This is the artifact associated with the ICFP 2020 paper "Parsing with Zippers (Functional Pearl)" by Pierce Darragh and Michael D Adams.

This artifact is organized into two top-level directories:

• benchmark provides the code for running the benchmarking tests we use in the paper.
• interact provides a minimal implementation of the Parsing with Zippers algorithm and a set of example grammars that can be used for interactive testing.
• appendix contains a copy of the code listed in the appendix of the paper.

Instructions for compilation, setup, and use appear in the README.md files located within each of these directories.

These are notes that are relevant to the AEC.

Both of the top-level sub-components have their own README files. These contain installation and configuration instructions which are not relevant to the AEC when using the QEmu virtual machine, because all such dependencies have already been installed. However, for the curious reviewer (or later paper-reader) who chooses to install the dependencies themselves, we leave these instructions intact.

The benchmark code produces a significant number of warnings. This is mostly due to the way we copied code from previous papers' work for comparative benchmarks. OCaml has very specific style guidelines that were not observed in the previous work, and this stylistic deviations cause a significant number of warnings to appear during compilation. We apologize for the inconvenience, but we feel it best not to fix the code to alleviate these constraints at this time. (However, we will note that we may adjust the code stored on GitHub at a later date to attend to these warnings.)

Our benchmarks can take a long time to run (certainly more than 10 minutes!). However, they can be stopped and resumed as-needed. Alternatively, a low timeout or quota multiplier can be set, or you can remove some of the input files to reduce the total time taken. These procedures are explained in the associated README.md file.

There is a minor discrepancy between the files that were used for benchmarking in our paper compared to the files that are now used automatically by the benchmarking suite. This is because the original group of files tested on were manually curated from a previous project by a former member of our research group, which we had not realized until after submission of the paper. The difference is fewer than 10 files out of approximately 660, and our recent results do not show any significant difference from the results shown in the paper. We intend to update the figures and numerical references accordingly prior to submitting the camera-ready copy.

Here we provide the set of steps we used to install the necessary components in the QEmu Debian installation. This is provided as both a historical record as well as to help anybody in installing these packages manually. Hypothetically, this section could be copied into a shell script and run with super-user privileges, but we do not recommend this.

NOTE that these instructions were tested on Ubuntu 20.04 (LTS) in a Digital Ocean droplet. We do not guarantee that these instructions will work on all platforms.

####################
# SET UP UBUNTU
##
# Update the list of packages.
sudo apt update
# Normally, one would perform a system upgrade after this step to ensure all
# pacakges are up to date. However, for the purposes of creating an archival
# copy of our system, we did not. If you wanted to upgrade, you would uncomment
# the following line and execute it:
#sudo apt upgrade -y

####################
# SET UP OCAML
##
# Install the OCaml runtime and additional dependencies.
sudo apt install m4 opam -y
opam init  # Accept the prompts as you choose. We used y and y as our responses.
eval $(opam env)
# We install OCaml version 4.05.
#   NOTE: In some environments, this can fail with a note that the switch
#         couldn't be found. If this happens, use
#         `opam switch create pwz 4.05.0`
# NOTE: There is a step early on, which says (in our instance)
#       "ocaml-base-compiler: make world.opt", that takes a very long time.
opam switch create pwz ocaml-system.4.05.0
eval $(opam env)
##########
# C) OCAML LIBRARIES
##
# Install needed OCaml libraries.
# NOTE: There is one step early on, which says (in our instance)
#       "ocaml-secondary-compiler: make world.opt", that takes a very long time.
opam install core core_bench menhir dypgen -y

####################
# SET UP PYTHON
##
# Update Python 3, install pip, and install additional dependencies.
sudo apt install python3-distutils -y
wget https://bootstrap.pypa.io/get-pip.py
sudo python3 get-pip.py --prefix /usr/local/
rm get-pip.py
pip3 install parso==0.4.0

####################
# SET UP LUALATEX
##
# Install LuaLaTeX for generating the results PDF.
sudo apt install luatex texlive-luatex xzdec -y
# Install additional needed libraries.
# NOTE: If you have the space (~6GB), we would recommend instead doing
#       `sudo apt install texlive-full` as this will install all the libraries
#       and options to render the document better. The QEMU VM is limited in
$       size, so we opted to manually install only the bare minimum.
tlmgr init-usertree  # Sometimes this will say "Cannot determing type of tlpdb".
                     # Just run it again and it should work!
tlmgr option repository ftp://tug.org/historic/systems/texlive/2017/tlnet-final
tlmgr install xstring iftex totpages environ trimspaces ncctools comment pgf pgfplots

####################
# SET UP ARTIFACT
##
# Clone the artifact repository from GitHub.
git clone https://github.com/pdarragh/parsing-with-zippers-paper-artifact.git
cd parsing-with-zippers-paper-artifact
cat README.md