opMixin or mixin function templates with convenience operator?

[Paul Backus]

On Friday, 13 December 2019 at 16:44:17 UTC, Ola Fosheim Grøstad 
wrote:
> On Friday, 13 December 2019 at 16:07:01 UTC, Paul Backus wrote:
>> You'll notice that there's no direct manipulation of the 
>> AST--everything is done by substitution.
>
> Yes, and there are many ways to do substitution.

The youtube link in my previous post has a time code that will 
bring you directly to the start of the segment on macros. In that 
segment, Walter explains in detail how macros would be expanded, 
with worked examples on the whiteboard. Pattern matching is also 
discussed.