Feature: Add in prefix and suffix modifiers

README.mkd

@@ -110,3 +110,20 @@ require 'progress_bar/core_ext/enumerable_with_progress'
 
 (1..400).with_progress.select{|i| (i % 2).zero?}
 ```
+
+## Using prefix and suffix overrides to add styling to the progress bar
+
+If you want to change the style of the progress bar such as its color you can
+do so by using the prefix and suffix modifiers
+
+Let's say you want to the progress_bar to be inverted green which has the style
+code 42, then initialize the progress bar:
+
+```ruby
+style_code = 42
+bar = ProgressBar.new(100, prefix: "\e[#{style_code}m", suffix: "\e[0m")
+```
+
+### Some examples of ASCII styles you can apply
+
+![style_examples](example_ascii_styles.png)

lib/progress_bar.rb

@@ -6,9 +6,10 @@ class ProgressBar
   Error = Class.new(StandardError)
   ArgumentError = Class.new(Error)
 
-  attr_accessor :count, :max, :meters
+  attr_accessor :count, :max, :meters, :prefix, :suffix
+  attr_reader :terminal_width # Useful for prefix and suffix changes
 
-  def initialize(*args)
+  def initialize(*args, prefix: nil, suffix: nil)
 
     @count      = 0
     @max        = 100
@@ -19,6 +20,12 @@ def initialize(*args)
 
     @meters     = args unless args.empty?
 
+    raise ArgumentError, 'Prefix must be a valid string' unless prefix.nil? || prefix.is_a?(String)
+    @prefix = prefix
+
+    raise ArgumentError, 'Suffix must be a valid string' unless suffix.nil? || suffix.is_a?(String)
+    @suffix = suffix
+
     @last_write = ::Time.at(0)
     @start      = ::Time.now
 
@@ -73,9 +80,12 @@ def eta
 
   def to_s
     self.count = max if count > max
-    meters.inject("") do |text, meter|
+
+    progress_bar_text = meters.inject("") do |text, meter|
       text << render(meter) + " "
     end.strip
+
+    "#{prefix}#{progress_bar_text}#{suffix}"
   end
 
   protected

spec/arguments_spec.rb

@@ -18,6 +18,12 @@
     bar.meters.should == @default_meters
   end
 
+  it "should allow prefix and suffix arguments and set their instance variables" do
+    bar = ProgressBar.new(prefix: "\e[42m", suffix: "\e[0m")
+    bar.prefix.should == "\e[42m"
+    bar.suffix.should == "\e[0m"
+  end
+
   it "should allow specifying just the meters" do
     bar = ProgressBar.new(:bar, :eta)
     bar.max.should == @default_max
@@ -36,5 +42,15 @@
     }.should raise_error(ProgressBar::ArgumentError)
   end
 
-end
+  it "should raise an error when initial prefix is nonsense" do
+    lambda {
+      bar = ProgressBar.new(prefix: 200)
+    }.should raise_error(ProgressBar::ArgumentError)
+  end
 
+  it "should raise an error when initial suffix is nonsense" do
+    lambda {
+      bar = ProgressBar.new(suffix: 200)
+    }.should raise_error(ProgressBar::ArgumentError)
+  end
+end

spec/progress_bar_spec.rb

@@ -42,6 +42,13 @@
     it { should == "[##############] [100/100] [100%] [00:10] [00:00] [ 10.00/s]" }
   end
 
-end
-
+  describe 'at count=100 with style prefix and suffix' do
+    before do
+      @progress_bar.count = 100
+      @progress_bar.prefix = "\e[42m"
+      @progress_bar.suffix = "\e[0m"
+    end
 
+    it { should == "\e[42m[##############] [100/100] [100%] [00:10] [00:00] [ 10.00/s]\e[0m" }
+  end
+end