-// Copyright 2002 Adam Megacz, see the COPYING file for licensing [GPL]
-package org.xwt.js;
-
-import java.io.*;
-import org.xwt.util.*;
-
-/** sorta like gcc trees */
-public class Expr {
- int code = -1;
-
- final Expr left;
- final Expr right;
- Expr next = null; // if this expr is part of a list
-
- String string = null;
- Number number = null;
-
- public String toString() { return toString(0); }
- public String toString(int indent) {
- String ret = "";
- for(int i=0; i<indent; i++) ret += " ";
- ret += Lexer.codeToString[code];
- if (code == Lexer.NUMBER) ret += " " + number;
- else if (string != null) ret += " \"" + string + "\"";
- ret += "\n";
- if (left != null) ret += left.toString(indent + 2);
- if (right != null) ret += right.toString(indent + 2);
- if (next != null) ret += next.toString(indent);
- return ret;
- }
-
- public Expr(String s) { this(Lexer.STRING); this.string = s; } // an identifier or label
- public Expr(int code, String s) { this(code); this.string = s; }
- public Expr(Number n) { this(Lexer.NUMBER); this.number = n; } // an identifier or label
- public Expr(int code) { this(code, null, null); }
- public Expr(int code, Expr left) { this(code, left, null); }
- public Expr(int code, Expr left, Expr right) { this.code = code; this.left = left; this.right = right; }
-
- public static Number toNumber(Object o) {
- if (o == null) return new Long(0);
- if (o instanceof Number) return ((Number)o);
- if (o instanceof String) return new Double((String)o);
- 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());
- }
-
- public static double toDouble(Object o) { return toNumber(o).doubleValue(); }
- public static long toLong(Object o) { return toNumber(o).longValue(); }
- 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;
- }
-
- public Object eval(final JS.Scope s) throws ControlTransferException, JS.Exn {
- switch(code) {
-
- case Lexer.BITOR: return new Long(toLong(left.eval(s)) | toLong(right.eval(s)));
- case Lexer.BITXOR: return new Long(toLong(left.eval(s)) ^ toLong(right.eval(s)));
- case Lexer.BITAND: return new Long(toLong(left.eval(s)) & toLong(right.eval(s)));
- case Lexer.BITNOT: return new Long(~toLong(left.eval(s)));
-
- case Lexer.ADD: {
- Object l = left.eval(s);
- Object r = right.eval(s);
- if (l instanceof String || r instanceof String) return l.toString() + r.toString();
- return new Double(toDouble(l) + toDouble(r));
- }
-
- case Lexer.SUB: return new Double(toDouble(left.eval(s)) - toDouble(right.eval(s)));
- case Lexer.MUL: return new Double(toDouble(left.eval(s)) * toDouble(right.eval(s)));
- case Lexer.DIV: return new Double(toDouble(left.eval(s)) / toDouble(right.eval(s)));
- case Lexer.MOD: return new Double(toDouble(left.eval(s)) % toDouble(right.eval(s)));
-
- case Lexer.LSH: return new Long(toLong(left.eval(s)) << toLong(right.eval(s)));
- case Lexer.RSH: return new Long(toLong(left.eval(s)) >> toLong(right.eval(s)));
- case Lexer.URSH: return new Long(toLong(left.eval(s)) >>> toLong(right.eval(s)));
-
- case Lexer.LT: return toDouble(left.eval(s)) < toDouble(right.eval(s)) ? Boolean.TRUE : Boolean.FALSE;
- case Lexer.LE: return toDouble(left.eval(s)) <= toDouble(right.eval(s)) ? Boolean.TRUE : Boolean.FALSE;
- case Lexer.GT: return toDouble(left.eval(s)) > toDouble(right.eval(s)) ? Boolean.TRUE : Boolean.FALSE;
- case Lexer.GE: return toDouble(left.eval(s)) >= toDouble(right.eval(s)) ? Boolean.TRUE : Boolean.FALSE;
-
- case Lexer.OR: return new Boolean(toBoolean(left.eval(s)) || toBoolean(right.eval(s)));
- case Lexer.AND: return new Boolean(toBoolean(left.eval(s)) && toBoolean(right.eval(s)));
-
- case Lexer.EQ:
- case Lexer.NE: {
- // FIXME: should use Javascript coercion-equality rules
- boolean ret = left.eval(s).equals(right.eval(s));
- return new Boolean(code == Lexer.EQ ? ret : !ret);
- }
-
- case Lexer.INC:
- case Lexer.DEC:
- case Lexer.ASSIGN: {
- Object v = (code == Lexer.ASSIGN) ? right.eval(s) : new Double(toDouble(left.eval(s)) + (code == Lexer.INC ? 1 : -1));
- if (left.code == Lexer.DOT) {
- Object o = left.left.eval(s);
- if (o instanceof String) {
- throw new Error("can't set properties on a String");
- } else if (o instanceof Number) {
- throw new Error("can't set properties on a Number");
- } else if (o instanceof Boolean) {
- throw new Error("can't set properties on a Boolean");
- } else {
- ((JS)left.left.eval(s)).put(left.right.eval(s), v);
- return v;
- }
- } else {
- s.put(left.string, v);
- return v;
- }
- }
-
- case Lexer.TYPEOF: {
- Object o = left.eval(s);
- if (o == null) return "null";
- if (o.getClass() == String.class) return "string";
- if (o.getClass() == Boolean.class) return "boolean";
- if (o instanceof Number) return "number";
- if (o instanceof JS.Array) return "array";
- if (o instanceof JS) return "object";
- throw new Error("typeof " + o.getClass().getName() + " unknown");
- }
-
- case Lexer.NUMBER: return number;
- case Lexer.STRING: return string;
-
- case Lexer.NULL: return null;
- case Lexer.THIS: return s;
- case Lexer.FALSE: return Boolean.FALSE;
- case Lexer.TRUE: return Boolean.TRUE;
- case Lexer.ASSERT: if (!toBoolean(left.eval(s))) throw new Error("assertion failed");
- case Lexer.THROW: throw new JS.Exn(left.eval(s));
-
- case Lexer.NAME: return s.get(string);
- case Lexer.DOT: {
- Object o = left.eval(s);
- Object v = right.eval(s);
- if (o instanceof String) {
- if (v.equals("length")) return new Integer(((String)o).length());
- throw new Error("Not Implemented: properties on String objects");
- } else if (o instanceof Boolean) {
- throw new Error("Not Implemented: properties on Boolean objects");
- } else if (o instanceof Number) {
- throw new Error("Not Implemented: properties on Number objects");
- } else if (o instanceof JS) {
- return ((JS)o).get(v);
- }
- }
-
- case Lexer.TRY: {
- boolean safeToExit = false;
- try {
- Object ret = left.eval(s);
- safeToExit = true;
- return ret;
- } catch (JS.Exn e) {
- Expr c = right;
- if (c.code == Lexer.CATCH) {
- JS.Scope scope = new JS.Scope(s);
- s.put(c.left.string, e);
- c.right.eval(scope);
- c = c.next;
- }
- if (c.code == Lexer.FINALLY) {
- JS.Scope scope = new JS.Scope(s);
- c.left.eval(scope);
- }
- } finally {
- if (!safeToExit) Log.log(this, "WARNING: Java exception penetrated a JavaScript try{} block");
- }
- return null;
- }
-
- case Lexer.LP:
- JS.Function f = (JS.Function)left.eval(s);
- JS.Array arguments = new JS.Array();
- for(Expr e = right; e != null; e = e.next) arguments.addElement(e.eval(s));
- return f.call(arguments);
-
- case Lexer.FUNCTION:
- return new JS.ObjFunction() {
- public JS.Scope getParentScopeOfDeclaration() { return s; }
- public Object call(JS.Array args) throws JS.Exn {
- JS.Scope scope = new JS.Scope(getParentScopeOfDeclaration()) {
- public Object get(Object key) throws JS.Exn {
- if (key.equals("trapee")) return org.xwt.Trap.currentTrapee();
- return super.get(key);
- }
- }
- // FIXME
- args.put("cascade", org.xwt.Trap.cascadeFunction);
- scope.put("arguments", args);
- int i = 0;
- for(Expr e = left; e != null; e = e.next) scope.put(e.string, args.get(new Integer(i++)));
- try {
- return right.eval(scope);
- } catch (ReturnException r) {
- return r.retval;
- } catch (ControlTransferException c) {
- throw new Error("error, ControlTransferException tried to leave a function: " + c);
- }
- }
- };
-
- case Lexer.FOR:
- Object[] keys = ((JS)left.right.eval(s)).enumerateProperties();
- try {
- for(int i=0; i<keys.length; i++) {
- JS.Scope scope = new JS.Scope(s);
- scope.put(left.left.string, keys[i]);
- try {
- right.eval(scope);
- } catch (ContinueException c) { /* FIXME: handle labels */ }
- }
- } catch (BreakException b) { /* FIXME: handle labels */ }
- return null;
-
- case Lexer.SWITCH:
- Object switchVal = left.eval(s);
- boolean go = false;
- try {
- for(Expr e = right; e != null; e = e.next) {
- if (go || e.code == Lexer.DEFAULT || e.left.eval(s).equals(switchVal)) go = true;
- if (go) e.right.eval(s);
- }
- } catch (BreakException b) { /* FIXME: handle labels */ }
- return null;
-
- case Lexer.LB: {
- JS.Array ret = new JS.Array();
- for(Expr e = left; e != null; e = e.next) ret.addElement(e.eval(s));
- return ret;
- }
-
- case Lexer.LC: // block
- for(Expr e = left; e != null; e = e.next) e.eval(s);
- return null;
-
- case Lexer.RC: { // Object ctor
- JS.Obj ret = new JS.Obj();
- for(Expr e = left; e != null; e = e.next)
- ret.put(e.left.string, e.right.eval(s));
- return ret;
- }
-
- case Lexer.VAR:
- for(Expr e = left; e != null; e = e.next)
- if (e.code == Lexer.NAME) {
- s.declare(e.string);
- } else {
- s.declare(e.left.string);
- e.eval(s);
- }
- return null;
-
- case Lexer.HOOK: return toBoolean(left.eval(s)) ? right.left.eval(s) : right.right.eval(s);
- case Lexer.IF: return toBoolean(left.eval(s)) ? right.left.eval(s) : right.right.eval(s);
-
- case Lexer.BREAK: throw new BreakException(string);
- case Lexer.CONTINUE: throw new ContinueException(string);
- case Lexer.RETURN: throw new ReturnException(left == null ? null : left.eval(s));
-
- case Lexer.WHILE:
- case Lexer.DO:
- try {
- boolean first = true;
- while((first && code == Lexer.DO) || toBoolean(left.eval(s))) {
- first = false;
- try { right.eval(s); }
- catch (ContinueException e) {
- if (e.label != null && !e.label.equals(string)) throw e;
- }
- }
- } catch (BreakException e) {
- if (e.label != null && !e.label.equals(string)) throw e;
- }
- return null;
-
- default: throw new Error("don't know how to eval an Expr with code " + Lexer.codeToString[code]);
- }
- }
-
- private static abstract class ControlTransferException extends Exception { }
- private static class BreakException extends ControlTransferException {
- public String label;
- BreakException(String label) { this.label = label; }
- }
- private static class ContinueException extends ControlTransferException {
- public String label;
- ContinueException(String label) { this.label = label; }
- }
- private static class ReturnException extends ControlTransferException {
- public Object retval;
- ReturnException(Object retval) { this.retval = retval; }
- }
-}
-
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