Add more math functions and unite them with Trig.

Added math functions are as follows:

- e()
- log(number[, base])
- sqrt(number)
- pow(number, exponent)

Because trigonometry is also math, these functions are united with
Compass' trigonometry functions under the Math module.

doc-src/content/reference/compass/helpers.haml

@@ -23,8 +23,9 @@ layout: core
   * [adjust-saturation()](/reference/compass/helpers/colors/#adjust-saturation)
   * [append-selector()](/reference/compass/helpers/selectors/#append-selector)
   * [color-stops()](/reference/compass/helpers/color-stops/)
-  * [cos()](/reference/compass/helpers/trig/#cos)
+  * [cos()](/reference/compass/helpers/math/#cos)
   * [css2-fallback()](/reference/compass/helpers/cross-browser/#css2-fallback)
+  * [e()](/reference/compass/helpers/math/#e)
   * [elements-of-type()](/reference/compass/helpers/display/)
   * [enumerate()](/reference/compass/helpers/selectors/#enumerate)
   * [font-files()](/reference/compass/helpers/font-files/)
@@ -35,14 +36,17 @@ layout: core
   * [image-url()](/reference/compass/helpers/urls/#image-url)
   * [inline-font-files()](/reference/compass/helpers/inline-data/#inline-font-files)
   * [inline-image()](/reference/compass/helpers/inline-data/#inline-image)
+  * [log()](/reference/compass/helpers/math/#log)
   * [nest()](/reference/compass/helpers/selectors/#nest)
+  * [pow()](/reference/compass/helpers/math/#pow)
   * [prefix()](/reference/compass/helpers/cross-browser/#prefix)
   * [prefixed()](/reference/compass/helpers/cross-browser/#prefixed)
-  * [pi()](/reference/compass/helpers/trig/#pi)
-  * [sin()](/reference/compass/helpers/trig/#sin)
+  * [pi()](/reference/compass/helpers/math/#pi)
+  * [sin()](/reference/compass/helpers/math/#sin)
+  * [sqrt()](/reference/compass/helpers/math/#sqrt)
   * [stylesheet-url()](/reference/compass/helpers/urls/#stylesheet-url)
   * [scale-lightness()](/reference/compass/helpers/colors/#scale-lightness)
-  * [tan()](/reference/compass/helpers/trig/#tan)
+  * [tan()](/reference/compass/helpers/math/#tan)
   * [-css2()](/reference/compass/helpers/cross-browser/#-css2)
   * [-moz()](/reference/compass/helpers/cross-browser/#-moz)
   * [-ms()](/reference/compass/helpers/cross-browser/#-ms)

doc-src/content/reference/compass/helpers/math.haml

@@ -1,8 +1,8 @@
 --- 
-title: Compass Trigonometric Helpers
-crumb: Trig
+title: Compass Math Helpers
+crumb: Math
 framework: compass
-meta_description: Helper functions for working with angles.
+meta_description: Helper math functions.
 layout: core
 classnames:
   - reference
@@ -13,12 +13,15 @@ documented_functions:
   - "sin"
   - "cos"
   - "tan"
+  - "e"
+  - "log"
+  - "sqrt"
+  - "pow"
 ---
-%h1 Compass Trig Helpers
+%h1 Compass Math Helpers
 
 :markdown
-  Trigonometric functions can help you manage complex calculations involving angles.
-  Or maybe they can be used to create pretty pictures. Who knows?
+  Sass math functions are sufficient for most cases, but in those moments of extreme geekiness these additional functions can really come in handy.
 
 
 #pi.helper
@@ -50,6 +53,7 @@ documented_functions:
       then it will return a unitless result. Degrees will first be converted to radians.
       If the number is any other unit, the units will be passed thru to the result,
       and the number will be treated as radians.
+
 #tan.helper
   %h3
     %a(href="#tan")
@@ -60,3 +64,35 @@ documented_functions:
       then it will return a unitless result. Degrees will first be converted to radians.
       If the number is any other unit, the units will be passed thru to the result,
       and the number will be treated as radians.
+
+#e.helper
+  %h3
+    %a(href="#e")
+      e()
+  .details
+    %p
+      Returns the value of <a href="http://en.wikipedia.org/wiki/E_(mathematical_constant)">e</a>.
+
+#log.helper
+  %h3
+    %a(href="#log")
+      log($number, [$base])
+  .details
+    %p
+      Calculates the logarithm of a number to a base. Base defaults to <code>e</code>.
+
+#sqrt.helper
+  %h3
+    %a(href="#sqrt")
+      sqrt($number)
+  .details
+    %p
+      Calculates the square root of a number.
+
+#pow.helper
+  %h3
+    %a(href="#pow")
+      pow($number, $exponent)
+  .details
+    %p
+      Calculates the value of a number raised to the power of an exponent.

lib/compass/sass_extensions/functions.rb

@@ -4,7 +4,7 @@ end
 %w(
   selectors enumerate urls display
   inline_image image_size constants gradient_support
-  font_files lists colors trig sprites cross_browser_support
+  font_files lists colors math sprites cross_browser_support
 ).each do |func|
   require "compass/sass_extensions/functions/#{func}"
 end
@@ -21,7 +21,7 @@ module Sass::Script::Functions
   include Compass::SassExtensions::Functions::Constants
   include Compass::SassExtensions::Functions::Lists
   include Compass::SassExtensions::Functions::Colors
-  include Compass::SassExtensions::Functions::Trig
+  include Compass::SassExtensions::Functions::Math
   include Compass::SassExtensions::Functions::Sprites
   include Compass::SassExtensions::Functions::CrossBrowserSupport
 end

lib/compass/sass_extensions/functions/math.rb

@@ -0,0 +1,47 @@
+module Compass::SassExtensions::Functions::Math
+
+  def pi()
+    Sass::Script::Number.new(Math::PI)
+  end
+
+  def sin(number)
+    trig(:sin, number)
+  end
+
+  def cos(number)
+    trig(:cos, number)
+  end
+
+  def tan(number)
+    trig(:tan, number)
+  end
+
+  def e()
+    Sass::Script::Number.new(Math::E)
+  end
+
+  def log(number, base = Sass::Script::Number.new(Math::E))
+    assert_type number, :Number
+    assert_type base, :Number
+    Sass::Script::Number.new(Math.log(number.value, base.value), number.numerator_units, number.denominator_units)
+  end
+
+  def sqrt(number)
+    numeric_transformation(number) { |n| Math.sqrt(n) }
+  end
+
+  def pow(number, exponent)
+    assert_type number, :Number
+    assert_type exponent, :Number
+    Sass::Script::Number.new(number.value**exponent.value, number.numerator_units, number.denominator_units)
+  end
+
+  private
+  def trig(operation, number)
+    if number.numerator_units == ["deg"] && number.denominator_units == []
+      Sass::Script::Number.new(Math.send(operation, Math::PI * number.value / 180))
+    else
+      Sass::Script::Number.new(Math.send(operation, number.value), number.numerator_units, number.denominator_units)
+    end
+  end
+end

lib/compass/sass_extensions/functions/trig.rb

@@ -1,27 +0,0 @@
-module Compass::SassExtensions::Functions::Trig
-
-  def pi()
-    Sass::Script::Number.new(Math::PI)
-  end
-
-  def sin(number)
-    trig(:sin, number)
-  end
-
-  def cos(number)
-    trig(:cos, number)
-  end
-
-  def tan(number)
-    trig(:tan, number)
-  end
-  
-  private
-  def trig(operation, number)
-    if number.numerator_units == ["deg"] && number.denominator_units == []
-      Sass::Script::Number.new(Math.send(operation, Math::PI * number.value / 180))
-    else
-      Sass::Script::Number.new(Math.send(operation, number.value), number.numerator_units, number.denominator_units)
-    end
-  end
-end