jsparse.c

一个基于alice开发的机器人

         * kid3 is the finally Statement
         *
         * catch nodes are ternary.
         * kid1 is the discriminant
         * kid2 is the next catch node, or NULL
         * kid3 is the catch block (on kid3 so that we can always append a
         *                          new catch pn on catchtail->kid2)
         *
         * catch discriminant nodes are binary
         * atom is the receptacle
         * expr is the discriminant code
         *
         * finally nodes are unary (just the finally expression)
         */
        pn = NewParseNode(cx, &CURRENT_TOKEN(ts), PN_TERNARY, tc);
        pn->pn_op = JSOP_NOP;

        MUST_MATCH_TOKEN(TOK_LC, JSMSG_CURLY_BEFORE_TRY);
        js_PushStatement(tc, &stmtInfo, STMT_TRY, -1);
        pn->pn_kid1 = Statements(cx, ts, tc);
        if (!pn->pn_kid1)
            return NULL;
        MUST_MATCH_TOKEN(TOK_RC, JSMSG_CURLY_AFTER_TRY);
        js_PopStatement(tc);

        catchtail = pn;
        while (js_PeekToken(cx, ts) == TOK_CATCH) {
            /* check for another catch after unconditional catch */
            if (catchtail != pn && !catchtail->pn_kid1->pn_expr) {
                js_ReportCompileErrorNumber(cx, ts, NULL, JSREPORT_ERROR,
                                            JSMSG_CATCH_AFTER_GENERAL);
                return NULL;
            }

            /*
             * legal catch forms are:
             * catch (v)
             * catch (v if <boolean_expression>)
             * (the latter is legal only #ifdef JS_HAS_CATCH_GUARD)
             */
            (void) js_GetToken(cx, ts); /* eat `catch' */
            pn2 = NewParseNode(cx, &CURRENT_TOKEN(ts), PN_TERNARY, tc);
            if (!pn2)
                return NULL;

            /*
             * We use a PN_NAME for the discriminant (catchguard) node
             * with the actual discriminant code in the initializer spot
             */
            MUST_MATCH_TOKEN(TOK_LP, JSMSG_PAREN_BEFORE_CATCH);
            MUST_MATCH_TOKEN(TOK_NAME, JSMSG_CATCH_IDENTIFIER);
            pn3 = NewParseNode(cx, &CURRENT_TOKEN(ts), PN_NAME, tc);
            if (!pn3)
                return NULL;

            pn3->pn_atom = CURRENT_TOKEN(ts).t_atom;
            pn3->pn_expr = NULL;
#if JS_HAS_CATCH_GUARD
            /*
             * We use `catch (x if x === 5)' (not `catch (x : x === 5)') to
             * avoid conflicting with the JS2/ECMA2 proposed catchguard syntax.
             */
            if (js_PeekToken(cx, ts) == TOK_IF) {
                (void)js_GetToken(cx, ts); /* eat `if' */
                pn3->pn_expr = Expr(cx, ts, tc);
                if (!pn3->pn_expr)
                    return NULL;
            }
#endif
            pn2->pn_kid1 = pn3;

            MUST_MATCH_TOKEN(TOK_RP, JSMSG_PAREN_AFTER_CATCH);

            MUST_MATCH_TOKEN(TOK_LC, JSMSG_CURLY_BEFORE_CATCH);
            js_PushStatement(tc, &stmtInfo, STMT_CATCH, -1);
            stmtInfo.label = pn3->pn_atom;
            pn2->pn_kid3 = Statements(cx, ts, tc);
            if (!pn2->pn_kid3)
                return NULL;
            MUST_MATCH_TOKEN(TOK_RC, JSMSG_CURLY_AFTER_CATCH);
            js_PopStatement(tc);

            catchtail = catchtail->pn_kid2 = pn2;
        }
        catchtail->pn_kid2 = NULL;

        if (js_MatchToken(cx, ts, TOK_FINALLY)) {
            tc->tryCount++;
            MUST_MATCH_TOKEN(TOK_LC, JSMSG_CURLY_BEFORE_FINALLY);
            js_PushStatement(tc, &stmtInfo, STMT_FINALLY, -1);
            pn->pn_kid3 = Statements(cx, ts, tc);
            if (!pn->pn_kid3)
                return NULL;
            MUST_MATCH_TOKEN(TOK_RC, JSMSG_CURLY_AFTER_FINALLY);
            js_PopStatement(tc);
        } else {
            pn->pn_kid3 = NULL;
        }
        if (!pn->pn_kid2 && !pn->pn_kid3) {
            js_ReportCompileErrorNumber(cx, ts, NULL, JSREPORT_ERROR,
                                        JSMSG_CATCH_OR_FINALLY);
            return NULL;
        }
        tc->tryCount++;
        return pn;
      }

      case TOK_THROW:
        pn = NewParseNode(cx, &CURRENT_TOKEN(ts), PN_UNARY, tc);
        if (!pn)
            return NULL;
        pn2 = Expr(cx, ts, tc);
        if (!pn2)
            return NULL;
        pn->pn_pos.end = pn2->pn_pos.end;
        pn->pn_op = JSOP_THROW;
        pn->pn_kid = pn2;
        break;

      /* TOK_CATCH and TOK_FINALLY are both handled in the TOK_TRY case */
      case TOK_CATCH:
        js_ReportCompileErrorNumber(cx, ts, NULL, JSREPORT_ERROR,
                                    JSMSG_CATCH_WITHOUT_TRY);
        return NULL;

      case TOK_FINALLY:
        js_ReportCompileErrorNumber(cx, ts, NULL, JSREPORT_ERROR,
                                    JSMSG_FINALLY_WITHOUT_TRY);
        return NULL;

#endif /* JS_HAS_EXCEPTIONS */

      case TOK_BREAK:
        pn = NewParseNode(cx, &CURRENT_TOKEN(ts), PN_NULLARY, tc);
        if (!pn)
            return NULL;
        if (!MatchLabel(cx, ts, pn))
            return NULL;
        stmt = tc->topStmt;
        label = pn->pn_atom;
        if (label) {
            for (; ; stmt = stmt->down) {
                if (!stmt) {
                    js_ReportCompileErrorNumber(cx, ts, NULL, JSREPORT_ERROR,
                                                JSMSG_LABEL_NOT_FOUND);
                    return NULL;
                }
                if (stmt->type == STMT_LABEL && stmt->label == label)
                    break;
            }
        } else {
            for (; ; stmt = stmt->down) {
                if (!stmt) {
                    js_ReportCompileErrorNumber(cx, ts, NULL, JSREPORT_ERROR,
                                                JSMSG_TOUGH_BREAK);
                    return NULL;
                }
                if (STMT_IS_LOOP(stmt) || stmt->type == STMT_SWITCH)
                    break;
            }
        }
        if (label)
            pn->pn_pos.end = CURRENT_TOKEN(ts).pos.end;
        break;

      case TOK_CONTINUE:
        pn = NewParseNode(cx, &CURRENT_TOKEN(ts), PN_NULLARY, tc);
        if (!pn)
            return NULL;
        if (!MatchLabel(cx, ts, pn))
            return NULL;
        stmt = tc->topStmt;
        label = pn->pn_atom;
        if (label) {
            for (stmt2 = NULL; ; stmt = stmt->down) {
                if (!stmt) {
                    js_ReportCompileErrorNumber(cx, ts, NULL, JSREPORT_ERROR,
                                                JSMSG_LABEL_NOT_FOUND);
                    return NULL;
                }
                if (stmt->type == STMT_LABEL) {
                    if (stmt->label == label) {
                        if (!stmt2 || !STMT_IS_LOOP(stmt2)) {
                            js_ReportCompileErrorNumber(cx, ts, NULL,
                                                        JSREPORT_ERROR,
                                                        JSMSG_BAD_CONTINUE);
                            return NULL;
                        }
                        break;
                    }
                } else {
                    stmt2 = stmt;
                }
            }
        } else {
            for (; ; stmt = stmt->down) {
                if (!stmt) {
                    js_ReportCompileErrorNumber(cx, ts, NULL, JSREPORT_ERROR,
                                                JSMSG_BAD_CONTINUE);
                    return NULL;
                }
                if (STMT_IS_LOOP(stmt))
                    break;
            }
        }
        if (label)
            pn->pn_pos.end = CURRENT_TOKEN(ts).pos.end;
        break;

      case TOK_WITH:
        pn = NewParseNode(cx, &CURRENT_TOKEN(ts), PN_BINARY, tc);
        if (!pn)
            return NULL;
        MUST_MATCH_TOKEN(TOK_LP, JSMSG_PAREN_BEFORE_WITH);
        pn2 = Expr(cx, ts, tc);
        if (!pn2)
            return NULL;
        MUST_MATCH_TOKEN(TOK_RP, JSMSG_PAREN_AFTER_WITH);
        pn->pn_left = pn2;

        js_PushStatement(tc, &stmtInfo, STMT_WITH, -1);
        pn2 = Statement(cx, ts, tc);
        if (!pn2)
            return NULL;
        js_PopStatement(tc);

        /* Deprecate after parsing, in case of WERROR option. */
        if (!js_ReportCompileErrorNumber(cx, ts, NULL,
                                         JSREPORT_WARNING | JSREPORT_STRICT,
                                         JSMSG_DEPRECATED_USAGE,
                                         js_with_statement_str)) {
            return NULL;
        }

        pn->pn_pos.end = pn2->pn_pos.end;
        pn->pn_right = pn2;
        tc->flags |= TCF_FUN_HEAVYWEIGHT;
        return pn;

      case TOK_VAR:
        pn = Variables(cx, ts, tc);
        if (!pn)
            return NULL;

        /* Tell js_EmitTree to generate a final POP. */
        pn->pn_extra = JS_TRUE;
        break;

      case TOK_RETURN:
        if (!(tc->flags & TCF_IN_FUNCTION)) {
            js_ReportCompileErrorNumber(cx, ts, NULL, JSREPORT_ERROR,
                                        JSMSG_BAD_RETURN);
            return NULL;
        }
        pn = NewParseNode(cx, &CURRENT_TOKEN(ts), PN_UNARY, tc);
        if (!pn)
            return NULL;

        /* This is ugly, but we don't want to require a semicolon. */
        ts->flags |= TSF_REGEXP;
        tt = js_PeekTokenSameLine(cx, ts);
        ts->flags &= ~TSF_REGEXP;
        if (tt == TOK_ERROR)
            return NULL;

        if (tt != TOK_EOF && tt != TOK_EOL && tt != TOK_SEMI && tt != TOK_RC) {
            pn2 = Expr(cx, ts, tc);
            if (!pn2)
                return NULL;
            tc->flags |= TCF_RETURN_EXPR;
            pn->pn_pos.end = pn2->pn_pos.end;
            pn->pn_kid = pn2;
        } else {
            tc->flags |= TCF_RETURN_VOID;
            pn->pn_kid = NULL;
        }

        if (JS_HAS_STRICT_OPTION(cx) &&
            (~tc->flags & (TCF_RETURN_EXPR | TCF_RETURN_VOID)) == 0) {
            /*
             * We must be in a frame with a non-native function, because
             * we're compiling one.
             */
            if (!ReportNoReturnValue(cx, ts))
                return NULL;
        }
        break;

      case TOK_LC:
        js_PushStatement(tc, &stmtInfo, STMT_BLOCK, -1);
        pn = Statements(cx, ts, tc);
        if (!pn)
            return NULL;

        MUST_MATCH_TOKEN(TOK_RC, JSMSG_CURLY_IN_COMPOUND);
        js_PopStatement(tc);
        return pn;

      case TOK_EOL:
      case TOK_SEMI:
        pn = NewParseNode(cx, &CURRENT_TOKEN(ts), PN_UNARY, tc);
        if (!pn)
            return NULL;
        pn->pn_type = TOK_SEMI;
        pn->pn_kid = NULL;
        return pn;

#if JS_HAS_DEBUGGER_KEYWORD
      case TOK_DEBUGGER:
        pn = NewParseNode(cx, &CURRENT_TOKEN(ts), PN_NULLARY, tc);
        if (!pn)
            return NULL;
        pn->pn_type = TOK_DEBUGGER;
        tc->flags |= TCF_FUN_HEAVYWEIGHT;
        break;
#endif /* JS_HAS_DEBUGGER_KEYWORD */

      case TOK_ERROR:
        return NULL;

      default:
        js_UngetToken(ts);
        pn2 = Expr(cx, ts, tc);
        if (!pn2)
            return NULL;

        if (js_PeekToken(cx, ts) == TOK_COLON) {
            if (pn2->pn_type != TOK_NAME) {
                js_ReportCompileErrorNumber(cx, ts, NULL, JSREPORT_ERROR,
                                            JSMSG_BAD_LABEL);
                return NULL;
            }
            label = pn2->pn_atom;
            for (stmt = tc->topStmt; stmt; stmt = stmt->down) {
                if (stmt->type == STMT_LABEL && stmt->label == label) {
                    js_ReportCompileErrorNumber(cx, ts, NULL, JSREPORT_ERROR,
                                                JSMSG_DUPLICATE_LABEL);
                    return NULL;
                }
            }
            (void) js_GetToken(cx, ts);

            /* Push a label struct and parse the statement. */
            js_PushStatement(tc, &stmtInfo, STMT_LABEL, -1);
            stmtInfo.label = label;
            pn = Statement(cx, ts, tc);
            if (!pn)
                return NULL;

            /* Pop the label, set pn_expr, and return early. */
            js_PopStatement(tc);
            pn2->pn_type = TOK_COLON;
            pn2->pn_pos.end = pn->pn_pos.end;
            pn2->pn_expr = pn;
            return pn2;
        }

        pn = NewParseNode(cx, &CURRENT_TOKEN(ts), PN_UNARY, tc);
        if (!pn)
            return NULL;
        pn->pn_type = TOK_SEMI;
        pn->pn_pos = pn2->pn_pos;
        pn->pn_kid = pn2;
        break;
    }

    /* Check termination of this primitive statement. */
    if (ON_CURRENT_LINE(ts, pn->pn_pos)) {
        tt = js_PeekTokenSameLine(cx, ts);
        if (tt == TOK_ERROR)
            return NULL;
        if (tt != TOK_EOF && tt != TOK_EOL && tt != TOK_SEMI && tt != TOK_RC) {
            js_ReportCompileErrorNumber(cx, ts, NULL, JSREPORT_ERROR,
                                        JSMSG_SEMI_BEFORE_STMNT);
            return NULL;
        }
    }

    (void) js_MatchToken(cx, ts, TOK_SEMI);
    return pn;
}

static JSParseNode *
Variables(JSContext *cx, JSTokenS