I mean, the basics of parsing and lexing are easy enough to understand & do and forming an AST is straightforward but all the "clever stuff" adfer that, all the hundreds and thousands of optimisation tests that are done - they are mind boggling.
Each one by itself is pretty straightfoward but start adding them up and layering them on top of each other and it gets crazy pretty quick.
I mean, the basics of parsing and lexing are easy enough to understand & do and forming an AST is straightforward but all the "clever stuff" adfer that, all the hundreds and thousands of optimisation tests that are done - they are mind boggling.
Each one by itself is pretty straightfoward but start adding them up and layering them on top of each other and it gets crazy pretty quick.