Read whole lines from $stdin without pressing enter with crystal-lang

Question

How do I read whole lines with crystal-lang ? I assume to use following Ruby equivalent code:

lines = $stdin.read
lines.each{|line| puts line}

How would you send a line to stdin without pressing enter/newline character? — Johannes Müller, Jul 20 '17 at 16:45
see this https://groups.google.com/forum/m/#!msg/crystal-lang/2y-JTQ6a_7Q/YfwVEpSSGgAJ — hiropon, Jul 20 '17 at 16:48

score 2 · Answer 1 · answered Jul 20 '17 at 13:52

2

Again, you use STDIN.raw but this time you want to fetch a whole line at a time using IO#gets. The easiest way to do that is this:

while line = STDIN.raw &.gets
  puts line
end

Alternatively you could do this:

STDIN.raw do |stdin|
  stdin.each_line do |line|
    puts line
  end
end

answered Jul 20 '17 at 13:52

Stephie

thanks but, it seems #raw method always requires tty. it's inconvenient for me because I wanted using it for competitive programming – hiropon Jul 20 '17 at 16:46

score 1 · Answer 2 · answered Jul 20 '17 at 16:51

1

To use this code with online compiler

I just used STDIN directly

STDIN.each_line do |line|
  puts line
end

answered Jul 20 '17 at 16:51

hiropon

Thanks this avoids a "can't set IO#raw: Inappropriate ioctl for device (Errno)" error message :) – rogerdpack Jun 19 '18 at 16:04

score 0 · Accepted Answer · answered Jun 19 '18 at 17:34

0

Apparently the equivalent of read is STDIN.gets_to_end FWIW.

answered Jun 19 '18 at 17:34

rogerdpack

1

@rogerpack Thanks, it's the most ideal answer. I should have asked for the forum. – hiropon Jun 20 '18 at 00:55

3 Answers3