Linux News
Change of associativity for a given recursive grammar.
In section 3.7.1, of the book (made available freely online, by the author himself at: https://holub.com/goodies/compiler/c...rDesignInC.pdf, have on page #176), the mention of grammar, for a right-recursive list:
Code: stmt_list -> stmt stmt_list | stmt
stmt -> A | B| C while on the previous page, the left recursive version is given:
Code: stmt_list -> stmt_list stmt| stmt
stmt -> A | B| C (But, am at-first, concerned with the right-recursive version.)
The figure 3.4, on page #176, shows the corresponding parse tree for a right-recursive list(grammar).
On page #177, there is listing 3.1 for: Left Associativity with a Right-Recursive Grammar; given below:
Code: 1 stmt_list()
2 {
3 /* Code is generated as you create the tree, before the subtree is
4 * processed.
5 */
6
7 remember= stmt();
8
9 process statement( remember);
10
II if( not_at_end_of_input () )
12 stmt_list();
13 }
14
15 stmt ()
16 {
17 return( read() );
18 } So, it means that given the arithmetic expression: 2*3*5 -112 +2 +3; the parse tree would have the sequence of operators processed as shown by the order imposed by the enclosing parenthesis: ((((2*3)*5) -112 )+2)+3
But, in the next listing (3.2), the author by the below code states to achieve, right-to-left associativity, in the right-recursive grammar.
So, now the given arithmetic expression: 2*3*5 -112 +2; the parse tree would have the sequence of operators processed as shown by the order imposed by the enclosing parenthesis: ((2*(3*5) -112 +(2+3).
Code: 1 stmt_list()
2 {
3 /* Code is generated as you create the tree, before the subtree is
4 * processed.
5 */
6
7 remember= stmt();
8
9 if( not_at_end_of_input () )
10 stmt_list();
II
12 process statement( remember); //the statement is changed, as per errata at: https://holub.com/goodies/compiler/compiler.design.in.c.docs.pdf; page #19
13 }
14
15 stmt ()
16 {
17 return( read() );
18 }
Am totally confused, how the change of associativity occurs with change of position, of the line: Code: process statement( remember); , wrt the recursive call.
Code: stmt_list -> stmt stmt_list | stmt
stmt -> A | B| C while on the previous page, the left recursive version is given:
Code: stmt_list -> stmt_list stmt| stmt
stmt -> A | B| C (But, am at-first, concerned with the right-recursive version.)
The figure 3.4, on page #176, shows the corresponding parse tree for a right-recursive list(grammar).
On page #177, there is listing 3.1 for: Left Associativity with a Right-Recursive Grammar; given below:
Code: 1 stmt_list()
2 {
3 /* Code is generated as you create the tree, before the subtree is
4 * processed.
5 */
6
7 remember= stmt();
8
9 process statement( remember);
10
II if( not_at_end_of_input () )
12 stmt_list();
13 }
14
15 stmt ()
16 {
17 return( read() );
18 } So, it means that given the arithmetic expression: 2*3*5 -112 +2 +3; the parse tree would have the sequence of operators processed as shown by the order imposed by the enclosing parenthesis: ((((2*3)*5) -112 )+2)+3
But, in the next listing (3.2), the author by the below code states to achieve, right-to-left associativity, in the right-recursive grammar.
So, now the given arithmetic expression: 2*3*5 -112 +2; the parse tree would have the sequence of operators processed as shown by the order imposed by the enclosing parenthesis: ((2*(3*5) -112 +(2+3).
Code: 1 stmt_list()
2 {
3 /* Code is generated as you create the tree, before the subtree is
4 * processed.
5 */
6
7 remember= stmt();
8
9 if( not_at_end_of_input () )
10 stmt_list();
II
12 process statement( remember); //the statement is changed, as per errata at: https://holub.com/goodies/compiler/compiler.design.in.c.docs.pdf; page #19
13 }
14
15 stmt ()
16 {
17 return( read() );
18 }
Am totally confused, how the change of associativity occurs with change of position, of the line: Code: process statement( remember); , wrt the recursive call.
Categories: Software and Help
LXer: Linux lover consumed a quarter of the network
Published at LXer:
Penguins are OK with glaciers. Academics not so muchAh, gentle reader, we find ourselves once again at that juncture of the week we call Who, Me? in which your fellow Regizens' tales of technical not-quite-competence brighten an otherwise dull Monday.�
Read More...
Penguins are OK with glaciers. Academics not so muchAh, gentle reader, we find ourselves once again at that juncture of the week we call Who, Me? in which your fellow Regizens' tales of technical not-quite-competence brighten an otherwise dull Monday.�
Read More...
Categories: Software and Help
Linux lover consumed a quarter of the network
Penguins are OK with glaciers. Academics not so muchAh, gentle reader, we find ourselves once again at that juncture of the week we call Who, Me? in which your fellow Regizens' tales of technical not-quite-competence brighten an otherwise dull Monday.…
Categories: General News
Distribution Release: NuTyX 23.07.0
NuTyX is a French Linux distribution (with multi-language support) built from Linux From Scratch and Beyond Linux From Scratch, with a custom package manager called "cards". The project's latest snapshot is NuTyX 23.07.0 which introduces a JWM edition. "With the invaluable help of Dan (MiyoLinux), we're offering a....
Categories: Distributions
CERTBOT: fullchain.pem vs privkey.pem
Hi!
I have used CERTBOT and successfully get the SSL certificates.
However, I don't understand the purpose and difference between these 2 files:
/etc/letsencrypt/live/domain.com/fullchain.pem
/etc/letsencrypt/live/domain.com/privkey.pem
What does each one do?
Thanks!
I have used CERTBOT and successfully get the SSL certificates.
However, I don't understand the purpose and difference between these 2 files:
/etc/letsencrypt/live/domain.com/fullchain.pem
/etc/letsencrypt/live/domain.com/privkey.pem
What does each one do?
Thanks!
Categories: Software and Help
Guide to Set up Chrony as NTP Server and Client on AlmaLinux 9
In the following guide, you’ll learn how to install Chrony as an NTP server and client on an AlmaLinux 9 server.
The post Guide to Set up Chrony as NTP Server and Client on AlmaLinux 9 appeared first on Linux Today.
Categories: General News
LXer: Zorin OS 16.3 Released with New Upgrade Utility, Zorin Connect Improvements
Published at LXer:
Zorin OS devs informed 9to5Linux today about the general availability of Zorin OS 16.3 as the third update to the latest Zorin OS 16 operating system series based on Ubuntu 22.04 LTS (Jammy Jellyfish).
Read More...
Zorin OS devs informed 9to5Linux today about the general availability of Zorin OS 16.3 as the third update to the latest Zorin OS 16 operating system series based on Ubuntu 22.04 LTS (Jammy Jellyfish).
Read More...
Categories: Software and Help
Zorin OS 16.3 Released with New Upgrade Utility, Zorin Connect Improvements
Zorin OS devs informed 9to5Linux today about the general availability of Zorin OS 16.3 as the third update to the latest Zorin OS 16 operating system series based on Ubuntu 22.04 LTS (Jammy Jellyfish).
Categories: General News
6.5-rc4: mainline
Categories: Linux Kernel
Thinkpad T400 shows red light on bezel
This is an elderly Thinkpad that I keep as a spare or a loaner. Last week I was asked for it, so I installed the current crop of updates for Linux Mint.
Soon after I delivered it, they told me that they were unable to log-in; when I checked, I too was told 'Invalid password', so I simply took it home and reinstalled Mint, and for the moment it is running happily enough.
I did notice that while I was trying to log-in, and while the re-installation was proceeding, that a red light had appeared in the top right-hand corner of the bezel (photo attached). When the laptop was restarted with the new installation it did not reappear.
I would simply like to know, what does the light signify? I had never even noticed it was there, and it does not appear on my later model Thinkpad.
Thanks!
Attached Thumbnails
Soon after I delivered it, they told me that they were unable to log-in; when I checked, I too was told 'Invalid password', so I simply took it home and reinstalled Mint, and for the moment it is running happily enough.
I did notice that while I was trying to log-in, and while the re-installation was proceeding, that a red light had appeared in the top right-hand corner of the bezel (photo attached). When the laptop was restarted with the new installation it did not reappear.
I would simply like to know, what does the light signify? I had never even noticed it was there, and it does not appear on my later model Thinkpad.
Thanks!
Attached Thumbnails
Categories: Software and Help
LXer: Google's browser security plan slammed as dangerous, terrible, DRM for websites
Published at LXer:
'The solution to the surveillance economy seems to be more surveillance' Vivaldi boss tells El Reg. Google's Web Environment Integrity (WEI) proposal, according to one of the developers working on the controversial fraud fighting project, aims to make the web "more private and safe."�
Read More...
'The solution to the surveillance economy seems to be more surveillance' Vivaldi boss tells El Reg. Google's Web Environment Integrity (WEI) proposal, according to one of the developers working on the controversial fraud fighting project, aims to make the web "more private and safe."�
Read More...
Categories: Software and Help
Google's browser security plan slammed as dangerous, terrible, DRM for websites
'The solution to the surveillance economy seems to be more surveillance' Vivaldi boss tells El Reg. Google's Web Environment Integrity (WEI) proposal, according to one of the developers working on the controversial fraud fighting project, aims to make the web "more private and safe."…
Categories: General News
Wordpress at Ubuntu
Hi
I'm trying to solve the test task.
I need to install Wordpress with Nginx, MySQL, PHP (7.3, 7.4, 8.0).
The 1st virtual host need to be handled via 7.3 PHP through the port 'pool' to 'inet'.
The 2nd virtual host need to be handled via 7.4 PHP through the port 'pool' to 'www'.
The 3rd virtual host need to be handled via 8 PHP through the socket.
Each vhost need to display phpinfo via the browser.
One of the puncts is "create directories /var/www/wp(1-3)". That let me suggest that there'd be 3 separate WP hosts (like 3 instances) each of them would be processed via own PHP version.
The question is: Does it possible to make such thing through one instance of Wordpress (and make WP handle separate host through separate PHP version) or there really should be 3 different instances?
I'm trying to solve the test task.
I need to install Wordpress with Nginx, MySQL, PHP (7.3, 7.4, 8.0).
The 1st virtual host need to be handled via 7.3 PHP through the port 'pool' to 'inet'.
The 2nd virtual host need to be handled via 7.4 PHP through the port 'pool' to 'www'.
The 3rd virtual host need to be handled via 8 PHP through the socket.
Each vhost need to display phpinfo via the browser.
One of the puncts is "create directories /var/www/wp(1-3)". That let me suggest that there'd be 3 separate WP hosts (like 3 instances) each of them would be processed via own PHP version.
The question is: Does it possible to make such thing through one instance of Wordpress (and make WP handle separate host through separate PHP version) or there really should be 3 different instances?
Categories: Software and Help
New Old Guy Here
Hello, I�m new to this forum and relatively new to Linux. I decided to try Linux Mint in an old HP Pavilion dv7t-6100 that was about 13 years old. It was ok, but I never got my Wi-Fi working quite right. And tried everything I could find on the internet.
I heard that the architecture of the motherboard of most Windows PC�s are optimized for the Windows operating system and that they don�t always work perfectly in Linux. So I decided that I would buy a Linux certified computer to give Linux (any distribution) a fair try, and I�m glad I did. I have tried many distributions that I ran from a thumb drive, just to check them out first, and I never had any problems with any device on my computer. It has worked flawlessly. I have had a few problems installing programs that gave me a fit.
My Lenovo ThinkPad T16 was certified for Ubuntu but I had a few problems with it. Some of the programs were not installed correctly out of the box so I decided to go with Kubuntu (Kubuntu 22.4.2 LTS KDE Plasma 5.24.7). I have really enjoyed it so far and have learned a few things (like stay away from BleachBit). I�m also trying to get better with the terminal and learning new commands.
Thanks thanks for accepting me as a member and I�m sure you�ll see more posts from me. Cheers!
I heard that the architecture of the motherboard of most Windows PC�s are optimized for the Windows operating system and that they don�t always work perfectly in Linux. So I decided that I would buy a Linux certified computer to give Linux (any distribution) a fair try, and I�m glad I did. I have tried many distributions that I ran from a thumb drive, just to check them out first, and I never had any problems with any device on my computer. It has worked flawlessly. I have had a few problems installing programs that gave me a fit.
My Lenovo ThinkPad T16 was certified for Ubuntu but I had a few problems with it. Some of the programs were not installed correctly out of the box so I decided to go with Kubuntu (Kubuntu 22.4.2 LTS KDE Plasma 5.24.7). I have really enjoyed it so far and have learned a few things (like stay away from BleachBit). I�m also trying to get better with the terminal and learning new commands.
Thanks thanks for accepting me as a member and I�m sure you�ll see more posts from me. Cheers!
Categories: Software and Help
5.4.249: Sign bzImage
Hello,
Using "make ARCH=x86_64 defconfig" + make, I created bzImage.
This image boots my PC when secure boot is disabled.
Grub 2.06 is used to boot bzImage
In order to boot when secure boot is enabled, can I use a signed bzImage ?
Or should I use another format ?
I tried to sign bzImage with sbsign and got:
error: bad shim signature
Of course - I enrolled the key created in the sign process.
I used the procedure described in:
https://ubuntu.com/blog/how-to-sign-...or-secure-boot
Thank you,
Zvika
Using "make ARCH=x86_64 defconfig" + make, I created bzImage.
This image boots my PC when secure boot is disabled.
Grub 2.06 is used to boot bzImage
In order to boot when secure boot is enabled, can I use a signed bzImage ?
Or should I use another format ?
I tried to sign bzImage with sbsign and got:
error: bad shim signature
Of course - I enrolled the key created in the sign process.
I used the procedure described in:
https://ubuntu.com/blog/how-to-sign-...or-secure-boot
Thank you,
Zvika
Categories: Software and Help
LXer: Plasma 6 Development Update: Unveiling Features Removals
Published at LXer:
KDE developers have announced which features they will remove in the upcoming Plasma 6 desktop environment. Here�s what they are!
Read More...
KDE developers have announced which features they will remove in the upcoming Plasma 6 desktop environment. Here�s what they are!
Read More...
Categories: Software and Help
Plasma 6 Development Update: Unveiling Features Removals
KDE developers have announced which features they will remove in the upcoming Plasma 6 desktop environment. Here’s what they are!
Categories: General News
Drunk Satellites
I sleep outside during Oregon's dry season, so I can stargaze myself to sleep, and during the periodic intervals where I wake up and look up.
There are way more satellites than there were when I stargazed as a child... it used to be we might see one or two a night... but now its difficult to at anytime look up and not see one... nevertheless, until last night, the satellites always travelled linearly. Even starlink's convoys of satellites still travelled linearly.
But last night, I saw multiple satellites zigzagging back and forth like drunk divers in their lane... or like skiiers of a slalom course; or like sine waves of shallow amplitude.
Has anyone else observed these phenomena? Any ideas?
There are way more satellites than there were when I stargazed as a child... it used to be we might see one or two a night... but now its difficult to at anytime look up and not see one... nevertheless, until last night, the satellites always travelled linearly. Even starlink's convoys of satellites still travelled linearly.
But last night, I saw multiple satellites zigzagging back and forth like drunk divers in their lane... or like skiiers of a slalom course; or like sine waves of shallow amplitude.
Has anyone else observed these phenomena? Any ideas?
Categories: Software and Help
Can I recover booting already installed Slackware on a modern hd-less laptop?
Hi all.
Yesterday, after trying to get an Access Point running on my new Dell Vostro 3405, I found, on rebooting, that my Slackware 15.0 wasn't accessible anymore. On boot, the only thing I could do was going into the UEFI 'bios', where the Slackware partition wasn't listed anymore, or continue and get a grub (2.06) prompt.
This model is a hd-less, SSD-only laptop. I also tried with the bootable USB Slackware64 image I used to install the OS originally, but the pendrive doesn't appear in the bootable devices.
I looked over the grub commands, but did not see any familiar commands to manage disks.
Unless grub offers some way to repair things, I was thinking about trying to boot a minimal slack system over the network connection, and maybe be able to repair things from there.
I'd appreciate suggestions! I'm somewhat pressed because I need the machine for my teaching in a few days... Help!
Yesterday, after trying to get an Access Point running on my new Dell Vostro 3405, I found, on rebooting, that my Slackware 15.0 wasn't accessible anymore. On boot, the only thing I could do was going into the UEFI 'bios', where the Slackware partition wasn't listed anymore, or continue and get a grub (2.06) prompt.
This model is a hd-less, SSD-only laptop. I also tried with the bootable USB Slackware64 image I used to install the OS originally, but the pendrive doesn't appear in the bootable devices.
I looked over the grub commands, but did not see any familiar commands to manage disks.
Unless grub offers some way to repair things, I was thinking about trying to boot a minimal slack system over the network connection, and maybe be able to repair things from there.
I'd appreciate suggestions! I'm somewhat pressed because I need the machine for my teaching in a few days... Help!
Categories: Software and Help
Apt segmentatio9n fault
Any command I issue in a terminal for apt immediately ends with a segmentation fault. This occurred after my computer had a sudden loss of power while in suspend mode.
now any apt commands seg fault.My distro presently is pclinuxos.
now any apt commands seg fault.My distro presently is pclinuxos.
Categories: Software and Help