-// Copyright 2002 Adam Megacz, see the COPYING file for licensing [GPL]
+// Copyright 2003 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 ByteCodeBlock's */
+class Parser extends Lexer implements ByteCodes {
-/** parses a stream of lexed tokens into a tree of Expr's */
-public class Parser extends Lexer {
// Constructors //////////////////////////////////////////////////////
- public Parser(Reader r, String sourceName, int line) throws IOException {
- super(r);
- this.sourceName = sourceName;
- this.line = line;
- }
+ public Parser(Reader r, String sourceName, int line) throws IOException { super(r, sourceName, line); }
+ /** for debugging */
public static void main(String[] s) throws Exception {
Parser p = new Parser(new InputStreamReader(System.in), "stdin", 0);
while(true) {
- Expr block = p.parseBlock(false);
+ ByteCodeBlock block = new ByteCodeBlock(0, "stdin");
+ p.parseStatement(false, block);
if (block == null) return;
System.out.println(block);
if (p.peekToken() == -1) return;
static byte[] precedence = new byte[MAX_TOKEN + 1];
static boolean[] isRightAssociative = new boolean[MAX_TOKEN + 1];
static {
- precedence[ASSIGN] = 1;
isRightAssociative[ASSIGN] = true;
+
+ precedence[ASSIGN] = 1;
precedence[HOOK] = 2;
precedence[COMMA] = 3;
- precedence[GT] = precedence[GE] = 4;
- precedence[OR] = precedence[AND] = 5;
+ precedence[OR] = precedence[AND] = 4;
+ precedence[GT] = precedence[GE] = 5;
precedence[BITOR] = 6;
precedence[BITXOR] = 7;
precedence[BITAND] = 8;
precedence[LSH] = precedence[RSH] = precedence[URSH] = 12;
precedence[ADD] = precedence[SUB] = 13;
precedence[MUL] = precedence[DIV] = precedence[MOD] = 14;
- precedence[BITNOT] = precedence[INSTANCEOF] = 15;
+ precedence[BITNOT] = 15;
precedence[INC] = precedence[DEC] = 16;
precedence[LP] = 17;
precedence[LB] = 18;
// Parsing Logic /////////////////////////////////////////////////////////
- /** a block is either a single statement or a list of statements surrounded by curly braces; all expressions are also statements */
- public Expr parseBlock(boolean requireBraces) throws IOException {
- Expr ret = null;
- int tok = peekToken();
- boolean braced = tok == LC;
- if (requireBraces && !braced) throw new ParserException("expected {");
- if (braced) getToken();
- Expr head = null;
- Expr tail = null;
+ private ByteCodeBlock newbb(int line) { return new ByteCodeBlock(line, sourceName); }
+
+ /** gets a token and throws an exception if it is not <tt>code</tt> */
+ public void consume(int code) throws IOException {
+ if (getToken() != code)
+ throw new ParserException("expected " + codeToString[code] + ", got " + (op == -1 ? "EOF" : codeToString[op]));
+ }
+
+ /** append the largest expression beginning with prefix containing no operators of precedence below <tt>minPrecedence</tt> */
+ public void startExpr(ByteCodeBlock block) throws IOException { startExpr(-1, block); }
+ /*
+ public ByteCodeBlock startExpr(int minPrecedence) throws IOException {
+ ByteCodeBlock ret = new ByteCodeBlock(line, sourceName);
+ startExpr(minPrecedence, ret);
+ return ret.size() == 0 ? null : ret;
+ }
+ */
+
+ public void startExpr(int minPrecedence, ByteCodeBlock appendTo) throws IOException {
+ int tok = getToken();
int curLine = line;
- OUTER: while(true) {
- Expr smt;
+ if (tok == -1) return;
- switch(tok = peekToken()) {
- case -1: break OUTER;
- case LC: smt = parseBlock(true); break;
- case THROW: case RETURN: case ASSERT:
- getToken();
- smt = new Expr(curLine, tok, parseMaximalExpr());
- if (getToken() != SEMI) throw new ParserException("expected ;");
- break;
+ ByteCodeBlock b = appendTo;
- /*
- FIXME
- case NAME: {
- getToken();
- String str = string;
- if (getToken() != COLON) throw new ParserException("expected COLON after label");
- Expr labeledBlock = parseBlock(false);
- if (labeledBlock.code != WHILE && labeledBlock.code != FOR && labeledBlock.code != SWITCH)
- throw new ParserException("you can only label a WHILE, FOR, or SWITCH block");
- labeledBlock.string = str;
- return labeledBlock;
+ switch (tok) {
+ case NUMBER: continueExpr(b.add(ByteCodeBlock.LITERAL, number), minPrecedence); return;
+ case STRING: continueExpr(b.add(ByteCodeBlock.LITERAL, string), minPrecedence); return;
+ case THIS: continueExpr(b.add(TOPSCOPE, null), minPrecedence); return;
+ case NULL: continueExpr(b.add(ByteCodeBlock.LITERAL, null), minPrecedence); return;
+ case TRUE: case FALSE: continueExpr(b.add(ByteCodeBlock.LITERAL, new Boolean(tok == TRUE)), minPrecedence); return;
+ case LB: {
+ b.add(ARRAY, new Integer(0));
+ int i = 0;
+ while(true) {
+ int size = b.size();
+ startExpr(b);
+ if (size == b.size())
+ if (peekToken() == RB) { consume(RB); continueExpr(b, minPrecedence); return; }
+ b.add(LITERAL, new Integer(i++));
+ if (size == b.size()) b.add(LITERAL, null);
+ b.add(PUT);
+ b.add(POP);
+ if (peekToken() == RB) { consume(RB); continueExpr(b, minPrecedence); return; }
+ consume(COMMA);
}
- */
-
- case GOTO: case BREAK: case CONTINUE: {
+ }
+ case SUB: {
+ consume(NUMBER);
+ b.add(ByteCodeBlock.LITERAL, new Double(number.doubleValue() * -1));
+ continueExpr(b, minPrecedence);
+ return;
+ }
+ case LP: {
+ startExpr(b);
+ consume(RP);
+ continueExpr(b, minPrecedence);
+ return;
+ }
+ case INC: case DEC: {
+ // prefix
+ startExpr(precedence[tok], b);
+ b.set(b.size() - 1, tok, new Boolean(true));
+ continueExpr(b, minPrecedence);
+ return;
+ }
+ case BANG: case BITNOT: case TYPEOF: {
+ startExpr(precedence[tok], b);
+ b.add(tok);
+ continueExpr(b, minPrecedence);
+ return;
+ }
+ case LC: {
+ b.add(OBJECT, null);
+ if (peekToken() != RC) while(true) {
+ if (peekToken() != NAME && peekToken() != STRING) throw new Error("expected NAME or STRING");
getToken();
- int t = peekToken();
- if (t == NAME) {
- getToken();
- smt = new Expr(curLine, tok, new Expr(curLine, string));
- } else if (t == GOTO) {
- throw new ParserException("goto must be followed by a label");
- } else if (t == SEMI) {
- getToken();
- smt = new Expr(curLine, tok);
- } else {
- throw new ParserException(codeToString[tok] + " followed by a " + codeToString[t] + "; expected NAME or SEMI");
- }
- break;
+ b.add(LITERAL, string);
+ consume(COLON);
+ startExpr(b);
+ b.add(PUT);
+ b.add(POP);
+ if (peekToken() == RC) break;
+ consume(COMMA);
+ if (peekToken() == RC) break;
}
+ consume(RC);
+ continueExpr(b, minPrecedence);
+ return;
+ }
+ case NAME: {
+ String name = string;
+ if (peekToken() == ASSIGN) {
+ consume(ASSIGN);
+ b.add(TOPSCOPE);
+ b.add(ByteCodeBlock.LITERAL, name);
+ startExpr(minPrecedence, b);
+ b.add(ByteCodeBlock.PUT);
+ b.add(ByteCodeBlock.SWAP);
+ b.add(ByteCodeBlock.POP);
+ } else {
+ b.add(TOPSCOPE);
+ b.add(ByteCodeBlock.LITERAL, name);
+ b.add(ByteCodeBlock.GET);
+ }
+ continueExpr(b, minPrecedence);
+ return;
+ }
+ case FUNCTION: {
+ consume(LP);
+ int numArgs = 0;
+ ByteCodeBlock b2 = newbb(curLine);
+ b2.add(TOPSCOPE);
+ b2.add(SWAP);
+ b2.add(LITERAL, "arguments");
+ b2.add(LITERAL, "arguments");
+ b2.add(DECLARE);
+ b2.add(SWAP);
+ b2.add(PUT);
+ b2.add(SWAP);
+ b2.add(POP);
+ if (peekToken() == RP) consume(RP);
+ else while(true) {
+ if (peekToken() == COMMA) {
+ consume(COMMA);
- case RC:
- if (braced) getToken();
- break OUTER;
-
- case SEMI:
- getToken();
- if (!braced) break OUTER;
- continue;
-
- default:
- smt = parseMaximalExpr();
- if (smt == null) {
- if (head == null) throw new ParserException("empty statement list; next token is " + codeToString[peekToken()]);
- break OUTER;
+ } else {
+ consume(NAME);
+
+ // declare the name
+ b2.add(LITERAL, string);
+ b2.add(DECLARE);
+
+ // retrieve it from the arguments array
+ b2.add(LITERAL, new Integer(numArgs));
+ b2.add(GET_PRESERVE);
+ b2.add(SWAP);
+ b2.add(POP);
+
+ // put it to the current scope
+ b2.add(TOPSCOPE);
+ b2.add(SWAP);
+ b2.add(LITERAL, string);
+ b2.add(SWAP);
+ b2.add(PUT);
+
+ // clean the stack
+ b2.add(POP);
+ b2.add(POP);
+
+ if (peekToken() == RP) { consume(RP); break; }
+ consume(COMMA);
}
- break;
+ numArgs++;
}
- if (head == null) head = tail = smt; else tail = (tail.next = smt);
+ // pop off the arguments array
+ b2.add(POP);
+ parseStatement(true, b2);
+ b2.add(LITERAL, null);
+ b2.add(RETURN);
+ continueExpr(b.add(NEWFUNCTION, b2), minPrecedence);
+ return;
}
- return new Expr(curLine, LC, head);
- }
-
- /** throws an error if the next token is not <tt>code</tt> */
- public void expect(int code) throws IOException {
- int got = peekToken();
- if (got != code)
- throw new ParserException("expected " + codeToString[code] + ", got " + (got == -1 ? "EOL" : codeToString[got]));
- }
-
- /** parses the largest possible expression */
- public Expr parseMaximalExpr() throws IOException { return parseMaximalExpr(null, -1); }
- public Expr parseMaximalExpr(Expr prefix, int minPrecedence) throws IOException {
- while(true) {
- if (peekToken() == -1) break;
- Expr save = prefix;
- prefix = parseSingleExpr(prefix, minPrecedence);
- if (save == prefix) break;
- if (prefix == null) throw new ParserException("parseSingleExpr() returned null");
+ default: pushBackToken(); return;
}
- return prefix;
}
- public Expr parseSingleExpr(Expr prefix, int minPrecedence) throws IOException {
- Expr e1 = null, e2 = null, e3 = null, head = null, tail = null, ret = null;
-
- int tok = peekToken();
- if (minPrecedence > 0 &&
- tok < precedence.length &&
- precedence[tok] != 0 &&
- (isRightAssociative[tok] ?
- (precedence[tok] < minPrecedence) :
- (precedence[tok] <= minPrecedence))) {
- return prefix;
- }
- getToken();
+ public void continueExpr(ByteCodeBlock prefix, int minPrecedence) throws IOException {
+ int tok = getToken();
int curLine = line;
+ if (tok == -1) return;
+ if (minPrecedence > 0 && precedence[tok] != 0)
+ if (precedence[tok] < minPrecedence || (precedence[tok] == minPrecedence && !isRightAssociative[tok]))
+ { pushBackToken(); return; }
- // these case arms match the precedence of operators; each arm is a precedence level.
- switch (tok) {
+ if (prefix == null) throw new Error("got null prefix");
+ ByteCodeBlock b = prefix;
- case WITH: throw new ParserException("XWT does not allow the WITH keyword");
- case VOID: case RESERVED: throw new ParserException("reserved word that you shouldn't be using");
- case NAME: if (prefix != null) { pushBackToken(); return prefix; } else return parseMaximalExpr(new Expr(curLine, NAME, string), minPrecedence);
- case STRING: if (prefix != null) { pushBackToken(); return prefix; } else return new Expr(curLine, string);
- case NUMBER: if (prefix != null) { pushBackToken(); return prefix; } else return new Expr(curLine, number);
- case NULL: case TRUE: case FALSE: case NOP: if (prefix != null) { pushBackToken(); return prefix; } else return new Expr(curLine, tok);
+ switch (tok) {
- case ASSIGN_BITOR: case ASSIGN_BITXOR: case ASSIGN_BITAND: case ASSIGN_LSH:
- case ASSIGN_RSH: case ASSIGN_URSH: case ASSIGN_ADD: case ASSIGN_SUB: case ASSIGN_MUL: case ASSIGN_DIV: case ASSIGN_MOD:
- return new Expr(curLine, ASSIGN, prefix, new Expr(curLine, tok - 1, prefix, parseMaximalExpr(null, precedence[ASSIGN])));
+ case ASSIGN_BITOR: case ASSIGN_BITXOR: case ASSIGN_BITAND: case ASSIGN_LSH: case ASSIGN_RSH: case ASSIGN_URSH:
+ case ASSIGN_ADD: case ASSIGN_SUB: case ASSIGN_MUL: case ASSIGN_DIV: case ASSIGN_MOD: {
+ prefix.set(prefix.size() - 1, b.GET_PRESERVE, new Boolean(true));
+ startExpr(precedence[tok - 1], b);
+ prefix.add(tok - 1);
+ prefix.add(PUT);
+ prefix.add(SWAP);
+ prefix.add(POP);
+ continueExpr(b, minPrecedence);
+ return;
+ }
- case COMMA: pushBackToken();return prefix;
+ case INC: case DEC: {
+ // postfix
+ b.set(b.size() - 1, tok, new Boolean(false));
+ continueExpr(b, minPrecedence);
+ return;
+ }
- case THIS:
- if (prefix != null) { pushBackToken(); return prefix; }
- return new Expr(curLine, THIS);
+ case LP: {
+ // invocation
+ int i = 0;
+ while(peekToken() != RP) {
+ i++;
+ startExpr(b);
+ if (peekToken() == RP) break;
+ consume(COMMA);
+ }
+ consume(RP);
+ b.add(CALL, new Integer(i));
+ continueExpr(b, minPrecedence);
+ return;
+ }
- case SUB:
- if (prefix == null && peekToken() == NUMBER) {
- getToken();
- return new Expr(curLine, new Double(number.doubleValue() * -1));
- } // else fall through
case BITOR: case BITXOR: case BITAND: case SHEQ: case SHNE: case LSH:
case RSH: case URSH: case ADD: case MUL: case DIV: case MOD:
- case ASSIGN: case GT: case GE: case OR: case AND:
- case EQ: case NE: case LT: case LE:
- if (prefix == null) throw new ParserException("the " + codeToString[tok] + " token cannot start an expression");
- return new Expr(curLine, tok, prefix, parseMaximalExpr(null, precedence[tok]));
-
- case DOT: {
- //e1 = parseMaximalExpr(null, precedence[DOT]);
- //if (e1.code == NAME) e1.code = STRING;
- //else throw new ParserException("argument to DOT must be a NAME; got a " + codeToString[e1.code]);
- //return new Expr(curLine, DOT, prefix, e1);
- tok = getToken();
- if (tok != NAME) throw new ParserException("DOT must be followed by a NAME");
- return new Expr(curLine, DOT, prefix, new Expr(curLine, STRING, string));
+ case GT: case GE: case EQ: case NE: case LT: case LE: case SUB: {
+ startExpr(precedence[tok], b);
+ b.add(tok);
+ continueExpr(b, minPrecedence);
+ return;
}
- case BANG: case BITNOT: case INSTANCEOF: case TYPEOF:
- if (prefix != null) { pushBackToken(); return prefix; }
- return new Expr(curLine, tok, parseMaximalExpr(null, precedence[tok]));
+ case OR: case AND: {
+ b.add(tok == AND ? b.JF : b.JT, new Integer(0));
+ int size = b.size();
+ startExpr(precedence[tok], b);
+ b.set(size - 1, new Integer(b.size() - size + 2));
+ b.add(JMP, new Integer(2));
+ b.add(LITERAL, tok == AND ? new Boolean(false) : new Boolean(true));
+ continueExpr(b, minPrecedence);
+ return;
+ }
- case INC: case DEC:
- if (prefix == null) {
- // prefix
- e1 = parseMaximalExpr(null, precedence[tok]);
- return new Expr(curLine, ASSIGN, e1, new Expr(curLine, tok == INC ? ADD : SUB, e1, new Expr(curLine, new Integer(1))));
+ case DOT: {
+ consume(NAME);
+ String target = string;
+ if (peekToken() == ASSIGN) {
+ consume(ASSIGN);
+ b.add(LITERAL, target);
+ startExpr(b);
+ b.add(PUT);
+ b.add(SWAP);
+ b.add(POP);
} else {
- // postfix
- return new Expr(curLine, tok, prefix);
- }
-
- case LP:
- if (prefix == null) { // grouping
- Expr r = parseMaximalExpr();
- expect(RP); getToken();
- return r;
-
- } else { // invocation
- while(peekToken() != RP) {
- Expr e = parseMaximalExpr();
- if (head == null) head = tail = e; else tail = tail.next = e;
- tok = getToken();
- if (tok == RP) { pushBackToken(); break; }
- if (tok != COMMA) throw new ParserException("expected comma or right paren, got " + codeToString[tok]);
- }
- getToken();
- return new Expr(curLine, LP, prefix, head);
+ b.add(LITERAL, target);
+ b.add(GET);
}
+ continueExpr(b, minPrecedence);
+ return;
+ }
- case LB:
- if (prefix != null) {
- // subscripting
- e1 = parseMaximalExpr();
- if (getToken() != RB) throw new ParserException("expected a right brace");
- return new Expr(curLine, DOT, prefix, e1);
+ case LB: {
+ startExpr(b);
+ consume(RB);
+ if (peekToken() == ASSIGN) {
+ consume(ASSIGN);
+ startExpr(b);
+ b.add(PUT);
+ b.add(SWAP);
+ b.add(POP);
} else {
- // array ctor
- while(true) {
- if (peekToken() == RB) { getToken(); return new Expr(curLine, LB, prefix, head); }
- Expr eee = parseMaximalExpr();
- if (eee != null) {
- if (head == null) head = tail = eee;
- else tail.next = tail = eee;
- }
- tok = getToken();
- if (tok == RB) return new Expr(curLine, LB, prefix, head);
- if (tok != COMMA) throw new ParserException("expected right bracket or comma");
- }
- }
-
- case LC:
- if (prefix != null) { pushBackToken(); return prefix; }
- tok = getToken();
- if (tok == RC) return new Expr(curLine, RC, head);
- while(true) {
- if (tok != NAME && tok != STRING) throw new ParserException("expecting name, got " + codeToString[tok]);
- Expr name = new Expr(curLine, NAME, string);
- if (getToken() != COLON) throw new ParserException("expecting colon");
- e1 = new Expr(curLine, COLON, name, parseMaximalExpr());
- if (head == null) head = tail = e1; else tail = tail.next = e1;
- tok = getToken();
- if (tok != COMMA && tok != RC) throw new ParserException("expected right curly or comma, got " + codeToString[tok]);
- if (tok == RC) return new Expr(curLine, RC, head);
- tok = getToken();
- if (tok == RC) return new Expr(curLine, RC, head);
- }
-
- case HOOK:
- e2 = parseMaximalExpr();
- if (getToken() != COLON) throw new ParserException("expected colon to close ?: expression");
- e3 = parseMaximalExpr();
- return new Expr(curLine, HOOK, prefix, new Expr(curLine, ELSE, e2, e3));
-
- case SWITCH: {
- if (prefix != null) { pushBackToken(); return prefix; }
- if (getToken() != LP) throw new ParserException("expected left paren");
- Expr switchExpr = parseMaximalExpr();
- if (getToken() != RP) throw new ParserException("expected left paren");
- if (getToken() != LC) throw new ParserException("expected left brace");
- Expr firstExpr = null;
- Expr lastExpr = null;
- while(true) {
- tok = getToken();
- Expr caseExpr;
- if (tok == DEFAULT) {
- caseExpr = null;
- } else if (tok == CASE) {
- // FIXME: we don't support non-brace-enclosed CASE blocks
- caseExpr = parseMaximalExpr();
- } else {
- throw new ParserException("expected CASE");
- }
- expect(COLON); getToken();
- head = tail = null;
- while(peekToken() != CASE && peekToken() != DEFAULT && peekToken() != RC) {
- e1 = parseBlock(false);
- if (e1 == null) break;
- if (head == null) head = tail = e1; else tail = tail.next = e1;
- }
- e1 = new Expr(curLine, tok, caseExpr, new Expr(curLine, LC, head));
- if (lastExpr == null) firstExpr = e1; else lastExpr.next = e1;
- lastExpr = e1;
- if (peekToken() == RC) {getToken(); return new Expr(curLine, SWITCH, switchExpr, firstExpr); }
+ b.add(GET);
}
+ continueExpr(b, minPrecedence);
+ return;
}
-
- case FUNCTION: {
- if (prefix != null) { pushBackToken(); return prefix; }
- if (getToken() != LP) throw new ParserException("function keyword must be followed by a left paren");
- Expr formalArgs = null, cur = null;
- tok = getToken();
- while(tok != RP) {
- if (tok != NAME) throw new ParserException("expected a variable name");
- if (cur == null) { formalArgs = cur = new Expr(curLine, string); }
- else { cur.next = new Expr(curLine, NAME, string); cur = cur.next; }
- tok = getToken();
- if (tok == RP) break;
- if (tok != COMMA) throw new ParserException("function argument list must consist of alternating NAMEs and COMMAs");
- tok = getToken();
- }
- return new Expr(curLine, FUNCTION, formalArgs, parseBlock(true));
+
+ case HOOK: {
+ b.add(JF, new Integer(0));
+ int size = b.size();
+ startExpr(b);
+ b.set(size - 1, new Integer(b.size() - size + 2));
+ b.add(JMP, new Integer(0));
+ consume(COLON);
+ size = b.size();
+ startExpr(b);
+ b.set(size - 1, new Integer(b.size() - size + 1));
+ continueExpr(b, minPrecedence);
+ return;
}
- case VAR:
- if (prefix != null) { pushBackToken(); return prefix; }
- while(true) {
- if (getToken() != NAME) throw new ParserException("variable declarations must start with a variable name");
- Expr name = new Expr(curLine, NAME, string);
- Expr initVal = null;
- tok = peekToken();
- Expr e = null;
- if (tok == ASSIGN) {
- getToken();
- initVal = parseMaximalExpr();
- tok = peekToken();
- e = new Expr(curLine, ASSIGN, name, initVal);
- } else {
- e = new Expr(curLine, NAME, name);
- }
- if (head == null) head = tail = e; else tail = tail.next = e;
- if (tok != COMMA) break;
- getToken();
- }
- return new Expr(curLine, VAR, head);
+ default: { pushBackToken(); return; }
+ }
+ }
+
+ /** a block is either a single statement or a list of statements surrounded by curly braces; all expressions are also statements */
- case TRY: {
- // We deliberately allow you to omit braces in catch{}/finally{} if they are single statements...
- if (prefix != null) { pushBackToken(); return prefix; }
- Expr tryBlock = parseBlock(true);
-
- tok = peekToken();
- if (tok == CATCH) {
- getToken();
- if (getToken() != LP) throw new ParserException("expected (");
- if (getToken() != NAME) throw new ParserException("expected name");
- Expr name = new Expr(curLine, NAME, string);
- if (getToken() != RP) throw new ParserException("expected )");
- head = tail = new Expr(curLine, CATCH, name, parseBlock(false));
- tok = peekToken();
- }
- if (tok == FINALLY) {
- getToken();
- e1 = new Expr(curLine, FINALLY, parseBlock(false));
- if (head == null) head = tail = e1; else tail = tail.next = e1;
- }
+ public ByteCodeBlock parseStatement() throws IOException {
+ ByteCodeBlock ret = new ByteCodeBlock(line, sourceName);
+ ret.add(ret.LITERAL, null);
+ parseStatement(false, ret);
+ if (ret.size() == 1) return null;
+ return ret;
+ }
- if (head == null) throw new ParserException("try without catch or finally");
- return new Expr(curLine, TRY, tryBlock, head);
- }
+ public void parseStatement(boolean requireBraces, ByteCodeBlock b) throws IOException {
+ int tok = peekToken();
+ if (tok == -1) return;
+ boolean braced = tok == LC;
+ if (requireBraces && !braced) throw new ParserException("expected {, got " + codeToString[tok]);
+ if (braced) consume(LC);
+ int curLine = line;
+ while(true) {
+ switch(tok = peekToken()) {
- case IF: case WHILE: {
- if (prefix != null) { pushBackToken(); return prefix; }
- if (getToken() != LP) throw new ParserException("expected left paren");
- Expr parenExpr = parseMaximalExpr();
- int t;
- if ((t = getToken()) != RP) throw new ParserException("expected right paren, but got " + codeToString[t]);
- Expr firstBlock = parseBlock(false);
- if (tok == IF && peekToken() == ELSE) {
+ case THROW: case RETURN: case ASSERT: {
getToken();
- return new Expr(curLine, tok, parenExpr, new Expr(curLine, ELSE, firstBlock, parseBlock(false)));
- } else if (tok == IF) {
- return new Expr(curLine, tok, parenExpr, new Expr(curLine, ELSE, firstBlock, new Expr(curLine, LC)));
- } else if (tok == WHILE) {
- return new Expr(curLine, tok, parenExpr, firstBlock);
+ if (tok == RETURN && peekToken() == SEMI) b.add(LITERAL, null);
+ else startExpr(b);
+ consume(SEMI);
+ b.add(tok);
+ break;
}
- }
- case IN: pushBackToken(); return prefix;
-
- case FOR:
- if (prefix != null) { pushBackToken(); return prefix; }
- if (getToken() != LP) throw new ParserException("expected left paren");
- e1 = parseMaximalExpr(null, -1);
- if (peekToken() == IN) {
+ case BREAK: case CONTINUE: {
getToken();
- e2 = parseMaximalExpr(null, -1);
- if (getToken() != RP) throw new ParserException("expected right paren");
- return new Expr(curLine, FOR, new Expr(curLine, IN, e1, e2), parseBlock(false));
+ if (peekToken() == NAME) consume(NAME);
+ b.add(tok, string);
+ consume(SEMI);
+ break;
+ }
- } else {
- if (getToken() != SEMI) throw new ParserException("expected ;");
- e2 = parseMaximalExpr();
- if (getToken() != SEMI) throw new ParserException("expected ;");
- e3 = parseMaximalExpr();
- if (getToken() != RP) throw new ParserException("expected right paren");
- return new Expr(curLine, LC, e1, new Expr(curLine, WHILE, e2, new Expr(curLine, LC, parseBlock(false), e3)));
+ case SEMI:
+ consume(SEMI);
+ if (!braced) return;
+ break;
+
+ case VAR: {
+ consume(VAR);
+ b.add(TOPSCOPE); // push the current scope
+ while(true) {
+ consume(NAME);
+ String name = string;
+ b.add(LITERAL, name); // push the name to be declared
+ b.add(DECLARE); // declare it
+ if (peekToken() == ASSIGN) { // if there is an '=' after the variable name
+ b.add(LITERAL, name); // put the var name back on the stack
+ consume(ASSIGN);
+ startExpr(b);
+ b.add(PUT);
+ b.add(POP);
+ }
+ if (peekToken() != COMMA) break;
+ consume(COMMA);
+ }
+ b.add(POP);
+ if (peekToken() == SEMI) consume(SEMI);
+ break;
}
-
- case DO: {
- if (prefix != null) { pushBackToken(); return prefix; }
- Expr firstBlock = parseBlock(false);
- if (getToken() != WHILE) throw new ParserException("expecting WHILE");
- if (getToken() != LP) throw new ParserException("expected left paren");
- Expr whileExpr = parseMaximalExpr();
- if (getToken() != RP) throw new ParserException("expected right paren");
- if (getToken() != SEMI) throw new ParserException("semicolon");
- return new Expr(curLine, DO, firstBlock, whileExpr);
- }
-
- default:
- pushBackToken();
- return prefix;
- }
- }
-
- // Expr //////////////////////////////////////////////////////////////////////
-
- /** sorta like gcc trees */
- class Expr {
- int code = -1;
-
- final Expr left;
- final Expr right;
- Expr next = null; // if this expr is part of a list
- int line = -1;
- String sourceName = "unknown";
-
- String string = null;
- Number number = null;
-
- public String toString() { return toString(0); }
- public String toString(int indent) {
- String ret = "";
- for(int i=0; i<indent; i++) ret += " ";
- ret += Lexer.codeToString[code];
- if (code == Lexer.NUMBER) ret += " " + number;
- else if (string != null) ret += " \"" + string + "\"";
- ret += "\n";
- if (left != null) ret += left.toString(indent + 2);
- if (right != null) ret += right.toString(indent + 2);
- if (next != null) ret += next.toString(indent);
- return ret;
- }
-
- public Expr(int line, String s) { this(line, Lexer.STRING); this.string = s; } // an identifier or label
- public Expr(int line, int code, String s) { this(line, code); this.string = s; }
- public Expr(int line, Number n) { this(line, Lexer.NUMBER); this.number = n; } // an identifier or label
- public Expr(int line, int code) { this(line, code, null, null); }
- public Expr(int line, int code, Expr left) { this(line, code, left, null); }
- public Expr(int line, int code, Expr left, Expr right) {
- this.code = code; this.left = left; this.right = right;
- this.line = line;
- this.sourceName = Parser.this.sourceName;
- }
-
- public double toDouble(Object o) { return toNumber(o).doubleValue(); }
- public long toLong(Object o) { return toNumber(o).longValue(); }
- public boolean toBoolean(Object o) {
- if (o == null) return false;
- if (o instanceof Boolean) return ((Boolean)o).booleanValue();
- if (o instanceof Number) return o.equals(new Integer(0));
- return true;
- }
-
- public Object eval(final JS.Scope s) throws ControlTransferException, JS.Exn {
- switch(code) {
-
- case Lexer.BITOR: return new Long(toLong(left.eval(s)) | toLong(right.eval(s)));
- case Lexer.BITXOR: return new Long(toLong(left.eval(s)) ^ toLong(right.eval(s)));
- case Lexer.BITAND: return new Long(toLong(left.eval(s)) & toLong(right.eval(s)));
- case Lexer.BITNOT: return new Long(~toLong(left.eval(s)));
-
- case Lexer.ADD: {
- Object l = left.eval(s);
- Object r = right.eval(s);
- if (l instanceof String || r instanceof String) {
- if (l == null) l = "null";
- if (r == null) r = "null";
- if (l instanceof Number && ((Number)l).doubleValue() == ((Number)l).longValue())
- l = new Long(((Number)l).longValue());
- if (r instanceof Number && ((Number)r).doubleValue() == ((Number)r).longValue())
- r = new Long(((Number)r).longValue());
- return l.toString() + r.toString();
+
+ case IF: {
+ consume(IF);
+ consume(LP);
+ startExpr(b);
+ consume(RP);
+
+ b.add(JF, new Integer(0));
+ int size = b.size();
+ parseStatement(false, b);
+
+ if (peekToken() == ELSE) {
+ consume(ELSE);
+ b.set(size - 1, new Integer(2 + b.size() - size));
+ b.add(JMP, new Integer(0));
+ size = b.size();
+ parseStatement(false, b);
}
- return new Double(toDouble(l) + toDouble(r));
+ b.set(size - 1, new Integer(1 + b.size() - size));
+ break;
}
- case Lexer.SUB: return new Double(toDouble(left.eval(s)) - toDouble(right.eval(s)));
- case Lexer.MUL: return new Double(toDouble(left.eval(s)) * toDouble(right.eval(s)));
- case Lexer.DIV: return new Double(toDouble(left.eval(s)) / toDouble(right.eval(s)));
- case Lexer.MOD: return new Double(toDouble(left.eval(s)) % toDouble(right.eval(s)));
-
- case Lexer.LSH: return new Long(toLong(left.eval(s)) << toLong(right.eval(s)));
- case Lexer.RSH: return new Long(toLong(left.eval(s)) >> toLong(right.eval(s)));
- case Lexer.URSH: return new Long(toLong(left.eval(s)) >>> toLong(right.eval(s)));
-
- case Lexer.LT: return toDouble(left.eval(s)) < toDouble(right.eval(s)) ? Boolean.TRUE : Boolean.FALSE;
- case Lexer.LE: return toDouble(left.eval(s)) <= toDouble(right.eval(s)) ? Boolean.TRUE : Boolean.FALSE;
- case Lexer.GT: return toDouble(left.eval(s)) > toDouble(right.eval(s)) ? Boolean.TRUE : Boolean.FALSE;
- case Lexer.GE: return toDouble(left.eval(s)) >= toDouble(right.eval(s)) ? Boolean.TRUE : Boolean.FALSE;
-
- case Lexer.OR: return new Boolean(toBoolean(left.eval(s)) || toBoolean(right.eval(s)));
- case Lexer.AND: return new Boolean(toBoolean(left.eval(s)) && toBoolean(right.eval(s)));
- case Lexer.BANG: return new Boolean(!toBoolean(left.eval(s)));
-
- case Lexer.EQ:
- case Lexer.NE: {
- // FIXME: should use Javascript coercion-equality rules
- Object l = left.eval(s);
- Object r = right.eval(s);
- boolean ret = (l == null && r == null) || (l != null && l.equals(r));
- return new Boolean(code == Lexer.EQ ? ret : !ret);
+ case WHILE: {
+ consume(WHILE);
+ consume(LP);
+ b.add(LOOP);
+ int size = b.size();
+ b.add(POP);
+ startExpr(b);
+ b.add(JT, new Integer(2));
+ b.add(BREAK);
+ consume(RP);
+ parseStatement(false, b);
+ b.add(CONTINUE); // if we fall out of the end, definately continue
+ b.set(size - 1, new Integer(b.size() - size + 1)); // end of the loop
+ break;
}
- case Lexer.INC:
- case Lexer.DEC:
- case Lexer.ASSIGN: {
- Object v = (code == Lexer.ASSIGN) ? right.eval(s) : new Double(toDouble(left.eval(s)) + (code == Lexer.INC ? 1 : -1));
- if (left.code == Lexer.DOT) {
- Object o = left.left.eval(s);
- if (o instanceof String) {
- throw new EvaluatorException("can't set properties on a String");
- } else if (o instanceof Number) {
- throw new EvaluatorException("can't set properties on a Number");
- } else if (o instanceof Boolean) {
- throw new EvaluatorException("can't set properties on a Boolean");
+ case SWITCH: {
+ consume(SWITCH);
+ consume(LP);
+ b.add(LOOP);
+ int size0 = b.size();
+ startExpr(b);
+ consume(RP);
+ consume(LC);
+ while(true)
+ if (peekToken() == CASE) {
+ consume(CASE);
+ b.add(DUP);
+ startExpr(b);
+ consume(COLON);
+ b.add(EQ);
+ b.add(JF, new Integer(0));
+ int size = b.size();
+ while(peekToken() != CASE && peekToken() != DEFAULT && peekToken() != RC) {
+ int size2 = b.size();
+ parseStatement(false, b);
+ if (size2 == b.size()) break;
+ }
+ b.set(size - 1, new Integer(1 + b.size() - size));
+ } else if (peekToken() == DEFAULT) {
+ consume(DEFAULT);
+ consume(COLON);
+ while(peekToken() != CASE && peekToken() != DEFAULT && peekToken() != RC) {
+ int size2 = b.size();
+ parseStatement(false, b);
+ if (size2 == b.size()) break;
+ }
+ } else if (peekToken() == RC) {
+ consume(RC);
+ b.add(BREAK);
+ break;
} else {
- JS target = (JS)left.left.eval(s);
- if (target == null) throw new JS.Exn(new EvaluatorException("attempted to put to the null value"));
- target.put(left.right.eval(s), v);
- return v;
+ throw new ParserException("expected CASE, DEFAULT, or RC; got " + codeToString[peekToken()]);
}
- } else {
- s.put(left.string, v);
- return v;
- }
+ b.add(BREAK);
+ b.set(size0 - 1, new Integer(b.size() - size0 + 1)); // end of the loop
+ break;
}
-
- case Lexer.TYPEOF: {
- Object o = left.eval(s);
- if (o == null) return "null";
- if (o.getClass() == String.class) return "string";
- if (o.getClass() == Boolean.class) return "boolean";
- if (o instanceof Number) return "number";
- if (o instanceof JS.Array) return "array";
- if (o instanceof JS) return "object";
- throw new EvaluatorException("typeof " + o.getClass().getName() + " unknown");
+
+ case DO: {
+ consume(DO);
+ b.add(LOOP);
+ int size = b.size();
+ parseStatement(false, b);
+ consume(WHILE);
+ consume(LP);
+ startExpr(b);
+ b.add(JT, new Integer(2));
+ b.add(BREAK);
+ b.add(CONTINUE);
+ consume(RP);
+ consume(SEMI);
+ b.set(size - 1, new Integer(b.size() - size + 1)); // end of the loop
+ break;
}
-
- case Lexer.NUMBER: return number;
- case Lexer.STRING: return string;
-
- case Lexer.NULL: return null;
- case Lexer.FALSE: return Boolean.FALSE;
- case Lexer.TRUE: return Boolean.TRUE;
- case Lexer.ASSERT: if (!toBoolean(left.eval(s))) throw new EvaluatorException("assertion failed");
- case Lexer.THROW: throw new JS.Exn(left.eval(s));
- case Lexer.NAME: return s.get(string);
- case Lexer.THIS: return s.isTransparent() ? s : this.eval(s.getParentScope());
-
- case Lexer.DOT: {
- final Object o = left.eval(s);
- Object v = ((right.code == Lexer.NAME) || (right.code == Lexer.STRING)) ? right.string : right.eval(s);
- if (o instanceof String) {
- if (v.equals("length")) return new Integer(((String)o).length());
- else if (v.equals("substring")) return new JS.Function() {
- public Object _call(JS.Array args) {
- if (args.length() == 1) return ((String)o).substring(toNumber(args.elementAt(0)).intValue());
- else if (args.length() == 2) return ((String)o).substring(toNumber(args.elementAt(0)).intValue(),
- toNumber(args.elementAt(1)).intValue());
- else throw new EvaluatorException("String.substring() can only take one or two arguments");
- }
- };
- else if (v.equals("indexOf")) return new JS.Function() {
- public Object _call(JS.Array args) {
- if (args.length() != 1) return null;
- return new Integer(((String)o).indexOf(args.elementAt(0).toString()));
- }
- };
- throw new EvaluatorException("Not Implemented: properties on String objects");
- } else if (o instanceof Boolean) {
- throw new EvaluatorException("Not Implemented: properties on Boolean objects");
- } else if (o instanceof Number) {
- throw new EvaluatorException("Not Implemented: properties on Number objects");
- } else if (o instanceof JS) {
- return ((JS)o).get(v);
+
+ case TRY: {
+ // We deliberately allow you to omit braces in catch{}/finally{} if they are single statements...
+ consume(TRY);
+ parseStatement(true, b);
+
+ if (peekToken() == CATCH) {
+ getToken();
+ consume(LP);
+ consume(NAME);
+ consume(RP);
+ parseStatement(); // just discard the catchblock
}
- }
- case Lexer.TRY: {
- boolean safeToExit = false;
- try {
- Object ret = left.eval(s);
- safeToExit = true;
- return ret;
- } catch (JS.Exn e) {
- Expr c = right;
- if (c.code == Lexer.CATCH) {
- JS.Scope scope = new JS.Scope(s);
- s.put(c.left.string, e);
- c.right.eval(scope);
- c = c.next;
- }
- if (c.code == Lexer.FINALLY) {
- JS.Scope scope = new JS.Scope(s);
- c.left.eval(scope);
- }
- } finally {
- if (!safeToExit) Log.log(this, "WARNING: Java exception penetrated a JavaScript try{} block");
+ if (peekToken() == FINALLY) {
+ consume(FINALLY);
+ parseStatement(false, b);
}
- return null;
+ break;
}
- case Lexer.LP:
- JS.Function f = (JS.Function)left.eval(s);
- JS.Array arguments = new JS.Array();
- for(Expr e = right; e != null; e = e.next) arguments.addElement(e.eval(s));
- if (f == null) throw new JS.Exn(new EvaluatorException("attempted to call null"));
- return f.call(arguments);
-
- case Lexer.FUNCTION:
- return new JS.Function() {
- public String toString() { return right.sourceName + ":" + right.line; }
- public String getSourceName() throws JS.Exn { return right.sourceName; }
- public Object _call(final JS.Array args) throws JS.Exn {
- Function save = JS.getCurrentFunction();
- JS.currentFunction.put(Thread.currentThread(), this);
- JS.Scope scope = new JS.Scope(s) {
- // FIXME
- public String getSourceName() { return sourceName; }
- public boolean isTransparent() { return true; }
- public Object get(Object key) throws JS.Exn {
- if (key.equals("trapee")) return org.xwt.Trap.currentTrapee();
- else if (key.equals("cascade")) return org.xwt.Trap.cascadeFunction;
- else if (key.equals("arguments")) return args;
- return super.get(key);
- }
- };
- int i = 0;
- for(Expr e = left; e != null; e = e.next) scope.put(e.string, args.get(new Integer(i++)));
- try {
- return right.eval(scope);
- } catch (ReturnException r) {
- return r.retval;
- } catch (ControlTransferException c) {
- throw new EvaluatorException("error, ControlTransferException tried to leave a function: "
- + c);
- } finally {
- if (save == null) JS.currentFunction.remove(Thread.currentThread());
- else JS.currentFunction.put(Thread.currentThread(), save);
- }
- }
- };
-
- case Lexer.FOR:
- Object[] keys = ((JS)left.right.eval(s)).keys();
- for(int i=0; i<keys.length; i++) {
- JS.Scope scope = new JS.Scope(s);
- scope.put(left.left.string, keys[i]);
- try {
- right.eval(scope);
- } catch (ContinueException c) {
- if (c.label == null || c.label.equals(string)) continue;
- } catch (BreakException b) {
- if (b.label == null || b.label.equals(string)) return null;
- throw (BreakException)b.fillInStackTrace();
- }
- }
- return null;
-
- case Lexer.SWITCH:
- Object switchVal = left.eval(s);
- boolean go = false;
- try {
- for(Expr e = right; e != null; e = e.next) {
- if (go || e.code == Lexer.DEFAULT || e.left.eval(s).equals(switchVal)) go = true;
- if (go) e.right.eval(s);
- }
- } catch (BreakException b) {
- if (b.label == null || b.label.equals(string)) return null;
- throw (BreakException)b.fillInStackTrace();
- }
- return null;
+ case FOR: {
+ consume(FOR);
+ consume(LP);
- case Lexer.LB: {
- JS.Array ret = new JS.Array();
- for(Expr e = left; e != null; e = e.next) ret.addElement(e.eval(s));
- return ret;
- }
-
- case Lexer.LC: // block
- for(Expr e = left; e != null; e = e.next) e.eval(s);
- return null;
-
- case Lexer.RC: { // Object ctor
- JS.Obj ret = new JS.Obj();
- for(Expr e = left; e != null; e = e.next)
- ret.put(e.left.string, e.right.eval(s));
- return ret;
+ tok = getToken();
+ boolean hadVar = false;
+ if (tok == VAR) { hadVar = true; tok = getToken(); }
+ String varName = string;
+ boolean forIn = peekToken() == IN;
+ pushBackToken(tok, varName);
+
+ if (forIn) {
+ // FIXME: break needs to work in here
+ consume(NAME);
+ consume(IN);
+ startExpr(b);
+ b.add(PUSHKEYS);
+ b.add(LITERAL, "length");
+ b.add(GET);
+ consume(RP);
+ ByteCodeBlock b2 = newbb(curLine);
+
+ b.add(PUSHSCOPE);
+
+ b.add(LITERAL, new Integer(1));
+ b.add(SUB);
+ b.add(DUP);
+ b.add(LITERAL, new Integer(0));
+ b.add(LT);
+ b.add(JT, new Integer(7));
+ b.add(GET_PRESERVE);
+ b.add(LITERAL, varName);
+ b.add(LITERAL, varName);
+ b.add(DECLARE);
+ b.add(PUT);
+ parseStatement(false, b);
+
+ b.add(POPSCOPE);
+
+ break;
+
+ } else {
+ if (hadVar) pushBackToken(VAR, null);
+ b.add(PUSHSCOPE);
+
+ parseStatement(false, b);
+ ByteCodeBlock e2 = new ByteCodeBlock(line, sourceName);
+ startExpr(e2);
+ consume(SEMI);
+ if (e2 == null) e2 = newbb(curLine).add(b.LITERAL, Boolean.TRUE);
+
+ b.add(LOOP);
+ int size2 = b.size();
+
+ b.add(JT, new Integer(0));
+ int size = b.size();
+ startExpr(b);
+ if (b.size() > size) b.add(POP);
+ b.set(size - 1, new Integer(b.size() - size + 1));
+ consume(RP);
+
+ b.paste(e2);
+ b.add(JT, new Integer(2));
+ b.add(BREAK);
+ parseStatement(false, b);
+ b.add(CONTINUE);
+ b.set(size2 - 1, new Integer(b.size() - size2 + 1)); // end of the loop
+
+ b.add(POPSCOPE);
+ break;
}
+ }
- case Lexer.VAR:
- for(Expr e = left; e != null; e = e.next)
- if (e.code == Lexer.NAME) {
- s.declare(e.string);
- } else {
- s.declare(e.left.string);
- e.eval(s);
- }
- return null;
-
- case Lexer.HOOK: return toBoolean(left.eval(s)) ? right.left.eval(s) : right.right.eval(s);
- case Lexer.IF: return toBoolean(left.eval(s)) ? right.left.eval(s) : right.right.eval(s);
- case Lexer.BREAK: throw new BreakException(string);
- case Lexer.CONTINUE: throw new ContinueException(string);
- case Lexer.RETURN: throw new ReturnException(left == null ? null : left.eval(s));
-
- case Lexer.WHILE:
- case Lexer.DO:
- try {
- boolean first = true;
- while((first && code == Lexer.DO) || toBoolean(left.eval(s))) {
- first = false;
- try { right.eval(s);
- } catch (ContinueException c) {
- if (c.label == null || c.label.equals(string)) continue;
- } catch (BreakException b) {
- if (b.label == null || b.label.equals(string)) return null;
- throw (BreakException)b.fillInStackTrace();
- }
- }
- } catch (BreakException e) {
- if (e.label != null && !e.label.equals(string)) throw e;
+ case NAME: {
+ consume(NAME);
+ String name = string;
+ if (peekToken() == COLON) {
+ consume(COLON);
+ b.add(ByteCodeBlock.LABEL, string);
+ break;
+ } else {
+ pushBackToken(NAME, name);
+ // fall through to default case
}
- return null;
-
- default: throw new EvaluatorException("don't know how to eval an Expr with code " + Lexer.codeToString[code] + "\n" + this);
}
- }
-
- class EvaluatorException extends RuntimeException {
- public EvaluatorException(String s) { super(sourceName + ":" + line + " " + s); }
+ // fall through
+ case RC:
+ if (tok == RC && braced) { consume(RC); return; }
+ // fall through
+ default: {
+ int size = b.size();
+ startExpr(b);
+ if (size == b.size()) return;
+ b.add(POP);
+ if (peekToken() == SEMI) consume(SEMI);
+ break;
+ }
+ }
+
+ if (!braced) return;
}
}
-
- static abstract class ControlTransferException extends Exception { }
- static class BreakException extends ControlTransferException {
- public String label;
- BreakException(String label) { this.label = label; }
- }
- static class ContinueException extends ControlTransferException {
- public String label;
- ContinueException(String label) { this.label = label; }
- }
- static class ReturnException extends ControlTransferException {
- public Object retval;
- ReturnException(Object retval) { this.retval = retval; }
- }
-
+
class ParserException extends RuntimeException {
public ParserException(String s) { super(sourceName + ":" + line + " " + s); }
}
-
- public static Number toNumber(Object o) {
- if (o == null) return new Long(0);
- if (o instanceof Number) return ((Number)o);
- if (o instanceof String) return new Double((String)o);
- if (o instanceof Boolean) return ((Boolean)o).booleanValue() ? new Long(1) : new Long(0);
- if (o instanceof JS) return ((JS)o).coerceToNumber();
- // FIXME
- throw new Error("toNumber() got object of type " + o.getClass().getName());
- }
- }
+
+}
projects / org.ibex.core.git / blobdiff