1 // Copyright 2004 Adam Megacz, see the COPYING file for licensing [GPL]
4 import org.ibex.util.*;
8 * Parses a stream of lexed tokens into a tree of JSFunction's.
10 * There are three kinds of things we parse: blocks, statements, and
13 * - Expressions are a special type of statement that evaluates to a
14 * value (for example, "break" is not an expression, * but "3+2"
15 * is). Some tokens sequences start expressions (for * example,
16 * literal numbers) and others continue an expression which * has
17 * already been begun (for example, '+'). Finally, some *
18 * expressions are valid targets for an assignment operation; after
19 * * each of these expressions, continueExprAfterAssignable() is
20 * called * to check for an assignment operation.
22 * - A statement ends with a semicolon and does not return a value.
24 * - A block is a single statement or a sequence of statements
25 * surrounded by curly braces.
27 * Each parsing method saves the parserLine before doing its actual
28 * work and restores it afterwards. This ensures that parsing a
29 * subexpression does not modify the line number until a token
30 * *after* the subexpression has been consumed by the parent
33 * Technically it would be a better design for this class to build an
34 * intermediate parse tree and use that to emit bytecode. Here's the
37 * Advantages of building a parse tree:
38 * - easier to apply optimizations
39 * - would let us handle more sophisticated languages than JavaScript
41 * Advantages of leaving out the parse tree
42 * - faster compilation
43 * - less load on the garbage collector
44 * - much simpler code, easier to understand
47 * Fortunately JS is such a simple language that we can get away with
48 * the half-assed approach and still produce a working, complete
51 * The bytecode language emitted doesn't really cause any appreciable
52 * semantic loss, and is itself a parseable language very similar to
53 * Forth or a postfix variant of LISP. This means that the bytecode
54 * can be transformed into a parse tree, which can be manipulated.
55 * So if we ever want to add an optimizer, it could easily be done by
56 * producing a parse tree from the bytecode, optimizing that tree,
57 * and then re-emitting the bytecode. The parse tree node class
58 * would also be much simpler since the bytecode language has so few
61 * Actually, the above paragraph is slightly inaccurate -- there are
62 * places where we push a value and then perform an arbitrary number
63 * of operations using it before popping it; this doesn't parse well.
64 * But these cases are clearly marked and easy to change if we do
65 * need to move to a parse tree format.
67 class Parser extends Lexer implements ByteCodes {
70 // Constructors //////////////////////////////////////////////////////
72 public Parser(Reader r, String sourceName, int line) throws IOException { super(r, sourceName, line); }
75 public static void main(String[] s) throws IOException {
76 JS block = JS.fromReader("stdin", 0, new InputStreamReader(System.in));
77 if (block == null) return;
78 System.out.println(block);
82 // Statics ////////////////////////////////////////////////////////////
84 static byte[] precedence = new byte[MAX_TOKEN + 1];
85 static boolean[] isRightAssociative = new boolean[MAX_TOKEN + 1];
86 // Use this as the precedence when we want anything up to the comma
87 private final static int NO_COMMA = 2;
89 isRightAssociative[ASSIGN] =
90 isRightAssociative[ASSIGN_BITOR] =
91 isRightAssociative[ASSIGN_BITXOR] =
92 isRightAssociative[ASSIGN_BITAND] =
93 isRightAssociative[ASSIGN_LSH] =
94 isRightAssociative[ASSIGN_RSH] =
95 isRightAssociative[ASSIGN_URSH] =
96 isRightAssociative[ASSIGN_ADD] =
97 isRightAssociative[ASSIGN_SUB] =
98 isRightAssociative[ASSIGN_MUL] =
99 isRightAssociative[ASSIGN_DIV] =
100 isRightAssociative[ASSIGN_MOD] =
101 isRightAssociative[ADD_TRAP] =
102 isRightAssociative[DEL_TRAP] =
105 precedence[COMMA] = 1;
106 // 2 is intentionally left unassigned. we use minPrecedence==2 for comma separated lists
108 precedence[ASSIGN_BITOR] =
109 precedence[ASSIGN_BITXOR] =
110 precedence[ASSIGN_BITAND] =
111 precedence[ASSIGN_LSH] =
112 precedence[ASSIGN_RSH] =
113 precedence[ASSIGN_URSH] =
114 precedence[ASSIGN_ADD] =
115 precedence[ASSIGN_SUB] =
116 precedence[ASSIGN_MUL] =
117 precedence[ASSIGN_DIV] =
118 precedence[ADD_TRAP] =
119 precedence[DEL_TRAP] =
120 precedence[ASSIGN_MOD] = 3;
121 precedence[HOOK] = 4;
124 precedence[BITOR] = 7;
125 precedence[BITXOR] = 8;
126 precedence[BITAND] = 9;
127 precedence[EQ] = precedence[NE] = precedence[SHEQ] = precedence[SHNE] = 10;
128 precedence[LT] = precedence[LE] = precedence[GT] = precedence[GE] = 11;
129 precedence[LSH] = precedence[RSH] = precedence[URSH] = 12;
130 precedence[ADD] = precedence[SUB] = 12;
131 precedence[MUL] = precedence[DIV] = precedence[MOD] = 13;
132 precedence[BITNOT] = precedence[BANG] = precedence[TYPEOF] = 14;
133 precedence[DOT] = precedence[LB] = precedence[LP] = precedence[INC] = precedence[DEC] = 15;
137 // Parsing Logic /////////////////////////////////////////////////////////
139 /** gets a token and throws an exception if it is not <tt>code</tt> */
140 private void consume(int code) throws IOException {
141 if (getToken() != code) {
142 if(code == NAME) switch(op) {
143 case RETURN: case TYPEOF: case BREAK: case CONTINUE: case TRY: case THROW:
144 case ASSERT: case NULL: case TRUE: case FALSE: case IN: case IF: case ELSE:
145 case SWITCH: case CASE: case DEFAULT: case WHILE: case VAR: case WITH:
146 case CATCH: case FINALLY:
147 throw pe("Bad variable name; '" + codeToString[op].toLowerCase() + "' is a javascript keyword");
149 throw pe("expected " + codeToString[code] + ", got " + (op == -1 ? "EOF" : codeToString[op]));
154 * Parse the largest possible expression containing no operators
155 * of precedence below <tt>minPrecedence</tt> and append the
156 * bytecodes for that expression to <tt>appendTo</tt>; the
157 * appended bytecodes MUST grow the stack by exactly one element.
159 private void startExpr(JSFunction appendTo, int minPrecedence) throws IOException {
160 int saveParserLine = parserLine;
161 _startExpr(appendTo, minPrecedence);
162 parserLine = saveParserLine;
164 private void _startExpr(JSFunction appendTo, int minPrecedence) throws IOException {
165 int tok = getToken();
166 JSFunction b = appendTo;
169 case -1: throw pe("expected expression");
171 // all of these simply push values onto the stack
172 case NUMBER: b.add(parserLine, LITERAL, number); break;
173 case STRING: b.add(parserLine, LITERAL, string); break;
174 case NULL: b.add(parserLine, LITERAL, null); break;
175 case TRUE: case FALSE: b.add(parserLine, LITERAL, JS.B(tok == TRUE)); break;
180 b.add(parserLine, TOPSCOPE);
181 b.add(parserLine, LITERAL, "");
182 b.add(parserLine, GET);
183 b.add(parserLine, LITERAL, string);
184 b.add(parserLine, GET);
185 continueExpr(b, minPrecedence);
190 b.add(parserLine, ARRAY, JS.ZERO); // push an array onto the stack
193 if (peekToken() != RB)
194 while(true) { // iterate over the initialization values
195 b.add(parserLine, LITERAL, JS.N(i++)); // push the index in the array to place it into
196 if (peekToken() == COMMA || peekToken() == RB)
197 b.add(parserLine, LITERAL, null); // for stuff like [1,,2,]
199 startExpr(b, NO_COMMA); // push the value onto the stack
200 b.add(parserLine, PUT); // put it into the array
201 b.add(parserLine, POP); // discard the value remaining on the stack
202 if (peekToken() == RB) break;
205 b.set(size0 - 1, JS.N(i)); // back at the ARRAY instruction, write the size of the array
209 case SUB: { // negative literal (like "3 * -1")
211 b.add(parserLine, LITERAL, JS.N(number.doubleValue() * -1));
214 case LP: { // grouping (not calling)
219 case INC: case DEC: { // prefix (not postfix)
220 startExpr(b, precedence[tok]);
221 int prev = b.size - 1;
222 if (b.get(prev) == GET && b.getArg(prev) != null)
223 b.set(prev, LITERAL, b.getArg(prev));
224 else if(b.get(prev) == GET)
227 throw pe("prefixed increment/decrement can only be performed on a valid assignment target");
228 b.add(parserLine, GET_PRESERVE, Boolean.TRUE);
229 b.add(parserLine, LITERAL, JS.N(1));
230 b.add(parserLine, tok == INC ? ADD : SUB, JS.N(2));
231 b.add(parserLine, PUT, null);
232 b.add(parserLine, SWAP, null);
233 b.add(parserLine, POP, null);
236 case BANG: case BITNOT: case TYPEOF: {
237 startExpr(b, precedence[tok]);
238 b.add(parserLine, tok);
241 case LC: { // object constructor
242 b.add(parserLine, OBJECT, null); // put an object on the stack
243 if (peekToken() != RC)
245 if (peekToken() != NAME && peekToken() != STRING)
246 throw pe("expected NAME or STRING");
248 b.add(parserLine, LITERAL, string); // grab the key
250 startExpr(b, NO_COMMA); // grab the value
251 b.add(parserLine, PUT); // put the value into the object
252 b.add(parserLine, POP); // discard the remaining value
253 if (peekToken() == RC) break;
255 if (peekToken() == RC) break; // we permit {,,} -- I'm not sure if ECMA does
261 b.add(parserLine, TOPSCOPE);
262 b.add(parserLine, LITERAL, string);
263 continueExprAfterAssignable(b,minPrecedence);
269 JSFunction b2 = new JSFunction(sourceName, parserLine, null);
270 b.add(parserLine, NEWFUNCTION, b2);
272 // function prelude; arguments array is already on the stack
273 b2.add(parserLine, TOPSCOPE);
274 b2.add(parserLine, SWAP);
275 b2.add(parserLine, DECLARE, "arguments"); // declare arguments (equivalent to 'var arguments;')
276 b2.add(parserLine, SWAP); // set this.arguments and leave the value on the stack
277 b2.add(parserLine, PUT);
279 while(peekToken() != RP) { // run through the list of argument names
281 if (peekToken() == NAME) {
282 consume(NAME); // a named argument
283 String varName = string;
285 b2.add(parserLine, DUP); // dup the args array
286 b2.add(parserLine, GET, JS.N(numArgs - 1)); // retrieve it from the arguments array
287 b2.add(parserLine, TOPSCOPE);
288 b2.add(parserLine, SWAP);
289 b2.add(parserLine, DECLARE, varName); // declare the name
290 b2.add(parserLine, SWAP);
291 b2.add(parserLine, PUT);
292 b2.add(parserLine, POP); // pop the value
293 b2.add(parserLine, POP); // pop the scope
295 if (peekToken() == RP) break;
300 b2.numFormalArgs = numArgs;
301 b2.add(parserLine, POP); // pop off the arguments array
302 b2.add(parserLine, POP); // pop off TOPSCOPE
304 if(peekToken() != LC)
305 throw pe("JSFunctions must have a block surrounded by curly brackets");
307 parseBlock(b2, null); // the function body
309 b2.add(parserLine, LITERAL, null); // in case we "fall out the bottom", return NULL
310 b2.add(parserLine, RETURN);
314 default: throw pe("expected expression, found " + codeToString[tok] + ", which cannot start an expression");
317 // attempt to continue the expression
318 continueExpr(b, minPrecedence);
321 private Grammar parseGrammar(Grammar g) throws IOException {
322 int tok = getToken();
325 case BITOR: return new Grammar.Alternative(g, parseGrammar(null));
326 case ADD: return parseGrammar(new Grammar.Repetition(g, 1, Integer.MAX_VALUE));
327 case MUL: return parseGrammar(new Grammar.Repetition(g, 0, Integer.MAX_VALUE));
328 case HOOK: return parseGrammar(new Grammar.Repetition(g, 0, 1));
332 //case NUMBER: g0 = new Grammar.Literal(number); break;
333 case NAME: g0 = new Grammar.Reference(string); break;
335 g0 = new Grammar.Literal(string);
336 if (peekToken() == DOT) {
341 if (old.length() != 1 || string.length() != 1) throw pe("literal ranges must be single-char strings");
342 g0 = new Grammar.Range(old.charAt(0), string.charAt(0));
345 case LP: g0 = parseGrammar(null); consume(RP); break;
346 default: pushBackToken(); return g;
348 if (g == null) return parseGrammar(g0);
349 return parseGrammar(new Grammar.Juxtaposition(g, g0));
353 * Assuming that a complete assignable (lvalue) has just been
354 * parsed and the object and key are on the stack,
355 * <tt>continueExprAfterAssignable</tt> will attempt to parse an
356 * expression that modifies the assignable. This method always
357 * decreases the stack depth by exactly one element.
359 private void continueExprAfterAssignable(JSFunction b,int minPrecedence) throws IOException {
360 int saveParserLine = parserLine;
361 _continueExprAfterAssignable(b,minPrecedence);
362 parserLine = saveParserLine;
364 private void _continueExprAfterAssignable(JSFunction b,int minPrecedence) throws IOException {
365 if (b == null) throw new Error("got null b; this should never happen");
366 int tok = getToken();
367 if (minPrecedence != -1 && (precedence[tok] < minPrecedence || (precedence[tok] == minPrecedence && !isRightAssociative[tok])))
368 // force the default case
373 b.add(parserLine, GET_PRESERVE);
374 Grammar g = parseGrammar(null);
375 if (peekToken() == LC) {
376 g.action = new JSFunction(sourceName, parserLine, null);
377 parseBlock((JSFunction)g.action);
378 ((JSFunction)g.action).add(parserLine, LITERAL, null); // in case we "fall out the bottom", return NULL
379 ((JSFunction)g.action).add(parserLine, RETURN);
381 b.add(parserLine, MAKE_GRAMMAR, g);
382 b.add(parserLine, PUT);
386 case ASSIGN_BITOR: case ASSIGN_BITXOR: case ASSIGN_BITAND: case ASSIGN_LSH: case ASSIGN_RSH: case ASSIGN_URSH:
387 case ASSIGN_MUL: case ASSIGN_DIV: case ASSIGN_MOD: case ASSIGN_ADD: case ASSIGN_SUB: case ADD_TRAP: case DEL_TRAP: {
388 if (tok != ADD_TRAP && tok != DEL_TRAP) b.add(parserLine, GET_PRESERVE);
390 startExpr(b, precedence[tok]);
392 if (tok != ADD_TRAP && tok != DEL_TRAP) {
393 // tok-1 is always s/^ASSIGN_// (0 is BITOR, 1 is ASSIGN_BITOR, etc)
394 b.add(parserLine, tok - 1, tok-1==ADD ? JS.N(2) : null);
395 b.add(parserLine, PUT);
396 b.add(parserLine, SWAP);
397 b.add(parserLine, POP);
399 b.add(parserLine, tok);
403 case INC: case DEC: { // postfix
404 b.add(parserLine, GET_PRESERVE, Boolean.TRUE);
405 b.add(parserLine, LITERAL, JS.N(1));
406 b.add(parserLine, tok == INC ? ADD : SUB, JS.N(2));
407 b.add(parserLine, PUT, null);
408 b.add(parserLine, SWAP, null);
409 b.add(parserLine, POP, null);
410 b.add(parserLine, LITERAL, JS.N(1));
411 b.add(parserLine, tok == INC ? SUB : ADD, null); // undo what we just did, since this is postfix
415 startExpr(b, precedence[tok]);
416 b.add(parserLine, PUT);
417 b.add(parserLine, SWAP);
418 b.add(parserLine, POP);
423 // Method calls are implemented by doing a GET_PRESERVE
424 // first. If the object supports method calls, it will
426 int n = parseArgs(b, 2);
427 b.add(parserLine, GET_PRESERVE);
428 b.add(parserLine, CALLMETHOD, JS.N(n));
433 if(b.get(b.size-1) == LITERAL && b.getArg(b.size-1) != null)
434 b.set(b.size-1,GET,b.getArg(b.size-1));
436 b.add(parserLine, GET);
444 * Assuming that a complete expression has just been parsed,
445 * <tt>continueExpr</tt> will attempt to extend this expression by
446 * parsing additional tokens and appending additional bytecodes.
448 * No operators with precedence less than <tt>minPrecedence</tt>
451 * If any bytecodes are appended, they will not alter the stack
454 private void continueExpr(JSFunction b, int minPrecedence) throws IOException {
455 int saveParserLine = parserLine;
456 _continueExpr(b, minPrecedence);
457 parserLine = saveParserLine;
459 private void _continueExpr(JSFunction b, int minPrecedence) throws IOException {
460 if (b == null) throw new Error("got null b; this should never happen");
461 int tok = getToken();
462 if (tok == -1) return;
463 if (minPrecedence != -1 && (precedence[tok] < minPrecedence || (precedence[tok] == minPrecedence && !isRightAssociative[tok]))) {
469 case LP: { // invocation (not grouping)
470 int n = parseArgs(b, 1);
471 b.add(parserLine, CALL, JS.N(n));
474 case BITOR: case BITXOR: case BITAND: case SHEQ: case SHNE: case LSH:
475 case RSH: case URSH: case MUL: case DIV: case MOD:
476 case GT: case GE: case EQ: case NE: case LT: case LE: case SUB: {
477 startExpr(b, precedence[tok]);
478 b.add(parserLine, tok);
485 startExpr(b,precedence[tok]);
487 nextTok = getToken();
488 } while(nextTok == tok);
490 b.add(parserLine, tok, JS.N(count));
494 b.add(parserLine, tok == AND ? JSFunction.JF : JSFunction.JT, JS.ZERO); // test to see if we can short-circuit
496 startExpr(b, precedence[tok]); // otherwise check the second value
497 b.add(parserLine, JMP, JS.N(2)); // leave the second value on the stack and jump to the end
498 b.add(parserLine, LITERAL, tok == AND ?
499 JS.B(false) : JS.B(true)); // target of the short-circuit jump is here
500 b.set(size - 1, JS.N(b.size - size)); // write the target of the short-circuit jump
504 // support foo..bar syntax for foo[""].bar
505 if (peekToken() == DOT) {
510 b.add(parserLine, LITERAL, string);
511 continueExprAfterAssignable(b,minPrecedence);
514 case LB: { // subscripting (not array constructor)
517 continueExprAfterAssignable(b,minPrecedence);
521 b.add(parserLine, JF, JS.ZERO); // jump to the if-false expression
523 startExpr(b, minPrecedence); // write the if-true expression
524 b.add(parserLine, JMP, JS.ZERO); // if true, jump *over* the if-false expression
525 b.set(size - 1, JS.N(b.size - size + 1)); // now we know where the target of the jump is
528 startExpr(b, minPrecedence); // write the if-false expression
529 b.set(size - 1, JS.N(b.size - size + 1)); // this is the end; jump to here
533 // pop the result of the previous expression, it is ignored
534 b.add(parserLine,POP);
544 continueExpr(b, minPrecedence); // try to continue the expression
547 // parse a set of comma separated function arguments, assume LP has already been consumed
548 // if swap is true, (because the function is already on the stack) we will SWAP after each argument to keep it on top
549 private int parseArgs(JSFunction b, int pushdown) throws IOException {
551 while(peekToken() != RP) {
553 if (peekToken() != COMMA) {
554 startExpr(b, NO_COMMA);
555 b.add(parserLine, SWAP, JS.N(pushdown));
556 if (peekToken() == RP) break;
564 /** Parse a block of statements which must be surrounded by LC..RC. */
565 void parseBlock(JSFunction b) throws IOException { parseBlock(b, null); }
566 void parseBlock(JSFunction b, String label) throws IOException {
567 int saveParserLine = parserLine;
568 _parseBlock(b, label);
569 parserLine = saveParserLine;
571 void _parseBlock(JSFunction b, String label) throws IOException {
572 if (peekToken() == -1) return;
573 else if (peekToken() != LC) parseStatement(b, null);
576 while(peekToken() != RC && peekToken() != -1) parseStatement(b, null);
581 /** Parse a single statement, consuming the RC or SEMI which terminates it. */
582 void parseStatement(JSFunction b, String label) throws IOException {
583 int saveParserLine = parserLine;
584 _parseStatement(b, label);
585 parserLine = saveParserLine;
587 void _parseStatement(JSFunction b, String label) throws IOException {
588 int tok = peekToken();
589 if (tok == -1) return;
590 switch(tok = getToken()) {
592 case THROW: case ASSERT: case RETURN: {
593 if (tok == RETURN && peekToken() == SEMI)
594 b.add(parserLine, LITERAL, null);
597 b.add(parserLine, tok);
601 case BREAK: case CONTINUE: {
602 if (peekToken() == NAME) consume(NAME);
603 b.add(parserLine, tok, string);
608 b.add(parserLine, TOPSCOPE); // push the current scope
611 b.add(parserLine, DECLARE, string); // declare it
612 if (peekToken() == ASSIGN) { // if there is an '=' after the variable name
614 startExpr(b, NO_COMMA);
615 b.add(parserLine, PUT); // assign it
616 b.add(parserLine, POP); // clean the stack
618 b.add(parserLine, POP); // pop the string pushed by declare
620 if (peekToken() != COMMA) break;
623 b.add(parserLine, POP); // pop off the topscope
624 if ((mostRecentlyReadToken != RC || peekToken() == SEMI) && peekToken() != -1 && mostRecentlyReadToken != SEMI) consume(SEMI);
632 b.add(parserLine, JF, JS.ZERO); // if false, jump to the else-block
634 parseStatement(b, null);
636 if (peekToken() == ELSE) {
638 b.add(parserLine, JMP, JS.ZERO); // if we took the true-block, jump over the else-block
639 b.set(size - 1, JS.N(b.size - size + 1));
641 parseStatement(b, null);
643 b.set(size - 1, JS.N(b.size - size + 1)); // regardless of which branch we took, b[size] needs to point here
648 if (label != null) b.add(parserLine, LABEL, label);
649 b.add(parserLine, LOOP);
651 b.add(parserLine, POP); // discard the first-iteration indicator
653 b.add(parserLine, JT, JS.N(2)); // if the while() clause is true, jump over the BREAK
654 b.add(parserLine, BREAK);
656 parseStatement(b, null);
657 b.add(parserLine, CONTINUE); // if we fall out of the end, definately continue
658 b.set(size - 1, JS.N(b.size - size + 1)); // end of the loop
663 if (label != null) b.add(parserLine, LABEL, label);
664 b.add(parserLine, LOOP);
670 if (peekToken() == CASE) { // we compile CASE statements like a bunch of if..else's
672 b.add(parserLine, DUP); // duplicate the switch() value; we'll consume one copy
675 b.add(parserLine, EQ); // check if we should do this case-block
676 b.add(parserLine, JF, JS.ZERO); // if not, jump to the next one
678 while(peekToken() != CASE && peekToken() != DEFAULT && peekToken() != RC) parseStatement(b, null);
679 b.set(size - 1, JS.N(1 + b.size - size));
680 } else if (peekToken() == DEFAULT) {
683 while(peekToken() != CASE && peekToken() != DEFAULT && peekToken() != RC) parseStatement(b, null);
684 } else if (peekToken() == RC) {
686 b.add(parserLine, BREAK); // break out of the loop if we 'fall through'
689 throw pe("expected CASE, DEFAULT, or RC; got " + codeToString[peekToken()]);
691 b.set(size0 - 1, JS.N(b.size - size0 + 1)); // end of the loop
696 if (label != null) b.add(parserLine, LABEL, label);
697 b.add(parserLine, LOOP);
699 parseStatement(b, null);
703 b.add(parserLine, JT, JS.N(2)); // check the while() clause; jump over the BREAK if true
704 b.add(parserLine, BREAK);
705 b.add(parserLine, CONTINUE);
708 b.set(size - 1, JS.N(b.size - size + 1)); // end of the loop; write this location to the LOOP instruction
713 b.add(parserLine, TRY); // try bytecode causes a TryMarker to be pushed
714 int tryInsn = b.size - 1;
715 // parse the expression to be TRYed
716 parseStatement(b, null);
717 // pop the try marker. this is pushed when the TRY bytecode is executed
718 b.add(parserLine, POP);
719 // jump forward to the end of the catch block, start of the finally block
720 b.add(parserLine, JMP);
721 int successJMPInsn = b.size - 1;
723 if (peekToken() != CATCH && peekToken() != FINALLY)
724 throw pe("try without catch or finally");
726 int catchJMPDistance = -1;
727 if (peekToken() == CATCH) {
728 Vec catchEnds = new Vec();
729 boolean catchAll = false;
731 catchJMPDistance = b.size - tryInsn;
733 while(peekToken() == CATCH && !catchAll) {
738 exceptionVar = string;
739 int[] writebacks = new int[] { -1, -1, -1 };
740 if (peekToken() != RP) {
741 // extended Ibex catch block: catch(e faultCode "foo.bar.baz")
743 b.add(parserLine, DUP);
744 b.add(parserLine, LITERAL, string);
745 b.add(parserLine, GET);
746 b.add(parserLine, DUP);
747 b.add(parserLine, LITERAL, null);
748 b.add(parserLine, EQ);
749 b.add(parserLine, JT);
750 writebacks[0] = b.size - 1;
751 if (peekToken() == STRING) {
753 b.add(parserLine, DUP);
754 b.add(parserLine, LITERAL, string);
755 b.add(parserLine, LT);
756 b.add(parserLine, JT);
757 writebacks[1] = b.size - 1;
758 b.add(parserLine, DUP);
759 b.add(parserLine, LITERAL, string + "/"); // (slash is ASCII after dot)
760 b.add(parserLine, GE);
761 b.add(parserLine, JT);
762 writebacks[2] = b.size - 1;
765 b.add(parserLine, DUP);
766 b.add(parserLine, LITERAL, number);
767 b.add(parserLine, EQ);
768 b.add(parserLine, JF);
769 writebacks[1] = b.size - 1;
771 b.add(parserLine, POP); // pop the element thats on the stack from the compare
776 // the exception is on top of the stack; put it to the chosen name
777 b.add(parserLine, NEWSCOPE);
778 b.add(parserLine, TOPSCOPE);
779 b.add(parserLine, SWAP);
780 b.add(parserLine, LITERAL,exceptionVar);
781 b.add(parserLine, DECLARE);
782 b.add(parserLine, SWAP);
783 b.add(parserLine, PUT);
784 b.add(parserLine, POP);
785 b.add(parserLine, POP);
787 b.add(parserLine, OLDSCOPE);
789 b.add(parserLine, JMP);
790 catchEnds.addElement(new Integer(b.size-1));
792 for(int i=0; i<3; i++) if (writebacks[i] != -1) b.set(writebacks[i], JS.N(b.size-writebacks[i]));
793 b.add(parserLine, POP); // pop the element thats on the stack from the compare
797 b.add(parserLine, THROW);
799 for(int i=0;i<catchEnds.size();i++) {
800 int n = ((Integer)catchEnds.elementAt(i)).intValue();
801 b.set(n, JS.N(b.size-n));
804 // pop the try and catch markers
805 b.add(parserLine,POP);
806 b.add(parserLine,POP);
809 // jump here if no exception was thrown
810 b.set(successJMPInsn, JS.N(b.size - successJMPInsn));
812 int finallyJMPDistance = -1;
813 if (peekToken() == FINALLY) {
814 b.add(parserLine, LITERAL, null); // null FinallyData
815 finallyJMPDistance = b.size - tryInsn;
817 parseStatement(b, null);
818 b.add(parserLine,FINALLY_DONE);
821 // setup the TRY arguments
822 b.set(tryInsn, new int[] { catchJMPDistance, finallyJMPDistance });
831 boolean hadVar = false; // if it's a for..in, we ignore the VAR
832 if (tok == VAR) { hadVar = true; tok = getToken(); }
833 String varName = string;
834 boolean forIn = peekToken() == IN; // determine if this is a for..in loop or not
835 pushBackToken(tok, varName);
838 b.add(parserLine, NEWSCOPE); // for-loops always create new scopes
839 b.add(parserLine, LITERAL, varName); // declare the new variable
840 b.add(parserLine, DECLARE);
842 b.add(parserLine, LOOP); // we actually only add this to ensure that BREAK works
843 b.add(parserLine, POP); // discard the first-iteration indicator
848 b.add(parserLine, PUSHKEYS); // push the keys as an array; check the length
849 b.add(parserLine, LITERAL, "length");
850 b.add(parserLine, GET);
853 b.add(parserLine, LITERAL, JS.N(1)); // decrement the length
854 b.add(parserLine, SUB);
855 b.add(parserLine, DUP);
856 b.add(parserLine, LITERAL, JS.ZERO); // see if we've exhausted all the elements
857 b.add(parserLine, LT);
858 b.add(parserLine, JF, JS.N(2));
859 b.add(parserLine, BREAK); // if we have, then BREAK
860 b.add(parserLine, GET_PRESERVE); // get the key out of the keys array
861 b.add(parserLine, LITERAL, varName);
862 b.add(parserLine, PUT); // write it to this[varName]
863 parseStatement(b, null); // do some stuff
864 b.add(parserLine, CONTINUE); // continue if we fall out the bottom
866 b.set(size - 1, JS.N(b.size - size + 1)); // BREAK to here
867 b.add(parserLine, OLDSCOPE); // restore the scope
870 if (hadVar) pushBackToken(VAR, null); // yeah, this actually matters
871 b.add(parserLine, NEWSCOPE); // grab a fresh scope
873 parseStatement(b, null); // initializer
874 JSFunction e2 = // we need to put the incrementor before the test
875 new JSFunction(sourceName, parserLine, null); // so we save the test here
876 if (peekToken() != SEMI)
879 e2.add(parserLine, JSFunction.LITERAL, Boolean.TRUE); // handle the for(foo;;foo) case
881 if (label != null) b.add(parserLine, LABEL, label);
882 b.add(parserLine, LOOP);
885 b.add(parserLine, JT, JS.ZERO); // if we're on the first iteration, jump over the incrementor
887 if (peekToken() != RP) { // do the increment thing
889 b.add(parserLine, POP);
891 b.set(size - 1, JS.N(b.size - size + 1));
894 b.paste(e2); // ok, *now* test if we're done yet
895 b.add(parserLine, JT, JS.N(2)); // break out if we don't meet the test
896 b.add(parserLine, BREAK);
897 parseStatement(b, null);
898 b.add(parserLine, CONTINUE); // if we fall out the bottom, CONTINUE
899 b.set(size2 - 1, JS.N(b.size - size2 + 1)); // end of the loop
901 b.add(parserLine, OLDSCOPE); // get our scope back
906 case NAME: { // either a label or an identifier; this is the one place we're not LL(1)
907 String possiblyTheLabel = string;
908 if (peekToken() == COLON) { // label
910 parseStatement(b, possiblyTheLabel);
912 } else { // expression
913 pushBackToken(NAME, possiblyTheLabel);
915 b.add(parserLine, POP);
916 if ((mostRecentlyReadToken != RC || peekToken() == SEMI) && peekToken() != -1 && mostRecentlyReadToken != SEMI) consume(SEMI);
921 case SEMI: return; // yep, the null statement is valid
923 case LC: { // blocks are statements too
925 b.add(parserLine, NEWSCOPE);
926 parseBlock(b, label);
927 b.add(parserLine, OLDSCOPE);
931 default: { // hope that it's an expression
934 b.add(parserLine, POP);
935 if ((mostRecentlyReadToken != RC || peekToken() == SEMI) && peekToken() != -1 && mostRecentlyReadToken != SEMI) consume(SEMI);
942 // ParserException //////////////////////////////////////////////////////////////////////
943 private IOException pe(String s) { return new IOException(sourceName + ":" + line + " " + s); }