-// 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 ForthBlock's */
-public class Parser extends Lexer implements OpCodes {
+/** Parses a stream of lexed tokens into a tree of ByteCodeBlock's */
+class Parser extends Lexer implements ByteCodes {
+
// 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) {
- ForthBlock block = p.parseStatement(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[OR] = precedence[AND] = 4;
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 /////////////////////////////////////////////////////////
+ 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 ? "EOL" : codeToString[op]));
+ throw new ParserException("expected " + codeToString[code] + ", got " + (op == -1 ? "EOF" : codeToString[op]));
}
- /** parses the largest possible expression */
- public ForthBlock parseExpr() throws IOException { return parseExpr(null, -1); }
- public ForthBlock parseExpr(ForthBlock prefix, int minPrecedence) throws IOException {
- ForthBlock 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;
+ /** append the largest expression beginning with prefix containing no operators of precedence below <tt>minPrecedence</tt> */
+ public ByteCodeBlock startExpr() throws IOException { return startExpr(-1); }
+ 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;
+ }
- getToken();
+ public void startExpr(int minPrecedence, ByteCodeBlock appendTo) throws IOException {
+ int tok = getToken();
int curLine = line;
+ if (tok == -1) return;
- switch (tok) {
+ ByteCodeBlock b = appendTo;
- case VAR: {
- if (prefix != null) { pushBackToken(); return prefix; }
- ForthBlock b = new ForthBlock(curLine, sourceName);
- b.add(OpCodes.THIS);
+ 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) {
- 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;
+ 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);
}
- return parseExpr(b, minPrecedence);
}
-
- case IN: pushBackToken(); return prefix;
-
- case IF: {
- if (prefix != null) { pushBackToken(); return prefix; }
- ForthBlock b = new ForthBlock(curLine, sourceName);
- consume(LP);
- b.add(b.EXPR, parseExpr());
+ case SUB: {
+ consume(NUMBER);
+ b.add(ByteCodeBlock.LITERAL, new Double(number.doubleValue() * -1));
+ continueExpr(b, minPrecedence);
+ return;
+ }
+ case LP: {
+ startExpr(b);
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));
- return parseExpr(b, minPrecedence);
+ continueExpr(b, minPrecedence);
+ return;
}
-
- // 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));
- return parseExpr(b, minPrecedence);
- } else {
- // postfix
- ForthBlock b = (ForthBlock)prefix;
- b.set(b.size() - 1, tok, new Boolean(false));
- return parseExpr(b, minPrecedence);
- }
-
- case LP:
- if (prefix == null) { // grouping
- ForthBlock b = new ForthBlock(curLine, sourceName, ForthBlock.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) {
- b.add(b.EXPR, parseExpr());
- i++;
- if (peekToken() == RP) break;
- consume(COMMA);
- }
- consume(RP);
- b.add(b.CALL, new Integer(i));
- return parseExpr(b, minPrecedence);
- }
-
- 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 INC: case DEC: {
+ // prefix
+ startExpr(precedence[tok], b);
+ b.set(b.size() - 1, tok, new Boolean(true));
+ continueExpr(b, minPrecedence);
+ return;
}
-
- 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
- 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]));
+ case BANG: case BITNOT: case TYPEOF: {
+ startExpr(precedence[tok], b);
b.add(tok);
- return parseExpr(b, minPrecedence);
+ continueExpr(b, minPrecedence);
+ return;
}
-
- // 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));
- b.add(b.POP);
- b.add(b.EXPR, parseExpr(null, precedence[tok]));
- 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(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(ForthBlock.LITERAL, name);
- b.add(ForthBlock.GET);
- return parseExpr(parseExpr(b, minPrecedence), minPrecedence);
- }
- }
-
- case DOT: {
- consume(NAME);
- String target = string;
- ForthBlock b = new ForthBlock(curLine, sourceName);
- b.add(b.EXPR, prefix);
- if (peekToken() == ASSIGN) {
- consume(ASSIGN);
- ForthBlock val = parseExpr();
- b.add(b.LITERAL, target);
- b.add(b.EXPR, val);
- b.add(b.PUT);
- b.add(b.SWAP);
- b.add(b.POP);
- } else {
- b.add(b.LITERAL, target);
- b.add(b.GET);
- }
- return parseExpr(b, minPrecedence);
- }
-
- case LB: {
- ForthBlock b = new ForthBlock(curLine, sourceName);
- if (prefix == null) {
- b.add(b.ARRAY, new Integer(0));
- int i = 0;
- while(true) {
- ForthBlock e = parseExpr();
- if (e == null && peekToken() == RB) { consume(RB); return parseExpr(b, minPrecedence); }
- 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);
- b.add(b.POP);
- if (peekToken() == RB) { consume(RB); return parseExpr(b, minPrecedence); }
- consume(COMMA);
- }
- } else {
- b.add(b.EXPR, prefix);
- b.add(b.EXPR, parseExpr());
- consume(RB);
- if (peekToken() == ASSIGN) {
- consume(ASSIGN);
- b.add(b.EXPR, parseExpr());
- b.add(b.PUT);
- b.add(b.SWAP);
- b.add(b.POP);
- } else {
- b.add(b.GET);
- }
- return parseExpr(b, minPrecedence);
- }
- }
-
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) {
+ b.add(OBJECT, null);
+ if (peekToken() != RC) while(true) {
if (peekToken() != NAME && peekToken() != STRING) throw new Error("expected NAME or STRING");
getToken();
- b.add(b.LITERAL, string);
+ b.add(LITERAL, string);
consume(COLON);
- b.add(b.EXPR, parseExpr());
- b.add(b.PUT);
- b.add(b.POP);
- if (peekToken() == RC) { consume(RC); return parseExpr(b, minPrecedence); }
+ startExpr(b);
+ b.add(PUT);
+ b.add(POP);
+ if (peekToken() == RC) break;
consume(COMMA);
- if (peekToken() == RC) { consume(RC); return parseExpr(b, minPrecedence); }
+ if (peekToken() == RC) break;
}
+ consume(RC);
+ continueExpr(b, minPrecedence);
+ return;
}
-
- 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());
- b.add(b.JMP, new Integer(2));
- consume(COLON);
- b.add(b.EXPR, parseExpr());
- return parseExpr(b, minPrecedence);
+ 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 Tokens.FUNCTION: {
- if (prefix != null) { pushBackToken(); return prefix; }
+ case FUNCTION: {
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);
+ 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);
+
} else {
consume(NAME);
// declare the name
- b.add(b.LITERAL, string);
- b.add(b.DECLARE);
+ b2.add(LITERAL, string);
+ b2.add(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(LITERAL, new Integer(numArgs));
+ b2.add(GET_PRESERVE);
+ b2.add(SWAP);
+ b2.add(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(TOPSCOPE);
+ b2.add(SWAP);
+ b2.add(LITERAL, string);
+ b2.add(SWAP);
+ b2.add(PUT);
// clean the stack
- b.add(b.POP);
- b.add(b.POP);
+ b2.add(POP);
+ b2.add(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(POP);
+ parseStatement(true, b2);
+ b2.add(LITERAL, null);
+ b2.add(RETURN);
+ continueExpr(b.add(NEWFUNCTION, b2), minPrecedence);
+ return;
}
-
- 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;
}
+ }
- 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);
- }
- loop.add(loop.EXPR, b);
- if (peekToken() == RC) {
- consume(RC);
- r.add(BREAK);
- return parseExpr(r, minPrecedence);
- }
- }
+ 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; }
+
+ if (prefix == null) throw new Error("got null prefix");
+ ByteCodeBlock b = prefix;
+
+ 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: {
+ 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 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 INC: case DEC: {
+ // postfix
+ b.set(b.size() - 1, tok, new Boolean(false));
+ continueExpr(b, minPrecedence);
+ return;
}
- 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 LP: {
+ // invocation
+ int i = 0;
+ while(peekToken() != RP) {
+ i++;
+ startExpr(b);
+ if (peekToken() == RP) break;
+ consume(COMMA);
}
- if (tok == FINALLY) getToken();
-
- return parseExpr(tryBlock, minPrecedence);
+ consume(RP);
+ b.add(CALL, new Integer(i));
+ continueExpr(b, minPrecedence);
+ return;
}
- case FOR: {
- if (prefix != null) { pushBackToken(); return prefix; }
- if (getToken() != LP) throw new ParserException("expected left paren");
+ 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: case SUB: {
+ startExpr(precedence[tok], b);
+ b.add(tok);
+ continueExpr(b, minPrecedence);
+ return;
+ }
- tok = getToken();
- if (tok == VAR) tok = getToken();
- String varName = string;
- boolean forIn = peekToken() == IN;
- pushBackToken(tok, varName);
+ 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;
+ }
- ForthBlock b = new ForthBlock(curLine, sourceName);
- if (forIn) {
- consume(NAME);
- consume(IN);
- b.add(b.EXPR, parseExpr());
- b.add(b.PUSHKEYS);
- b.add(b.LITERAL, "length");
- b.add(b.GET);
- consume(RP);
- ForthBlock b2 = new ForthBlock(curLine, sourceName);
- b.add(b.SCOPE, b2);
- b2.add(b.LITERAL, new Integer(1));
- b2.add(SUB);
- b2.add(b.DUP);
- b2.add(b.LITERAL, new Integer(0));
- b2.add(LT);
- b2.add(b.JT, new Integer(7));
- b2.add(b.GET_PRESERVE);
- b2.add(b.LITERAL, varName);
- 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);
-
+ 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 {
- ForthBlock b2 = new ForthBlock(curLine, sourceName);
- b.add(b.SCOPE, b2);
-
- 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();
- consume(SEMI);
- e3 = parseExpr();
- consume(RP);
+ b.add(LITERAL, target);
+ b.add(GET);
+ }
+ continueExpr(b, minPrecedence);
+ return;
+ }
- if (e2 == null) e2 = new ForthBlock(curLine, sourceName, b.LITERAL, null);
- if (e3 == null) e3 = new ForthBlock(curLine, sourceName, b.LITERAL, null);
-
- ForthBlock b3 = new ForthBlock(curLine, sourceName);
- b2.add(b.LOOP, b3);
- b2.add(b.LITERAL, null);
- b3.add(b.JT, new Integer(3));
- b3.add(b.EXPR, e3);
- b3.add(b.POP);
- b3.add(b.EXPR, e2);
- b3.add(b.JT, new Integer(2));
- b3.add(BREAK);
- parseStatement(false, b3);
- return parseExpr(b, minPrecedence);
+ case LB: {
+ startExpr(b);
+ consume(RB);
+ if (peekToken() == ASSIGN) {
+ consume(ASSIGN);
+ startExpr(b);
+ b.add(PUT);
+ b.add(SWAP);
+ b.add(POP);
+ } else {
+ b.add(GET);
}
+ continueExpr(b, minPrecedence);
+ return;
+ }
+
+ 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;
}
- default:
- pushBackToken();
- return prefix;
+ default: { pushBackToken(); return; }
}
}
/** 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;
+ 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;
+ }
+
+ public void parseStatement(boolean requireBraces) throws IOException {
+ parseStatement(requireBraces, new ByteCodeBlock(line, sourceName));
+ }
+ public void parseStatement(boolean requireBraces, ByteCodeBlock b) throws IOException {
int tok = peekToken();
- if (tok == -1) return null;
+ 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;
- 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());
+ if (tok == RETURN && peekToken() == SEMI) b.add(LITERAL, null);
+ else startExpr(b);
consume(SEMI);
- r.add(tok);
- smt = r;
+ b.add(tok);
break;
}
case BREAK: case CONTINUE: {
getToken();
if (peekToken() == NAME) consume(NAME);
- smt = new ForthBlock(curLine, sourceName, tok, string);
+ b.add(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;
+ 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 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);
+ }
+ b.set(size - 1, new Integer(1 + b.size() - size));
+ break;
+ }
+
+ case WHILE: {
+ consume(WHILE);
+ consume(LP);
+ ByteCodeBlock loop = newbb(curLine);
+ b.add(LOOP, loop);
+
+ loop.add(POP);
+ startExpr(loop);
+ loop.add(JT, new Integer(2));
+ loop.add(BREAK);
+ consume(RP);
+ parseStatement(false, loop);
+
+ // if we fall out of the end, definately continue
+ loop.add(CONTINUE);
+ break;
+ }
+
+ case SWITCH: {
+ consume(SWITCH);
+ consume(LP);
+ ByteCodeBlock loop = newbb(curLine);
+ b.add(LOOP, loop);
+ startExpr(loop);
+ consume(RP);
+ consume(LC);
+ while(true)
+ if (peekToken() == CASE) {
+ consume(CASE);
+ loop.add(DUP);
+ startExpr(loop);
+ consume(COLON);
+ loop.add(EQ);
+ loop.add(JF, new Integer(0));
+ int size = loop.size();
+ while(peekToken() != CASE && peekToken() != DEFAULT && peekToken() != RC) {
+ int size2 = loop.size();
+ parseStatement(false, loop);
+ if (size2 == loop.size()) break;
+ }
+ loop.set(size - 1, new Integer(1 + loop.size() - size));
+ } else if (peekToken() == DEFAULT) {
+ consume(DEFAULT);
+ consume(COLON);
+ while(peekToken() != CASE && peekToken() != DEFAULT && peekToken() != RC) {
+ int size2 = loop.size();
+ parseStatement(false, loop);
+ if (size2 == loop.size()) break;
+ }
+ } else if (peekToken() == RC) {
+ consume(RC);
+ loop.add(BREAK);
+ break;
+ } else {
+ throw new ParserException("expected CASE, DEFAULT, or RC; got " + codeToString[peekToken()]);
+ }
+ break;
+ }
+
+ case DO: {
+ consume(DO);
+ ByteCodeBlock loop = newbb(curLine);
+ b.add(LOOP, loop);
+
+ parseStatement(false, loop);
+ consume(WHILE);
+ consume(LP);
+ startExpr(loop);
+ loop.add(JT, new Integer(2));
+ loop.add(BREAK);
+ loop.add(CONTINUE);
+ consume(RP);
+ consume(SEMI);
+ break;
+ }
+
+ 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
+ }
+
+ if (peekToken() == FINALLY) {
+ consume(FINALLY);
+ parseStatement(false, b);
+ }
+ break;
+ }
+
+ case FOR: {
+ consume(FOR);
+ consume(LP);
+
+ tok = getToken();
+ boolean hadVar = false;
+ if (tok == VAR) { hadVar = true; tok = getToken(); }
+ String varName = string;
+ boolean forIn = peekToken() == IN;
+ pushBackToken(tok, varName);
+
+ if (forIn) {
+ consume(NAME);
+ consume(IN);
+ startExpr(b);
+ b.add(PUSHKEYS);
+ b.add(LITERAL, "length");
+ b.add(GET);
+ consume(RP);
+ ByteCodeBlock b2 = newbb(curLine);
+ b.add(SCOPE, b2);
+ b2.add(LITERAL, new Integer(1));
+ b2.add(SUB);
+ b2.add(DUP);
+ b2.add(LITERAL, new Integer(0));
+ b2.add(LT);
+ b2.add(JT, new Integer(7));
+ b2.add(GET_PRESERVE);
+ b2.add(LITERAL, varName);
+ b2.add(LITERAL, varName);
+ b2.add(DECLARE);
+ b2.add(PUT);
+ parseStatement(false, b2);
+ break;
+ } else {
+ if (hadVar) pushBackToken(VAR, null);
+ ByteCodeBlock b2 = newbb(curLine);
+ b.add(SCOPE, b2);
+ b.add(POP);
+
+ int size = b2.size();
+ parseStatement(false, b2);
+ ByteCodeBlock e2 = startExpr();
+ consume(SEMI);
+ if (e2 == null) e2 = newbb(curLine).add(b.LITERAL, null);
+
+ ByteCodeBlock b3 = newbb(curLine);
+ b2.add(LOOP, b3);
+ b2.add(LITERAL, null);
+
+ b3.add(JT, new Integer(0));
+ size = b3.size();
+ startExpr(b3);
+ consume(RP);
+ if (b3.size() - size > 0) b3.add(POP);
+ b3.set(size - 1, new Integer(b3.size() - size + 1));
+
+ b3.paste(e2);
+ b3.add(JT, new Integer(2));
+ b3.add(BREAK);
+ parseStatement(false, b3);
+ b3.add(CONTINUE);
+ break;
+ }
+ }
+
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(ByteCodeBlock.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: {
+ int size = b.size();
+ startExpr(b);
+ if (size == b.size()) return;
+ b.add(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