import org.xwt.util.*;
import java.io.*;
+
/** parses a stream of lexed tokens into a tree of Expr's */
public class Parser extends Lexer {
// Constructors //////////////////////////////////////////////////////
- public Parser(Reader r) throws IOException { super(r); }
+ public Parser(Reader r, String sourceName, int line) throws IOException {
+ super(r);
+ this.sourceName = sourceName;
+ this.line = line;
+ }
+ /** for debugging */
public static void main(String[] s) throws Exception {
- Parser p = new Parser(new InputStreamReader(System.in));
+ Parser p = new Parser(new InputStreamReader(System.in), "stdin", 0);
while(true) {
Expr block = p.parseBlock(false);
if (block == null) return;
// Statics ////////////////////////////////////////////////////////////
static byte[] precedence = new byte[MAX_TOKEN + 1];
+ static boolean[] isRightAssociative = new boolean[MAX_TOKEN + 1];
static {
- precedence[COMMA] = 1;
- precedence[ASSIGN] = 2;
- precedence[GT] = precedence[GE] = 3;
+ precedence[ASSIGN] = 1;
+ isRightAssociative[ASSIGN] = true;
+ precedence[HOOK] = 2;
+ precedence[COMMA] = 3;
precedence[OR] = precedence[AND] = 4;
- precedence[BITOR] = 5;
- precedence[BITXOR] = 6;
- precedence[BITAND] = 7;
- precedence[EQ] = precedence[NE] = 8;
- precedence[LT] = precedence[LE] = 9;
- precedence[SHEQ] = precedence[SHNE] = 10;
- precedence[LSH] = precedence[RSH] = precedence[URSH] = 11;
- precedence[ADD] = precedence[SUB] = 12;
- precedence[MUL] = precedence[DIV] = precedence[MOD] = 13;
- precedence[BITNOT] = precedence[INSTANCEOF] = 14;
- precedence[INC] = precedence[DEC] = 15;
- precedence[LP] = 16;
- precedence[DOT] = 17;
+ precedence[GT] = precedence[GE] = 5;
+ precedence[BITOR] = 6;
+ precedence[BITXOR] = 7;
+ precedence[BITAND] = 8;
+ precedence[EQ] = precedence[NE] = 9;
+ precedence[LT] = precedence[LE] = 10;
+ precedence[SHEQ] = precedence[SHNE] = 11;
+ 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[INC] = precedence[DEC] = 16;
+ precedence[LP] = 17;
+ precedence[LB] = 18;
+ precedence[DOT] = 19;
}
// 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 Error("expected {");
- if (braced) getToken();
- Expr head = null;
- Expr tail = null;
- OUTER: while(true) {
- Expr smt;
- switch(tok = peekToken()) {
- case -1: break OUTER;
- case LC: smt = parseBlock(true); break;
- case THROW: case RETURN: case ASSERT:
- getToken();
- smt = new Expr(tok, parseMaximalExpr());
- if (getToken() != SEMI) throw new Error("expected ;");
- break;
- case GOTO: case BREAK: case CONTINUE:
- getToken();
- if (getToken() == NAME)
- smt = new Expr(tok, new Expr(string));
- else if (tok == GOTO)
- throw new Error("goto must be followed by a label");
- else
- smt = new Expr(tok);
- if (getToken() != SEMI) throw new Error("expected ;");
- break;
-
- 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 Error("empty statement list; next token is " + codeToString[peekToken()]);
- break OUTER;
- }
- break;
- }
- if (head == null) head = tail = smt; else tail = (tail.next = smt);
- }
- return new Expr(LC, head);
+ public void consume(int code) throws IOException {
+ int got = getToken();
+ if (got != code) throw new ParserException("expected " + codeToString[code] + ", got " + (got == -1 ? "EOL" : codeToString[got]));
+ }
+ public void consume(int code, int code2) throws IOException {
+ int got = getToken();
+ if (got != code && got != code2)
+ throw new ParserException("expected " + codeToString[code] + " or " + codeToString[code2] +
+ ", got " + (got == -1 ? "EOL" : codeToString[got]));
}
-
- /** 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 Error("expected " + codeToString[got] + ", got " + (got == -1 ? "EOL" : codeToString[got]));
+ 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 {
- Expr save = null;
while(true) {
- save = prefix;
if (peekToken() == -1) break;
+ Expr save = prefix;
prefix = parseSingleExpr(prefix, minPrecedence);
if (save == prefix) break;
- if (prefix == null) throw new Error("parseSingleExpr_() returned null");
+ if (prefix == null) throw new ParserException("parseSingleExpr() returned null");
}
return prefix;
}
- /** parses the smallest possible complete expression */
- public Expr parseSingleExpr() throws IOException { return parseSingleExpr(null, 0); }
-
- /** parses the smallest possible complete expression beginning with prefix and only using operators with at least minPrecedence */
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 && precedence[tok] <= minPrecedence) return prefix;
+ if (minPrecedence > 0 &&
+ tok < precedence.length &&
+ precedence[tok] != 0 &&
+ (isRightAssociative[tok] ?
+ (precedence[tok] < minPrecedence) :
+ (precedence[tok] <= minPrecedence))) {
+ return prefix;
+ }
getToken();
+ int curLine = line;
// these case arms match the precedence of operators; each arm is a precedence level.
switch (tok) {
- case WITH: throw new Error("XWT does not allow the WITH keyword");
- case VOID: case RESERVED: throw new Error("reserved word that you shouldn't be using");
- case NAME: if (prefix != null) { pushBackToken(); return prefix; } else return parseMaximalExpr(new Expr(NAME, string), minPrecedence);
- case STRING: if (prefix != null) { pushBackToken(); return prefix; } else return new Expr(string);
- case NUMBER: if (prefix != null) { pushBackToken(); return prefix; } else return new Expr(number);
- case NULL: case TRUE: case FALSE: case NOP: if (prefix != null) { pushBackToken(); return prefix; } else return new Expr(tok);
+ case VAR: {
+ if (prefix != null) { pushBackToken(); return prefix; }
+ ByteCode b = new ByteCode(curLine);
+ b.add(b.THIS, NO_ARG);
+ while(true) {
+ consume(NAME);
+ String name = string;
+ b.add(b.DECLARE, name);
+ if (peekToken() == ASSIGN) {
+ b.add(b.LITERAL, name);
+ consume(ASSIGN);
+ b.add(b.EXPR, parseMaximalExpr());
+ b.add(b.PUT, NO_ARG);
+ b.add(b.POP, NO_ARG);
+ }
+ if (peekToken() != COMMA) break;
+ consume(COMMA);
+ }
+ return b;
+ }
- 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(ASSIGN, prefix, new Expr(tok - 1, prefix, parseMaximalExpr(null, precedence[ASSIGN])));
+ case IN: pushBackToken(); return prefix;
- case BITOR: case BITXOR: case BITAND: case SHEQ: case SHNE: case LSH:
- case RSH: case URSH: case ADD: case SUB: case MUL: case DIV: case MOD:
- case COMMA: case ASSIGN: case GT: case GE: case OR: case AND:
- case EQ: case NE: case LT: case LE: case DOT:
- return new Expr(tok, prefix, parseMaximalExpr(null, precedence[tok]));
+ case IF: {
+ if (prefix != null) { pushBackToken(); return prefix; }
+ ByteCode b = new ByteCode(curLine);
+ consume(LP);
+ b.add(b.EXPR, parseMaximalExpr());
+ consume(RP);
+ b.add(b.JF, new Integer(3));
+ b.add(b.EXPR, parseBlock(false));
+ b.add(b.JMP, new Integer(2));
+ if (peekToken() != ELSE) return b.add(b.LITERAL, null);
+ consume(ELSE);
+ b.add(b.EXPR, parseBlock(false));
+ return b;
+ }
- case BITNOT: case INSTANCEOF:
- if (prefix != null) throw new Error("didn't expect non-null prefix!");
- return new Expr(tok, parseMaximalExpr(null, precedence[tok]));
+ // FIXME: ugly hack!!
+ case ASSIGN_BITOR: if (tok == ASSIGN_BITOR) tok = BITOR;
+ case ASSIGN_BITXOR: if (tok == ASSIGN_BITXOR) tok = BITXOR;
+ case ASSIGN_BITAND: if (tok == ASSIGN_BITAND) tok = BITAND;
+ case ASSIGN_LSH: if (tok == ASSIGN_LSH) tok = LSH;
+ case ASSIGN_RSH: if (tok == ASSIGN_RSH) tok = RSH;
+ case ASSIGN_URSH: if (tok == ASSIGN_URSH) tok = URSH;
+ case ASSIGN_ADD: if (tok == ASSIGN_ADD) tok = ADD;
+ case ASSIGN_SUB: if (tok == ASSIGN_SUB) tok = SUB;
+ case ASSIGN_MUL: if (tok == ASSIGN_MUL) tok = MUL;
+ case ASSIGN_DIV: if (tok == ASSIGN_DIV) tok = DIV;
+ case ASSIGN_MOD: if (tok == ASSIGN_MOD) tok = MOD;
+ {
+ ByteCode b = (ByteCode)prefix;
+ b.set(b.size() - 1, b.GET_PRESERVE, new Boolean(true));
+ b.add(b.EXPR, parseMaximalExpr(null, precedence[tok]));
+ b.add(tok, NO_ARG);
+ b.add(b.PUT, NO_ARG);
+ b.add(b.SWAP, NO_ARG);
+ b.add(b.POP, NO_ARG);
+ return b;
+ }
case INC: case DEC:
if (prefix == null) {
// prefix
- return new Expr(tok, parseMaximalExpr(null, precedence[tok]));
+ ByteCode b = (ByteCode)parseMaximalExpr(null, precedence[tok]);
+ b.set(b.size() - 1, tok, new Boolean(true));
+ return b;
} else {
// postfix
- return new Expr(tok, null, prefix);
+ ByteCode b = (ByteCode)prefix;
+ b.set(b.size() - 1, tok, new Boolean(false));
+ return b;
}
case LP:
if (prefix == null) { // grouping
- Expr r = parseMaximalExpr();
- expect(RP); getToken();
- return r;
+ ByteCode b = new ByteCode(curLine, ByteCode.EXPR, parseMaximalExpr());
+ consume(RP);
+ return b;
} else { // invocation
+ ByteCode b = new ByteCode(curLine);
+ int i = 0;
+ b.add(b.EXPR, prefix);
while(peekToken() != RP) {
- Expr e = parseMaximalExpr(null, precedence[COMMA]);
- if (head == null) head = tail = e; else tail = tail.next = e;
- tok = getToken();
- if (tok == RP) { pushBackToken(); break; }
- if (tok != COMMA) throw new Error("expected comma or right paren, got " + codeToString[tok]);
+ b.add(b.EXPR, parseMaximalExpr());
+ i++;
+ if (peekToken() == RP) break;
+ consume(COMMA);
}
+ consume(RP);
+ b.add(b.CALL, new Integer(i));
+ return b;
+ }
+
+ case BANG: case BITNOT: case INSTANCEOF: case TYPEOF: {
+ if (prefix != null) { pushBackToken(); return prefix; }
+ ByteCode b = new ByteCode(curLine);
+ b.add(b.EXPR, parseMaximalExpr(null, precedence[tok]));
+ b.add(tok, NO_ARG);
+ return b;
+ }
+
+ case SUB:
+ if (prefix == null && peekToken() == NUMBER) {
getToken();
- return new Expr(LP, prefix, head);
+ return new ByteCode(curLine, ByteCode.LITERAL, 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 GT: case GE: case EQ: case NE: case LT: case LE: {
+ if (prefix == null) throw new ParserException("the " + codeToString[tok] + " token cannot start an expression");
+ ByteCode b = new ByteCode(curLine);
+ b.add(b.EXPR, prefix);
+ b.add(b.EXPR, parseMaximalExpr(null, precedence[tok]));
+ b.add(tok, NO_ARG);
+ return b;
+ }
+
+ // includes short-circuit logic
+ case OR: case AND: {
+ if (prefix == null) throw new ParserException("the " + codeToString[tok] + " token cannot start an expression");
+ ByteCode b = new ByteCode(curLine);
+ b.add(b.LITERAL, tok == AND ? new Boolean(false) : new Boolean(true));
+ b.add(b.EXPR, prefix);
+ b.add(tok == AND ? b.JF : b.JT, new Integer(3));
+ b.add(b.POP, NO_ARG);
+ b.add(b.EXPR, parseMaximalExpr(null, precedence[tok]));
+ return b;
+ }
+
+ case ASSIGN: {
+ if (prefix == null) throw new ParserException("the " + codeToString[tok] + " token cannot start an expression");
+ ByteCode b = new ByteCode(curLine);
+ b.add(b.THIS, NO_ARG);
+ b.add(b.LITERAL, prefix.string); // FIXME, this is ass-ugly
+ b.add(b.EXPR, parseMaximalExpr(null, precedence[ASSIGN]));
+ b.add(b.PUT, NO_ARG);
+ b.add(b.SWAP, NO_ARG);
+ b.add(b.POP, NO_ARG);
+ return b;
+ }
+
+ 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 NUMBER:
+ if (prefix != null) { pushBackToken(); return prefix; }
+ return new ByteCode(curLine, ByteCode.LITERAL, number);
+
+ case STRING:
+ if (prefix != null) { pushBackToken(); return prefix; }
+ return new ByteCode(curLine, ByteCode.LITERAL, string);
+
+ case NULL: case TRUE: case FALSE: case NOP:
+ if (prefix != null) { pushBackToken(); return prefix; }
+ return new ByteCode(curLine, ByteCode.LITERAL, (tok == NULL || tok == NOP) ? null : new Boolean(tok == TRUE));
+
+ case COMMA: pushBackToken(); return prefix;
+
+ case THIS:
+ if (prefix != null) { pushBackToken(); return prefix; }
+ return new ByteCode(curLine, ByteCode.THIS, NO_ARG);
+
+ // potential lvalues
+
+ case NAME: {
+ if (prefix != null) { pushBackToken(); return prefix; }
+ String name = string;
+ ByteCode b = new ByteCode(curLine);
+ if (peekToken() == ASSIGN) {
+ consume(ASSIGN);
+ b.add(ByteCode.THIS, NO_ARG);
+ b.add(ByteCode.LITERAL, name);
+ b.add(ByteCode.EXPR, parseMaximalExpr(null, minPrecedence));
+ b.add(ByteCode.PUT, NO_ARG);
+ b.add(ByteCode.SWAP, NO_ARG);
+ b.add(ByteCode.POP, NO_ARG);
+ return b;
+ } else {
+ b.add(ByteCode.THIS, NO_ARG);
+ b.add(ByteCode.LITERAL, name);
+ b.add(ByteCode.GET, NO_ARG);
+ return parseMaximalExpr(b, minPrecedence);
}
+ }
- case LB:
- if (prefix != null) {
- // subscripting
- e1 = parseMaximalExpr();
- if (getToken() != RB) throw new Error("expected a right brace");
- return new Expr(LB, prefix, e1);
+ case DOT: {
+ consume(NAME);
+ String target = string;
+ ByteCode b = new ByteCode(curLine);
+ b.add(b.EXPR, prefix);
+ if (peekToken() == ASSIGN) {
+ consume(ASSIGN);
+ Expr val = parseMaximalExpr();
+ b.add(b.LITERAL, target);
+ b.add(b.EXPR, val);
+ b.add(b.PUT, NO_ARG);
+ b.add(b.SWAP, NO_ARG);
+ b.add(b.POP, NO_ARG);
} else {
- // array ctor
- tok = getToken();
+ b.add(b.LITERAL, target);
+ b.add(b.GET, NO_ARG);
+ }
+ return b;
+ }
+
+ case LB: {
+ ByteCode b = new ByteCode(curLine);
+ if (prefix == null) {
+ b.add(b.ARRAY, new Integer(0));
+ int i = 0;
while(true) {
- if (tok == RB) return new Expr(LB, prefix, head);
- if (head == null) head = tail = parseMaximalExpr(null, precedence[COMMA]);
- else tail = tail.next = parseMaximalExpr(null, precedence[COMMA]);
- tok = getToken();
- if (tok != COMMA && tok != RP) throw new Error("expected right bracket or comma");
+ Expr e = parseMaximalExpr();
+ if (e == null && peekToken() == RB) { consume(RB); return b; }
+ b.add(b.LITERAL, new Integer(i++));
+ if (e == null) b.add(b.LITERAL, null);
+ else b.add(b.EXPR, e);
+ b.add(b.PUT, NO_ARG);
+ b.add(b.POP, NO_ARG);
+ if (peekToken() == RB) { consume(RB); return b; }
+ consume(COMMA);
+ }
+ } else {
+ b.add(b.EXPR, prefix);
+ b.add(b.EXPR, parseMaximalExpr());
+ consume(RB);
+ if (peekToken() == ASSIGN) {
+ consume(ASSIGN);
+ b.add(b.EXPR, parseMaximalExpr());
+ b.add(b.PUT, NO_ARG);
+ b.add(b.SWAP, NO_ARG);
+ b.add(b.POP, NO_ARG);
+ } else {
+ b.add(b.GET, NO_ARG);
}
+ return b;
}
+ }
+
+ // end //
- case LC:
- if (prefix != null) throw new Error("didn't expect non-null prefix");
- tok = getToken();
+ case LC: {
+ if (prefix != null) { pushBackToken(); return prefix; }
+ ByteCode b = new ByteCode(curLine);
+ b.add(b.OBJECT, null);
+ if (peekToken() == RC) { consume(RC); return b; }
while(true) {
- if (tok == RC) return new Expr(LC, head);
- if (tok != NAME) throw new Error("expecting name");
- expect(NAME); getToken();
- Expr name = new Expr(NAME, string);
- if (tok != COLON) throw new Error("expecting colon");
- e1 = new Expr(COLON, name, parseMaximalExpr(null, precedence[COMMA]));
- if (head == null) head = tail = e1; else tail = tail.next = e1;
- tok = getToken();
- if (tok != COMMA && tok != RP) throw new Error("expected right curly or comma");
+ consume(NAME, STRING);
+ b.add(b.LITERAL, string);
+ consume(COLON);
+ b.add(b.EXPR, parseMaximalExpr());
+ b.add(b.PUT, NO_ARG);
+ b.add(b.POP, NO_ARG);
+ if (peekToken() == RC) { consume(RC); return b; }
+ consume(COMMA);
+ if (peekToken() == RC) { consume(RC); return b; }
}
+ }
- case HOOK:
- e2 = parseMaximalExpr();
- if (getToken() != COLON) throw new Error("expected colon to close ?: expression");
- e3 = parseMaximalExpr();
- return new Expr(HOOK, prefix, new Expr(ELSE, e2, e3));
-
- case SWITCH: {
- if (prefix != null) throw new Error("didn't expect non-null prefix");
- if (getToken() != LP) throw new Error("expected left paren");
- Expr switchExpr = parseMaximalExpr();
- if (getToken() != RP) throw new Error("expected left paren");
- if (getToken() != LC) throw new Error("expected left brace");
- Expr firstExpr = null;
- Expr lastExpr = null;
- while(true) {
- if (getToken() != CASE) throw new Error("expected CASE");
- Expr caseExpr = parseMaximalExpr();
- if (getToken() != COLON) throw new Error("expected COLON");
- Expr e = new Expr(CASE, caseExpr, parseBlock(false));
- if (lastExpr == null) firstExpr = e;
- else lastExpr.next = e;
- lastExpr = e;
- if (getToken() == RC) return new Expr(SWITCH, switchExpr, firstExpr);
- }
+ case HOOK: {
+ ByteCode b = new ByteCode(curLine);
+ b.add(b.EXPR, prefix);
+ b.add(b.JF, new Integer(3));
+ b.add(b.EXPR, parseMaximalExpr());
+ b.add(b.JMP, new Integer(2));
+ consume(COLON);
+ b.add(b.EXPR, parseMaximalExpr());
+ return b;
}
case FUNCTION: {
- if (prefix != null) throw new Error("didn't expect non-null prefix");
- if (getToken() != LP) throw new Error("function keyword must be followed by a left paren");
- Expr formalArgs = null, cur = null;
- tok = getToken();
- while(tok != RP) {
- if (tok != NAME) throw new Error("expected a variable name");
- if (cur == null) { formalArgs = cur = new Expr(string); }
- else { cur.next = new Expr(NAME, string); cur = cur.next; }
- tok = getToken();
- if (tok == RP) break;
- if (tok != COMMA) throw new Error("function argument list must consist of alternating NAMEs and COMMAs");
- tok = getToken();
+ if (prefix != null) { pushBackToken(); return prefix; }
+ consume(LP);
+ ByteCode b = new ByteCode(curLine);
+ int numArgs = 0;
+ b.add(b.THIS, NO_ARG);
+ b.add(b.SWAP, NO_ARG);
+ b.add(b.LITERAL, "arguments");
+ b.add(b.LITERAL, "arguments");
+ b.add(b.DECLARE, NO_ARG);
+ b.add(b.SWAP, NO_ARG);
+ b.add(b.PUT, NO_ARG);
+ b.add(b.SWAP, NO_ARG);
+ b.add(b.POP, NO_ARG);
+ if (peekToken() == RP) consume(RP);
+ else while(true) {
+ if (peekToken() == COMMA) {
+ consume(COMMA);
+ } else {
+ consume(NAME);
+
+ // declare the name
+ b.add(b.LITERAL, string);
+ b.add(b.DECLARE, NO_ARG);
+
+ // retrieve it from the arguments array
+ b.add(b.LITERAL, new Integer(numArgs));
+ b.add(b.GET_PRESERVE, NO_ARG);
+ b.add(b.SWAP, NO_ARG);
+ b.add(b.POP, NO_ARG);
+
+ // put it to the current scope
+ b.add(b.THIS, NO_ARG);
+ b.add(b.SWAP, NO_ARG);
+ b.add(b.LITERAL, string);
+ b.add(b.SWAP, NO_ARG);
+ b.add(b.PUT, NO_ARG);
+
+ // clean the stack
+ b.add(b.POP, NO_ARG);
+ b.add(b.POP, NO_ARG);
+
+ if (peekToken() == RP) { consume(RP); break; }
+ consume(COMMA);
+ }
+ numArgs++;
}
- return new Expr(FUNCTION, formalArgs, parseBlock(true));
+ // pop off the arguments array
+ b.add(b.POP, NO_ARG);
+ parseBlock(true, b);
+ return new ByteCode(curLine, b.FUNCTION, b);
}
- case VAR:
- if (prefix != null) throw new Error("didn't expect non-null prefix");
+ // Needs break //
+
+ case SWITCH: {
+ if (prefix != null) { pushBackToken(); return prefix; }
+ consume(LP);
+ Expr switchExpr = parseMaximalExpr();
+ consume(RP);
+ consume(LC);
+ ExprList toplevel = new ExprList(curLine, LC);
while(true) {
- if (getToken() != NAME) throw new Error("variable declarations must start with a variable name");
- Expr name = new Expr(NAME, string);
- Expr initVal = null;
- tok = peekToken();
- Expr e = null;
- if (tok == ASSIGN) {
- getToken();
- initVal = parseMaximalExpr(null, precedence[COMMA]);
- tok = peekToken();
- e = new Expr(ASSIGN, name, initVal);
- } else {
- e = new Expr(NAME, name);
+ tok = getToken();
+ Expr caseExpr;
+ if (tok == DEFAULT) caseExpr = null;
+ else if (tok == CASE) caseExpr = parseMaximalExpr();
+ else throw new ParserException("expected CASE or DEFAULT");
+ consume(COLON);
+ // FIXME: we shouldn't be creating a scope here
+ ExprList list = new ExprList(curLine, LC);
+ while(peekToken() != CASE && peekToken() != DEFAULT && peekToken() != RC) {
+ if ((e1 = parseBlock(false)) == null) break;
+ list.add(e1);
}
- if (head == null) head = tail = e; else tail = tail.next = e;
- if (tok != COMMA) break;
- getToken();
+ toplevel.add(new Expr(curLine, tok, caseExpr, list));
+ if (peekToken() == RC) { consume(RC); return new Expr(curLine, SWITCH, switchExpr, toplevel); }
}
- return new Expr(VAR, head);
-
+ }
+
case TRY: {
// We deliberately allow you to omit braces in catch{}/finally{} if they are single statements...
- if (prefix != null) throw new Error("didn't expect non-null prefix");
+ if (prefix != null) { pushBackToken(); return prefix; }
Expr tryBlock = parseBlock(true);
- while ((tok = peekToken()) == CATCH || tok == FINALLY) {
+
+ tok = peekToken();
+ ExprList list = new ExprList(curLine, TRY);
+ if (tok == CATCH) {
getToken();
- if (getToken() != LP) throw new Error("expected (");
- if (getToken() != NAME) throw new Error("expected name");
- Expr name = new Expr(NAME, string);
- if (getToken() != RP) throw new Error("expected )");
- e1 = new Expr(tok, name, parseBlock(false));
- if (head == null) head = tail = e1; else tail = tail.next = e1;
+ 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 )");
+ list.add(new Expr(curLine, CATCH, name, parseBlock(false)));
+ tok = peekToken();
}
- if (head == null) throw new Error("try without catch or finally");
- return new Expr(TRY, tryBlock, head);
+ if (tok == FINALLY) {
+ getToken();
+ list.add(new Expr(curLine, FINALLY, parseBlock(false)));
+ }
+
+ if (list.size() == 0) throw new ParserException("try without catch or finally");
+ return new Expr(curLine, TRY, tryBlock, list);
}
- case IF: case WHILE: {
- if (prefix != null) throw new Error("didn't expect non-null prefix");
- if (getToken() != LP) throw new Error("expected left paren");
+ case WHILE: {
+ if (prefix != null) { pushBackToken(); return prefix; }
+ consume(LP);
Expr parenExpr = parseMaximalExpr();
int t;
- if ((t = getToken()) != RP) throw new Error("expected right paren, but got " + codeToString[t]);
+ if ((t = getToken()) != RP)
+ throw new ParserException("expected right paren, but got " + codeToString[t]);
Expr firstBlock = parseBlock(false);
- if (tok == IF && peekToken() == ELSE) {
- getToken();
- return new Expr(tok, parenExpr, new Expr(ELSE, firstBlock, parseBlock(false)));
- }
- return new Expr(tok, parenExpr, firstBlock);
+ ExprList list = new ExprList(curLine, WHILE);
+ list.add(parenExpr);
+ list.add(firstBlock);
+ list.add(new Expr(curLine, NULL));
+ return list;
}
- case IN: return prefix;
case FOR:
- if (prefix != null) throw new Error("didn't expect non-null prefix");
- if (getToken() != LP) throw new Error("expected left paren");
- e1 = parseMaximalExpr(null, -1);
- if (e1.code == NAME && peekToken() == IN) {
+ if (prefix != null) { pushBackToken(); return prefix; }
+ if (getToken() != LP) throw new ParserException("expected left paren");
+ e1 = parseMaximalExpr();
+ if (peekToken() == IN) {
getToken();
- e2 = parseMaximalExpr(null, -1);
- if (getToken() != RP) throw new Error("expected right paren");
- return new Expr(FOR, new Expr(IN, e1, e2), parseBlock(false));
+ e2 = parseMaximalExpr();
+ if (getToken() != RP) throw new ParserException("expected right paren");
+ return new Expr(curLine, FOR, new Expr(curLine, IN, e1.left, e2), parseBlock(false));
} else {
- if (getToken() != SEMI) throw new Error("expected ;");
- e2 = parseMaximalExpr(null, -1);
- if (getToken() != SEMI) throw new Error("expected ;");
- e3 = parseMaximalExpr(null, -1);
- if (getToken() != RP) throw new Error("expected right paren");
- return new Expr(LC, e1, new Expr(WHILE, e2, new Expr(LC, parseBlock(false), e3)));
+ Expr initExpr = e1;
+ if (initExpr == null) initExpr = new Expr(curLine, NULL);
+ expect(SEMI); getToken();
+ Expr whileExpr = parseMaximalExpr();
+ expect(SEMI); getToken();
+ Expr incExpr = parseMaximalExpr();
+ expect(RP); getToken();
+ Expr body = parseBlock(false);
+ Expr loop = new Expr(curLine, WHILE, whileExpr, body);
+ ExprList list = new ExprList(curLine, LC);
+ list.add(initExpr);
+ ExprList list2 = new ExprList(curLine, WHILE);
+ list.add(list2);
+ list2.add(whileExpr);
+ list2.add(body);
+ list2.add(incExpr);
+ return list;
}
case DO: {
- if (prefix != null) throw new Error("didn't expect non-null prefix");
- Expr firstBlock = parseBlock(false);
- if (getToken() != WHILE) throw new Error("expecting WHILE");
- if (getToken() != LP) throw new Error("expected left paren");
- Expr whileExpr = parseMaximalExpr();
- if (getToken() != RP) throw new Error("expected right paren");
- if (getToken() != SEMI) throw new Error("semicolon");
- return new Expr(DO, firstBlock, whileExpr);
+ if (prefix != null) { pushBackToken(); return prefix; }
+ ExprList list = new ExprList(curLine, DO);
+ Expr body = parseBlock(false);
+ consume(WHILE);
+ consume(LP);
+ list.add(parseMaximalExpr());
+ list.add(body);
+ list.add(new Expr(curLine, NULL));
+ consume(RP);
+ consume(SEMI);
+ return list;
}
default:
}
}
-}
+ // Expr //////////////////////////////////////////////////////////////////////
+
+ public static final Object NO_ARG = new Object();
+
+ class ByteCode extends Expr {
+
+ // This class interprets a small forthlike bytecode language
+ // we use to represent JavaScript. It's a stack machine.
+
+ // Each instruction is an opcode and a literal. Any operation
+ // that accesses the top of the stack and does not have a
+ // mandatory literal can be performed on a literal instead of
+ // the top of the stack.
+
+ // opcodes:
+ public static final byte arithmetic = -1; // -- arithmetic operators from parser
+ public static final byte LITERAL = -2; // < String | Number | null > -- push a literal onto the stack
+ public static final byte ARRAY = -3; // < size > -- create a new array of size <size>
+ public static final byte OBJECT = -4; // -- push an empty object onto the stack
+ public static final byte FUNCTION = -5; // < bytecode_block > -- push a new instance of a function with the given bytecode
+ public static final byte DECLARE = -6; // < name > -- declare <name> in the current scope
+ public static final byte THIS = -7; // -- push the topmost non-transparent scope onto the stack
+ public static final byte GET = -8; // -- get stack[0] from stack[1]
+ public static final byte GET_PRESERVE = -80; // -- get stack[0] from stack[1]
+ public static final byte PUT = -9; // -- put stack[1] to key stack[0] on stack[2]; leaves object on the stack
+ public static final byte THROW = -10; // -- throw topmost element
+ public static final byte RETURN = -11; // -- return the topmost value on the stack
+ public static final byte ASSERT = -12; // -- fail if topmost element is not true
+ public static final byte JT = -13; // < relative_address > -- pop the stack; if true, jump to <relative_address>
+ public static final byte JF = -21; // < relative_address > -- pop the stack; if false, jump to <relative_address>
+ public static final byte JMP = -22; // < relative_address > -- jump to <relative_address>
+ static public final byte POP = -14; // -- discard the top element on the stack
+
+ public static final byte CALL = -15; // < numargs > -- call stack[0] with the topmost <numargs> values as arguments
+ public static final byte TRY = -16; // < bytecode_block > -- run the block pointed to; returns with thrown exn on top of stack
+
+ public static final byte INSTANCEOF = -17; // -- ??
+ public static final byte TYPEOF = -18; // --
+
+ public static final byte FOR__IN = -19; // -- ??
+ public static final byte EXPR = -20; // -- transitional
+ public static final byte SWAP = -23; // -- transitional
+ public static final byte SCOPE = -30; // -- transitional
+
+ int[] op = new int[10];
+ Object[] arg = new Object[10];
+ int size = 0;
+
+ public ByteCode(int line) { super(line, "foo"); }
+ public ByteCode(int line, int op_, Object arg_) { this(line); add(op_, arg_); }
+
+ public int size() { return size; }
+ public void set(int pos, int op_, Object arg_) { op[pos] = op_; arg[pos] = arg_; }
+ public ByteCode add(int op_, Object arg_) {
+ if (size == op.length - 1) {
+ int[] op2 = new int[op.length * 2]; System.arraycopy(op, 0, op2, 0, op.length); op = op2;
+ Object[] arg2 = new Object[op.length * 2]; System.arraycopy(arg, 0, arg2, 0, arg.length); arg = arg2;
+ }
+ op[size] = op_;
+ arg[size] = arg_;
+ size++;
+ return this;
+ }
+
+ public Object eval(final JS.Scope s) throws ControlTransferException, JS.Exn {
+ return eval(s, new Parser.Thread());
+ }
+ public Object eval(final JS.Scope s, Parser.Thread t) throws ControlTransferException {
+ for(int i=0; i<size; i++)
+ switch(op[i]) {
+ case arithmetic: break;
+ case LITERAL:
+ t.push(arg[i]);
+ break;
+ case OBJECT: t.push(new JS.Obj()); break;
+ case ARRAY: t.push(new JS.Array(toNumber(arg[i]).intValue())); break;
+ case DECLARE: s.declare(arg[i] == NO_ARG ? (String)t.pop() : (String)arg[i]); break;
+ case THIS: t.push(s); break; // FIXME: transparents
+ case ASSERT: if (!toBoolean(t.pop())) throw new EvaluatorException("assertion failed"); break;
+ case THROW: throw new JS.Exn(t.pop());
+ case JT: if (toBoolean(t.pop())) i += toNumber(arg[i]).intValue() - 1; break;
+ case JF: if (!toBoolean(t.pop())) i += toNumber(arg[i]).intValue() - 1; break;
+ case JMP: i += toNumber(arg[i]).intValue() - 1; break;
+ case POP: t.pop(); break;
+ case SWAP: t.swap(); break;
+
+ case PUT: {
+ Object val = arg[i] == NO_ARG ? t.pop() : arg[i];
+ Object key = t.pop();
+ ((JS)t.peek()).put(key, val);
+ t.push(val);
+ break;
+ }
+
+ case GET: {
+ Object v = arg[i] == NO_ARG ? t.pop() : arg[i];
+ Object o = t.pop();
+ t.push(doGet(o, v));
+ break;
+ }
+ case GET_PRESERVE: {
+ Object v = t.pop();
+ Object o = t.peek();
+ t.push(v);
+ t.push(doGet(o, v));
+ break;
+ }
+ case NOP: break;
+
+ case EXPR: t.push(((Expr)arg[i]).eval(s)); break;
+ case SCOPE: t.push(((Expr)arg[i]).eval(new JS.Scope(s))); break;
+
+ case CALL:
+ JS.Array arguments = new JS.Array();
+ int numArgs = toNumber(arg[i]).intValue();
+ arguments.setSize(numArgs);
+ for(int j=numArgs - 1; j >= 0; j--) arguments.setElementAt(t.pop(), j);
+ JS.Function f = (JS.Function)t.pop();
+ if (f == null) throw new JS.Exn(new EvaluatorException("attempted to call null"));
+ t.push(f.call(arguments));
+ break;
+
+ case FUNCTION: {
+ final ByteCode myBytes = (ByteCode)arg[i];
+ t.push(new JS.Function() {
+ public String toString() { return sourceName + ":" + line; }
+ public String getSourceName() throws JS.Exn { return sourceName; }
+ public Object _call(final JS.Array args) throws JS.Exn {
+ Function save = JS.getCurrentFunction();
+ JS.currentFunction.put(java.lang.Thread.currentThread(), this);
+ JS.Scope scope = new JS.Scope(s) {
+ // FIXME
+ public String getSourceName() { return sourceName; }
+ 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;
+ return super.get(key);
+ }
+ };
+ Parser.Thread t0 = new Parser.Thread();
+ t0.push(args);
+ try {
+ return myBytes.eval(scope, t0);
+ } 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(java.lang.Thread.currentThread());
+ else JS.currentFunction.put(java.lang.Thread.currentThread(), save);
+ }
+ }
+ });
+ break;
+ }
+
+ case RETURN: break;
+ case TRY: break;
+ case INSTANCEOF: break;
+ case TYPEOF: break;
+ case FOR__IN: break;
+
+ case Lexer.BITNOT: t.push(new Long(~toLong(t.pop()))); break;
+ case Lexer.BANG: t.push(new Boolean(!toBoolean(t.pop()))); break;
+
+ case Lexer.INC: case Lexer.DEC: {
+ boolean isPrefix = toBoolean(arg[i]);
+ Object key = t.pop();
+ JS obj = (JS)t.pop();
+ Number num = toNumber(obj.get(key));
+ Number val = new Double(op[i] == Lexer.INC ? num.doubleValue() + 1.0 : num.doubleValue() - 1.0);
+ obj.put(key, val);
+ t.push(isPrefix ? val : num);
+ break;
+ }
+
+ default: {
+ Object right = t.pop();
+ Object left = t.pop();
+ switch(op[i]) {
+
+ case Lexer.BITOR: t.push(new Long(toLong(left) | toLong(right))); break;
+ case Lexer.BITXOR: t.push(new Long(toLong(left) ^ toLong(right))); break;
+ case Lexer.BITAND: t.push(new Long(toLong(left) & toLong(right))); break;
+
+ case Lexer.ADD: {
+ Object l = left;
+ Object r = right;
+ 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());
+ t.push(l.toString() + r.toString()); break;
+ }
+ t.push(new Double(toDouble(l) + toDouble(r))); break;
+ }
+
+ case Lexer.SUB: t.push(new Double(toDouble(left) - toDouble(right))); break;
+ case Lexer.MUL: t.push(new Double(toDouble(left) * toDouble(right))); break;
+ case Lexer.DIV: t.push(new Double(toDouble(left) / toDouble(right))); break;
+ case Lexer.MOD: t.push(new Double(toDouble(left) % toDouble(right))); break;
+
+ case Lexer.LSH: t.push(new Long(toLong(left) << toLong(right))); break;
+ case Lexer.RSH: t.push(new Long(toLong(left) >> toLong(right))); break;
+ case Lexer.URSH: t.push(new Long(toLong(left) >>> toLong(right))); break;
+
+ // FIXME: these need to work on strings
+ case Lexer.LT: t.push(toDouble(left) < toDouble(right) ? Boolean.TRUE : Boolean.FALSE); break;
+ case Lexer.LE: t.push(toDouble(left) <= toDouble(right) ? Boolean.TRUE : Boolean.FALSE); break;
+ case Lexer.GT: t.push(toDouble(left) > toDouble(right) ? Boolean.TRUE : Boolean.FALSE); break;
+ case Lexer.GE: t.push(toDouble(left) >= toDouble(right) ? Boolean.TRUE : Boolean.FALSE); break;
+
+ case Lexer.EQ:
+ case Lexer.NE: {
+ // FIXME: should use Javascript coercion-equality rules
+ Object l = left;
+ Object r = right;
+ boolean ret;
+ if (l == null) { Object tmp = r; r = l; l = tmp; }
+ if (l == null && r == null) ret = true;
+ else if (l instanceof Boolean) ret = new Boolean(toBoolean(r)).equals(l);
+ else if (l instanceof Number) ret = toNumber(r).doubleValue() == toNumber(l).doubleValue();
+ else if (l instanceof String) ret = r != null && l.equals(r.toString());
+ else ret = l.equals(r);
+ t.push(new Boolean(op[i] == Lexer.EQ ? ret : !ret)); break;
+ }
+
+ default: throw new Error("unknown opcode " + op[i]);
+ } }
+ }
+ if (t.size() != 1) {
+ throw new EvaluatorException("eval() terminated with " + t.size() + " elements on the stack; one expected");
+ }
+ return t.pop();
+ }
+
+ public Object doGet(final Object o, final Object v) {
+ if (o == null) throw new EvaluatorException("tried to get property \"" + v + "\" from the null value");
+ 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 Error("String.substring() can only take one or two arguments");
+ }
+ };
+ else if (v.equals("toLowerCase")) return new JS.Function() {
+ public Object _call(JS.Array args) {
+ return ((String)o).toLowerCase();
+ } };
+ else if (v.equals("toUpperCase")) return new JS.Function() {
+ public Object _call(JS.Array args) {
+ return ((String)o).toString().toUpperCase();
+ } };
+ else if (v.equals("charAt")) return new JS.Function() {
+ public Object _call(JS.Array args) {
+ return ((String)o).charAt(toNumber(args.elementAt(0)).intValue()) + "";
+ } };
+ else if (v.equals("lastIndexOf")) return new JS.Function() {
+ public Object _call(JS.Array args) {
+ if (args.length() != 1) return null;
+ return new Integer(((String)o).lastIndexOf(args.elementAt(0).toString()));
+ } };
+ 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 Error("Not Implemented: propery " + v + " on String objects");
+ } else if (o instanceof Boolean) {
+ throw new Error("Not Implemented: properties on Boolean objects");
+ } else if (o instanceof Number) {
+ Log.log(this, "Not Implemented: properties on Number objects");
+ return null;
+ //throw new Error("Not Implemented: properties on Number objects");
+ } else if (o instanceof JS) {
+ return ((JS)o).get(v);
+ }
+ return null;
+ }
+ }
+
+ class Thread {
+ public Object[] os = new Object[256];
+ int size = 0;
+ public void push(Object o) { os[size++] = o; }
+ public Object pop() { return os[--size]; }
+ public Object peek() { return os[size - 1]; }
+ public void swap() { Object temp = os[size - 1]; os[size - 1] = os[size - 2]; os[size - 2] = temp; }
+ public int size() { return size; }
+ }
+
+ class ExprList extends Expr {
+ Vec v = new Vec();
+ public ExprList(int curLine, int code) { super(curLine, code); }
+ public void add(Expr e) { v.addElement(e); }
+ public int numExprs() { return v.size(); }
+ public int size() { return v.size(); }
+ public Expr elementAt(int i) { return (Expr)v.elementAt(i); }
+ public Object eval(final JS.Scope s) throws ControlTransferException, JS.Exn {
+ switch(code) {
+ case LC: {
+ // Block
+ JS.Scope scope = new JS.Scope(s);
+ for(int i=0; i<v.size(); i++) ((Expr)v.elementAt(i)).eval(scope);
+ return null;
+ }
+ case Lexer.LB: {
+ // Array ctor
+ JS.Array ret = new JS.Array();
+ for(int i=0; i<numExprs(); i++) ret.addElement(elementAt(i).eval(s));
+ return ret;
+ }
+ case Lexer.RC: {
+ // Object ctor
+ JS.Obj ret = new JS.Obj();
+ for(int i=0; i<numExprs(); i++) {
+ Expr e = elementAt(i);
+ Object key = e.left.string;
+ Object val = e.right.eval(s);
+ ret.put(key, val);
+ }
+ return ret;
+ }
+ case Lexer.WHILE:
+ case Lexer.DO:
+ try {
+ boolean first = true;
+ Object bogus = null;
+ ExprList list = this;
+ Expr whileExpr = list.elementAt(0);
+ Expr bodyExpr = list.elementAt(1);
+ Expr incExpr = list.elementAt(2);
+ for(;(first && code == Lexer.DO) || toBoolean(whileExpr.eval(s)); bogus = incExpr.eval(s)) {
+ first = false;
+ try {
+ bodyExpr.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;
+ }
+ return null;
+ case Lexer.VAR:
+ for(int i=0; i<size(); i++) {
+ Expr e = elementAt(i);
+ s.declare(e.left.string);
+ if (e.right != null) e.right.eval(s);
+ }
+ return null;
+ default: throw new Error("augh!");
+ }
+ }
+ }
+
+ /** 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 { return parseBlock(requireBraces, null); }
+ public Expr parseBlock(boolean requireBraces, ByteCode b) throws IOException {
+ Expr smt = null;
+ int tok = peekToken();
+ if (tok == -1) return null;
+ boolean braced = tok == LC;
+ if (requireBraces && !braced) throw new ParserException("expected {, got " + codeToString[tok]);
+ if (braced) consume(LC);
+ int curLine = line;
+ ByteCode ret = new ByteCode(curLine);
+ ByteCode block = b == null ? new ByteCode(curLine) : b;
+ block.add(ret.LITERAL, Boolean.TRUE);
+ ret.add(block.SCOPE, block);
+ while(true) {
+ switch(tok = peekToken()) {
+
+ case LC:
+ smt = parseBlock(true); break;
+
+ case THROW: case RETURN: case ASSERT:
+ getToken();
+ if (peekToken() == SEMI) {
+ if (tok == THROW || tok == ASSERT) throw new ParserException(codeToString[tok] + " requires an argument");
+ consume(SEMI);
+ smt = new Expr(curLine, tok);
+ } else {
+ smt = new Expr(curLine, tok, parseMaximalExpr());
+ consume(SEMI);
+ }
+ break;
+
+ case GOTO: case BREAK: case CONTINUE: {
+ getToken();
+ int t = peekToken();
+ if (t == NAME) {
+ getToken();
+ smt = new Expr(curLine, tok, new Expr(curLine, string));
+ } else if (tok == GOTO) {
+ throw new ParserException("goto must be followed by a label");
+ }
+ smt = new Expr(curLine, tok, new Expr(curLine, string));
+ consume(SEMI);
+ break;
+ }
+
+ case RC:
+ if (braced) consume(RC);
+ return block.size() == 0 ? null : ret;
+
+ case SEMI:
+ consume(SEMI);
+ if (!braced) return block.size() == 0 ? null : ret;
+ continue;
+
+ case NAME: {
+ String name = string;
+ consume(NAME);
+ if (peekToken() == COLON) {
+ consume(COLON);
+ smt = new Expr(curLine, COLON, new Expr(curLine, name), parseBlock(false));
+ break;
+ } else {
+ pushBackToken(NAME, name);
+ // fall through to default case
+ }
+ }
+
+ case -1:
+ default:
+ smt = parseMaximalExpr();
+ if (smt == null) return block.size() == 0 ? null : ret;
+ if (peekToken() == SEMI) getToken();
+ break;
+ }
+
+ if (!braced) return smt;
+ block.add(block.EXPR, smt);
+ block.add(block.POP, NO_ARG);
+ }
+ }
+
+
+ /** sorta like gcc trees */
+ class Expr {
+ int code = -1;
+
+ final Expr left;
+ final Expr right;
+ 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);
+ 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.NULL: return null;
+ 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 Lexer.THROW: throw new JS.Exn(left.eval(s));
+
+ case Lexer.TRY: {
+ boolean safeToExit = false;
+ try {
+ Object ret = left.eval(s);
+ safeToExit = true;
+ return ret;
+ } catch (JS.Exn e) {
+ ExprList list = (ExprList)right;
+ Expr c = list.elementAt(0);
+ if (c.code == Lexer.CATCH) {
+ JS.Scope scope = new JS.Scope(s);
+ s.put(c.left.string, e);
+ c.right.eval(scope);
+ c = list.elementAt(1);
+ }
+ 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");
+ }
+ return null;
+ }
+
+ 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.declare(left.string);
+ scope.put(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 {
+ ExprList list = (ExprList)right;
+ for(int i=0; i<list.size(); i++) {
+ Expr e = list.elementAt(i);
+ 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 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));
+
+ 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); }
+ }
+ }
+
+ 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) try { return new Double((String)o); } catch (NumberFormatException e) { return new Double(0); }
+ 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