rules_euler 🧮

About

rules_euler is a Bazel library for quickly iterating one's way through Project Euler problems. Using a repositories of verified answers, you can test, run, and verify your problems. It should just work out of the box:

We also provide some nice helpers to make development even easier. Want to see this code in use? Check out my haskell Project Euler repository.

Commerical Use

Commercial use is not allowed, as Project Euler questions are licensed under Non-Commercial Creative Commons, which come from our data source dependency euler-offline by David Corbin and PocketEuler by imsky.

Usage

This project exposes the euler_test rule, which will compare your code against known answers. The easiest way to get started is by including the following in your WORKSPACE file:

http_archive(
    name = "euler",
    strip_prefix = "euler-1.0",
    urls = ["https://github.com/dmadisetti/rules_euler/archive/v1.0.tar.gz"],
)

load("@euler//:euler.bzl", "euler_repositories", "euler_test")

euler_repositories()

To test one of your solutions, put the following in your BUILD file:

load(
    "@euler//:euler.bzl",
    "euler_test",
)

py_binary(
    name = "my_brilliant_python_solution_for_7",
    srcs = ["my_brilliant_python_solution_for_7.py"], # This is your code!
)

euler_test(
    name = "euler_7_test", # A name for you to keep track of the problem attempt.
    problem = 7, # The problem number you're solving. in this case we're doing 7
    solution = ":my_brilliant_python_solution_for_7", # It doesn't have to be a python solution, it just needs to be executable.
)

Now when you run bazel test :euler_7_test, you can determine whether you got the correct answer or not.

The best way to wrap your head around this might be by heading over to the example directory. In addition to python, there are haskell examples.

External Files

For problems that require additional files, you can access them directly through the euler_rules project. To do this, use a @euler//:external_files data dependency, and you can then access the file in external/euler/files/<file>. Refer to file_example.hs and the respective BUILD rules for an example on this.

Scripts

A few helper scripts are provided. bazel run @euler/examine <problem> Will show you the text for a given problem:

@euler//examine [--parse|--answer] PROBLEM [PROBLEM_FILE]

and bazel run @euler//stub -- --haskell <problem> will create a commented code stub for your use:

@euler//stub [b name]? [--python|--haskell] PROBLEM [PROBLEM_FILE]

The best way to use this is with redirection, e.g. bazel run @euler//stub -- --python 137 > problem_137.py. You can also generate the build rules with bazel run @euler//stub b my_file_name $PROBLEM. I wrapped these in a shell script and forgot about it. E.g.

#!/usr/bin/env bash
# euler.sh

PROBLEM=$1
NAMING_SCHEME="euler_${PROBLEM}"

pushd ~/projects/my_euler_stuff

bazel run @euler//stub -- b ${NAMING_SCHEME} --haskell $PROBLEM >> BUILD
bazel run @euler//stub -- --haskell $PROBLEM > ${NAMING_SCHEME}.hs

vim ${NAMING_SCHEME}.hs
popd

TODO

• Allow for better templating with stubs. PRs welcome.
• Consolidate data sources.

Solutions using rules_euler

• PainfulHaskell - dmadisetti
• YourContribution - You