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 //////////////////////////////////////////////////////////////////////
+ /** 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 Object getObject() { return js; }
}
+ /** 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); }
+ }
+
/** 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);
- if (parentScope == this) throw new Error("can't make a scope its own parent!");
- 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);
- }
+ 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); }
}
- public static CompiledFunction parse(String sourceName, int firstLine, Reader sourceCode, JS.Scope parentScope) throws IOException {
- return new CompiledFunction(sourceName, firstLine, sourceCode, parentScope);
- }
-
/** anything that is callable with the () operator */
public static abstract class Callable extends JS.Obj {
- public abstract Object call(Array args) throws JS.Exn;
+ public abstract Object call(JS.Array args) throws JS.Exn;
}
+ /** 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);
+ }
+ }
+
}
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