> move this to "Conditional Structures" section below
Or maybe not. The problem is that Pattern-matching is actually two features in one. First: pattern-matching by number of arguments perfectly belongs to the "parametric mixins" section. Second: pattern-matching by argument value, while technically being part of "parametric mixins", logically belongs to "conditional structures" (since its use-cases are basically the same as of "mixin guards").
Hmm... so I guess let it stay here.