Comment by kragen

I thought it was obvious that codegen was better than macros—at least, textual macros. You can't tell me Ken Thompson omitted macros from the Golang design because he didn't have experience using languages with macro systems!

Even AST-based macro systems have tricky problems like nontermination and variable capture. It can be tough to debug why your compiler is stuck in an infinite macro expansion loop. Macro systems that solve these problems, like the R⁵RS syntax-rules system, have other drawbacks like very complex implementations and limited expressive power.

And often there's no easy way to look at the code after it's been through the macro processor, which makes bugs in the generated code introduced by buggy macros hard to track down.

By contrast, if your code generator hangs in an infinite loop, you can debug it the same way you normally debug your programs; it doesn't suffer from tricky bugs due to variable capture; and it's easy to look at its output.