I've continued my journey with Singularity, and I'm enjoying experimenting with this framework. I've created an experimental site at Sassmonster.com (Github repository here at https://github.com/58bits/sassmonster).
I was discussing this framework, along with other 'semantic' frameworks (if that's the right term in this case) vs presentational markup frameworks like Foundation, and Bootstrap.
I was wondering if anyone could summarize the relative merits of the approach that Singularity (and the original Semantic Grid) takes - without requiring grid classes or attributes to be present in markup.
The main advantage, if I've understood this correctly, is the ability to dynamically change layouts independent of document source order or any fixed class attributes (e.g. new grid layouts and grid span settings at given breakpoints, including source order independent changes like a sidebar switching from the left to right sides).
I'm sure there are others but would be grateful for a summary from someone with more experience than I have ;-)
Lastly - in terms of the future of grid systems in general - will the general adoption of the CSS Grid Layout Module obsolete frameworks like Singularity?
The advantage to semantic frameworks is that they take abstraction a level deeper than class names. This gives you, the author, the flexibility to generate your own list of classes like Bootstrap or Foundation OR you can apply grid styles to any element without being restricted by classes. Classes are flat and inflexible but having logic abstracted to mixins provides significantly more flexibility.
The advantages you address have more to do with the output model. Singularitys default output mode is called isolation and you can read about how it works here: http://www.palantir.net/blog/responsive-design-s-dirty-little-secret. With singularity you can use old fashioned floats or even write modules for CSS grid layout if you want. Singularity was designed to be future-proof and provide a common framework to do many different things with grids.
Lastly, yes, grid layout does some really awesome stuff and I hope it makes Singularity and other grid systems obsolete. However the syntax and conventions of grid layout is not so great and you may want to abstract some of it out. Some of the conventions are similar to that of Singularity like ratio based column math so that is pretty cool.