Programming :: Yacc Conflicts - How To Understand Grammar Conflict
Jun 4, 2010
I am getting shift/reduce and reduce/reduce conflict in my yacc grammar code. yacc generates (i.e yacc -d -v parser.y) its grammar and state information in the parser.output file.
How can i interpret the below information and understand which grammar state is conflicting with other grammar state? Please help me to understand.
State 159 conflicts: 1 shift/reduce
State 1863 conflicts: 1 shift/reduce
State 1865 conflicts: 1 shift/reduce
State 1960 conflicts: 1 shift/reduce
I'm programming an SQL grammar using YACC and during compilation I got this error: conflits: 1 shift/reduce, 2 reduce/reduce the first error : shift/reduce
Code: scalar_exp: scalar_exp PLUS scalar_exp | scalar_exp NEG scalar_exp |scalar_exp MULT scalar_exp |scalar_exp DIV scalar_exp | atom |column_ref |function_ref .....
Probably a stupid sounding question, but bear with me please. I need to use the link grammar parser in order to do some part of speech tagging. It's freely available and works once you run the makefile or 'make' it or however it's correctly said. Thing is, it has a C API which I intend to use. And once I ran a bit of the sample code given in the documentation it gave a whole host of errors. This is very confusing because I'm including the path for the folder that has all the header files.
gcc -I/path/include/ filename.c. But it still gives me errors about not being able to find things that are clearly defined there. An hour of trudging around the internet tells me I need to 'compile' the API first. I'm not exactly sure how or if I'm supposed to do that. If someone could just shed light on this it would be greatly appreciated. I grow increasingly cynical to the musical swell of my tiny brain rattling in my skull.
I was going through this Lex/YACC tutorial: [URL]... and I was working along with it. The Lex examples worked fine, but the YACC one quit white compiling
Well I get my other 2 questions answered , I have one last question that has been buggy me.Anyone know why windows use so many files just to keep the OS going and so bloated? The under line of files of windows is messy and loads self every where and very bloated with windows and windows vista and windows 7 very much so.I'm not sure if Linux /Mac OS X is like this or not .
I know windows needs to support alot more software and hardwar but is that not where drivers come in for the hardware.And programmers need to write the software for windows or Linux / Mac OS X.
In my book, this is an example of a recursive algorithm:
var reverseArray = function(x,indx,str) { return indx == 0 ? str : reverseArray(x,--indx,(str+= " " + x[indx])) ;; } var arr = new Array('apple','orange','peach','lime'); var str = reverseArray(arr,arr.length,""); alert(str) ;
I'm trying to understand it, I'm stuck at the (str+= " " + x[indx])) part - that part of the function definition expects an ARGUMENT, am I right? What's being passed to it is a bit of PROGRAM, the str+= stuff. So - how is it working?
I have just started using Valgrind,which really is great. Most of the reported errors look kinda weird, though I can't really understand what's going on here, for example:
==00:00:02:52.033 7754== Invalid read of size 4 ==00:00:02:52.033 7754== at 0x80B0987: MyCls::MyPrintf(long, char*, ...) (MyCls.cpp:270) ... ==00:00:02:52.033 7754== Address 0x47a5ee8 is 0 bytes after a block of size 296 alloc'd ... ==00:00:02:52.033 7754== by 0x809A6C1: ClsMain::taskRun(int, char**) (ClsMain.cpp:177) ==00:00:02:52.033 7754== by 0x816CFE8: main (main-C.cpp:2060)
==7754== ---- Attach to debugger ? --- [Return/N/n/Y/y/C/c] ---- Y ==00:00:02:57.410 7754== starting debugger with cmd: /usr/bin/gdb -nw /proc/7765/fd/1014 7765 GNU gdb Red Hat Linux (6.5-25.el5rh) Copyright (C) 2006 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i386-redhat-linux-gnu"...Using host libthread_db library "/lib/libthread_db.so.1".
Attaching to program: /proc/7765/fd/1014, process 7765 MyCls::MyPrintf (this=0x47a5dc0, iPrm=3, sMsg=0x6974320 "blablabla"...) at MyCls.cpp:270 270 cout<<endl<<"m_FilePtr="<<hex<<m_FilePtr<<dec<<endl;
Basically, Valgrind reported the "Invalid Read" error at line 270 of file MyCls.cpp, which is simply a cout of the m_FilePtr variable, which is a member variable of the MyCls class. It's a FILE* variable I use to write repeatedly on a text file. The address reported (0x47a5ee8) is 296 bytes after the "this" pointer (0x47a5dc0),as Valgrind correctly tells me but I honestly don't understand that. And of course, I need to read that variable, not only for the cout (indeed,the error is reported at every reading attempt). Besides, the application doesn't crash, but still I would like to understand if I really have to worry about this "error".
I have got a program using semctl(). I cant understand the value returned by semctl using GETPID option and its difference with the actual pid obtined by getpid()as in the following code:
Code:
int semid,retval; semid=semget(0*20,1,0666 | IPC_CREAT); retval = semctl(semid,0,GETPID,0);
Whenever I enable gettimeofday in my code, previous working sendto(raw_eth, buffer, ...)
stopped working and Error: Bad file descriptor. the only thing I'm sure is it's not name pollution. Since all the variable defined in main() works if I make the wrap of gettimeofday an empty function.
I'm running OpenOffice.Org 3.1.1 out of the Fedora repositories. I'm using the UK locales and settings where possible. I can't seem to get the interface in en-gb, and my dictionary keeps recommending the Americanisation of words to me.
Also finally, is there not a grammar checker in OpenOffice.Org? I'm looking in the Language Settings - > Writing Aids and there isn't anything listed under grammar?
Finally, I might as well ask this in case anyone knows why. In the Writer settings I changed the default fonts to the Liberation font family however OpenOffice keeps attaching the Windows equivalents to the end e.g. 'Liberation Sans; Arial' it's really annoying and I don't know why it's doing this.
Anyone know any good word programs with a good grammar checker? i tried language tool with OOo but it is still buggy lags to find grammar, and unless the sentence is quite simple, it misses alot. tried lightproof too, it has yet to find any error, even in hyphenation which is what it is specifically meant to do. This would be nice to have so I can ween myself entirely off windows.
I have been going crazy trying to get some sort of grammar checker working in Libreoffice on Maverick. I installed language support-fr -en and -de through terminal but they only check spelling. I then installed the extension "languagetool" in libreoffice and while it does work a little bit it is very unstable. It makes libreoffice crash on start and randomly while in use. Is there any solution to getting a stable grammar checker with libreoffice or are my attempts useless?
I'm writing a parser using lex and yacc for an IEEE standard language ( STIL ). Here's the lex file ( some of ).
[Code]....
stil_language is the start symbol. The bus variable is initialised at 0 ( There's a check in the main ). The problem is that the parser does not recognises the NUM token ! It just re writes any expression that corresponds to the "number" regular expression. Here's a prompt example :
I am a linux newbie (more so with using RedHat). I am trying to use yum to install packages, but have never really able to get this thing right. I want to install libXp-devel package. However, running yum install libXp-devel doesn't work.
When I downloaded the rpm for libXp-devel and tried to run yum install libXp-devel-1.0.0-8.1.el5.x86_64.rpm, I get the following:
Code:
Resolving Dependencies --> Running transaction check ---> Package libXp-devel.x86_64 0:1.0.0-8.1.el5 set to be updated --> Processing Dependency: libXp = 1.0.0-8.1.el5 for package: libXp-devel --> Processing Dependency: libXau-devel for package: libXp-devel
I am anticipating that someone could give more further information about that, not only simple explanations. How to understand User Time, sys time, wait time, idle time of CPU
I'm in way over my head and have absolutely no idea what I am doing.I set up a lamp server earlier today on ubuntu 10.10 and I'm trying to upload files to wordpress which I installed at local host using vsftpd. I am so lost.Something about this entire process has not clicked in my head;
In the beginning there is MBR. MBR looks for the active partition and tranfers control to the VBR of the active partition. MBR is where grub may be installed. which allows the user to choose an OS(a VBR) I am not sure what the program in the VBR does,but it manages to loads the OS. What am I trying to do: Backup. I ma tired of losign my partitions my bootloaders. I want to backup them all! partitions/MBR /VBR everything short of creating an disk image.
My questions:
1. say the ubuntu partition is formatted, will grub still load? if not is there a bootloader that would?am I making sense? i hope so...
2. what exactly does the VBR contain ?
2. How do I go about backing up? The mbr and the partiton table are backed up with a simple dd command. Then what else needs to be backed ? VBR's of every partition?
I have taken putty session of a server from two separate machines namely HOST1(3 sessions) and HOST2(1 Session) . However w command says there are 5 users
Code: # w 09:29:36 up 34 days, 15:48, 5 users, load average: 0.62, 4.33, 8.16 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT root pts/17 HOST1 09:18 4:26 0.01s 0.01s -bash root pts/18 HOST1 09:27 1:21 0.00s 0.00s -bash root pts/21 HOST2 09:29 0.00s 0.00s 0.00s w root pts/20 HOST1 09:29 1:39 0.00s 0.00s -bash
This problem is occurring on Red Hat EL 5 WS. However, I have two CentOS 5 systems, with similar configuration to RH EL 5, where this problem does not occur.
I am getting this error:
Can't exec "sendmail": No such file or directory at ./0logwatch line 1018, <TESTFILE> line 1. Can't execute sendmail -t: No such file or directory
