It is not true.
You can declare classes (including the %-prefixed ones) in one file, import the first file into the second file and extend the classes in the second file.
Example:
foo.sass
%foo
color: red
bar.sass
@import foo.sass
html
@extend %foo
Run sass bar.sass bar.css
.
bar.css appears
html {
color: red; }
PS For real SASS experience, you should leverage Compass. Compass is a bunch of things under one name:
- a handy tool to compile SASS efficiently;
- a huge library of handy SASS styles for all occasions;
- an ecosystem of extensions that you can install and use in your projects effortlessly. This is what makes SASS stand out. You don't have to reinvent the wheel over and over again.
UPD Finally error text!
You're missing the dot in the name of the class. aside {@extend ruddy;}
should be aside {@extend .ruddy;}
.