feat(rust_style): Rust-style naming convention rule

docs/rules/rust_style.md

@@ -0,0 +1,89 @@
+Enforces the use of Rust-style naming conventions, see
+https://rust-lang.github.io/api-guidelines/naming.html
+
+Consistency in a code base is key for readability and maintainability. This rule
+is useful for deno projects that call rust functions via FFI. It attempts to
+unify naming conventions and enforces declarations and object property names
+which you create to be\
+in UpperCamelCase/PascalCase for classes, types, interfaces,\
+in snake_case for functions, methods, variables\
+and in SCREAMING_SNAKE_CASE for static class properties and constants.
+
+Of note:
+
+- `_` is allowed at the start or end of a variable
+- All uppercase variable names (e.g. constants) may have `_` in their name
+- If you have to use a camelCase key in an object for some reasons, wrap it in
+  quotation mark
+- This rule also applies to variables imported or exported via ES modules, but
+  not to object properties of those variables
+
+### Invalid:
+
+```typescript
+let firstName = "Ichigo";
+const obj1 = { lastName: "Hoshimiya" };
+const obj2 = { firstName };
+
+function doSomething() {}
+function foo({ camelCase = "default value" }) {}
+
+class snake_case_class {}
+class camelCaseClass {}
+class Also_Not_Valid_Class {}
+
+export * as camelCased from "mod.ts";
+
+enum snake_case_enum {
+  snake_case_variant,
+}
+
+enum camelCasedEnum {
+  camelCasedVariant,
+}
+
+type snake_case_type = { some_property: number };
+
+type camelCasedType = { someProperty: number };
+
+interface snake_case_interface {
+  some_property: number;
+}
+
+interface camelCasedInterface {
+  someProperty: number;
+}
+```
+
+### Valid:
+
+```typescript
+let first_name = "Ichigo";
+const FIRST_NAME = "Ichigo";
+const __my_private_variable = "Hoshimiya";
+const my_private_variable_ = "Hoshimiya";
+const obj1 = { "lastName": "Hoshimiya" }; // if an object key is wrapped in quotation mark, then it's valid
+const obj2 = { "firstName": firstName };
+const { lastName } = obj1; // valid, because one has no control over the identifier
+const { lastName: last_name } = obj;
+
+function do_something() {} // function declarations must be snake_case but...
+doSomething(); // ...camel_case function calls are allowed
+function foo({ camelCase: snake_case = "default value" }) {}
+
+class PascalCaseClass {}
+
+import { camelCased } from "external-module.js"; // valid, because one has no control over the identifier
+import { camelCased as not_camel_cased } from "external-module.js";
+export * as not_camel_cased from "mod.ts";
+
+enum PascalCaseEnum {
+  PascalCaseVariant,
+}
+
+type PascalCaseType = { some_property: number };
+
+interface PascalCaseInterface {
+  some_property: number;
+}
+```

src/rules.rs

@@ -105,6 +105,7 @@ pub mod prefer_namespace_keyword;
 pub mod prefer_primordials;
 pub mod require_await;
 pub mod require_yield;
+pub mod rust_style;
 pub mod single_var_declarator;
 pub mod triple_slash_reference;
 pub mod use_isnan;
@@ -339,6 +340,7 @@ fn get_all_rules_raw() -> Vec<Box<dyn LintRule>> {
     Box::new(prefer_primordials::PreferPrimordials),
     Box::new(require_await::RequireAwait),
     Box::new(require_yield::RequireYield),
+    Box::new(rust_style::RustStyle),
     Box::new(single_var_declarator::SingleVarDeclarator),
     Box::new(triple_slash_reference::TripleSlashReference),
     Box::new(use_isnan::UseIsNaN),