Reline functionality

[BurdetteLamar]

I am looking at contributing to Reline documentation. I have been studying https://www.gnu.org/software/readline/ to guide my work. I understand that not all of the Gnu functionality is implemented in Reline.

Questions:

• May I reasonably regard Reline as a proper subset of Gnu Readline?
• If not, is Reline a proper subset of some other implementation?

Thanks,
Burdette

[rubyFeedback]

I can not answer your questions as I have not written reline.

I have used Readline in the past though. Yesterday I looked to add a tab-completion example
(for reline) and it works; the API is either 1:1 or just about 1:1. What we lack is documentation
and examples though. (I think I have some old readline examples somewhere here locally
still. I remember I had to solve some problems in the past, because I wanted to replace
bash with a ruby-like shell that would work with both ruby code and bash-like instructions.
I never fully finished it though but it semi-works. I'll republish most of my old code on
gem.coop eventually once they accept new accounts etc...)

I am not sure if the word "subset" is correct. Subset means it would be derived and
potentially be either smaller; or have a different functionality, or both. This may be
technically correct, but the term subset I find confusing here.

Perhaps we can simply state it is API compatible? This of course requires of us to know
whether all of the API is supported. I think there was one difference at the least; not
sure if I remember correctly. That's why I need documentation, because my brain
forgets things sooo quickly.

But I think to answer your question: I think reline is fully compatible with readline
API-wise. We should programmatically test this though. Right now I don't know. We
probably need to add a document with all functions from readline, then programmatically
call them into reline e. g. "Reline.respond_to?(:this_is_a_fat_duck)" and what not. Like
perhaps a test. Or perhaps this already exists, as whoever ported reline probably had
to go through this.

[tompng]

It's a hard question to answer.
Reline claims to be compatible with GNU Readline and Editline.

In README

Reline is compatible with the API of Ruby's stdlib 'readline', GNU Readline and Editline by pure Ruby implementation.

In gemspec description

Alternative GNU Readline or Editline implementation by pure Ruby.

As a library, Reline is almost a superset of ruby/readline-ext. Only a few rarely-used methods are missing.
Key-binding functionality: Subset of GNU Readline and Editline.
Configuration system (inputrc): Subset of GNU Readline. Many missing features.
As a user-interface, I believe it's almost completely a superset of GNU Readline. Better rendering system, seamless single-line/multiline/full-screen editing, and more. The only missing feature is highlighted range selection, I think.