From 1e9aad752beb789df4f2232adf6b9a24efbdac8d Mon Sep 17 00:00:00 2001 From: est31 Date: Wed, 9 Nov 2016 07:23:57 +0100 Subject: Document the question mark operator --- src/doc/reference.md | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'src/doc/reference.md') diff --git a/src/doc/reference.md b/src/doc/reference.md index 4838ecd2d42..eb3a6c0de6d 100644 --- a/src/doc/reference.md +++ b/src/doc/reference.md @@ -2860,8 +2860,8 @@ assert_eq!(x, y); ### Unary operator expressions -Rust defines the following unary operators. They are all written as prefix operators, -before the expression they apply to. +Rust defines the following unary operators. With the exception of `?`, they are +all written as prefix operators, before the expression they apply to. * `-` : Negation. Signed integer types and floating-point types support negation. It @@ -2890,6 +2890,10 @@ before the expression they apply to. If the `&` or `&mut` operators are applied to an rvalue, a temporary value is created; the lifetime of this temporary value is defined by [syntactic rules](#temporary-lifetimes). +* `?` + : Propagating errors if applied to `Err(_)` and unwrapping if + applied to `Ok(_)`. Only works on the `Result` type, + and written in postfix notation. ### Binary operator expressions -- cgit 1.4.1-3-g733a5