Showing a spinner?

Ruby
1

How do I show a spinner on the command line interface when a ruby script
is working? I sometimes write things that take a while, and I know I get
impatient when all I see a blinking cursor :slight_smile:
A spinner has \ | / - all in one spot so it looks like a spinning wheel.

Thanks!

–Aldric

2

Aldric G. wrote:

How do I show a spinner on the command line interface when a ruby script
is working? I sometimes write things that take a while, and I know I get
impatient when all I see a blinking cursor :slight_smile:
A spinner has \ | / - all in one spot so it looks like a spinning wheel.

Thanks!

–Aldric

Here is the idea …you can make it better…

a=["-","\","|","/"]
n=0
while 1 do
print a[n % 4]
print “\b”
n+=1
sleep 0.1
puts “…#{n}.” if (n % 50==0)
end

3

I think a STDOUT.flush is needed after the second print “\b” to make it
work
properly.

On Tue, Nov 4, 2008 at 7:22 PM, Rodrigo B.

4

Great, thanks! What other special characters are there? Where can I find
a list? (I know - I could probably just google that, so if you don’t
have it handy I’ll go and do my own research when I get a chance).

–Aldric

5

The STDOUT.flush makes it seem frozen in time - not my idea of a
spinner! :wink: Still, thanks for showing me this, I’ve now got quite a bit
more that I can learn about :slight_smile:

–Aldric

6

a=["-","\","|","/"]
n=0
while 1 do
print a[n % 4]
print “\b”
n+=1
sleep 0.1
puts “…#{n}.” if (n % 50==0)
end

In ruby 1.9:

n=0
a=["-","\","|","/"].cycle do |a|
print a
print “\b”
n+=1
sleep 0.1
break if (n % 50).zero?
end

7

Mark T. wrote:

In ruby 1.9:

n=0
a=["-","\","|","/"].cycle do |a|
print a
print “\b”
n+=1
sleep 0.1
break if (n % 50).zero?
end

woooow ! - I’m becoming obsolete =c

8

Well, when I remove STDOUT.flush, the spinner doesn’t show at all, and I
only get:
…50.
…100.
…150.
…200.
[etc.]
with a 5-second “pause” at the beginning of each line.

I wonder if this behavior is somehow related to the OS (Ubuntu in my
case).

Regards,
Yaser S.

9

I don’t see anything different about this code, except ‘cycle’ which is
neat.
Why assign the array to ‘a’ if we’re just gonna iterate through it
anyway, though?

10

On Nov 5, 10:14 am, Aldric G. [email protected] wrote:

I don’t see anything different about this code, except ‘cycle’ which is
neat.
Why assign the array to ‘a’ if we’re just gonna iterate through it
anyway, though?

You’re right–that was a copy and paste error. The assignment
shouldn’t be there.

Another neat thing about cycle: you can do this

a = [“green”,“yellow”,“red”].cycle

Now a is an iterator with special behavior:

a.next #=> “green”
a.next #=> “yellow”
a.next #=> “red”
a.next #=> “green”

– Mark.

11

On Wed, Nov 5, 2008 at 1:22 AM, Rodrigo B.
[email protected] wrote:

Here is the idea …you can make it better…

a=[“-”,“\”,“|”,“/”]
n=0
while 1 do
print a[n % 4]
print “\b”
n+=1
sleep 0.1
puts “…#{n}.” if (n % 50==0)
end

Just had the same thing lying around to keep ssh alive, not much in
terms of progress though
See http://0xcc.net/ruby-progressbar/index.html.en for a full lib that
handles this problem

sigma ~prog/ruby % cat spinner.rb
a = %w[ | / - \ ]

$stdout.sync = true

loop do
print a.unshift(a.pop).last
sleep 0.1
print “\b”
end

12

That library looks interesting. Thanks for sharing, Michael!

Just want to mention that I tried the same code (posted by Rodrigo)
under
Windows Vista, and it worked fine without using STDOUT.flush.

Regards,
Yaser

13

Piling on…

Here’s my take…

require ‘thread’

class Spinner

C = [’|’, ‘/’, ‘-’, ‘\’]

def self.spin
@@thr = Thread.new do
$stdout.sync= true
Thread.current[:done]=false
until (Thread.current[:done])
4.times do |i|
print C[i]
sleep(0.1)
print “\b”
end
end
print "\b "
end
end

def self.quit
@@thr[:done]=true
end

end

if FILE == $0

Spinner.spin
sleep 3

Spinner.quit
sleep 3

end