15. User Interfaces

# This test program demonstrates parsing program arguments.
# It uses the optparse library, which is included with ruby 1.8
# It handles classic unix style and gnu style options
require 'optparse'

@debugmode = false
@verbose = false

ARGV.options do |opts|
    opts.banner = "Usage: ruby #{$0} [OPTIONS] INPUTFILES"

    opts.on("-h", "--help", "show this message") {
        puts opts
        exit
    }
    # The OptionParser#on method is called with a specification of short
    # options, of long options, a data type spezification and user help
    # messages for this option.
    # The method analyses the given parameter and decides what it is,
    # so you can leave out the long option if you don't need it
    opts.on("-v", "--[no-]verbose=[FLAG]", TrueClass, "run verbosly") {
        |@verbose|   # sets @verbose to true or false
    }
    opts.on("-D", "--DEBUG", TrueClass, "turns on debug mode" ){
        |@debugmode|   # sets @debugmode to true
    }
    opts.on("-c", "--count=NUMBER", Integer, "how many times we do it" ){
        |@count|      # sets @count to given integer
    }
    opts.on("-o", "--output=FILE", String, "file to write output to"){
        |@outputfile|   # sets @outputfile to given string
    }
    opts.parse!
end

# example to use the options in the main program
puts "Verbose is on" if @verbose
puts "Debugmode is on" if @debugmode
puts "Outfile is #{@outputfile}" if defined? @outputfile
puts "Count is #{@count}" if defined? @count
ARGV.each { |param|
    puts "Got parameter #{param}"
}

buf = "\0" * 8
$stdout.ioctl(0x5413, buf)
ws_row, ws_col, ws_xpixel, ws_ypixel = buf.unpack("S4")

raise "You must have at least 20 characters" unless ws_col >= 20
max = 0
values = (1..5).collect { rand(20) }  # generate an array[5] of rand values
for i in values
    max = i if max < i
end
ratio = Float(ws_col-12)/max          # chars per unit
for i in values
    printf "%8.1f %s\n", i, "*" * (ratio*i)
end

# gives, for example:
#   15.0 *******************************
#   10.0 *********************
#    5.0 **********
#   14.0 *****************************
#   18.0 **************************************