X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=src%2Forg%2Fxwt%2Fjs%2FParser.java;fp=src%2Forg%2Fxwt%2Fjs%2FParser.java;h=0000000000000000000000000000000000000000;hb=3591b88b94a6bb378af3d4abe6eb5233ce583104;hp=1914cc7e3226acaa6f8f57fe9ae85373515ed1de;hpb=de378041d5ca2aca1a2b5a31ef15ae90a86c977f;p=org.ibex.core.git
diff --git a/src/org/xwt/js/Parser.java b/src/org/xwt/js/Parser.java
deleted file mode 100644
index 1914cc7..0000000
--- a/src/org/xwt/js/Parser.java
+++ /dev/null
@@ -1,950 +0,0 @@
-// Copyright 2004 Adam Megacz, see the COPYING file for licensing [GPL]
-package org.xwt.js;
-
-import org.xwt.util.*;
-import java.io.*;
-
-/**
- * Parses a stream of lexed tokens into a tree of JSFunction's.
- *
- * There are three kinds of things we parse: blocks, statements, and
- * expressions.
- *
- * - Expressions are a special type of statement that evaluates to a
- * value (for example, "break" is not an expression, * but "3+2"
- * is). Some tokens sequences start expressions (for * example,
- * literal numbers) and others continue an expression which * has
- * already been begun (for example, '+'). Finally, some *
- * expressions are valid targets for an assignment operation; after
- * * each of these expressions, continueExprAfterAssignable() is
- * called * to check for an assignment operation.
- *
- * - A statement ends with a semicolon and does not return a value.
- *
- * - A block is a single statement or a sequence of statements
- * surrounded by curly braces.
- *
- * Each parsing method saves the parserLine before doing its actual
- * work and restores it afterwards. This ensures that parsing a
- * subexpression does not modify the line number until a token
- * *after* the subexpression has been consumed by the parent
- * expression.
- *
- * Technically it would be a better design for this class to build an
- * intermediate parse tree and use that to emit bytecode. Here's the
- * tradeoff:
- *
- * Advantages of building a parse tree:
- * - easier to apply optimizations
- * - would let us handle more sophisticated languages than JavaScript
- *
- * Advantages of leaving out the parse tree
- * - faster compilation
- * - less load on the garbage collector
- * - much simpler code, easier to understand
- * - less error-prone
- *
- * Fortunately JS is such a simple language that we can get away with
- * the half-assed approach and still produce a working, complete
- * compiler.
- *
- * The bytecode language emitted doesn't really cause any appreciable
- * semantic loss, and is itself a parseable language very similar to
- * Forth or a postfix variant of LISP. This means that the bytecode
- * can be transformed into a parse tree, which can be manipulated.
- * So if we ever want to add an optimizer, it could easily be done by
- * producing a parse tree from the bytecode, optimizing that tree,
- * and then re-emitting the bytecode. The parse tree node class
- * would also be much simpler since the bytecode language has so few
- * operators.
- *
- * Actually, the above paragraph is slightly inaccurate -- there are
- * places where we push a value and then perform an arbitrary number
- * of operations using it before popping it; this doesn't parse well.
- * But these cases are clearly marked and easy to change if we do
- * need to move to a parse tree format.
- */
-class Parser extends Lexer implements ByteCodes {
-
-
- // Constructors //////////////////////////////////////////////////////
-
- public Parser(Reader r, String sourceName, int line) throws IOException { super(r, sourceName, line); }
-
- /** for debugging */
- public static void main(String[] s) throws Exception {
- JS block = JS.fromReader("stdin", 0, new InputStreamReader(System.in));
- if (block == null) return;
- System.out.println(block);
- }
-
-
- // Statics ////////////////////////////////////////////////////////////
-
- static byte[] precedence = new byte[MAX_TOKEN + 1];
- static boolean[] isRightAssociative = new boolean[MAX_TOKEN + 1];
- // Use this as the precedence when we want anything up to the comma
- private final static int NO_COMMA = 2;
- static {
- isRightAssociative[ASSIGN] =
- isRightAssociative[ASSIGN_BITOR] =
- isRightAssociative[ASSIGN_BITXOR] =
- isRightAssociative[ASSIGN_BITAND] =
- isRightAssociative[ASSIGN_LSH] =
- isRightAssociative[ASSIGN_RSH] =
- isRightAssociative[ASSIGN_URSH] =
- isRightAssociative[ASSIGN_ADD] =
- isRightAssociative[ASSIGN_SUB] =
- isRightAssociative[ASSIGN_MUL] =
- isRightAssociative[ASSIGN_DIV] =
- isRightAssociative[ASSIGN_MOD] =
- isRightAssociative[ADD_TRAP] =
- isRightAssociative[DEL_TRAP] =
- true;
-
- precedence[COMMA] = 1;
- // 2 is intentionally left unassigned. we use minPrecedence==2 for comma separated lists
- precedence[ASSIGN] =
- precedence[ASSIGN_BITOR] =
- precedence[ASSIGN_BITXOR] =
- precedence[ASSIGN_BITAND] =
- precedence[ASSIGN_LSH] =
- precedence[ASSIGN_RSH] =
- precedence[ASSIGN_URSH] =
- precedence[ASSIGN_ADD] =
- precedence[ASSIGN_SUB] =
- precedence[ASSIGN_MUL] =
- precedence[ASSIGN_DIV] =
- precedence[ADD_TRAP] =
- precedence[DEL_TRAP] =
- precedence[ASSIGN_MOD] = 3;
- precedence[HOOK] = 4;
- precedence[OR] = 5;
- precedence[AND] = 6;
- precedence[BITOR] = 7;
- precedence[BITXOR] = 8;
- precedence[BITAND] = 9;
- precedence[EQ] = precedence[NE] = precedence[SHEQ] = precedence[SHNE] = 10;
- precedence[LT] = precedence[LE] = precedence[GT] = precedence[GE] = 11;
- precedence[LSH] = precedence[RSH] = precedence[URSH] = 12;
- precedence[ADD] = precedence[SUB] = 12;
- precedence[MUL] = precedence[DIV] = precedence[MOD] = 13;
- precedence[BITNOT] = precedence[BANG] = precedence[TYPEOF] = 14;
- precedence[DOT] = precedence[LB] = precedence[LP] = precedence[INC] = precedence[DEC] = 15;
- }
-
-
- // Parsing Logic /////////////////////////////////////////////////////////
-
- /** gets a token and throws an exception if it is not code */
- private void consume(int code) throws IOException {
- if (getToken() != code) {
- if(code == NAME) switch(op) {
- case RETURN: case TYPEOF: case BREAK: case CONTINUE: case TRY: case THROW:
- case ASSERT: case NULL: case TRUE: case FALSE: case IN: case IF: case ELSE:
- case SWITCH: case CASE: case DEFAULT: case WHILE: case VAR: case WITH:
- case CATCH: case FINALLY:
- throw pe("Bad variable name; '" + codeToString[op].toLowerCase() + "' is a javascript keyword");
- }
- throw pe("expected " + codeToString[code] + ", got " + (op == -1 ? "EOF" : codeToString[op]));
- }
- }
-
- /**
- * Parse the largest possible expression containing no operators
- * of precedence below minPrecedence and append the
- * bytecodes for that expression to appendTo; the
- * appended bytecodes MUST grow the stack by exactly one element.
- */
- private void startExpr(JSFunction appendTo, int minPrecedence) throws IOException {
- int saveParserLine = parserLine;
- _startExpr(appendTo, minPrecedence);
- parserLine = saveParserLine;
- }
- private void _startExpr(JSFunction appendTo, int minPrecedence) throws IOException {
- int tok = getToken();
- JSFunction b = appendTo;
-
- switch (tok) {
- case -1: throw pe("expected expression");
-
- // all of these simply push values onto the stack
- case NUMBER: b.add(parserLine, LITERAL, number); break;
- case STRING: b.add(parserLine, LITERAL, string); break;
- case NULL: b.add(parserLine, LITERAL, null); break;
- case TRUE: case FALSE: b.add(parserLine, LITERAL, JS.B(tok == TRUE)); break;
-
- // (.foo) syntax
- case DOT: {
- consume(NAME);
- b.add(parserLine, TOPSCOPE);
- b.add(parserLine, LITERAL, "");
- b.add(parserLine, GET);
- b.add(parserLine, LITERAL, string);
- b.add(parserLine, GET);
- continueExpr(b, minPrecedence);
- break;
- }
-
- case LB: {
- b.add(parserLine, ARRAY, JS.ZERO); // push an array onto the stack
- int size0 = b.size;
- int i = 0;
- if (peekToken() != RB)
- while(true) { // iterate over the initialization values
- int size = b.size;
- b.add(parserLine, LITERAL, JS.N(i++)); // push the index in the array to place it into
- if (peekToken() == COMMA || peekToken() == RB)
- b.add(parserLine, LITERAL, null); // for stuff like [1,,2,]
- else
- startExpr(b, NO_COMMA); // push the value onto the stack
- b.add(parserLine, PUT); // put it into the array
- b.add(parserLine, POP); // discard the value remaining on the stack
- if (peekToken() == RB) break;
- consume(COMMA);
- }
- b.set(size0 - 1, JS.N(i)); // back at the ARRAY instruction, write the size of the array
- consume(RB);
- break;
- }
- case SUB: { // negative literal (like "3 * -1")
- consume(NUMBER);
- b.add(parserLine, LITERAL, JS.N(number.doubleValue() * -1));
- break;
- }
- case LP: { // grouping (not calling)
- startExpr(b, -1);
- consume(RP);
- break;
- }
- case INC: case DEC: { // prefix (not postfix)
- startExpr(b, precedence[tok]);
- int prev = b.size - 1;
- if (b.get(prev) == GET && b.getArg(prev) != null)
- b.set(prev, LITERAL, b.getArg(prev));
- else if(b.get(prev) == GET)
- b.pop();
- else
- throw pe("prefixed increment/decrement can only be performed on a valid assignment target");
- b.add(parserLine, GET_PRESERVE, Boolean.TRUE);
- b.add(parserLine, LITERAL, JS.N(1));
- b.add(parserLine, tok == INC ? ADD : SUB, JS.N(2));
- b.add(parserLine, PUT, null);
- b.add(parserLine, SWAP, null);
- b.add(parserLine, POP, null);
- break;
- }
- case BANG: case BITNOT: case TYPEOF: {
- startExpr(b, precedence[tok]);
- b.add(parserLine, tok);
- break;
- }
- case LC: { // object constructor
- b.add(parserLine, OBJECT, null); // put an object on the stack
- if (peekToken() != RC)
- while(true) {
- if (peekToken() != NAME && peekToken() != STRING)
- throw pe("expected NAME or STRING");
- getToken();
- b.add(parserLine, LITERAL, string); // grab the key
- consume(COLON);
- startExpr(b, NO_COMMA); // grab the value
- b.add(parserLine, PUT); // put the value into the object
- b.add(parserLine, POP); // discard the remaining value
- if (peekToken() == RC) break;
- consume(COMMA);
- if (peekToken() == RC) break; // we permit {,,} -- I'm not sure if ECMA does
- }
- consume(RC);
- break;
- }
- case NAME: {
- b.add(parserLine, TOPSCOPE);
- b.add(parserLine, LITERAL, string);
- continueExprAfterAssignable(b,minPrecedence);
- break;
- }
- case FUNCTION: {
- consume(LP);
- int numArgs = 0;
- JSFunction b2 = new JSFunction(sourceName, parserLine, null);
- b.add(parserLine, NEWFUNCTION, b2);
-
- // function prelude; arguments array is already on the stack
- b2.add(parserLine, TOPSCOPE);
- b2.add(parserLine, SWAP);
- b2.add(parserLine, DECLARE, "arguments"); // declare arguments (equivalent to 'var arguments;')
- b2.add(parserLine, SWAP); // set this.arguments and leave the value on the stack
- b2.add(parserLine, PUT);
-
- while(peekToken() != RP) { // run through the list of argument names
- numArgs++;
- if (peekToken() == NAME) {
- consume(NAME); // a named argument
- String varName = string;
-
- b2.add(parserLine, DUP); // dup the args array
- b2.add(parserLine, GET, JS.N(numArgs - 1)); // retrieve it from the arguments array
- b2.add(parserLine, TOPSCOPE);
- b2.add(parserLine, SWAP);
- b2.add(parserLine, DECLARE, varName); // declare the name
- b2.add(parserLine, SWAP);
- b2.add(parserLine, PUT);
- b2.add(parserLine, POP); // pop the value
- b2.add(parserLine, POP); // pop the scope
- }
- if (peekToken() == RP) break;
- consume(COMMA);
- }
- consume(RP);
-
- b2.numFormalArgs = numArgs;
- b2.add(parserLine, POP); // pop off the arguments array
- b2.add(parserLine, POP); // pop off TOPSCOPE
-
- if(peekToken() != LC)
- throw pe("JSFunctions must have a block surrounded by curly brackets");
-
- parseBlock(b2, null); // the function body
-
- b2.add(parserLine, LITERAL, null); // in case we "fall out the bottom", return NULL
- b2.add(parserLine, RETURN);
-
- break;
- }
- default: throw pe("expected expression, found " + codeToString[tok] + ", which cannot start an expression");
- }
-
- // attempt to continue the expression
- continueExpr(b, minPrecedence);
- }
-
- private Grammar parseGrammar(Grammar g) throws IOException {
- int tok = getToken();
- if (g != null)
- switch(tok) {
- case BITOR: return new Grammar.Alternative(g, parseGrammar(null));
- case ADD: return parseGrammar(new Grammar.Repetition(g, 1, Integer.MAX_VALUE));
- case MUL: return parseGrammar(new Grammar.Repetition(g, 0, Integer.MAX_VALUE));
- case HOOK: return parseGrammar(new Grammar.Repetition(g, 0, 1));
- }
- Grammar g0 = null;
- switch(tok) {
- //case NUMBER: g0 = new Grammar.Literal(number); break;
- case NAME: g0 = new Grammar.Reference(string); break;
- case STRING:
- g0 = new Grammar.Literal(string);
- if (peekToken() == DOT) {
- String old = string;
- consume(DOT);
- consume(DOT);
- consume(STRING);
- if (old.length() != 1 || string.length() != 1) throw pe("literal ranges must be single-char strings");
- g0 = new Grammar.Range(old.charAt(0), string.charAt(0));
- }
- break;
- case LP: g0 = parseGrammar(null); consume(RP); break;
- default: pushBackToken(); return g;
- }
- if (g == null) return parseGrammar(g0);
- return parseGrammar(new Grammar.Juxtaposition(g, g0));
- }
-
- /**
- * Assuming that a complete assignable (lvalue) has just been
- * parsed and the object and key are on the stack,
- * continueExprAfterAssignable will attempt to parse an
- * expression that modifies the assignable. This method always
- * decreases the stack depth by exactly one element.
- */
- private void continueExprAfterAssignable(JSFunction b,int minPrecedence) throws IOException {
- int saveParserLine = parserLine;
- _continueExprAfterAssignable(b,minPrecedence);
- parserLine = saveParserLine;
- }
- private void _continueExprAfterAssignable(JSFunction b,int minPrecedence) throws IOException {
- if (b == null) throw new Error("got null b; this should never happen");
- int tok = getToken();
- if (minPrecedence != -1 && (precedence[tok] < minPrecedence || (precedence[tok] == minPrecedence && !isRightAssociative[tok])))
- // force the default case
- tok = -1;
- switch(tok) {
-
- case GRAMMAR: {
- b.add(parserLine, GET_PRESERVE);
- Grammar g = parseGrammar(null);
- if (peekToken() == LC) {
- g.action = new JSFunction(sourceName, parserLine, null);
- parseBlock((JSFunction)g.action);
- ((JSFunction)g.action).add(parserLine, LITERAL, null); // in case we "fall out the bottom", return NULL
- ((JSFunction)g.action).add(parserLine, RETURN);
- }
- b.add(parserLine, MAKE_GRAMMAR, g);
- b.add(parserLine, PUT);
- break;
- }
-
- case ASSIGN_BITOR: case ASSIGN_BITXOR: case ASSIGN_BITAND: case ASSIGN_LSH: case ASSIGN_RSH: case ASSIGN_URSH:
- case ASSIGN_MUL: case ASSIGN_DIV: case ASSIGN_MOD: case ASSIGN_ADD: case ASSIGN_SUB: case ADD_TRAP: case DEL_TRAP: {
- if (tok != ADD_TRAP && tok != DEL_TRAP) b.add(parserLine, GET_PRESERVE);
-
- startExpr(b, precedence[tok]);
-
- int size = b.size;
-
- if (tok != ADD_TRAP && tok != DEL_TRAP) {
- // tok-1 is always s/^ASSIGN_// (0 is BITOR, 1 is ASSIGN_BITOR, etc)
- b.add(parserLine, tok - 1, tok-1==ADD ? JS.N(2) : null);
- b.add(parserLine, PUT);
- b.add(parserLine, SWAP);
- b.add(parserLine, POP);
- } else {
- b.add(parserLine, tok);
- }
- break;
- }
- case INC: case DEC: { // postfix
- b.add(parserLine, GET_PRESERVE, Boolean.TRUE);
- b.add(parserLine, LITERAL, JS.N(1));
- b.add(parserLine, tok == INC ? ADD : SUB, JS.N(2));
- b.add(parserLine, PUT, null);
- b.add(parserLine, SWAP, null);
- b.add(parserLine, POP, null);
- b.add(parserLine, LITERAL, JS.N(1));
- b.add(parserLine, tok == INC ? SUB : ADD, null); // undo what we just did, since this is postfix
- break;
- }
- case ASSIGN: {
- startExpr(b, precedence[tok]);
- b.add(parserLine, PUT);
- b.add(parserLine, SWAP);
- b.add(parserLine, POP);
- break;
- }
- case LP: {
-
- // Method calls are implemented by doing a GET_PRESERVE
- // first. If the object supports method calls, it will
- // return JS.METHOD
- int n = parseArgs(b, 2);
- b.add(parserLine, GET_PRESERVE);
- b.add(parserLine, CALLMETHOD, JS.N(n));
- break;
- }
- default: {
- pushBackToken();
- if(b.get(b.size-1) == LITERAL && b.getArg(b.size-1) != null)
- b.set(b.size-1,GET,b.getArg(b.size-1));
- else
- b.add(parserLine, GET);
- return;
- }
- }
- }
-
-
- /**
- * Assuming that a complete expression has just been parsed,
- * continueExpr will attempt to extend this expression by
- * parsing additional tokens and appending additional bytecodes.
- *
- * No operators with precedence less than minPrecedence
- * will be parsed.
- *
- * If any bytecodes are appended, they will not alter the stack
- * depth.
- */
- private void continueExpr(JSFunction b, int minPrecedence) throws IOException {
- int saveParserLine = parserLine;
- _continueExpr(b, minPrecedence);
- parserLine = saveParserLine;
- }
- private void _continueExpr(JSFunction b, int minPrecedence) throws IOException {
- if (b == null) throw new Error("got null b; this should never happen");
- int tok = getToken();
- if (tok == -1) return;
- if (minPrecedence != -1 && (precedence[tok] < minPrecedence || (precedence[tok] == minPrecedence && !isRightAssociative[tok]))) {
- pushBackToken();
- return;
- }
-
- switch (tok) {
- case LP: { // invocation (not grouping)
- int n = parseArgs(b, 1);
- b.add(parserLine, CALL, JS.N(n));
- break;
- }
- case BITOR: case BITXOR: case BITAND: case SHEQ: case SHNE: case LSH:
- case RSH: case URSH: case MUL: case DIV: case MOD:
- case GT: case GE: case EQ: case NE: case LT: case LE: case SUB: {
- startExpr(b, precedence[tok]);
- b.add(parserLine, tok);
- break;
- }
- case ADD: {
- int count=1;
- int nextTok;
- do {
- startExpr(b,precedence[tok]);
- count++;
- nextTok = getToken();
- } while(nextTok == tok);
- pushBackToken();
- b.add(parserLine, tok, JS.N(count));
- break;
- }
- case OR: case AND: {
- b.add(parserLine, tok == AND ? b.JF : b.JT, JS.ZERO); // test to see if we can short-circuit
- int size = b.size;
- startExpr(b, precedence[tok]); // otherwise check the second value
- b.add(parserLine, JMP, JS.N(2)); // leave the second value on the stack and jump to the end
- b.add(parserLine, LITERAL, tok == AND ?
- JS.B(false) : JS.B(true)); // target of the short-circuit jump is here
- b.set(size - 1, JS.N(b.size - size)); // write the target of the short-circuit jump
- break;
- }
- case DOT: {
- // support foo..bar syntax for foo[""].bar
- if (peekToken() == DOT) {
- string = "";
- } else {
- consume(NAME);
- }
- b.add(parserLine, LITERAL, string);
- continueExprAfterAssignable(b,minPrecedence);
- break;
- }
- case LB: { // subscripting (not array constructor)
- startExpr(b, -1);
- consume(RB);
- continueExprAfterAssignable(b,minPrecedence);
- break;
- }
- case HOOK: {
- b.add(parserLine, JF, JS.ZERO); // jump to the if-false expression
- int size = b.size;
- startExpr(b, minPrecedence); // write the if-true expression
- b.add(parserLine, JMP, JS.ZERO); // if true, jump *over* the if-false expression
- b.set(size - 1, JS.N(b.size - size + 1)); // now we know where the target of the jump is
- consume(COLON);
- size = b.size;
- startExpr(b, minPrecedence); // write the if-false expression
- b.set(size - 1, JS.N(b.size - size + 1)); // this is the end; jump to here
- break;
- }
- case COMMA: {
- // pop the result of the previous expression, it is ignored
- b.add(parserLine,POP);
- startExpr(b,-1);
- break;
- }
- default: {
- pushBackToken();
- return;
- }
- }
-
- continueExpr(b, minPrecedence); // try to continue the expression
- }
-
- // parse a set of comma separated function arguments, assume LP has already been consumed
- // if swap is true, (because the function is already on the stack) we will SWAP after each argument to keep it on top
- private int parseArgs(JSFunction b, int pushdown) throws IOException {
- int i = 0;
- while(peekToken() != RP) {
- i++;
- if (peekToken() != COMMA) {
- startExpr(b, NO_COMMA);
- b.add(parserLine, SWAP, JS.N(pushdown));
- if (peekToken() == RP) break;
- }
- consume(COMMA);
- }
- consume(RP);
- return i;
- }
-
- /** Parse a block of statements which must be surrounded by LC..RC. */
- void parseBlock(JSFunction b) throws IOException { parseBlock(b, null); }
- void parseBlock(JSFunction b, String label) throws IOException {
- int saveParserLine = parserLine;
- _parseBlock(b, label);
- parserLine = saveParserLine;
- }
- void _parseBlock(JSFunction b, String label) throws IOException {
- if (peekToken() == -1) return;
- else if (peekToken() != LC) parseStatement(b, null);
- else {
- consume(LC);
- while(peekToken() != RC && peekToken() != -1) parseStatement(b, null);
- consume(RC);
- }
- }
-
- /** Parse a single statement, consuming the RC or SEMI which terminates it. */
- void parseStatement(JSFunction b, String label) throws IOException {
- int saveParserLine = parserLine;
- _parseStatement(b, label);
- parserLine = saveParserLine;
- }
- void _parseStatement(JSFunction b, String label) throws IOException {
- int tok = peekToken();
- if (tok == -1) return;
- switch(tok = getToken()) {
-
- case THROW: case ASSERT: case RETURN: {
- if (tok == RETURN && peekToken() == SEMI)
- b.add(parserLine, LITERAL, null);
- else
- startExpr(b, -1);
- b.add(parserLine, tok);
- consume(SEMI);
- break;
- }
- case BREAK: case CONTINUE: {
- if (peekToken() == NAME) consume(NAME);
- b.add(parserLine, tok, string);
- consume(SEMI);
- break;
- }
- case VAR: {
- b.add(parserLine, TOPSCOPE); // push the current scope
- while(true) {
- consume(NAME);
- b.add(parserLine, DECLARE, string); // declare it
- if (peekToken() == ASSIGN) { // if there is an '=' after the variable name
- consume(ASSIGN);
- startExpr(b, NO_COMMA);
- b.add(parserLine, PUT); // assign it
- b.add(parserLine, POP); // clean the stack
- } else {
- b.add(parserLine, POP); // pop the string pushed by declare
- }
- if (peekToken() != COMMA) break;
- consume(COMMA);
- }
- b.add(parserLine, POP); // pop off the topscope
- if ((mostRecentlyReadToken != RC || peekToken() == SEMI) && peekToken() != -1 && mostRecentlyReadToken != SEMI) consume(SEMI);
- break;
- }
- case IF: {
- consume(LP);
- startExpr(b, -1);
- consume(RP);
-
- b.add(parserLine, JF, JS.ZERO); // if false, jump to the else-block
- int size = b.size;
- parseStatement(b, null);
-
- if (peekToken() == ELSE) {
- consume(ELSE);
- b.add(parserLine, JMP, JS.ZERO); // if we took the true-block, jump over the else-block
- b.set(size - 1, JS.N(b.size - size + 1));
- size = b.size;
- parseStatement(b, null);
- }
- b.set(size - 1, JS.N(b.size - size + 1)); // regardless of which branch we took, b[size] needs to point here
- break;
- }
- case WHILE: {
- consume(LP);
- if (label != null) b.add(parserLine, LABEL, label);
- b.add(parserLine, LOOP);
- int size = b.size;
- b.add(parserLine, POP); // discard the first-iteration indicator
- startExpr(b, -1);
- b.add(parserLine, JT, JS.N(2)); // if the while() clause is true, jump over the BREAK
- b.add(parserLine, BREAK);
- consume(RP);
- parseStatement(b, null);
- b.add(parserLine, CONTINUE); // if we fall out of the end, definately continue
- b.set(size - 1, JS.N(b.size - size + 1)); // end of the loop
- break;
- }
- case SWITCH: {
- consume(LP);
- if (label != null) b.add(parserLine, LABEL, label);
- b.add(parserLine, LOOP);
- int size0 = b.size;
- startExpr(b, -1);
- consume(RP);
- consume(LC);
- while(true)
- if (peekToken() == CASE) { // we compile CASE statements like a bunch of if..else's
- consume(CASE);
- b.add(parserLine, DUP); // duplicate the switch() value; we'll consume one copy
- startExpr(b, -1);
- consume(COLON);
- b.add(parserLine, EQ); // check if we should do this case-block
- b.add(parserLine, JF, JS.ZERO); // if not, jump to the next one
- int size = b.size;
- while(peekToken() != CASE && peekToken() != DEFAULT && peekToken() != RC) parseStatement(b, null);
- b.set(size - 1, JS.N(1 + b.size - size));
- } else if (peekToken() == DEFAULT) {
- consume(DEFAULT);
- consume(COLON);
- while(peekToken() != CASE && peekToken() != DEFAULT && peekToken() != RC) parseStatement(b, null);
- } else if (peekToken() == RC) {
- consume(RC);
- b.add(parserLine, BREAK); // break out of the loop if we 'fall through'
- break;
- } else {
- throw pe("expected CASE, DEFAULT, or RC; got " + codeToString[peekToken()]);
- }
- b.set(size0 - 1, JS.N(b.size - size0 + 1)); // end of the loop
- break;
- }
-
- case DO: {
- if (label != null) b.add(parserLine, LABEL, label);
- b.add(parserLine, LOOP);
- int size = b.size;
- parseStatement(b, null);
- consume(WHILE);
- consume(LP);
- startExpr(b, -1);
- b.add(parserLine, JT, JS.N(2)); // check the while() clause; jump over the BREAK if true
- b.add(parserLine, BREAK);
- b.add(parserLine, CONTINUE);
- consume(RP);
- consume(SEMI);
- b.set(size - 1, JS.N(b.size - size + 1)); // end of the loop; write this location to the LOOP instruction
- break;
- }
-
- case TRY: {
- b.add(parserLine, TRY); // try bytecode causes a TryMarker to be pushed
- int tryInsn = b.size - 1;
- // parse the expression to be TRYed
- parseStatement(b, null);
- // pop the try marker. this is pushed when the TRY bytecode is executed
- b.add(parserLine, POP);
- // jump forward to the end of the catch block, start of the finally block
- b.add(parserLine, JMP);
- int successJMPInsn = b.size - 1;
-
- if (peekToken() != CATCH && peekToken() != FINALLY)
- throw pe("try without catch or finally");
-
- int catchJMPDistance = -1;
- if (peekToken() == CATCH) {
- Vec catchEnds = new Vec();
- boolean catchAll = false;
-
- catchJMPDistance = b.size - tryInsn;
-
- while(peekToken() == CATCH && !catchAll) {
- String exceptionVar;
- getToken();
- consume(LP);
- consume(NAME);
- exceptionVar = string;
- int[] writebacks = new int[] { -1, -1, -1 };
- if (peekToken() != RP) {
- // extended XWT catch block: catch(e faultCode "foo.bar.baz")
- consume(NAME);
- String propName = string;
- b.add(parserLine, DUP);
- b.add(parserLine, LITERAL, string);
- b.add(parserLine, GET);
- b.add(parserLine, DUP);
- b.add(parserLine, LITERAL, null);
- b.add(parserLine, EQ);
- b.add(parserLine, JT);
- writebacks[0] = b.size - 1;
- if (peekToken() == STRING) {
- consume(STRING);
- b.add(parserLine, DUP);
- b.add(parserLine, LITERAL, string);
- b.add(parserLine, LT);
- b.add(parserLine, JT);
- writebacks[1] = b.size - 1;
- b.add(parserLine, DUP);
- b.add(parserLine, LITERAL, string + "/"); // (slash is ASCII after dot)
- b.add(parserLine, GE);
- b.add(parserLine, JT);
- writebacks[2] = b.size - 1;
- } else {
- consume(NUMBER);
- b.add(parserLine, DUP);
- b.add(parserLine, LITERAL, number);
- b.add(parserLine, EQ);
- b.add(parserLine, JF);
- writebacks[1] = b.size - 1;
- }
- b.add(parserLine, POP); // pop the element thats on the stack from the compare
- } else {
- catchAll = true;
- }
- consume(RP);
- // the exception is on top of the stack; put it to the chosen name
- b.add(parserLine, NEWSCOPE);
- b.add(parserLine, TOPSCOPE);
- b.add(parserLine, SWAP);
- b.add(parserLine, LITERAL,exceptionVar);
- b.add(parserLine, DECLARE);
- b.add(parserLine, SWAP);
- b.add(parserLine, PUT);
- b.add(parserLine, POP);
- b.add(parserLine, POP);
- parseBlock(b, null);
- b.add(parserLine, OLDSCOPE);
-
- b.add(parserLine, JMP);
- catchEnds.addElement(new Integer(b.size-1));
-
- for(int i=0; i<3; i++) if (writebacks[i] != -1) b.set(writebacks[i], JS.N(b.size-writebacks[i]));
- b.add(parserLine, POP); // pop the element thats on the stack from the compare
- }
-
- if(!catchAll)
- b.add(parserLine, THROW);
-
- for(int i=0;i