Rust Needs The Ternary Conditional Operator (-?-:-)

[dangerrust]

Hello,

It looks like Rust forgot to implement the ternary conditional operator

It's operator that looks like this: condition ? trueExpression : falseExpression

This important feature lets you do things like return value == 5 ? success : failure;

Without this Ternary Conditional Operator you must use if statements which make ugly duplicated code (leads to bugs)

I think it easy to add support for this in Rust

[dscorbett]

Rust already has this: return if value == 5 { success } else { failure }.

[dangerrust]

@dscorbett That does not look very nice

[pnkfelix]

I have been very happy with our if-expression syntax. Not everyone loves the ternary-?:

[nagisa]

-1.

[pnkfelix]

(Downgrading so-called "importance")

[Gankra]

I continue to be against ever adding the ternary.

[jonas-schievink]

👎 We have if ... else, which does the same thing and is more readable IMO

[brendanzab]

Sorry, but 👎 from me too. I sympathise with the argument for terseness, but would rather we not duplicate the functionality of if/else.

[bstrie]

Rust tries to avoid having multiple ways to do the same thing. Furthermore, the : symbol is already more overloaded than I would like, and classic ternary syntax would be grammatically ambiguous with the already-accepted type ascription RFC. Furtherfurthermore, there are vague plans to use the ? symbol for language-level error-handling support in the future.

[graydon]

We added ternary at one point strictly to satisfy this aesthetic preference, and then later removed it due to deciding it didn't carry its weight.

Following the famous "time traveller rule of 3", one should only backtrack on such a decision at most twice; three times risks the integrity of spacetime.

[frewsxcv]

👎

I think if..else is more readable than dedicated ternary symbols

[nikomatsakis]

👎

EDIT: Sorry, I don't usually like being so terse, so let me just expand a touch. We have if/else, which is perfectly readable, and ternary just doesn't come up that often that it merits two similar bits of syntax. Also, I find very frequently I wind up using match or if let instead of a simple boolean expression, and I like the fact that which ever form of "ternary-like" thing I am using, it looks roughly the same. Basically, not needing a ternary expression is one of the great things about having an expression-oriented language!

[pnkfelix]

see also rust-lang/rust#1698 rust-lang/rust#1705

[tshepang]

I am grateful that this was removed, so 👎