First steps for the macro system

SWAP.md

@@ -1,6 +1,8 @@
-Since the macro AST is built as a custom tokenizer inside the system, it needs access to the import set. On the other hand, import sets aren't available until after parsing. Need a way to place this order in a lexer without restricting the expression value of the lexer.
+Decide whether we need patterns at runtime. Maybe macros aren't obligated to return MacTree so destructuring can be done in a safer and easier way?
 
-The daft option of accepting import resolution queries at runtime is available but consider better options.
+Double-check type and templating logic in the note, it's a bit fishy.
+
+Consider whether all macros need to be loaded or the const references could be used to pre-filter for a given let line.
 
 ## alternate extension mechanism