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. 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 {
+ // 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 CompiledFunction parse(String sourceName, int firstLine, Reader sourceCode) throws IOException {
+ return new CompiledFunction(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();
return true;
}
+ /** coerce an object to a Long */
public static long toLong(Object o) { return toNumber(o).longValue(); }
+
+ /** 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);
public boolean coerceToBoolean() { throw new Error("you cannot coerce a " + this.getClass().getName() + " into a Boolean"); }
- // Subclasses /////////////////////////////////////////////////////////////////////////
+ // Inner Classes /////////////////////////////////////////////////////////////////////////
- /** A slightly more featureful version of JS */
+ /** 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 Object[] keys() { return(entries.keys()); }
}
- /** An exception which can be thrown and caught by JavaScripts */
+ /** 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 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();
+ /** The publicly-visible face of JavaScript Array objects */
+ public static class Array extends ArrayImpl {
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;
- }
- }
+ 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); }
}
/** 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 static class Scope extends ScopeImpl {
public Scope(Scope parentScope) { this(parentScope, false); }
- public Scope(Scope parentScope, boolean sealed) { super(sealed); this.parentScope = parentScope; }
- public Scope getParentScope() { return parentScope; }
+ public Scope(Scope parentScope, boolean sealed) { super(parentScope, sealed); }
+ public Scope getParentScope() { return super.getParentScope(); }
+ public boolean isTransparent() { return super.isTransparent(); }
+ public boolean has(Object key) { return super.has(key); }
+ public void declare(String s) { super.declare(s); }
+ }
- // transparent scopes are not returned by THIS
- public boolean isTransparent() { return false; }
+ /** anything that is callable with the () operator */
+ public static abstract class Callable extends JS.Obj {
+ public abstract Object call(JS.Array args) throws JS.Exn;
+ }
- 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);
+ /** a Callable which was compiled from JavaScript code */
+ public static class CompiledFunction extends CompiledFunctionImpl {
+ public Object call(JS.Array args, JS.Scope scope) throws JS.Exn { return super.call(args, scope); }
+ CompiledFunction(String sourceName, int firstLine, Reader sourceCode, Scope scope) throws IOException {
+ super(sourceName, firstLine, sourceCode, scope);
}
}
+
}
projects / org.ibex.core.git / blobdiff