$icon-font-path fallback to relative for pure Sass

Refs #650 #662

README.md

@@ -196,9 +196,9 @@ The fonts are referenced as:
 "#{$icon-font-path}#{$icon-font-name}.eot"
 ```
 
-`$icon-font-path` defaults to `bootstrap/`.
+`$icon-font-path` defaults to `bootstrap/` if asset path helpers are used, and `../fonts/bootstrap/` otherwise.
 
-When using with Compass, Sprockets, or Mincer, make sure to import the relevant path helpers before Bootstrap itself, for example:.
+When using bootstrap-sass with Compass, Sprockets, or Mincer, you **must** import the relevant path helpers before Bootstrap itself, for example:
 
 ```scss
 @import "bootstrap-compass";

assets/stylesheets/bootstrap/_variables.scss

@@ -77,7 +77,10 @@ $headings-color:          inherit !default;
 //## Specify custom location and filename of the included Glyphicons icon font. Useful for those including Bootstrap via Bower.
 
 //** Load fonts from this directory.
-$icon-font-path:          "../fonts/bootstrap/" !default;
+
+// [converter] Asset helpers such as Sprockets and Node.js Mincer do not resolve relative paths
+$icon-font-path: if($bootstrap-sass-asset-helper, "bootstrap/", "../fonts/bootstrap/") !default;
+
 //** File name for all font files.
 $icon-font-name:          "glyphicons-halflings-regular" !default;
 //** Element ID within SVG icon file.

tasks/converter/less_conversion.rb

@@ -94,7 +94,12 @@ class Converter
               // in Sass 3.3 this can be improved with: function-exists(twbs-font-path)
               $bootstrap-sass-asset-helper: (twbs-font-path("") != unquote('twbs-font-path("")')) !default;
             SCSS
-            file = replace_all file, /(\$icon-font-path:\s+".*)(" !default)/, '\1bootstrap/\2'
+            file = replace_all file, %r{(\$icon-font-path): \s*"(.*)" (!default);}, <<-SCSS
+
+// [converter] Asset helpers such as Sprockets and Node.js Mincer do not resolve relative paths
+\\1: if($bootstrap-sass-asset-helper, "bootstrap/", "\\2bootstrap/") \\3;
+SCSS
+                               '\1: if($bootstrap-sass-asset-helper, "bootstrap/", "\2bootstrap/")\3'
           when 'close.less'
             # extract .close { button& {...} } rule
             file = extract_nested_rule file, 'button&'