source code has no semantic

I don’t want to repeat, so you first read

1. http://calculist.org/blog/2012/04/17/homoiconicity-isnt-the-point/

then you will see the whole secret of macro is just manipulate data structures that later expanded to AST. Combine

2. https://mathstodon.xyz/@jonmsterling/113890651941453080

name	meaning
elaborate	source code (no intrinsic semantics) → language (with semantics)
compile	language (with semantics) → language (with semantics)