Fix: String#tr implementation

[dnamsons]

No description provided.

[dnamsons]

It seems like support for character ranges has been implemented already, therefore i removed this TODO comment

[lopopolo]

The below use of Regexp is a hack. This does method does not properly validate that ranges are ascending.

For example, this must error:

[2.6.6] > "hello".tr("a-y", "z-b")
Traceback (most recent call last):
        5: from /usr/local/var/rbenv/versions/2.6.6/bin/irb:23:in `<main>'
        4: from /usr/local/var/rbenv/versions/2.6.6/bin/irb:23:in `load'
        3: from /usr/local/var/rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/irb-1.0.0/exe/irb:11:in `<top (required)>'
        2: from (irb):6
        1: from (irb):6:in `tr'
ArgumentError (invalid range "z-b" in string transliteration)

Can you restore the comment?

[lopopolo]

ruby-specs come from upstream. I'd consider this source file immutable. Can you back out this change?

If you think we're missing a test, add an integration test for String like these for Array:

artichoke/artichoke-backend/src/extn/core/array/mod.rs

Lines 418 to 440 in b99e3c1

	#[cfg(test)]
	mod tests {
	use bstr::ByteSlice;
	use crate::test::prelude::*;
	const FUNCTIONAL_TEST: &[u8] = include_bytes!("array_functional_test.rb");
	#[test]
	fn functional_test() {
	let mut interp = crate::interpreter().unwrap();
	let _ = interp.eval(FUNCTIONAL_TEST).unwrap();
	let result = interp.eval(b"spec");
	if let Err(exc) = result {
	let backtrace = exc.vm_backtrace(&mut interp);
	let backtrace = bstr::join("\n", backtrace.unwrap_or_default());
	panic!(
	"Array tests failed with backtrace:\n{:?}",
	backtrace.as_bstr()
	);
	}
	}
	}

https://github.com/artichoke/artichoke/blob/b99e3c1163381cec8ab505e33c2201dbe67c7ade/artichoke-backend/src/extn/core/array/array_functional_test.rb

[lopopolo]

The below use of Regexp is a hack. This does method does not properly validate that ranges are ascending.

For example, this must error:

[2.6.6] > "hello".tr("a-y", "z-b")
Traceback (most recent call last):
        5: from /usr/local/var/rbenv/versions/2.6.6/bin/irb:23:in `<main>'
        4: from /usr/local/var/rbenv/versions/2.6.6/bin/irb:23:in `load'
        3: from /usr/local/var/rbenv/versions/2.6.6/lib/ruby/gems/2.6.0/gems/irb-1.0.0/exe/irb:11:in `<top (required)>'
        2: from (irb):6
        1: from (irb):6:in `tr'
ArgumentError (invalid range "z-b" in string transliteration)

Can you restore the comment?

[lopopolo]

I tried this commit locally, and while it does improve spec compliance, there are still many ruby-spec failures. I'd like to take this PR with the changes I've requested.

Because String#tr still has some work to do, can you also edit the issue description to remove the "autoclose" annotation so GitHub does not close the attached ticket? Linking to it is fine.

[lopopolo]

Please squash and force push your changes so we don't add any extraneous commits to the specs directory.

[dnamsons]

@lopopolo Thank you for the review!

I've applied the requested changes

[lopopolo]

oh I didn't realize we had one of these for String 🚀

[lopopolo]

link to #765