[ruby-core:117413] [Ruby master Feature#13604] Exposing alternative interface of readline

3 Apr 2024

      Issue #13604 has been updated by hsbt (Hiroshi SHIBATA).

Status changed from Assigned to Closed

The C wrapper library of libreadline is extracted https://github.com/ruby/readline-ext from Ruby 3.3. If you still interest this, can you submit your proposal to upstream?

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Feature #13604: Exposing alternative interface of readline
https://bugs.ruby-lang.org/issues/13604#change-107592

* Author: graywolf (Gray Wolf)
* Status: Closed
* Assignee: aycabta (aycabta .)
----------------------------------------
GNU Readline has multiple modes of operation. At the moment, the readline extension only supports typical, `Readline.readline` mode. However, there is also alternative callback-based interface which is also useful.

```ruby
require_relative 'readline'

PROMPT = "rltest$ "

$running = true
$sigwinch_received = false

Readline.handler_install(PROMPT, add_hist: true) do |line|
	# Can use ^D (stty eof) or `exit' to exit.
	if !line || line == "exit"
		puts unless line
		puts "exit"
		Readline.handler_remove
		$running = false
	else
		puts "input line: #{line}"
	end
end

Signal.trap('SIGWINCH') { $sigwinch_received = true }

while $running do
	rs = IO.select([$stdin])
	if $sigwinch_received
		Readline.resize_terminal
		$sigwinch_received = false
	end
	Readline.read_char if r = rs[0]
end

puts "rltest: Event loop has exited"

```

Patch adding support for this is attached. This is my first try at contributing to ruby, so please tell me what I did wrong (I'm sure something, C is not my strong language).

---Files--------------------------------
readline_alternative_interface.diff (7.22 KB)
readline_alternative_interface_example.rb (606 Bytes)
readline_alternative_interface_update1.diff (7.08 KB)

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