[gentoo-soc] libbash final report

[Mu Qiao]

My GSoC project will end in this weekend so this is the final report.
This week, I spent most of my time making sure the project is in a good
state for future developers.

So far, libbash can generate correct ebuild metadata for 8414 out of
27586 ebuilds. What is blocking us from moving on? We need to be able to
parse all the eclasses. But there are still a few problems in the parser
grammar. On the other hand, our runtime is not complete. In one word,
more time is required. This is the ohloh page for libbash[1] where you
can learn some statistics of the code.

I wrote an ebuild for libbash and put it in my overlay. Now you can play
with it by
layman -a qiaomuf
emerge libbash

Although libbash is not powerful enough to generate all ebuild metadata,
it can do something useful now. As I said before, you can always check
what libbash can support from these test scripts[2]. One thing you
should notice is that we do not support running external command.

The library is quite easy to use. To give you a taste, here is a code
snippet showing how to use it:
#include <algorithm>
#include <iostream>
#include <iterator>

#include <libbash/libbash.h>

int main(int argc, char** argv)
{
  // store variable values and function names

  std::unordered_map<std::string, std::vector<std::string>> variables;
  std::vector<std::string> functions;

  // interpret the script specified by argv[1]
  libbash::interpret(argv[1], variables, functions);

  // do what ever you want with variables and functions
  std::copy(functions.begin(), functions.end(),
std::ostream_iterator<std::string>(std::cout, " "));
  std::cout << std::endl;
}


To get it compiled, run
g++ -std=c++0x $(pkg-config --cflags --libs libbash) test.cpp

The program will interpret the script like bash and store the result in
the variable map and function name list. All the variables are treated
as arrays. For more information, you can check the API documentation.
(P.S.: The library is not stable so please don’t use it in any serious
place)

So what’s next? I think it would be improving the parser grammar,
figuring out problems from the output of instruo and implement more
runtime. People are welcome to make contributions. I’ll continue making
contributions after GSoC.

Last but not least, I’d like to thank Google and Gentoo community for
giving me such great experience. Thank Petteri for mentoring me. I
enjoyed a wonderful summer with you and learned a lot including C++0x,
boost libraries, ANTLR, autotools, Scrum and so on. Thank Donnie, Robin
and other people who helped me.

OK, I’m going to get myself prepared and seek a job ;)

[1] https://www.ohloh.net/p/gentoo_libbash
[2]
http://git.overlays.gentoo.org/gitweb/?p=proj/libbash.git;a=tree;f=scripts;hb=HEAD

-- 
Best wishes,
Mu Qiao
GnuPG fingerprint: 92B1 B0C4 8D14 F8C4 EFA5  3ACC 30B3 0DE4 17B1 57E9