From fab57e2b9bc4577fcfcd9fbddbc35d96046c5d88 Mon Sep 17 00:00:00 2001 From: Pieter Wuille Date: Fri, 26 Jun 2020 13:47:48 -0700 Subject: [PATCH] doc: Mention Span in developer-notes.md --- doc/developer-notes.md | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/doc/developer-notes.md b/doc/developer-notes.md index b33b3ad18a..bd3daa3202 100644 --- a/doc/developer-notes.md +++ b/doc/developer-notes.md @@ -620,6 +620,19 @@ class A - *Rationale*: Easier to understand what is happening, thus easier to spot mistakes, even for those that are not language lawyers. +- Use `Span` as function argument when it can operate on any range-like container. + + - *Rationale*: Compared to `Foo(const vector&)` this avoids the need for a (potentially expensive) + conversion to vector if the caller happens to have the input stored in another type of container. + However, be aware of the pitfalls documented in [span.h](../src/span.h). + +```cpp +void Foo(Span data); + +std::vector vec{1,2,3}; +Foo(vec); +``` + - Prefer `enum class` (scoped enumerations) over `enum` (traditional enumerations) where possible. - *Rationale*: Scoped enumerations avoid two potential pitfalls/problems with traditional C++ enumerations: implicit conversions to `int`, and name clashes due to enumerators being exported to the surrounding scope.