Printf format as binary number

[Happypig375]

Printf format as binary number

I propose we allow printf "%B" 10 which outputs 1010.

The existing way of approaching this problem in F# is going through Convert.ToString(..., 2) which is not needed for bases 8 and 16.

This is arguably used more than base 8.

Pros and Cons

The advantages of making this adjustment to F# are

1. Convenience
2. Consistency, as the standard bases (2, 8, 10, 16) should receive the same treatment.
3. Conciseness

The disadvantages of making this adjustment to F# are that this brings multiple ways to do the same thing, but then %o and %x/%X exist.

Extra information

Estimated cost (XS, S, M, L, XL, XXL): S

Related suggestions: (put links to related suggestions here)

Affidavit (please submit!)

Please tick this by placing a cross in the box:

• This is not a question (e.g. like one you might ask on stackoverflow) and I have searched stackoverflow for discussions of this issue
• I have searched both open and closed suggestions on this site and believe this is not a duplicate
• This is not something which has obviously "already been decided" in previous versions of F#. If you're questioning a fundamental design decision that has obviously already been taken (e.g. "Make F# untyped") then please don't submit it.

Please tick all that apply:

• This is not a breaking change to the F# language design
• I or my company would be willing to help implement and/or test this

For Readers

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[dsyme]

Seems reasonable. You might want to check with OCaml since our printf design largely aligns with that

[Happypig375]

https://stackoverflow.com/questions/39962412/why-is-b-deprecated-in-printf %b is deprecated and %B is recommended for booleans, and there was an attempt to redefine %b for binary numbers but got rejected.

[jackfoxy]

This would be a useful formatter, but %B having a different function than %b would be confusing. I can't think of another letter that would be intuitive. Maybe %t (for two)? Or if the parser could handle it %2?

[Happypig375]

@jackfoxy %a and %A already do two different things. Same for %o and %O.

[Happypig375]

Also %t is already defined.

[jackfoxy]

Darn it, I was looking at an obsolete reference. The problems with searching for documentation...

[Happypig375]

@jackfoxy These have been in F# since 1.0. Are you looking at the right language?

[jackfoxy]

Nope, looked at the first (or at least most prominent) result of a Bing search for "F# printf".
I've long been of the opinion MS does a poor job of optimizing Bing searches into their own tech documentation.
In this case what I got was https://www.c-sharpcorner.com/article/printing-and-formatting-outputs-in-fsharp/ which to someone in a hurry (me) looked like a reliable source from its layout.

[Happypig375]

Ah yes, c-sharpcorner.com, the website deemed as low quality by the C# subreddit.

[baronfel]

For reference, a quick search for "F# printf" got me the official docs for printf specifiers in the language: https://docs.microsoft.com/en-us/dotnet/fsharp/language-reference/plaintext-formatting#format-specifiers-for-printf

[Happypig375]

@jackfoxy %2 won't work either because it's a width specifier like in %2d.

[Happypig375]

Closing as implemented in dotnet/fsharp#11603