From 3f6980e4e146163de85ff780432f6f0c7b7645e7 Mon Sep 17 00:00:00 2001 From: Aleksey Kladov Date: Tue, 4 May 2021 22:20:04 +0300 Subject: simplify macro expansion code Using `Option` arguments such that you always pass `None` or `Some` at the call site is a code smell. --- docs/dev/style.md | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) (limited to 'docs') diff --git a/docs/dev/style.md b/docs/dev/style.md index 6ab60b50e..00de7a711 100644 --- a/docs/dev/style.md +++ b/docs/dev/style.md @@ -449,6 +449,39 @@ fn query_all(name: String, case_sensitive: bool) -> Vec { ... } fn query_first(name: String, case_sensitive: bool) -> Option { ... } ``` +## Prefer Separate Functions Over Parameters + +If a function has a `bool` or an `Option` parameter, and it is always called with `true`, `false`, `Some` and `None` literals, split the function in two. + +```rust +// GOOD +fn caller_a() { + foo() +} + +fn caller_b() { + foo_with_bar(Bar::new()) +} + +fn foo() { ... } +fn foo_with_bar(bar: Bar) { ... } + +// BAD +fn caller_a() { + foo(None) +} + +fn caller_b() { + foo(Some(Bar::new())) +} + +fn foo(bar: Option) { ... } +``` + +**Rationale:** more often than not, such functions display "`false sharing`" -- they have additional `if` branching inside for two different cases. +Splitting the two different control flows into two functions simplifies each path, and remove cross-dependencies between the two paths. +If there's common code between `foo` and `foo_with_bar`, extract *that* into a common helper. + ## Avoid Monomorphization Avoid making a lot of code type parametric, *especially* on the boundaries between crates. -- cgit v1.2.3