# 2. FAQ

jsre works only for python3 - will there be a py2.7 version?

At the moment I don’t plan to build against Python 2, the string handling is sufficiently different to make it a fair amount of work and the applications I’m using this for are all Python 3.

What does the acronym jsre stand for?

Just jsre! (If you really must know the js stands for Jigsaw which is a private forensic processing framework.)

Is the module is built on some standard C regexp implementation or some custom one?

It is built on a custom extension, not an existing library. The extension is not strictly a regex implementation, it is a bytecode virtual machine - the compilation is done in Python. The extension does not require anything other than standard C libraries so pip will compile the extension in Windows or Linux; the extension is installed automatically when you install the module.

I assume the module is rather new?

It has been in development from 2014. I moved it to full release at the start of 2016 after around 6 months of integration and use in my forensics framework.

Are you planning any further development?

At some point this year I aim to replace the current character encoding library which should improve compilation times, I may then provide better support for processing string (as opposed to byte) input. The current API, however, will remain stable.

Please ask if you have any issues or wish-lists, I would like to hear about both (and success stories are also encouraging if you use the package).

I have seen performance comparisons, but have not had time to test. In common usage is jsre much faster than the standard python re?

It depends on what you mean by ‘common use’. If you are using expressions of any complexity against large sized byte buffers then yes, jsre will be much faster than re or regex. If you are using expressions which are compile-heavy against small text strings then you probably won’t see any benefit. I’m afraid that performance in all these implementations must be measured in your own problem space. The point is that the asymptotic performance of this is well behaved unlike the execution time of most of the standard software libraries.

The performance issue, and the lack of a portable (Windows & Linux) alternative for Python 3, was the primary reason that I started this project. Another factor was the need for efficient handling of multiple user-specified encodings.

I could not find the repository of the source code in documentation; is the module open source and if it is, where is the source code?

The module is open source (see licence section of documentation).

The install section of the documentation will tell you how to get and install the module using pip, which will pull the source into your site package directory. If you want to download it manually then it is on pypi, the standard python open repository.