Alt+Enter to forced insert newline doesn't work on macOS

[aycabta]

No description provided.

[nobu]

As keyboards of Mac don't have Alt key, option+Enter seems inserting a newline.

[aycabta]

http://osxdaily.com/2013/02/01/use-option-as-meta-key-in-mac-os-x-terminal/

So sad.

[JoshCheek]

Additional context

I'm using iTerm2 and have option set to send ESC+key. For option+return, it sends \e\r

versions

$ ruby -r reline -r readline -e 'p ruby: RUBY_VERSION, readline: Readline::VERSION, reline: Reline::VERSION'
{:ruby=>"2.7.0", :readline=>"8.0", :reline=>"0.1.2"}

inputrc

https://github.com/JoshCheek/dotfiles/blob/149bcb6d74c1aeaef0d5502e2982fc050b8ff9d7/inputrc

Readline

$ ruby -e 'print "abc def\e\r"' | ruby -r readline -e 'p Readline.readline "> "'
> abc def
"abc def"

Reline (via pipe)

$ ruby -e 'print "abc def \e\r"' | ruby -r reline -e 'p Reline.readline "> "'
▽Traceback (most recent call last):
	6: from -e:1:in `<main>'
	5: from /Users/josh/.rubies/ruby-2.7.0/lib/ruby/2.7.0/forwardable.rb:235:in `readline'
	4: from /Users/josh/.gem/ruby/2.7.0/gems/reline-0.1.2/lib/reline.rb:183:in `readline'
	3: from /Users/josh/.gem/ruby/2.7.0/gems/reline-0.1.2/lib/reline.rb:203:in `inner_readline'
	2: from /Users/josh/.gem/ruby/2.7.0/gems/reline-0.1.2/lib/reline.rb:336:in `may_req_ambiguous_char_width'
	1: from /Users/josh/.gem/ruby/2.7.0/gems/reline-0.1.2/lib/reline/ansi.rb:69:in `cursor_pos'
/Users/josh/.gem/ruby/2.7.0/gems/reline-0.1.2/lib/reline/ansi.rb:69:in `raw': Inappropriate ioctl for device (Errno::ENOTTY)
	7: from -e:1:in `<main>'
	6: from /Users/josh/.rubies/ruby-2.7.0/lib/ruby/2.7.0/forwardable.rb:235:in `readline'
	5: from /Users/josh/.gem/ruby/2.7.0/gems/reline-0.1.2/lib/reline.rb:183:in `readline'
	4: from /Users/josh/.gem/ruby/2.7.0/gems/reline-0.1.2/lib/reline.rb:203:in `inner_readline'
	3: from /Users/josh/.gem/ruby/2.7.0/gems/reline-0.1.2/lib/reline.rb:336:in `may_req_ambiguous_char_width'
	2: from /Users/josh/.gem/ruby/2.7.0/gems/reline-0.1.2/lib/reline/ansi.rb:66:in `cursor_pos'
	1: from /Users/josh/.gem/ruby/2.7.0/gems/reline-0.1.2/lib/reline/ansi.rb:83:in `rescue in cursor_pos'
/Users/josh/.gem/ruby/2.7.0/gems/reline-0.1.2/lib/reline/ansi.rb:83:in `pread': not opened for reading (IOError)

Reline (via TTY)

Okay, in the above, we can see it's trying to do tty operations on the pipe, which goes into some failure block where it fails while trying to read from stdout. If we try typing those keys instead of piping them into it, nothing happens. This matches Readline's behaviour, but my understanding was the purpose of the lib was to allow multiline editing, so I would expect it to treat this as a non-submitting newline.

[tompng]

This is a terminal emulator setting thing.
TTY problem is about another issue #537