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| <h1 id="syntax-and-the-ast"><a class="header" href="#syntax-and-the-ast">Syntax and the AST</a></h1> |
| <p>Working directly with source code is very inconvenient and error-prone. |
| Thus, before we do anything else, we convert raw source code into an |
| <a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustc_parse/index.html">Abstract Syntax Tree (AST)</a>. It turns out that doing this involves a lot of work, |
| including <a href="./the-parser.html">lexing, parsing</a>, <a href="./macro-expansion.html">macro expansion</a>, <a href="./name-resolution.html">name resolution</a>, conditional |
| compilation, <a href="./feature-gate-ck.html">feature-gate checking</a>, and <a href="./ast-validation.html">validation</a> of the <a href="https://doc.rust-lang.org/nightly/nightly-rustc/rustc_parse/index.html">AST</a>. |
| In this chapter, we take a look at all of these steps.</p> |
| <p>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.</p> |
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