walter is a command line tool that aims to keep your crystal clean, simplifying the routine checks on staged files that are ready to be committed and help you maintain a healthy and clean codebase.
From a consistency perspective, there are plenty of tools that support us on our never-ending pursue of code-cleanliness. Linters, static code analyzers, code formatters… Great! However, more often than not, our git history ends up cluttered with
angry commits fixing violations detected by those tools.
One way to avoid these commits from getting into our history is to run your linters and code formatters before committing your changes. But running these tools against the entire project every time you're committing something can be slow and lead to unexpected or irrelevant results.
This tool allows you to specify a series of commands to run on staged files that match a given pattern.
Add the following entry to your
shard.yml on the
development_dependencies section and run
walter.cr: github: gtramontina/walter.cr version: <current-version>
Next, create a
.walter.yml at the root of your project with the following content:
expression: \.cr$ command: - crystal tool format - git add
bin/walter now would run
crystal tool format and
git add on your staged files that match the
\.cr$ regular expression. For example, if you have
water will run, in this order:
crystal tool format file2.cr
git add file2.cr
crystal tool format file3.cr
git add file3.cr
file1.txt was not referenced, as it doesn't match the
\.cr$ regular expression.
Running the commands on each individual staged file was deliberate. The idea is that it would foster a small/atomic commit mindset.
Here's a few more configuration examples for you to draw inspiration from:
- Run ameba linting:
expression: \.cr$ command: bin/ameba
- Optimize PNG images with pngcrush:
expression: \.png$ command: - pngcrush -ow - git add
- All examples at once:
- expression: - \.cr$ command: - bin/ameba - crystal tool format - git add - expression: - \.png$ command: - pngcrush -ow - git add
- Although you can manually run
bin/walterbefore every commit, this quickly becomes boring and quite often forgotten. You can leverage the
precommitgit hook. Take a look at ghooks.cr. It makes versioning your git hooks easier! Here's an example of a ghooks pre-commit hook (
.githooks/pre-commit) configured to run
#!/usr/bin/env sh bin/walter
Walter - Keeping your Crystal clean! Usage: walter walter (-c <config> | -C <config-file>) walter (-h | --help | -v | --version) Options: -h --help Show this screen. -v --version Show version. -c --config=<config> Rules configuration in YAML. -C --config-file=<config-file> Rules configuration file in YAML [default: .walter.yml]
$ bin/walter --help
- Every interaction with the operating system is abstracted;
- Methods have only one output (no exceptions or nils). If needed, use the
- Favor composition over inheritance: augment behavior by decorating existing implementations;
Contributions of any kind are very welcome!
At the root of the project, you'll find a
Makefile. This is meant to be the entry point for any build step during development. Running
make help will yield you a list of existing phony targets:
make build make clean make format make help make install (default) make lint make test
$ make help