a Regex script for port ruby code to crystal, reduce friction.

Include only the easiest, most obvious, and safest parts.

with minimal effort and cost.

Note: Run this tool at your own risk.

Dependency

The only dependency is the ruby builtin regex engine, MRI 2.0+ should work.

How to use it

1. run bin/rubocop_double_quotes to change all single-quoted strings to double-quoted strings.

2. renamed the extension .rb to .cr for files will in-place use this script.

3. run bin/port_ruby_to_crystal, this will do in replace all "*.cr" use known rules. You bet added those files into git before do it to track changes.

4. if it give message like syntax error in '???': ..., this may be a bug of the script making the wrong substitution, Or it's just not covered by the rules. for this case, you need fix it manually, until no any error.

$: cd you_project_root
$: port_ruby_to_crystal

This project can also be used as a learning resource to see exactly what Ruby APIs are different with Crystal, just check the diff of ./test/test.rb with ./test/test.cr.

Why not replace [] to [] of SomeType, {} to {} of SomeType => SomeType, it's really annoying of those syntax error.

There is no good default SomeType for this case, following is a good advice, you can replace all unkown type to BlackHole, make formatter check pass, then figure the correct type out.

Contributing

1. Add new rule into ./port_ruby_to_crystal.
2. Add test cases into test/test.rb.
3. Run ./test.sh ensure no error, like this:

 ╰─ $ ./test.sh
Running ruby test.rb successful.
Running crystal run test.cr successful.