======================================================= Known Problems In PCCTS - Last revised 14 November 1998 ======================================================= #14. Parsing bug in dlg THM: I have been unable to reproduce this problem. Reported by Rick Howard Mijenix Corporation (rickh@mijenix.com). The regular expression parser (in rexpr.c) fails while trying to parse the following regular expression: {[a-zA-Z]:}(\\\\[a-zA-Z0-9]*)+ See my comment in the following excerpt from rexpr.c: /* * ::= ( '|' {} )* * * Return -1 if syntax error * Return 0 if none found * Return 1 if a regExrp was found */ static regExpr(g) GraphPtr g; { Graph g1, g2; if ( andExpr(&g1) == -1 ) { return -1; } while ( token == '|' ) { int a; next(); a = andExpr(&g2); if ( a == -1 ) return -1; /* syntax error below */ else if ( !a ) return 1; /* empty alternative */ g1 = BuildNFA_AorB(g1, g2); } if ( token!='\0' ) return -1; ***** ***** It appears to fail here becuause token is 125 - the closing '}' ***** If I change it to: ***** if ( token!='\0' && token!='}' && token!= ')' ) return -1; ***** ***** It succeeds, but I'm not sure this is the corrrect approach. ***** *g = g1; return 1; } #13. dlg reports an invalid range for: [\0x00-\0xff] Diagnosed by Piotr Eljasiak (eljasiak@no-spam.zt.gdansk.tpsa.pl): Fixed in MR16. #12. Strings containing comment actions Sequences that looked like C style comments appearing in string literals are improperly parsed by antlr/dlg. << fprintf(out," /* obsolete */ "); For this case use: << fprintf(out," \/\* obsolete \*\/ "); Reported by K.J. Cummings (cummings@peritus.com). #11. User hook for deallocation of variables on guess fail The mechanism outlined in Item #108 works only for heap allocated variables. #10. Label re-initialization in ( X {y:Y} )* If a label assignment is optional and appears in a (...)* or (...)+ block it will not be reset to NULL when it is skipped by a subsequent iteration. Consider the example: ( X { y:Y })* Z with input: X Y X Z The first time through the block Y will be matched and y will be set to point to the token. On the second iteration of the (...)* block there is no match for Y. But y will not be reset to NULL, as the user might expect, it will contain a reference to the Y that was matched in the first iteration. The work-around is to manually reset y: ( X << y = NULL; >> { y:Y } )* Z or ( X ( y:Y | << y = NULL; >> /* epsilon */ ) )* Z Reported by Jeff Vincent (JVincent@novell.com). #9. PCCTAST.h PCCTSAST::setType() is a noop #8. #tokdefs with ~Token and . THM: I have been unable to reproduce this problem. When antlr uses #tokdefs to define tokens the fields of #errclass and #tokclass do not get properly defined. When it subsequently attempts to take the complement of the set of tokens (using ~Token or .) it can refer to tokens which don't have names, generating a fatal error. #7. DLG crashes on some invalid inputs THM: In MR20 have fixed the most common cases. The following token defintion will cause DLG to crash. #token "()" Reported by Mengue Olivier (dolmen@bigfoot.com). #6. On MS systems \n\r is treated as two new lines Fixed. #5. Token expressions in #tokclass #errclass does not support TOK1..TOK2 or ~TOK syntax. #tokclass does not support ~TOKEN syntax A workaround for #errclass TOK1..TOK2 is to use a #tokclass. Reported by Dave Watola (dwatola@amtsun.jpl.nasa.gov) #4. A #tokdef must appear "early" in the grammar file. The "early" section of the grammar file is the only place where the following directives may appear: #header #first #tokdefs #parser Any other kind of statement signifiies the end of the "early" section. #3. Use of PURIFY macro for C++ mode Item #93 of the CHANGES_FROM_1.33 describes the use of the PURIFY macro to zero arguments to be passed by upward inheritance. #define PURIFY(r, s) memset((char *) &(r), '\0', (s)); This may not be the right thing to do for C++ objects that have constructors. Reported by Bonny Rais (bonny@werple.net.au). For those cases one should #define PURIFY to be an empty macro in the #header or #first actions. #2. Fixed in 1.33MR10 - See CHANGES_FROM_1.33 Item #80. #1. The quality of support for systems with 8.3 file names leaves much to be desired. Since the kit is distributed using the long file names and the make file uses long file names it requires some effort to generate. This will probably not be changed due to the large number of systems already written using the long file names.