SatCSS

Minimise CSS files through semantics-preserving refactoring. E.g.

.a { color: red }
.b { color: red }

can be refactored

.a, .b { color: red }

but

.a { color: red }
.c { color: blue }
.b { color: red }

cannot, since

.a, .b { color: red }
.c { color: blue }

changes the color of an element with class=“b c”.

Can also be used to test whether two selectors may match the same node in some DOM.

Can also be used as a tool/library for building an abstract
representation of a CSS file as a set of pairs (selector, declaration)
with an ordering (representing the order selectors must appear in the
CSS file to maintain the overriding semantics).

Requirements:

Python 3.7 or compatible.

• cssselect 1.2.0
• docopt 0.6.2
• lxml 4.9.2
• tinycss2 1.2.1
• toposort 1.10
• z3-solver 4.12.2.0

Borrowed and modified code from

• cssselect 0.9.1

The recommended build system is Poetry. Tested
with version 1.7.0.

External Requirements

In the same directory as satcss/main.py, ensure that running

./z3

runs the Z3 SMT solver. For example, this can be a symlink to the
Z3 installed on your machine.

The tool was last tested with Z3 v4.12.2.0.

Running with Poetry

To setup and run the project with Poetry, from the root directory run

poetry install

Then

poetry run satcss --help

To try a benchmark:

poetry run satcss benchmarks/dblp-2015-07-09-stripmq.css

To output the file:

poetry run satcss -o --file=blah.min.css benchmarks/dblp-2015-07-09-stripmq.css

Running without Poetry

Two scripts main.py and test.py are provided in the root directory for
running without Poetry. First install the requirements manually. You can use
requirements.txt.

pip install -r requirements.txt

Then run

python main.py --help

where “python” is your python 3.7 or above command.

TOPLAS Version

The version current as of the TOPLAS paper is tagged
TOPLAS-Release.