-// 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.*;
public static void main(String[] s) throws Exception {
Parser p = new Parser(new InputStreamReader(System.in), "stdin", 0);
while(true) {
- ForthBlock block = p.parseStatement(false);
+ ForthBlock block = new ForthBlock(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 boolean[] mustStartExpression = new boolean[MAX_TOKEN + 1];
+ static boolean[] cannotStartExpression = new boolean[MAX_TOKEN + 1];
static {
- precedence[ASSIGN] = 1;
+
+ mustStartExpression[VAR] = true;
+ mustStartExpression[IF] = true;
+ mustStartExpression[BANG] = true;
+ mustStartExpression[BITNOT] = true;
+ mustStartExpression[INSTANCEOF] = true;
+ mustStartExpression[TYPEOF] = true;
+ mustStartExpression[NUMBER] = true;
+ mustStartExpression[STRING] = true;
+ mustStartExpression[NULL] = true;
+ mustStartExpression[TRUE] = true;
+ mustStartExpression[FALSE] = true;
+ mustStartExpression[Tokens.FUNCTION] = true;
+ mustStartExpression[NAME] = true;
+ mustStartExpression[LC] = true;
+ mustStartExpression[THIS] = true;
+
+ cannotStartExpression[OR] = true;
+ cannotStartExpression[AND] = true;
+ cannotStartExpression[BITOR] = true;
+ cannotStartExpression[BITXOR] = true;
+ cannotStartExpression[BITAND] = true;
+ cannotStartExpression[SHEQ] = true;
+ cannotStartExpression[SHNE] = true;
+ cannotStartExpression[LSH] = true;
+ cannotStartExpression[RSH] = true;
+ cannotStartExpression[URSH] = true;
+ cannotStartExpression[ADD] = true;
+ cannotStartExpression[MUL] = true;
+ cannotStartExpression[DIV] = true;
+ cannotStartExpression[MOD] = true;
+ cannotStartExpression[GT] = true;
+ cannotStartExpression[GE] = true;
+ cannotStartExpression[EQ] = true;
+ cannotStartExpression[NE] = true;
+ cannotStartExpression[LT] = true;
+ cannotStartExpression[LE] = true;
+ cannotStartExpression[DOT] = true;
+ cannotStartExpression[HOOK] = true;
+ cannotStartExpression[ASSIGN_BITOR] = true;
+ cannotStartExpression[ASSIGN_BITXOR] = true;
+ cannotStartExpression[ASSIGN_BITAND] = true;
+ cannotStartExpression[ASSIGN_LSH] = true;
+ cannotStartExpression[ASSIGN_RSH] = true;
+ cannotStartExpression[ASSIGN_URSH] = true;
+ cannotStartExpression[ASSIGN_ADD] = true;
+ cannotStartExpression[ASSIGN_SUB] = true;
+ cannotStartExpression[ASSIGN_MUL] = true;
+ cannotStartExpression[ASSIGN_DIV] = true;
+ cannotStartExpression[ASSIGN_MOD] = true;
+
isRightAssociative[ASSIGN] = true;
+
+ precedence[ASSIGN] = 1;
precedence[HOOK] = 2;
precedence[COMMA] = 3;
precedence[OR] = precedence[AND] = 4;
// Parsing Logic /////////////////////////////////////////////////////////
+ /** 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 ? "EOL" : codeToString[op]));
/** parses the largest possible expression */
public ForthBlock parseExpr() throws IOException { return parseExpr(null, -1); }
+
+ /** return the largest expression beginning with prefix containing no operators of precedence below <tt>minPrecedence</tt> */
public ForthBlock parseExpr(ForthBlock prefix, int minPrecedence) throws IOException {
- ForthBlock e1 = null, e2 = null, e3 = null, head = null, tail = null, ret = null;
+ return parseExpr(prefix, minPrecedence, new ForthBlock(line, sourceName));
+ }
- int tok = peekToken();
- if (minPrecedence > 0 && tok < precedence.length && precedence[tok] != 0 &&
- (isRightAssociative[tok] ? (precedence[tok] < minPrecedence) : (precedence[tok] <= minPrecedence)))
- return prefix;
+ /** append the largest expression beginning with prefix containing no operators of precedence below <tt>minPrecedence</tt> */
+ public ForthBlock parseExpr(ForthBlock prefix, int minPrecedence, ForthBlock appendTo) throws IOException {
- getToken();
+ int tok = getToken();
int curLine = line;
+ if (tok == -1) return prefix;
+ if (minPrecedence > 0 && precedence[tok] != 0)
+ if (precedence[tok] < minPrecedence || (precedence[tok] == minPrecedence && !isRightAssociative[tok]))
+ { pushBackToken(); return prefix; }
- switch (tok) {
+ if (prefix != null && mustStartExpression[tok]) { pushBackToken(); return prefix; }
+ if (prefix == null && cannotStartExpression[tok]) { pushBackToken(); return prefix; }
- case VAR: {
- if (prefix != null) { pushBackToken(); return prefix; }
- ForthBlock b = new ForthBlock(curLine, sourceName);
- b.add(OpCodes.THIS);
- while(true) {
- consume(NAME);
- String name = string;
- b.add(b.LITERAL, name);
- b.add(b.DECLARE);
- if (peekToken() == ASSIGN) {
- b.add(b.LITERAL, name);
- consume(ASSIGN);
- b.add(b.EXPR, parseExpr());
- b.add(b.PUT);
- b.add(b.POP);
- }
- if (peekToken() != COMMA) break;
- consume(COMMA);
- }
- return parseExpr(b, minPrecedence);
- }
+ ForthBlock b = appendTo;
+
+ switch (tok) {
- case IN: pushBackToken(); return prefix;
+ case NUMBER: return parseExpr(b.add(ForthBlock.LITERAL, number), minPrecedence);
+ case STRING: return parseExpr(b.add(ForthBlock.LITERAL, string), minPrecedence);
+ case THIS: return parseExpr(b.add(THIS, null), minPrecedence);
+ case NULL: return parseExpr(b.add(ForthBlock.LITERAL, null), minPrecedence);
+ case TRUE: case FALSE: return parseExpr(b.add(ForthBlock.LITERAL, new Boolean(tok == TRUE)), minPrecedence);
- case IF: {
- if (prefix != null) { pushBackToken(); return prefix; }
- ForthBlock b = new ForthBlock(curLine, sourceName);
- consume(LP);
- b.add(b.EXPR, parseExpr());
- consume(RP);
- b.add(b.JF, new Integer(3));
- b.add(b.EXPR, parseStatement(false));
- b.add(b.JMP, new Integer(2));
- if (peekToken() != ELSE) return parseExpr(b.add(b.LITERAL, null), minPrecedence);
- consume(ELSE);
- b.add(b.EXPR, parseStatement(false));
+ 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: {
+ b.add(b.EXPR, prefix);
+ prefix.set(prefix.size() - 1, b.GET_PRESERVE, new Boolean(true));
+ prefix.add(prefix.EXPR, parseExpr(null, precedence[tok - 1]));
+ prefix.add(tok - 1);
+ prefix.add(b.PUT);
+ prefix.add(b.SWAP);
+ prefix.add(b.POP);
return parseExpr(b, minPrecedence);
}
- // 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;
- {
- ForthBlock b = (ForthBlock)prefix;
- b.set(b.size() - 1, b.GET_PRESERVE, new Boolean(true));
- b.add(b.EXPR, parseExpr(null, precedence[tok]));
- b.add(tok);
- b.add(b.PUT);
- b.add(b.SWAP);
- b.add(b.POP);
- return parseExpr(b, minPrecedence);
- }
-
case INC: case DEC:
if (prefix == null) {
// prefix
- ForthBlock b = (ForthBlock)parseExpr(null, precedence[tok]);
- b.set(b.size() - 1, tok, new Boolean(true));
+ ForthBlock subexp = parseExpr(null, precedence[tok]);
+ subexp.set(subexp.size() - 1, tok, new Boolean(true));
+ b.add(b.EXPR, subexp);
return parseExpr(b, minPrecedence);
} else {
// postfix
- ForthBlock b = (ForthBlock)prefix;
- b.set(b.size() - 1, tok, new Boolean(false));
+ prefix.set(prefix.size() - 1, tok, new Boolean(false));
+ b.add(b.EXPR, prefix);
return parseExpr(b, minPrecedence);
}
case LP:
if (prefix == null) { // grouping
- ForthBlock b = new ForthBlock(curLine, sourceName, ForthBlock.EXPR, parseExpr());
+ b.add(EXPR, parseExpr());
consume(RP);
return parseExpr(b, minPrecedence);
} else { // invocation
- ForthBlock b = new ForthBlock(curLine, sourceName);
int i = 0;
b.add(b.EXPR, prefix);
while(peekToken() != RP) {
}
case BANG: case BITNOT: case INSTANCEOF: case TYPEOF: {
- if (prefix != null) { pushBackToken(); return prefix; }
- ForthBlock b = new ForthBlock(curLine, sourceName);
b.add(b.EXPR, parseExpr(null, precedence[tok]));
b.add(tok);
return parseExpr(b, minPrecedence);
}
case SUB:
- if (prefix == null && peekToken() == NUMBER) {
- getToken();
- return parseExpr(new ForthBlock(curLine, sourceName, ForthBlock.LITERAL, new Double(number.doubleValue() * -1)), minPrecedence);
- } // else fall through
+ if (prefix == null) {
+ consume(NUMBER);
+ return parseExpr(b.add(ForthBlock.LITERAL, new Double(number.doubleValue() * -1)), minPrecedence);
+ }
+ // 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");
- ForthBlock b = new ForthBlock(curLine, sourceName);
b.add(b.EXPR, prefix);
b.add(b.EXPR, parseExpr(null, precedence[tok]));
b.add(tok);
return parseExpr(b, minPrecedence);
}
- // includes short-circuit logic
case OR: case AND: {
- if (prefix == null) throw new ParserException("the " + codeToString[tok] + " token cannot start an expression");
- ForthBlock b = new ForthBlock(curLine, sourceName);
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));
return parseExpr(b, minPrecedence);
}
- 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 parseExpr(new ForthBlock(curLine, sourceName, ForthBlock.LITERAL, number), minPrecedence);
-
- case STRING:
- if (prefix != null) { pushBackToken(); return prefix; }
- return parseExpr(new ForthBlock(curLine, sourceName, ForthBlock.LITERAL, string), minPrecedence);
-
- case NULL: case TRUE: case FALSE: case NOP:
- if (prefix != null) { pushBackToken(); return prefix; }
- return parseExpr(new ForthBlock(curLine, sourceName, ForthBlock.LITERAL, (tok == NULL || tok == NOP) ? null : new Boolean(tok == TRUE)), minPrecedence);
-
- case COMMA: pushBackToken(); return prefix;
-
- case Tokens.THIS:
- if (prefix != null) { pushBackToken(); return prefix; }
- return parseExpr(new ForthBlock(curLine, sourceName, OpCodes.THIS, null), minPrecedence);
-
case NAME: {
- if (prefix != null) { pushBackToken(); return prefix; }
String name = string;
- ForthBlock b = new ForthBlock(curLine, sourceName);
if (peekToken() == ASSIGN) {
consume(ASSIGN);
- b.add(OpCodes.THIS);
+ b.add(THIS);
b.add(ForthBlock.LITERAL, name);
b.add(ForthBlock.EXPR, parseExpr(null, minPrecedence));
b.add(ForthBlock.PUT);
b.add(ForthBlock.SWAP);
b.add(ForthBlock.POP);
- return parseExpr(b, minPrecedence);
} else {
- b.add(OpCodes.THIS);
+ b.add(THIS);
b.add(ForthBlock.LITERAL, name);
b.add(ForthBlock.GET);
- return parseExpr(parseExpr(b, minPrecedence), minPrecedence);
}
+ return parseExpr(b, minPrecedence);
}
case DOT: {
consume(NAME);
String target = string;
- ForthBlock b = new ForthBlock(curLine, sourceName);
b.add(b.EXPR, prefix);
if (peekToken() == ASSIGN) {
consume(ASSIGN);
}
case LB: {
- ForthBlock b = new ForthBlock(curLine, sourceName);
if (prefix == null) {
b.add(b.ARRAY, new Integer(0));
int i = 0;
}
case LC: {
- if (prefix != null) { pushBackToken(); return prefix; }
- ForthBlock b = new ForthBlock(curLine, sourceName);
b.add(b.OBJECT, null);
if (peekToken() == RC) { consume(RC); return parseExpr(b, minPrecedence); }
while(true) {
}
case HOOK: {
- ForthBlock b = new ForthBlock(curLine, sourceName);
b.add(b.EXPR, prefix);
b.add(b.JF, new Integer(3));
b.add(b.EXPR, parseExpr());
}
case Tokens.FUNCTION: {
- if (prefix != null) { pushBackToken(); return prefix; }
consume(LP);
- ForthBlock b = new ForthBlock(curLine, sourceName);
int numArgs = 0;
- b.add(OpCodes.THIS);
- b.add(b.SWAP);
- b.add(b.LITERAL, "arguments");
- b.add(b.LITERAL, "arguments");
- b.add(b.DECLARE);
- b.add(b.SWAP);
- b.add(b.PUT);
- b.add(b.SWAP);
- b.add(b.POP);
+ ForthBlock b2 = new ForthBlock(curLine, sourceName);
+ b2.add(THIS);
+ b2.add(b.SWAP);
+ b2.add(b.LITERAL, "arguments");
+ b2.add(b.LITERAL, "arguments");
+ b2.add(b.DECLARE);
+ b2.add(b.SWAP);
+ b2.add(b.PUT);
+ b2.add(b.SWAP);
+ b2.add(b.POP);
if (peekToken() == RP) consume(RP);
else while(true) {
if (peekToken() == COMMA) {
+ // FIXME: pop an item off the stack here?
consume(COMMA);
} else {
consume(NAME);
// declare the name
- b.add(b.LITERAL, string);
- b.add(b.DECLARE);
+ b2.add(b.LITERAL, string);
+ b2.add(b.DECLARE);
// retrieve it from the arguments array
- b.add(b.LITERAL, new Integer(numArgs));
- b.add(b.GET_PRESERVE);
- b.add(b.SWAP);
- b.add(b.POP);
+ b2.add(b.LITERAL, new Integer(numArgs));
+ b2.add(b.GET_PRESERVE);
+ b2.add(b.SWAP);
+ b2.add(b.POP);
// put it to the current scope
- b.add(OpCodes.THIS);
- b.add(b.SWAP);
- b.add(b.LITERAL, string);
- b.add(b.SWAP);
- b.add(b.PUT);
+ b2.add(THIS);
+ b2.add(b.SWAP);
+ b2.add(b.LITERAL, string);
+ b2.add(b.SWAP);
+ b2.add(b.PUT);
// clean the stack
- b.add(b.POP);
- b.add(b.POP);
+ b2.add(b.POP);
+ b2.add(b.POP);
if (peekToken() == RP) { consume(RP); break; }
consume(COMMA);
numArgs++;
}
// pop off the arguments array
- b.add(b.POP);
- parseStatement(true, b);
- return parseExpr(new ForthBlock(curLine, sourceName, OpCodes.FUNCTION, b), minPrecedence);
+ b2.add(b.POP);
+ parseStatement(true, b2);
+ b2.add(b.LITERAL, null);
+ b2.add(RETURN);
+ return parseExpr(b.add(OpCodes.FUNCTION, b2), minPrecedence);
}
- case WHILE: {
- if (prefix != null) { pushBackToken(); return prefix; }
- consume(LP);
- ForthBlock r = new ForthBlock(curLine, sourceName);
- ForthBlock loop = new ForthBlock(curLine, sourceName);
- r.add(loop.LOOP, loop);
- r.add(r.LITERAL, null);
-
- loop.add(loop.EXPR, parseExpr());
- loop.add(loop.JT, new Integer(2));
- loop.add(Lexer.BREAK);
- consume(RP);
- parseStatement(false, loop);
-
- // if we fall out of the end, definately continue
- loop.add(CONTINUE);
- return parseExpr(r, minPrecedence);
+ default: pushBackToken(); return prefix;
}
+ }
+
+ /** a block is either a single statement or a list of statements surrounded by curly braces; all expressions are also statements */
+ public ForthBlock parseStatement() throws IOException {
+ ForthBlock ret = new ForthBlock(line, sourceName);
+ ret.add(ret.LITERAL, null);
+ parseStatement(false, ret);
+ if (ret.size() == 1) return null;
+ return ret;
+ }
- case SWITCH: {
- if (prefix != null) { pushBackToken(); return prefix; }
- consume(LP);
- ForthBlock r = new ForthBlock(curLine, sourceName);
- ForthBlock loop = new ForthBlock(curLine, sourceName);
- r.add(loop.LOOP, loop);
- r.add(r.LITERAL, null);
- loop.add(loop.EXPR, parseExpr());
- consume(RP);
- consume(LC);
- while(true) {
- ForthBlock caseForthBlock;
- tok = getToken();
- if (tok == CASE) {
- loop.add(loop.DUP);
- loop.add(loop.EXPR, parseExpr());
- loop.add(EQ);
- loop.add(loop.JF, new Integer(2));
- } else if (tok != DEFAULT) throw new ParserException("expected CASE or DEFAULT");
- consume(COLON);
- ForthBlock b = new ForthBlock(curLine, sourceName);
- while(peekToken() != CASE && peekToken() != DEFAULT && peekToken() != RC) {
- if ((e1 = parseStatement(false)) == null) break;
- b.add(b.EXPR, e1);
+ public void parseStatement(boolean requireBraces) throws IOException {
+ parseStatement(requireBraces, new ForthBlock(line, sourceName));
+ }
+ public void parseStatement(boolean requireBraces, ForthBlock 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 THROW: case RETURN: case ASSERT: {
+ getToken();
+ if (tok == RETURN && peekToken() == SEMI) b.add(b.LITERAL, null);
+ else b.add(b.EXPR, parseExpr());
+ consume(SEMI);
+ b.add(tok);
+ break;
+ }
+
+ case BREAK: case CONTINUE: {
+ getToken();
+ if (peekToken() == NAME) consume(NAME);
+ b.add(tok, string);
+ consume(SEMI);
+ break;
+ }
+
+ case SEMI:
+ consume(SEMI);
+ if (!braced) return;
+ break;
+
+ case VAR: {
+ consume(VAR);
+ b.add(THIS); // push the current scope
+ while(true) {
+ consume(NAME);
+ String name = string;
+ b.add(b.LITERAL, name); // push the name to be declared
+ b.add(b.DECLARE); // declare it
+ if (peekToken() == ASSIGN) { // if there is an '=' after the variable name
+ b.add(b.LITERAL, name); // put the var name back on the stack
+ consume(ASSIGN);
+ b.add(b.EXPR, parseExpr());
+ b.add(b.PUT);
+ b.add(b.POP);
+ }
+ if (peekToken() != COMMA) break;
+ consume(COMMA);
}
- loop.add(loop.EXPR, b);
- if (peekToken() == RC) {
- consume(RC);
- r.add(BREAK);
- return parseExpr(r, minPrecedence);
+ b.add(b.POP);
+ if (peekToken() == SEMI) consume(SEMI);
+ break;
+ }
+
+ case IF: {
+ consume(IF);
+ consume(LP);
+ b.add(b.EXPR, parseExpr());
+ consume(RP);
+ b.add(b.JF, new Integer(4));
+ b.add(b.EXPR, parseStatement());
+ b.add(b.POP);
+ b.add(b.JMP, new Integer(3));
+ if (peekToken() == ELSE) {
+ consume(ELSE);
+ b.add(b.EXPR, parseStatement());
+ b.add(b.POP);
+ } else {
+ b.add(b.JMP, new Integer(1)); // nop
+ b.add(b.JMP, new Integer(1)); // nop
}
+ break;
}
- }
-
- case DO: {
- if (prefix != null) { pushBackToken(); return prefix; }
- ForthBlock r = new ForthBlock(curLine, sourceName);
- ForthBlock loop = new ForthBlock(curLine, sourceName);
- r.add(loop.LOOP, loop);
- r.add(r.LITERAL, null);
-
- parseStatement(false, loop);
- consume(WHILE);
- consume(LP);
- loop.add(loop.EXPR, parseExpr());
- loop.add(loop.JT, new Integer(2));
- loop.add(Lexer.BREAK);
- loop.add(Lexer.CONTINUE);
- consume(RP);
- consume(SEMI);
- return parseExpr(r, minPrecedence);
- }
- case TRY: {
- // FIXME: don't just ignore this!
- // We deliberately allow you to omit braces in catch{}/finally{} if they are single statements...
- if (prefix != null) { pushBackToken(); return prefix; }
- ForthBlock tryBlock = parseStatement(true);
-
- tok = peekToken();
- if (tok == CATCH) {
- getToken();
- if (getToken() != LP) throw new ParserException("expected (");
- if (getToken() != NAME) throw new ParserException("expected name");
- if (getToken() != RP) throw new ParserException("expected )");
- tok = peekToken();
+ case WHILE: {
+ consume(WHILE);
+ consume(LP);
+ ForthBlock loop = new ForthBlock(curLine, sourceName);
+ b.add(loop.LOOP, loop);
+
+ loop.add(loop.POP);
+ loop.add(loop.EXPR, parseExpr());
+ loop.add(loop.JT, new Integer(2));
+ loop.add(Lexer.BREAK);
+ consume(RP);
+ parseStatement(false, loop);
+
+ // if we fall out of the end, definately continue
+ loop.add(CONTINUE);
+ break;
}
- if (tok == FINALLY) getToken();
- return parseExpr(tryBlock, minPrecedence);
- }
+ case SWITCH: {
+ consume(SWITCH);
+ consume(LP);
+ ForthBlock loop = new ForthBlock(curLine, sourceName);
+ b.add(loop.LOOP, loop);
+ loop.add(loop.EXPR, parseExpr());
+ consume(RP);
+ consume(LC);
+ while(true) {
+ ForthBlock caseForthBlock;
+ tok = getToken();
+ if (tok == CASE) {
+ loop.add(loop.DUP);
+ loop.add(loop.EXPR, parseExpr());
+ loop.add(EQ);
+ loop.add(loop.JF, new Integer(2));
+ } else if (tok != DEFAULT) throw new ParserException("expected CASE or DEFAULT");
+ consume(COLON);
+ ForthBlock b2 = new ForthBlock(curLine, sourceName);
+ ForthBlock e1 = null;
+ while(peekToken() != CASE && peekToken() != DEFAULT && peekToken() != RC) {
+ if ((e1 = parseStatement()) == null) break;
+ b2.add(b.EXPR, e1);
+ b2.add(b.POP);
+ }
+ loop.add(loop.EXPR, b2);
+ if (peekToken() == RC) {
+ consume(RC);
+ loop.add(BREAK);
+ break;
+ }
+ }
+ break;
+ }
+
+ case DO: {
+ consume(DO);
+ ForthBlock loop = new ForthBlock(curLine, sourceName);
+ b.add(loop.LOOP, loop);
+
+ parseStatement(false, loop);
+ consume(WHILE);
+ consume(LP);
+ loop.add(loop.EXPR, parseExpr());
+ loop.add(loop.JT, new Integer(2));
+ loop.add(Lexer.BREAK);
+ loop.add(Lexer.CONTINUE);
+ consume(RP);
+ consume(SEMI);
+ break;
+ }
+
+ case TRY: {
+ // FIXME: don't just ignore this!
+ // 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
+ }
+
+ if (peekToken() == FINALLY) {
+ consume(FINALLY);
+ parseStatement(false, b);
+ }
+ break;
+ }
case FOR: {
- if (prefix != null) { pushBackToken(); return prefix; }
- if (getToken() != LP) throw new ParserException("expected left paren");
+ consume(FOR);
+ consume(LP);
tok = getToken();
if (tok == VAR) tok = getToken();
boolean forIn = peekToken() == IN;
pushBackToken(tok, varName);
- ForthBlock b = new ForthBlock(curLine, sourceName);
if (forIn) {
consume(NAME);
consume(IN);
b2.add(b.LITERAL, varName);
b2.add(b.DECLARE);
b2.add(b.PUT);
- b2.add(b.EXPR, parseStatement(false));
- b2.add(b.LITERAL, null);
- return parseExpr(b, minPrecedence);
+ b2.add(b.EXPR, parseStatement());
+ //b2.add(b.LITERAL, null);
+ break;
} else {
ForthBlock b2 = new ForthBlock(curLine, sourceName);
b.add(b.SCOPE, b2);
+ b.add(b.POP);
- e1 = parseExpr();
+ ForthBlock e1 = parseExpr();
if (e1 == null) e1 = new ForthBlock(curLine, sourceName, b.LITERAL, null);
b2.add(b.EXPR, e1);
b2.add(b.POP);
consume(SEMI);
- e2 = parseExpr();
+ ForthBlock e2 = parseExpr();
consume(SEMI);
- e3 = parseExpr();
+ ForthBlock e3 = parseExpr();
consume(RP);
if (e2 == null) e2 = new ForthBlock(curLine, sourceName, b.LITERAL, null);
b3.add(b.JT, new Integer(2));
b3.add(BREAK);
parseStatement(false, b3);
- return parseExpr(b, minPrecedence);
+ b3.add(BREAK);
+ break;
}
}
- default:
- pushBackToken();
- return prefix;
- }
- }
-
- /** a block is either a single statement or a list of statements surrounded by curly braces; all expressions are also statements */
- public ForthBlock parseStatement(boolean requireBraces) throws IOException { return parseStatement(requireBraces, null); }
- public ForthBlock parseStatement(boolean requireBraces, ForthBlock b) throws IOException {
- ForthBlock 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;
- ForthBlock ret = new ForthBlock(curLine, sourceName);
- ForthBlock block = b == null ? new ForthBlock(curLine, sourceName) : b;
- block.add(ret.LITERAL, Boolean.TRUE);
- ret.add(block.SCOPE, block);
- while(true) {
- switch(tok = peekToken()) {
-
- case LC: smt = parseStatement(true); break;
- case GOTO: throw new ParserException("goto not supported");
-
- case THROW: case RETURN: case ASSERT: {
- getToken();
- ForthBlock r = new ForthBlock(curLine, sourceName);
- if (tok == RETURN && peekToken() == SEMI) r.add(b.LITERAL, null);
- else r.add(b.EXPR, parseExpr());
- consume(SEMI);
- r.add(tok);
- smt = r;
- break;
- }
-
- case BREAK: case CONTINUE: {
- getToken();
- if (peekToken() == NAME) consume(NAME);
- smt = new ForthBlock(curLine, sourceName, tok, 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);
+ String name = string;
if (peekToken() == COLON) {
consume(COLON);
- smt = new ForthBlock(curLine, sourceName, ForthBlock.LABEL, string);
+ b.add(ForthBlock.LABEL, string);
break;
} else {
pushBackToken(NAME, name);
// fall through to default case
}
}
-
- case -1:
- default:
- smt = parseExpr();
- if (smt == null) return block.size() == 0 ? null : ret;
- if (peekToken() == SEMI) getToken();
+ // fall through
+ case RC:
+ if (tok == RC && braced) { consume(RC); return; }
+ // fall through
+ default: {
+ ForthBlock ret = parseExpr();
+ if (ret == null) return;
+ b.add(b.EXPR, ret);
+ b.add(b.POP);
+ if (peekToken() == SEMI) consume(SEMI);
break;
}
-
- if (!braced) return smt;
- block.add(block.EXPR, smt);
- block.add(block.POP);
+ }
+
+ if (!braced) return;
}
}
projects / org.ibex.core.git / blobdiff