add "Rust's Almost-Rules and Almost-Almost-Rules"

_languages/rust-almost-rules.md

@@ -0,0 +1,41 @@
+---
+title:  "Language Design: Rust's Almost-Rules and Almost-Almost-Rules"
+date:   2024-08-05
+---
+
+(Inspired by [Almost Rules](https://matklad.github.io/2022/07/10/almost-rules.html).)
+
+### Syntax edition
+
+##### `:` is followed by a type
+
+- except inside struct initializers, where it is followed by a value
+- except function result types, that are preceded with `->`
+
+##### generics use `<>`
+
+- except in expression contexts, where `::<>` is used
+
+##### invocations use `()`
+
+- except where `{}` or `[]` is used, because "they convey important information"
+  - except for macro invocations, where `()`, `{}`, `[]` are equivalent and interchangeable
+
+##### `T {}` initializes a struct
+
+- except inside an `if`, where `{` starts a branch
+
+##### Rust has no varargs
+
+- except for `extern` functions
+- except for macros
+
+##### `let` introduces a binding
+
+- except in pattern matching, where `let` is implied
+  - except if the match starts with an uppercase letter, then it refers to an identifier in the outer scope
+  - except in macro pattern matching, where it is matched verbatim
+
+##### types with a total order implement `Eq` and `Ord`
+
+- except `f64` and `f32`, which do not

index.md

@@ -72,8 +72,9 @@ navigation: true
           <li><a href="languages/popular-but-wrong">Popular, but Wrong</a></li>
           <li><a href="languages/implicit-numeric-conversions" class="compact">Implicit Numeric Conversions</a></li>
           <li><a href="languages/package-objects-in-scala">Package Objects in Scala</a></li>
-          <li><a href="languages/lower-bar-of-rust-2">The lower bar of "Rust 2.0"</a></li>
+          <li><a href="languages/rust-almost-rules">Rust's Almost-Rules</a></li>
           <li><a href="languages/rust-struct-initializer-mistake">Struct initialization in Rust</a></li>
+          <li><a href="languages/lower-bar-of-rust-2">The lower bar of "Rust 2.0"</a></li>
           <li><a href="languages/design-mistakes-in-rust">(More) Rust Design Mistakes</a></li>
         </ul>
       </section>