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, JS.N(number)); break;
173 case STRING: b.add(parserLine, LITERAL, JSString.intern(string)); break;
174 case NULL: b.add(parserLine, LITERAL, null); break;
175 case TRUE: case FALSE: b.add(parserLine, LITERAL, tok == TRUE ? JS.T : JS.F); break;
180 b.add(parserLine, TOPSCOPE);
181 b.add(parserLine, LITERAL, JSString.intern(""));
182 b.add(parserLine, GET);
183 b.add(parserLine, LITERAL, JSString.intern(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: case ADD: {
210 if(peekToken() == NUMBER) { // literal
212 b.add(parserLine, LITERAL, JS.N(number.doubleValue() * (tok == SUB ? -1 : 1)));
213 } else { // unary +/- operator
214 if(tok == SUB) b.add(parserLine, LITERAL, JS.ZERO);
215 // BITNOT has the same precedence as the unary +/- operators
216 startExpr(b,precedence[BITNOT]);
217 if(tok == ADD) b.add(parserLine, LITERAL, JS.ZERO); // HACK to force expr into a numeric context
218 b.add(parserLine, SUB);
222 case LP: { // grouping (not calling)
227 case INC: case DEC: { // prefix (not postfix)
228 startExpr(b, precedence[tok]);
229 int prev = b.size - 1;
230 if (b.get(prev) == GET && b.getArg(prev) != null)
231 b.set(prev, LITERAL, b.getArg(prev));
232 else if(b.get(prev) == GET)
235 throw pe("prefixed increment/decrement can only be performed on a valid assignment target");
236 b.add(parserLine, GET_PRESERVE, Boolean.TRUE);
237 b.add(parserLine, LITERAL, JS.N(1));
238 b.add(parserLine, tok == INC ? ADD : SUB, JS.N(2));
239 b.add(parserLine, PUT, null);
240 b.add(parserLine, SWAP, null);
241 b.add(parserLine, POP, null);
244 case BANG: case BITNOT: case TYPEOF: {
245 startExpr(b, precedence[tok]);
246 b.add(parserLine, tok);
249 case LC: { // object constructor
250 b.add(parserLine, OBJECT, null); // put an object on the stack
251 if (peekToken() != RC)
253 if (peekToken() != NAME && peekToken() != STRING)
254 throw pe("expected NAME or STRING");
256 b.add(parserLine, LITERAL, JSString.intern(string)); // grab the key
258 startExpr(b, NO_COMMA); // grab the value
259 b.add(parserLine, PUT); // put the value into the object
260 b.add(parserLine, POP); // discard the remaining value
261 if (peekToken() == RC) break;
263 if (peekToken() == RC) break; // we permit {,,} -- I'm not sure if ECMA does
269 b.add(parserLine, TOPSCOPE);
270 b.add(parserLine, LITERAL, JSString.intern(string));
271 continueExprAfterAssignable(b,minPrecedence);
277 JSFunction b2 = new JSFunction(sourceName, parserLine, null);
278 b.add(parserLine, NEWFUNCTION, b2);
280 // function prelude; arguments array is already on the stack
281 b2.add(parserLine, TOPSCOPE);
282 b2.add(parserLine, SWAP);
283 b2.add(parserLine, DECLARE, JSString.intern("arguments")); // declare arguments (equivalent to 'var arguments;')
284 b2.add(parserLine, SWAP); // set this.arguments and leave the value on the stack
285 b2.add(parserLine, PUT);
287 while(peekToken() != RP) { // run through the list of argument names
289 if (peekToken() == NAME) {
290 consume(NAME); // a named argument
291 JS varName = JSString.intern(string);
293 b2.add(parserLine, DUP); // dup the args array
294 b2.add(parserLine, GET, JS.N(numArgs - 1)); // retrieve it from the arguments array
295 b2.add(parserLine, TOPSCOPE);
296 b2.add(parserLine, SWAP);
297 b2.add(parserLine, DECLARE, varName); // declare the name
298 b2.add(parserLine, SWAP);
299 b2.add(parserLine, PUT);
300 b2.add(parserLine, POP); // pop the value
301 b2.add(parserLine, POP); // pop the scope
303 if (peekToken() == RP) break;
308 b2.numFormalArgs = numArgs;
309 b2.add(parserLine, POP); // pop off the arguments array
310 b2.add(parserLine, POP); // pop off TOPSCOPE
312 if(peekToken() != LC)
313 throw pe("JSFunctions must have a block surrounded by curly brackets");
315 parseBlock(b2, null); // the function body
317 b2.add(parserLine, LITERAL, null); // in case we "fall out the bottom", return NULL
318 b2.add(parserLine, RETURN);
322 default: throw pe("expected expression, found " + codeToString[tok] + ", which cannot start an expression");
325 // attempt to continue the expression
326 continueExpr(b, minPrecedence);
329 private Grammar parseGrammar(Grammar g) throws IOException {
330 int tok = getToken();
333 case BITOR: return new Grammar.Alternative(g, parseGrammar(null));
334 case ADD: return parseGrammar(new Grammar.Repetition(g, 1, Integer.MAX_VALUE));
335 case MUL: return parseGrammar(new Grammar.Repetition(g, 0, Integer.MAX_VALUE));
336 case HOOK: return parseGrammar(new Grammar.Repetition(g, 0, 1));
340 //case NUMBER: g0 = new Grammar.Literal(number); break;
341 case NAME: g0 = new Grammar.Reference(string); break;
343 g0 = new Grammar.Literal(string);
344 if (peekToken() == DOT) {
349 if (old.length() != 1 || string.length() != 1) throw pe("literal ranges must be single-char strings");
350 g0 = new Grammar.Range(old.charAt(0), string.charAt(0));
353 case LP: g0 = parseGrammar(null); consume(RP); break;
354 default: pushBackToken(); return g;
356 if (g == null) return parseGrammar(g0);
357 return parseGrammar(new Grammar.Juxtaposition(g, g0));
361 * Assuming that a complete assignable (lvalue) has just been
362 * parsed and the object and key are on the stack,
363 * <tt>continueExprAfterAssignable</tt> will attempt to parse an
364 * expression that modifies the assignable. This method always
365 * decreases the stack depth by exactly one element.
367 private void continueExprAfterAssignable(JSFunction b,int minPrecedence) throws IOException {
368 int saveParserLine = parserLine;
369 _continueExprAfterAssignable(b,minPrecedence);
370 parserLine = saveParserLine;
372 private void _continueExprAfterAssignable(JSFunction b,int minPrecedence) throws IOException {
373 if (b == null) throw new Error("got null b; this should never happen");
374 int tok = getToken();
375 if (minPrecedence != -1 && (precedence[tok] < minPrecedence || (precedence[tok] == minPrecedence && !isRightAssociative[tok])))
376 // force the default case
381 b.add(parserLine, GET_PRESERVE);
382 Grammar g = parseGrammar(null);
383 if (peekToken() == LC) {
384 g.action = new JSFunction(sourceName, parserLine, null);
385 parseBlock((JSFunction)g.action);
386 ((JSFunction)g.action).add(parserLine, LITERAL, null); // in case we "fall out the bottom", return NULL
387 ((JSFunction)g.action).add(parserLine, RETURN);
389 b.add(parserLine, MAKE_GRAMMAR, g);
390 b.add(parserLine, PUT);
394 case ASSIGN_BITOR: case ASSIGN_BITXOR: case ASSIGN_BITAND: case ASSIGN_LSH: case ASSIGN_RSH: case ASSIGN_URSH:
395 case ASSIGN_MUL: case ASSIGN_DIV: case ASSIGN_MOD: case ASSIGN_ADD: case ASSIGN_SUB: case ADD_TRAP: case DEL_TRAP: {
396 if (tok != ADD_TRAP && tok != DEL_TRAP) b.add(parserLine, GET_PRESERVE);
398 startExpr(b, precedence[tok]);
400 if (tok != ADD_TRAP && tok != DEL_TRAP) {
401 // tok-1 is always s/^ASSIGN_// (0 is BITOR, 1 is ASSIGN_BITOR, etc)
402 b.add(parserLine, tok - 1, tok-1==ADD ? JS.N(2) : null);
403 b.add(parserLine, PUT);
404 b.add(parserLine, SWAP);
405 b.add(parserLine, POP);
407 b.add(parserLine, tok);
411 case INC: case DEC: { // postfix
412 b.add(parserLine, GET_PRESERVE, Boolean.TRUE);
413 b.add(parserLine, LITERAL, JS.N(1));
414 b.add(parserLine, tok == INC ? ADD : SUB, JS.N(2));
415 b.add(parserLine, PUT, null);
416 b.add(parserLine, SWAP, null);
417 b.add(parserLine, POP, null);
418 b.add(parserLine, LITERAL, JS.N(1));
419 b.add(parserLine, tok == INC ? SUB : ADD, JS.N(2)); // undo what we just did, since this is postfix
423 startExpr(b, precedence[tok]);
424 b.add(parserLine, PUT);
425 b.add(parserLine, SWAP);
426 b.add(parserLine, POP);
431 // Method calls are implemented by doing a GET_PRESERVE
432 // first. If the object supports method calls, it will
434 b.add(parserLine, GET_PRESERVE);
435 int n = parseArgs(b);
436 b.add(parserLine, CALLMETHOD, JS.N(n));
441 if(b.get(b.size-1) == LITERAL && b.getArg(b.size-1) != null)
442 b.set(b.size-1,GET,b.getArg(b.size-1));
444 b.add(parserLine, GET);
452 * Assuming that a complete expression has just been parsed,
453 * <tt>continueExpr</tt> will attempt to extend this expression by
454 * parsing additional tokens and appending additional bytecodes.
456 * No operators with precedence less than <tt>minPrecedence</tt>
459 * If any bytecodes are appended, they will not alter the stack
462 private void continueExpr(JSFunction b, int minPrecedence) throws IOException {
463 int saveParserLine = parserLine;
464 _continueExpr(b, minPrecedence);
465 parserLine = saveParserLine;
467 private void _continueExpr(JSFunction b, int minPrecedence) throws IOException {
468 if (b == null) throw new Error("got null b; this should never happen");
469 int tok = getToken();
470 if (tok == -1) return;
471 if (minPrecedence != -1 && (precedence[tok] < minPrecedence || (precedence[tok] == minPrecedence && !isRightAssociative[tok]))) {
477 case LP: { // invocation (not grouping)
478 int n = parseArgs(b);
479 b.add(parserLine, CALL, JS.N(n));
482 case BITOR: case BITXOR: case BITAND: case SHEQ: case SHNE: case LSH:
483 case RSH: case URSH: case MUL: case DIV: case MOD:
484 case GT: case GE: case EQ: case NE: case LT: case LE: case SUB: {
485 startExpr(b, precedence[tok]);
486 b.add(parserLine, tok);
493 startExpr(b,precedence[tok]);
495 nextTok = getToken();
496 } while(nextTok == tok);
498 b.add(parserLine, tok, JS.N(count));
502 b.add(parserLine, tok == AND ? JSFunction.JF : JSFunction.JT, JS.ZERO); // test to see if we can short-circuit
504 startExpr(b, precedence[tok]); // otherwise check the second value
505 b.add(parserLine, JMP, JS.N(2)); // leave the second value on the stack and jump to the end
506 b.add(parserLine, LITERAL, tok == AND ?
507 JS.B(false) : JS.B(true)); // target of the short-circuit jump is here
508 b.set(size - 1, JS.N(b.size - size)); // write the target of the short-circuit jump
512 // support foo..bar syntax for foo[""].bar
513 if (peekToken() == DOT) {
518 b.add(parserLine, LITERAL, JSString.intern(string));
519 continueExprAfterAssignable(b,minPrecedence);
522 case LB: { // subscripting (not array constructor)
525 continueExprAfterAssignable(b,minPrecedence);
529 b.add(parserLine, JF, JS.ZERO); // jump to the if-false expression
531 startExpr(b, minPrecedence); // write the if-true expression
532 b.add(parserLine, JMP, JS.ZERO); // if true, jump *over* the if-false expression
533 b.set(size - 1, JS.N(b.size - size + 1)); // now we know where the target of the jump is
536 startExpr(b, minPrecedence); // write the if-false expression
537 b.set(size - 1, JS.N(b.size - size + 1)); // this is the end; jump to here
541 // pop the result of the previous expression, it is ignored
542 b.add(parserLine,POP);
552 continueExpr(b, minPrecedence); // try to continue the expression
555 // parse a set of comma separated function arguments, assume LP has already been consumed
556 private int parseArgs(JSFunction b) throws IOException {
558 while(peekToken() != RP) {
560 if (peekToken() != COMMA) {
561 startExpr(b, NO_COMMA);
562 if (peekToken() == RP) break;
570 /** Parse a block of statements which must be surrounded by LC..RC. */
571 void parseBlock(JSFunction b) throws IOException { parseBlock(b, null); }
572 void parseBlock(JSFunction b, String label) throws IOException {
573 int saveParserLine = parserLine;
574 _parseBlock(b, label);
575 parserLine = saveParserLine;
577 void _parseBlock(JSFunction b, String label) throws IOException {
578 if (peekToken() == -1) return;
579 else if (peekToken() != LC) parseStatement(b, null);
582 while(peekToken() != RC && peekToken() != -1) parseStatement(b, null);
587 /** Parse a single statement, consuming the RC or SEMI which terminates it. */
588 void parseStatement(JSFunction b, String label) throws IOException {
589 int saveParserLine = parserLine;
590 _parseStatement(b, label);
591 parserLine = saveParserLine;
593 void _parseStatement(JSFunction b, String label) throws IOException {
594 int tok = peekToken();
595 if (tok == -1) return;
596 switch(tok = getToken()) {
598 case THROW: case ASSERT: case RETURN: {
599 if (tok == RETURN && peekToken() == SEMI)
600 b.add(parserLine, LITERAL, null);
603 b.add(parserLine, tok);
607 case BREAK: case CONTINUE: {
608 if (peekToken() == NAME) consume(NAME);
609 b.add(parserLine, tok, string);
614 b.add(parserLine, TOPSCOPE); // push the current scope
617 b.add(parserLine, DECLARE, JSString.intern(string)); // declare it
618 if (peekToken() == ASSIGN) { // if there is an '=' after the variable name
620 startExpr(b, NO_COMMA);
621 b.add(parserLine, PUT); // assign it
622 b.add(parserLine, POP); // clean the stack
624 b.add(parserLine, POP); // pop the string pushed by declare
626 if (peekToken() != COMMA) break;
629 b.add(parserLine, POP); // pop off the topscope
630 if ((mostRecentlyReadToken != RC || peekToken() == SEMI) && peekToken() != -1 && mostRecentlyReadToken != SEMI) consume(SEMI);
638 b.add(parserLine, JF, JS.ZERO); // if false, jump to the else-block
640 parseStatement(b, null);
642 if (peekToken() == ELSE) {
644 b.add(parserLine, JMP, JS.ZERO); // if we took the true-block, jump over the else-block
645 b.set(size - 1, JS.N(b.size - size + 1));
647 parseStatement(b, null);
649 b.set(size - 1, JS.N(b.size - size + 1)); // regardless of which branch we took, b[size] needs to point here
654 if (label != null) b.add(parserLine, LABEL, label);
655 b.add(parserLine, LOOP);
657 b.add(parserLine, POP); // discard the first-iteration indicator
659 b.add(parserLine, JT, JS.N(2)); // if the while() clause is true, jump over the BREAK
660 b.add(parserLine, BREAK);
662 parseStatement(b, null);
663 b.add(parserLine, CONTINUE); // if we fall out of the end, definately continue
664 b.set(size - 1, JS.N(b.size - size + 1)); // end of the loop
669 if (label != null) b.add(parserLine, LABEL, label);
670 b.add(parserLine, LOOP);
676 if (peekToken() == CASE) { // we compile CASE statements like a bunch of if..else's
678 b.add(parserLine, DUP); // duplicate the switch() value; we'll consume one copy
681 b.add(parserLine, EQ); // check if we should do this case-block
682 b.add(parserLine, JF, JS.ZERO); // if not, jump to the next one
684 while(peekToken() != CASE && peekToken() != DEFAULT && peekToken() != RC) parseStatement(b, null);
685 b.set(size - 1, JS.N(1 + b.size - size));
686 } else if (peekToken() == DEFAULT) {
689 while(peekToken() != CASE && peekToken() != DEFAULT && peekToken() != RC) parseStatement(b, null);
690 } else if (peekToken() == RC) {
692 b.add(parserLine, BREAK); // break out of the loop if we 'fall through'
695 throw pe("expected CASE, DEFAULT, or RC; got " + codeToString[peekToken()]);
697 b.set(size0 - 1, JS.N(b.size - size0 + 1)); // end of the loop
702 if (label != null) b.add(parserLine, LABEL, label);
703 b.add(parserLine, LOOP);
705 parseStatement(b, null);
709 b.add(parserLine, JT, JS.N(2)); // check the while() clause; jump over the BREAK if true
710 b.add(parserLine, BREAK);
711 b.add(parserLine, CONTINUE);
714 b.set(size - 1, JS.N(b.size - size + 1)); // end of the loop; write this location to the LOOP instruction
719 b.add(parserLine, TRY); // try bytecode causes a TryMarker to be pushed
720 int tryInsn = b.size - 1;
721 // parse the expression to be TRYed
722 parseStatement(b, null);
723 // pop the try marker. this is pushed when the TRY bytecode is executed
724 b.add(parserLine, POP);
725 // jump forward to the end of the catch block, start of the finally block
726 b.add(parserLine, JMP);
727 int successJMPInsn = b.size - 1;
729 if (peekToken() != CATCH && peekToken() != FINALLY)
730 throw pe("try without catch or finally");
732 int catchJMPDistance = -1;
733 if (peekToken() == CATCH) {
734 Vec catchEnds = new Vec();
735 boolean catchAll = false;
737 catchJMPDistance = b.size - tryInsn;
739 while(peekToken() == CATCH && !catchAll) {
744 exceptionVar = string;
745 int[] writebacks = new int[] { -1, -1, -1 };
746 if (peekToken() != RP) {
747 // extended Ibex catch block: catch(e faultCode "foo.bar.baz")
749 b.add(parserLine, DUP);
750 b.add(parserLine, LITERAL, JSString.intern(string));
751 b.add(parserLine, GET);
752 b.add(parserLine, DUP);
753 b.add(parserLine, LITERAL, null);
754 b.add(parserLine, EQ);
755 b.add(parserLine, JT);
756 writebacks[0] = b.size - 1;
757 if (peekToken() == STRING) {
759 b.add(parserLine, DUP);
760 b.add(parserLine, LITERAL, string);
761 b.add(parserLine, LT);
762 b.add(parserLine, JT);
763 writebacks[1] = b.size - 1;
764 b.add(parserLine, DUP);
765 b.add(parserLine, LITERAL, string + "/"); // (slash is ASCII after dot)
766 b.add(parserLine, GE);
767 b.add(parserLine, JT);
768 writebacks[2] = b.size - 1;
771 b.add(parserLine, DUP);
772 b.add(parserLine, LITERAL, number);
773 b.add(parserLine, EQ);
774 b.add(parserLine, JF);
775 writebacks[1] = b.size - 1;
777 b.add(parserLine, POP); // pop the element thats on the stack from the compare
782 // the exception is on top of the stack; put it to the chosen name
783 b.add(parserLine, NEWSCOPE);
784 b.add(parserLine, TOPSCOPE);
785 b.add(parserLine, SWAP);
786 b.add(parserLine, LITERAL,JSString.intern(exceptionVar));
787 b.add(parserLine, DECLARE);
788 b.add(parserLine, SWAP);
789 b.add(parserLine, PUT);
790 b.add(parserLine, POP);
791 b.add(parserLine, POP);
793 b.add(parserLine, OLDSCOPE);
795 b.add(parserLine, JMP);
796 catchEnds.addElement(new Integer(b.size-1));
798 for(int i=0; i<3; i++) if (writebacks[i] != -1) b.set(writebacks[i], JS.N(b.size-writebacks[i]));
799 b.add(parserLine, POP); // pop the element thats on the stack from the compare
803 b.add(parserLine, THROW);
805 for(int i=0;i<catchEnds.size();i++) {
806 int n = ((Integer)catchEnds.elementAt(i)).intValue();
807 b.set(n, JS.N(b.size-n));
810 // pop the try and catch markers
811 b.add(parserLine,POP);
812 b.add(parserLine,POP);
815 // jump here if no exception was thrown
816 b.set(successJMPInsn, JS.N(b.size - successJMPInsn));
818 int finallyJMPDistance = -1;
819 if (peekToken() == FINALLY) {
820 b.add(parserLine, LITERAL, null); // null FinallyData
821 finallyJMPDistance = b.size - tryInsn;
823 parseStatement(b, null);
824 b.add(parserLine,FINALLY_DONE);
827 // setup the TRY arguments
828 b.set(tryInsn, new int[] { catchJMPDistance, finallyJMPDistance });
837 boolean hadVar = false; // if it's a for..in, we ignore the VAR
838 if (tok == VAR) { hadVar = true; tok = getToken(); }
839 String varName = string;
840 boolean forIn = peekToken() == IN; // determine if this is a for..in loop or not
841 pushBackToken(tok, varName);
849 b.add(parserLine, PUSHKEYS);
852 b.add(parserLine, LOOP);
853 b.add(parserLine, POP);
855 b.add(parserLine,SWAP); // get the keys enumeration object on top
856 b.add(parserLine,DUP);
857 b.add(parserLine,GET,JS.S("hasMoreElements"));
859 b.add(parserLine,JT);
860 b.add(parserLine,SWAP);
861 b.add(parserLine,BREAK);
862 b.set(size2, JS.N(b.size - size2));
863 b.add(parserLine,DUP);
864 b.add(parserLine,GET,JS.S("nextElement"));
866 b.add(parserLine, NEWSCOPE);
868 b.add(parserLine,TOPSCOPE);
869 b.add(parserLine,SWAP);
870 b.add(parserLine, hadVar ? DECLARE : LITERAL, JSString.intern(varName));
871 b.add(parserLine,SWAP);
872 b.add(parserLine,PUT);
873 b.add(parserLine,POP);
874 b.add(parserLine,POP);
875 b.add(parserLine,SWAP);
877 parseStatement(b, null);
879 b.add(parserLine, OLDSCOPE);
880 b.add(parserLine, CONTINUE);
881 // jump here on break
882 b.set(size, JS.N(b.size - size));
884 b.add(parserLine, POP);
886 if (hadVar) pushBackToken(VAR, null); // yeah, this actually matters
887 b.add(parserLine, NEWSCOPE); // grab a fresh scope
889 parseStatement(b, null); // initializer
890 JSFunction e2 = // we need to put the incrementor before the test
891 new JSFunction(sourceName, parserLine, null); // so we save the test here
892 if (peekToken() != SEMI)
895 e2.add(parserLine, JSFunction.LITERAL, JS.T); // handle the for(foo;;foo) case
897 if (label != null) b.add(parserLine, LABEL, label);
898 b.add(parserLine, LOOP);
901 b.add(parserLine, JT, JS.ZERO); // if we're on the first iteration, jump over the incrementor
903 if (peekToken() != RP) { // do the increment thing
905 b.add(parserLine, POP);
907 b.set(size - 1, JS.N(b.size - size + 1));
910 b.paste(e2); // ok, *now* test if we're done yet
911 b.add(parserLine, JT, JS.N(2)); // break out if we don't meet the test
912 b.add(parserLine, BREAK);
913 parseStatement(b, null);
914 b.add(parserLine, CONTINUE); // if we fall out the bottom, CONTINUE
915 b.set(size2 - 1, JS.N(b.size - size2 + 1)); // end of the loop
917 b.add(parserLine, OLDSCOPE); // get our scope back
922 case NAME: { // either a label or an identifier; this is the one place we're not LL(1)
923 String possiblyTheLabel = string;
924 if (peekToken() == COLON) { // label
926 parseStatement(b, possiblyTheLabel);
928 } else { // expression
929 pushBackToken(NAME, possiblyTheLabel);
931 b.add(parserLine, POP);
932 if ((mostRecentlyReadToken != RC || peekToken() == SEMI) && peekToken() != -1 && mostRecentlyReadToken != SEMI) consume(SEMI);
937 case SEMI: return; // yep, the null statement is valid
939 case LC: { // blocks are statements too
941 b.add(parserLine, NEWSCOPE);
942 parseBlock(b, label);
943 b.add(parserLine, OLDSCOPE);
947 default: { // hope that it's an expression
950 b.add(parserLine, POP);
951 if ((mostRecentlyReadToken != RC || peekToken() == SEMI) && peekToken() != -1 && mostRecentlyReadToken != SEMI) consume(SEMI);
958 // ParserException //////////////////////////////////////////////////////////////////////
959 private IOException pe(String s) { return new IOException(sourceName + ":" + line + " " + s); }