Add Numeric#pos? & Numeric#neg?

README.md

@@ -23,6 +23,9 @@ Or install it yourself as:
 
 * [Hash](http://rdoc.info/github/bbatsov/powerpack/Hash)
     * [#symbolize_keys](http://rdoc.info/github/bbatsov/powerpack/Hash#symbolize_keys-instance_method)
+* [Numeric](http://rdoc.info/github/bbatsov/powerpack/Numeric)
+    * [#pos?](http://rdoc.info/github/bbatsov/powerpack/Numeric#pos?-instance_method)
+    * [#neg?](http://rdoc.info/github/bbatsov/powerpack/Numeric#neg?-instance_method)
 * [String](http://rdoc.info/github/bbatsov/powerpack/String)
     * [#blank?](http://rdoc.info/github/bbatsov/powerpack/String#blank?-instance_method)
     * [#format](http://rdoc.info/github/bbatsov/powerpack/String#format-instance_method)

lib/powerpack.rb

@@ -2,4 +2,6 @@
 
 require 'powerpack/hash'
 
+require 'powerpack/numeric'
+
 require 'powerpack/string'

lib/powerpack/numeric.rb

@@ -0,0 +1,2 @@
+require_relative 'numeric/neg'
+require_relative 'numeric/pos'

lib/powerpack/numeric/neg.rb

@@ -0,0 +1,19 @@
+unless Numeric.method_defined? :neg?
+  class Numeric
+    # Checks whether a number is negative.
+    #
+    # @return [Boolean] true is the number is negative, false otherwise
+    #
+    # @example
+    #   5.neg? #=> false
+    #
+    # @example
+    #   -0.5.neg? #=> true
+    #
+    # @example
+    #   0.neg? #=> false
+    def neg?
+      self < 0
+    end
+  end
+end

lib/powerpack/numeric/pos.rb

@@ -0,0 +1,19 @@
+unless Numeric.method_defined? :pos?
+  class Numeric
+    # Checks whether a number is positive.
+    #
+    # @return [Boolean] true is the number is positive, false otherwise
+    #
+    # @example
+    #   5.pos? #=> true
+    #
+    # @example
+    #   -0.5.pos? #=> false
+    #
+    # @example
+    #   0.pos? #=> false
+    def pos?
+      self > 0
+    end
+  end
+end

spec/powerpack/numeric/neg_spec.rb

@@ -0,0 +1,24 @@
+require 'spec_helper'
+
+describe 'Numeric#neg?' do
+  it 'returns false for positive integer' do
+    expect(1.neg?).to be_false
+  end
+
+  it 'returns false for positive float' do
+    expect(0.1.neg?).to be_false
+  end
+
+  it 'returns true for negative integer' do
+    expect(-1.neg?).to be_true
+  end
+
+  it 'returns true for negative float' do
+    expect(-0.01.neg?).to be_true
+  end
+
+  it 'returns false for 0' do
+    expect(0.neg?).to be_false
+    expect(0.0.neg?).to be_false
+  end
+end

spec/powerpack/numeric/pos_spec.rb

@@ -0,0 +1,24 @@
+require 'spec_helper'
+
+describe 'Numeric#pos?' do
+  it 'returns true for positive integer' do
+    expect(1.pos?).to be_true
+  end
+
+  it 'returns true for positive float' do
+    expect(0.1.pos?).to be_true
+  end
+
+  it 'returns false for negative integer' do
+    expect(-1.pos?).to be_false
+  end
+
+  it 'returns false for negative float' do
+    expect(-0.01.pos?).to be_false
+  end
+
+  it 'returns false for 0' do
+    expect(0.pos?).to be_false
+    expect(0.0.pos?).to be_false
+  end
+end