As I'm looking at adding builtins, it feels a bit like the types of args will end up scaling close to the number of semantic kinds. Rather than having this lead to a bunch of macros, this approach drops the macros for plain code.
Note, this adds Get functions too -- I'd planned those regardless for type safety, this is just getting ahead of the issue so that the Print function is pretty clean.
As a step towards builtins, provide more blocks. The intent is that any significant scope change will become its own NodeBlock. Builtins should produce the first set of node blocks.
Note, SemanticsIR as set up here isn't handling ordering of import processing -- I haven't thought that through much beyond that we probably want some lighter-weight processing of the parse tree to achieve it. But I think the essence of loading builtins first as their own IR block is... probably right?
This rewrites semantics towards a more pure instruction model, in pursuit of the simple instruction-style output.
I think I can get this approach to type-check as it goes along, but obviously this change doesn't prove that yet. I'm separating it out because it's a large rewrite of the semantics structure, tossing out a lot of what was there before. But I think it does help towards several requests, like setting up a clear path for consolidating duplicate identifiers and making the node style more standardized.
I expect to need to pass multiple args to function calls, that'd probably be storing vectors of args similar to how I'm showing identifiers and integer literals stored.
This removes the semantics namespace because (a) it was getting annoying writing the `::` everywhere, and (b) I think the leaning with Carbon is to avoid namespaces (@chandlerc asked not to put SemanticsIR/SemanticsFactory in a namespace, which is the crux of the issue). But, it's still necessary to avoid name conflicts so I just prefix everything with "Semantics" (still a lot of typing, but no `::`).
Jon Ross-Perkins