erg/doc/EN/dev_guide/rust_code_guideline.md

Guidelines for Rust code

Local rules

• Use log! for debugging output (use println! etc. for output processing required for release).
• Unused or internal variables and methods (private and used only for specific functions) should be prefixed with _. To avoid conflicts with reserved words, add one trailing _.

Encouraged code

• Define domain-specific Enums instead of numeric enumerations or bools.
• Minimize access modifiers. Use pub(mod) or pub(crate) in preference even when publishing.
• Explicitly convert iterable objects in for expressions to iterators (for i in x.iter() instead of for i in x).
• Evaluate Lazily. For example, use unwrap_or_else instead of unwrap_or if default is not a literal.

Unsolicited code

• Use return-type overloading a lot. Specifically, code that uses non-trivial .into too often. This is because the result of type inference may be counter-intuitive. In this case, it is recommended to use from instead.

• Codes that use Deref a lot. This causes practically the same problem as inheritance.

Code that changes its decision depending on the context

• Define unused helper methods.
• Uses unwrap, clone. In some cases, there is no choice but to do so.