| # Syntax and the AST |
| |
| Working directly with source code is very inconvenient and error-prone. Thus, |
| before we do anything else, we convert raw source code into an AST. It turns |
| out that doing even this involves a lot of work, including lexing, parsing, |
| macro expansion, name resolution, conditional compilation, feature-gate |
| checking, and validation of the AST. In this chapter, we take a look at all |
| of these steps. |
| |
| Notably, there isn't always a clean ordering between these tasks. For example, |
| macro expansion relies on name resolution to resolve the names of macros and |
| imports. And parsing requires macro expansion, which in turn may require |
| parsing the output of the macro. |
