Function)currentFunction.get(Thread.currentThread()); }
- public static String getCurrentFunctionSourceName() { return getCurrentFunctionSourceName(Thread.currentThread()); }
- public static String getFileAndLine() { return getCurrentFunctionSourceName() + ":" + getCurrentFunction().getLine(); }
- public static String getCurrentFunctionSourceName(Thread t) {
- Function f = (Function)currentFunction.get(t);
- if (f == null) return "null";
- return f.getSourceName();
+ /** parse and compile a function */
+ public static JSFunction parse(String sourceName, int firstLine, Reader sourceCode) throws IOException {
+ return new JSFunction(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();
- throw new Error("toNumber() got object of type " + o.getClass().getName() + " which we don't know how to handle");
+ 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[] 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"); }
-
-
- // Subclasses /////////////////////////////////////////////////////////////////////////
-
- /** A slightly more featureful version of JS */
- 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()); }
- }
-
- /** An exception which can be thrown and caught by JavaScripts */
+ // this gets around a wierd fluke in the Java type checking rules for ?..:
+ public static final Object T = Boolean.TRUE;
+ public static final Object F = Boolean.FALSE;
+
+ // FEATURE: be smart here; perhaps intern
+ public static final Number N(int i) { return new Integer(i); }
+ public static final Number N(long l) { return new Long(l); }
+ public static final Number N(double d) { return new Double(d); }
+ public static final Boolean B(boolean b) { return b ? Boolean.TRUE : Boolean.FALSE; }
+
+ private static Enumeration emptyEnumeration = new Enumeration() {
+ public boolean hasMoreElements() { return false; }
+ public Object nextElement() { throw new NoSuchElementException(); }
+ };
+
+ private Hash entries = null;
+ public Enumeration keys() { return entries == null ? emptyEnumeration : entries.keys(); }
+ public Object get(Object key) { return entries == null ? null : entries.get(key, null); }
+ public void put(Object key, Object val) { if (entries == null) entries = new Hash(); entries.put(key, null, val); }
+
+ // note that we don't actually implement trappable... we just provide these for subclasses which choose to
+ public JSTrap getTrap(Object key) { return entries == null ? null : (JSTrap)entries.get(key, JSTrap.class); }
+ public void putTrap(Object key, JSTrap t) { if (entries == null) entries = new Hash(); entries.put(key, JSTrap.class, t); }
+
+ 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"; }
+
+
+ // Inner Classes /////////////////////////////////////////////////////////////////////////
+
+ /** 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; }
- 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; }
}
- /** A JavaScript Array */
- 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); }
- }
-
- /** Anything that is callable */
- public static class Function extends Obj {
- ByteCodeBlock bytecodes;
- int line;
- String sourceName;
- Scope parentScope;
- public Function() { this(-1, "unknown", null, null); }
- public Function(int line, String sourceName, ByteCodeBlock bytecodes, Scope parentScope) {
- this.sourceName = sourceName;
- this.line = line;
- this.bytecodes = bytecodes;
- this.parentScope = parentScope;
- }
- public String getSourceName() throws JS.Exn { return sourceName; }
- public int getLine() throws JS.Exn { return line; }
- public Object _call(JS.Array args) throws JS.Exn, ByteCodeBlock.ControlTransferException {
- if (bytecodes == null) throw new Error("tried to call() a JS.Function with bytecodes == null");
- Vec stack = new Vec();
- stack.push(args);
- return bytecodes.eval(new FunctionScope(sourceName, parentScope), stack);
- }
- public final Object call(JS.Array args) throws JS.Exn {
- Function saved = (Function)currentFunction.get(Thread.currentThread());
- currentFunction.put(Thread.currentThread(), this);
- try {
- return _call(args);
- } catch (ByteCodeBlock.ReturnException e) { // ignore
- return e.retval;
- } catch (ByteCodeBlock.ControlTransferException e) {
- throw new RuntimeException(getSourceName() + ":" + getLine() +
- " error, ControlTransferException tried to leave a function");
- } finally {
- if (saved == null) currentFunction.remove(Thread.currentThread());
- else currentFunction.put(Thread.currentThread(), saved);
- }
- }
- }
-
- public static class Script extends Function {
- Vector e = null;
- private Script(Vector e) { this.e = e; }
- public String getSourceName() throws JS.Exn { return ((ByteCodeBlock)e.elementAt(0)).getSourceName(); }
- public Object _call(JS.Array args) throws JS.Exn, ByteCodeBlock.ControlTransferException {
- Scope rootScope = (Scope)args.elementAt(0);
- for(int i=0; i<e.size(); i++) ((ByteCodeBlock)e.elementAt(i)).eval(rootScope, new Vec());
- 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) {
- ByteCodeBlock ret = p.parseStatement();
- if (ret == null) break;
- exprs.addElement(ret);
- }
- return new Script(exprs);
- } catch (Exception e) {
- if (Log.on) Log.log(Parser.class, e);
- return null;
- }
- }
- }
-
- /** 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);
- }
- }
-
- private 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);
- }
+ /** the result of a graft */
+ // FIXME: uber-broken
+ public static class Graft extends JSCallable {
+ private JS graftee;
+ private Object replaced_key;
+ private Object replaced_val;
+ public Graft(Object graftee, Object key, Object val) {
+ if (graftee instanceof JSArray) throw new JS.Exn("can't graft onto JSArrays (yet)");
+ if (graftee instanceof JSCallable) throw new JS.Exn("can't graft onto JSCallables (yet)");
+ if (graftee instanceof JSScope) throw new JS.Exn("can't graft onto JSScopes (yet)");
+ this.graftee = (JS)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 void put(Object key, Object val) { graftee.put(key, val); }
+ /*
+ public Object call(Object method, JSArray args) {
+ if (replaced_key.equals(method)) return ((JSCallable)replaced_val).call(null, args);
+ else if (graftee instanceof JSCallable) return ((JSCallable)graftee).call(method, args);
+ else throw new JS.Exn("cannot call this value");
+ }
+ */
+ 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 Enumeration keys() {
+ return new Enumeration() {
+ Enumeration graftee_enumeration = graftee.keys();
+ boolean returned_replaced = false;
+ public boolean hasMoreElements() {
+ if (graftee_enumeration.hasMoreElements()) return true;
+ return !returned_replaced;
+ }
+ public Object nextElement() {
+ if (!graftee_enumeration.hasMoreElements()) {
+ if (returned_replaced) throw new NoSuchElementException();
+ returned_replaced = true;
+ return replaced_key;
+ } else {
+ Object ret = graftee_enumeration.nextElement();
+ if (!returned_replaced && ret.equals(replaced_key)) returned_replaced = true;
+ return ret;
+ }
+ }
+ };
+ }
}
}
projects / org.ibex.core.git / blobdiff