Ruby gets input goes to the console command line after program terminates - ruby

Question

I am trying to set up a simple ruby program with a two additional threads.
One thread is to check the serial port for data and populate a variable if anything is found.
The second thread is is a call to 'gets', which when returned will stop the program.
The main thread simply ouputs the values stored by the first additional thread to the console (The program is a console based data logger).
My problem is that the second thread starts ok, as you can see from the "Press Enter..." note in the output.
D:\Documents and Settings\JMEDDING\My Documents\Ruby scripts>c-scope.rb -t
"Press 'Enter' to end process"
511, 511, 485 | | | | | + | | | | | 536
511, 511, 485 | | | | | + | | | | | 536
512, 511, 485 | | | | | XO | | | | | 536
512, 512, 485 | | | | | |+ | | | | | 536
but any data returned from
input = gets
does not make it into the program. Instead, it can be seen on the console command line after the program is killed with ctrl-c.
I am running this in the ruby console on windows. This used to work properly before, but I re-arranged the code at one point and now it is not cooperating. I have copied the entire program below. I guess this is something very simple, but I'm totally stuck, so thanks for taking a look.
Jon
require 'serialport'
TEST = true if ARGV[0] == '--test' || ARGV[0] == '-t'
# Edit the two settings below
port = "COM6" #"/dev/tty.usbserial-A600b1Q6"
baud = 9600
begin
if RUBY_PLATFORM =~ /win32/ || RUBY_PLATFORM == "i386-mingw32"
require 'Win32/Console/ANSI'
end
rescue LoadError
raise "You must 'gem install win32console' to use color on Windows"
end
if TEST
sp = nil
else
sp = SerialPort.new port, baud, 8, 1, SerialPort::NONE
end
symbols = ["X", "O", "#", "#"]
vals = [] #max four values to plot
input = nil
len = 50
max = 0
min = 1200
if TEST
vals = [511, 511]
end
def colorize(text, color_code)
"\033[1;#{color_code}m#{text}\033[0m"
end
def red(text); colorize(text, "31"); end
def green(text); colorize(text, "32"); end
def blue(text); colorize(text, "34"); end
def color_the_symbols(text, symbols)
color = 31 # "+" = red, then green, yellow, blue, pink
chars = ["+"] + symbols
chars.each_with_index do |s,i|
text.gsub!(s, colorize(s, "#{color + i}"))
end
text
end
def base_string (len, min, max, vals, symbols)
s = ""
(0..len).each {|i| s += i%5 == 0 ? "|" : " "}
vals.each_with_index do |val, i|
pos = len * (val - min)/ (max - min)
char = symbols.include?(s[pos] ) ? "+" : symbols[i]
s[pos] = char
end
color_the_symbols s, symbols
end
#listen to STDIN for stop signal
Thread.new do
p "Press 'Enter' to end process"
input = gets #pressing enter will stop the other loops
end
sleep(1)
#listening thread
Thread.new do
while !input
if TEST
(0...vals.count).each {|i| vals[i] += rand(3) - 1}
else
c = ""
word = ""
until c == "\n"
c = sp.getc
word << c.to_s
#p "Flushing buffer #{c}"
end
#p word.chomp
vals[0] = Integer(word.chomp)
end
sleep(0.5)
end
end
while !input #will be true until enter key is pressed
while vals.count == 0
#wait for firs data to show up
sleep (0.1)
end
for i in (0...vals.count) do
#validate min and max
max = (vals[i] * 1.05).to_i if vals[i] > max
min = (vals[i] * 0.95).to_i if vals[i] < min
end
output = base_string(len, min, max, vals, symbols)
output = " #{red(min.to_s)} " + output + " #{red(max.to_s)}"
color = 32
vals.each_with_index do |val,i|
output = " #{colorize("%4d," % val, "#{color + i}")}" + output
end
puts output
sleep(1)
end

Answer 1

I think there was a error somewhere, but the notification was being obscured by the threading behavior. I made some unrelated changes and after some debugging, it started working again. Sorry I can't be more specific.

Answer 2

You need to have
thread = Thread.new
# blah
end
thread.join
If you want that thread to finish its work before the program finishes.