// Copyright 2000-2005 the Contributors, as shown in the revision logs.
// Licensed under the Apache Public Source License 2.0 ("the License").
// You may not use this file except in compliance with the License.
package org.ibex.js;
import java.io.*;
import java.util.*;
import org.ibex.util.*;
/**
* 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 //////////////////////////////////////////////////////
private Parser(Reader r, String sourceName, int line) throws IOException { super(r, sourceName, line); }
/** for debugging */
public static void main(String[] s) throws IOException {
JS block = JSU.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;
}
// Local variable management
Basket.Array scopeStack = new Basket.Array();
static class ScopeInfo {
int base;
int end;
int newScopeInsn;
Map mapping = new HashMap();
}
Map globalCache = new HashMap();
JS scopeKey(String name) {
if(globalCache.get(name) != null) return null;
for(int i=scopeStack.size()-1;i>=0;i--) {
JS key = (JS)((ScopeInfo) scopeStack.get(i)).mapping.get(name);
if(key != null) return key;
}
globalCache.put(name,Boolean.TRUE);
return null;
}
void scopeDeclare(String name) throws IOException {
ScopeInfo si = (ScopeInfo) scopeStack.peek();
if(si.mapping.get(name) != null) throw pe("" + name + " already declared in this scope");
si.mapping.put(name,JSU.N(si.end++));
globalCache.put(name,null);
}
void scopePush(JSFunction b) {
ScopeInfo prev = (ScopeInfo) scopeStack.peek();
ScopeInfo si = new ScopeInfo();
si.base = prev.end;
si.end = si.base;
si.newScopeInsn = b.size;
scopeStack.push(si);
b.add(parserLine, NEWSCOPE);
}
void scopePop(JSFunction b) {
ScopeInfo si = (ScopeInfo) scopeStack.pop();
b.add(parserLine, OLDSCOPE);
b.set(si.newScopeInsn,JSU.N((si.base<<16)|((si.end-si.base)<<0)));
}
// Parsing Logic /////////////////////////////////////////////////////////
/** parse and compile a function */
public static JSFunction fromReader(String sourceName, int firstLine, Reader sourceCode) throws IOException {
JSFunction ret = new JSFunction(sourceName, firstLine, null);
if (sourceCode == null) return ret;
Parser p = new Parser(sourceCode, sourceName, firstLine);
p.scopeStack.clear();
p.scopeStack.push(new ScopeInfo());
p.scopePush(ret);
while(true) {
//int s = ret.size;
if(p.peekToken() == -1) break; // FIXME: Check this logic one more time
p.parseStatement(ret, null);
//if (s == ret.size) break;
}
p.scopePop(ret);
if(p.scopeStack.size() != 1) throw new Error("scopeStack height mismatch");
ret.add(-1, LITERAL, null);
ret.add(-1, RETURN);
return ret;
}
/** 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, JSU.N(number)); break;
case STRING: b.add(parserLine, LITERAL, JSString.intern(string)); break;
case NULL: b.add(parserLine, LITERAL, null); break;
case TRUE: case FALSE: b.add(parserLine, LITERAL, tok == TRUE ? JSU.T : JSU.F); break;
// (.foo) syntax
case DOT: {
consume(NAME);
b.add(parserLine, GLOBALSCOPE);
b.add(parserLine, GET, JSU.S("",true));
b.add(parserLine, LITERAL, JSU.S(string,true));
continueExprAfterAssignable(b,minPrecedence,null);
break;
}
case LB: {
b.add(parserLine, ARRAY, JSU.ZERO); // push an array onto the stack
int size0 = b.size;
int i = 0;
if (peekToken() != RB)
while(true) { // iterate over the initialization values
b.add(parserLine, LITERAL, JSU.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, JSU.N(i)); // back at the ARRAY instruction, write the size of the array
consume(RB);
break;
}
case SUB: case ADD: {
if(peekToken() == NUMBER) { // literal
consume(NUMBER);
b.add(parserLine, LITERAL, JSU.N(number.doubleValue() * (tok == SUB ? -1 : 1)));
} else { // unary +/- operator
if(tok == SUB) b.add(parserLine, LITERAL, JSU.ZERO);
// BITNOT has the same precedence as the unary +/- operators
startExpr(b,precedence[BITNOT]);
if(tok == ADD) b.add(parserLine, LITERAL, JSU.ZERO); // HACK to force expr into a numeric context
b.add(parserLine, SUB);
}
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;
boolean sg = b.get(prev) == SCOPEGET;
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 if(!sg)
throw pe("prefixed increment/decrement can only be performed on a valid assignment target");
if(!sg) b.add(parserLine, GET_PRESERVE, Boolean.TRUE);
b.add(parserLine, LITERAL, JSU.N(1));
b.add(parserLine, tok == INC ? ADD : SUB, JSU.N(2));
if(sg) {
b.add(parserLine, SCOPEPUT, b.getArg(prev));
} else {
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, JSString.intern(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: {
JS varKey = scopeKey(string);
if(varKey == null) {
b.add(parserLine, GLOBALSCOPE);
b.add(parserLine, LITERAL, JSString.intern(string));
}
continueExprAfterAssignable(b,minPrecedence,varKey);
break;
}
case CASCADE: {
if(peekToken() == ASSIGN) {
consume(ASSIGN);
startExpr(b, precedence[ASSIGN]);
b.add(parserLine, CASCADE, JSU.T);
} else {
b.add(parserLine, CASCADE, JSU.F);
}
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
scopePush(b2);
scopeDeclare("arguments");
b2.add(parserLine, SCOPEPUT,scopeKey("arguments"));
while(peekToken() != RP) { // run through the list of argument names
numArgs++;
if (peekToken() == NAME) {
consume(NAME); // a named argument
b2.add(parserLine, DUP); // dup the args array
b2.add(parserLine, GET, JSU.N(numArgs - 1)); // retrieve it from the arguments array
scopeDeclare(string);
b2.add(parserLine, SCOPEPUT, scopeKey(string));
b2.add(parserLine, POP);
}
if (peekToken() == RP) break;
consume(COMMA);
}
consume(RP);
b2.numFormalArgs = numArgs;
b2.add(parserLine, POP); // pop off the arguments array
if(peekToken() != LC)
throw pe("JSFunctions must have a block surrounded by curly brackets");
parseBlock(b2, null); // the function body
scopePop(b2);
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);
}
/**
* 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, JS varKey) throws IOException {
int saveParserLine = parserLine;
_continueExprAfterAssignable(b,minPrecedence,varKey);
parserLine = saveParserLine;
}
private void _continueExprAfterAssignable(JSFunction b,int minPrecedence, JS varKey) 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 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, varKey == null ? GET_PRESERVE : SCOPEGET, varKey);
startExpr(b, precedence[tok]);
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 ? JSU.N(2) : null);
if(varKey == null) {
b.add(parserLine, PUT);
b.add(parserLine, SWAP);
b.add(parserLine, POP);
} else {
b.add(parserLine, SCOPEPUT, varKey);
}
} else {
if(varKey != null) throw pe("cannot place traps on local variables");
b.add(parserLine, tok);
}
break;
}
case INC: case DEC: { // postfix
if(varKey == null) {
b.add(parserLine, GET_PRESERVE, Boolean.TRUE);
b.add(parserLine, LITERAL, JSU.N(1));
b.add(parserLine, tok == INC ? ADD : SUB, JSU.N(2));
b.add(parserLine, PUT, null);
b.add(parserLine, SWAP, null);
b.add(parserLine, POP, null);
b.add(parserLine, LITERAL, JSU.N(1));
b.add(parserLine, tok == INC ? SUB : ADD, JSU.N(2)); // undo what we just did, since this is postfix
} else {
b.add(parserLine, SCOPEGET, varKey);
b.add(parserLine, DUP);
b.add(parserLine, LITERAL, JSU.ONE);
b.add(parserLine, tok == INC ? ADD : SUB, JSU.N(2));
b.add(parserLine, SCOPEPUT, varKey);
}
break;
}
case ASSIGN: {
startExpr(b, precedence[tok]);
if(varKey == null) {
b.add(parserLine, PUT);
b.add(parserLine, SWAP);
b.add(parserLine, POP);
} else {
b.add(parserLine, SCOPEPUT, varKey);
}
break;
}
case LP: {
// Method calls are implemented by doing a GET_PRESERVE
// first. If the object supports method calls, it will
// return JS.METHOD
b.add(parserLine, varKey == null ? GET_PRESERVE : SCOPEGET, varKey);
int n = parseArgs(b);
b.add(parserLine, varKey == null ? CALLMETHOD : CALL, JSU.N(n));
break;
}
default: {
pushBackToken();
if(varKey != null)
b.add(parserLine, SCOPEGET, varKey);
else 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);
b.add(parserLine, CALL, JSU.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, JSU.N(count));
break;
}
case OR: case AND: {
b.add(parserLine, tok == AND ? JSFunction.JF : JSFunction.JT, JSU.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, JSU.N(2)); // leave the second value on the stack and jump to the end
b.add(parserLine, LITERAL, tok == AND ?
JSU.B(false) : JSU.B(true)); // target of the short-circuit jump is here
b.set(size - 1, JSU.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, JSString.intern(string));
continueExprAfterAssignable(b,minPrecedence,null);
break;
}
case LB: { // subscripting (not array constructor)
startExpr(b, -1);
consume(RB);
continueExprAfterAssignable(b,minPrecedence,null);
break;
}
case HOOK: {
b.add(parserLine, JF, JSU.ZERO); // jump to the if-false expression
int size = b.size;
startExpr(b, minPrecedence); // write the if-true expression
b.add(parserLine, JMP, JSU.ZERO); // if true, jump *over* the if-false expression
b.set(size - 1, JSU.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, JSU.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
private int parseArgs(JSFunction b) throws IOException {
int i = 0;
while(peekToken() != RP) {
i++;
if (peekToken() != COMMA) {
startExpr(b, NO_COMMA);
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: {
while(true) {
consume(NAME);
String var = string;
scopeDeclare(var);
if (peekToken() == ASSIGN) { // if there is an '=' after the variable name
consume(ASSIGN);
startExpr(b, NO_COMMA);
b.add(parserLine, SCOPEPUT, scopeKey(var)); // assign it
b.add(parserLine, POP); // clean the stack
}
if (peekToken() != COMMA) break;
consume(COMMA);
}
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, JSU.ZERO); // if false, jump to the else-block
int size = b.size;
parseStatement(b, null);
if (peekToken() == ELSE) {
consume(ELSE);
b.add(parserLine, JMP, JSU.ZERO); // if we took the true-block, jump over the else-block
b.set(size - 1, JSU.N(b.size - size + 1));
size = b.size;
parseStatement(b, null);
}
b.set(size - 1, JSU.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, JSU.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, JSU.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, JSU.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, JSU.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, JSU.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, JSU.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, JSU.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) {
Basket.List catchEnds = new Basket.Array();
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 Ibex catch block: catch(e faultCode "foo.bar.baz")
consume(NAME);
b.add(parserLine, DUP);
b.add(parserLine, LITERAL, JSString.intern(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
scopePush(b);
scopeDeclare(exceptionVar);
b.add(parserLine, SCOPEPUT, scopeKey(exceptionVar));
b.add(parserLine, POP);
parseBlock(b, null);
scopePop(b);
b.add(parserLine, JMP);
catchEnds.add(new Integer(b.size-1));
for(int i=0; i<3; i++) if (writebacks[i] != -1) b.set(writebacks[i], JSU.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