[yast-devel] yast documentation
Hallo everybody, I have tried to renew the greman webappearance of YaST (because it was the oldest layout). Now I am needing some help. I'm getting to the developers documentation, and somethings don't make sense. -- basic YCP questions 1. Why do we need YCP. (an other scripting language would have done the same trick) 2. Why is YCP type based. 3. What is the use of Symbol and Trem Datatypes in YCP. (not the format) 4. What is the use of Byteblock Datatype. -- Modul design question Why is the SCR concept not used like it was defined in the documentation, to be the system IO. According to the Tutorial one should write a global API of the Modul to access data the Modul works with. This HACK would be redundant if SCR like described in the documentation, would provide the data. OK this would meen the SCR tree would be something like the Registry from the evil Empire of Redmond, founded by Darth Gates. :-) If anyone could help me, it would meen much to me, thanks. best regards Stefan Eisenwiener Unbegrenzter Speicher, Top-Spamschutz, 120 SMS und eigene E-MailDomain inkl. http://office.freenet.de/dienste/emailoffice/produktuebersicht/power/mail/in...
Hi, On 29.1.2010 02:04, stefan.eisenwiener@freenet.de wrote:
Hallo everybody, I have tried to renew the greman webappearance of YaST (because it was the oldest layout). Now I am needing some help. I'm getting to the developers documentation, and somethings don't make sense.
-- basic YCP questions 1. Why do we need YCP. (an other scripting language would have done the same trick)
That's for historical reasons, we have too much code written in YCP. Rewriting it into another language would require much effort without any real advantage. But YCP is not mandatory anymore, you can write a YaST module in Perl, Python, Ruby or even in C++.
2. Why is YCP type based.
This prevents from some runtime problems, like passing wrong argument type. Such errors are found during compile time. The problem is that YaST is an installation system and when such an error occurs during installation (in some corner case, or on a specific HW) the installation simply crashes and user have non-functional system. We really had such a bug in the past and fixing it is not trivial, esp. if it's found when the product is released.
3. What is the use of Symbol and Trem Datatypes in YCP. (not the format)
Symbol is like an enum, term is a symbol with additional arguments.
4. What is the use of Byteblock Datatype.
Byteblok is a raw binary data which cannot be displayed directly on a terminal (like PNG image data). Currently it's not needed, IIRC it was needed for passing an image to the UI. Now the UI's can load images directly from a file.
-- Modul design question Why is the SCR concept not used like it was defined in the documentation, to be the system IO. According to the Tutorial one should write a global API of the Modul to access data the Modul works with. This HACK would be redundant if SCR like described in the documentation, would provide the data.
The SCR is low-level library, a Module cannot directly read files or access the system (execute commands, etc.). It has to use an SCR agent for that. (Well, that's valid for YCP modules, in other languages you can of course use read/write system functions. But the same concept should be used also there so it's unified.) I hope this helps, if you have more questions just ask. -- Best Regards Ladislav Slezák Yast Developer ------------------------------------------------------------------------ SUSE LINUX, s.r.o. e-mail: lslezak@suse.cz Lihovarská 1060/12 tel: +420 284 028 960 190 00 Prague 9 fax: +420 284 028 951 Czech Republic http://www.suse.cz/ -- To unsubscribe, e-mail: yast-devel+unsubscribe@opensuse.org For additional commands, e-mail: yast-devel+help@opensuse.org
On Friday 29 January 2010 02:04:09 am stefan.eisenwiener@freenet.de wrote:
Hallo everybody, I have tried to renew the greman webappearance of YaST (because it was the oldest layout). Now I am needing some help. I'm getting to the developers documentation, and somethings don't make sense. -- basic YCP questions 1. Why do we need YCP. (an other scripting language would have done the same trick) 2. Why is YCP type based.
In YaST, YCP serves more as component communication protocol than a language. The YaST core is very similar to what you see in stuff like http://github.com/jhaynie/kroll from Appcelerator. At that time there was not really a good language to pick up therefore a language very close to the definition of the component model was designed. However, there are plugins which are able to load other languages. So if a ruby module uses a function defined in a perl module, the communication happens trough the ycp types.
3. What is the use of Symbol and Trem Datatypes in YCP. (not the format)
Symbol is very similar to ruby symbols :hello.
4. What is the use of Byteblock Datatype.
AFAIK this is only used internally by the vm. The core is designed as a client/server component model, therefore you can pass the types across the wire, and a byteblock is basically code. -- Duncan Mac-Vicar P. - Novell® Making IT Work As One™ SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nuernberg) -- To unsubscribe, e-mail: yast-devel+unsubscribe@opensuse.org For additional commands, e-mail: yast-devel+help@opensuse.org
unsubscribe wenji.huang@oracle.com -- To unsubscribe, e-mail: yast-devel+unsubscribe@opensuse.org For additional commands, e-mail: yast-devel+help@opensuse.org
participants (4)
-
Duncan Mac-Vicar P. -
Ladislav Slezak -
stefan.eisenwiener＠freenet.de -
Wenji Huang