The section on "Formatting Whitespace in Expressions" in the F# coding guidelines is misguiding

[abelbraaksma]

I think we ought to mention that whitespace is sometimes necessary and since this is a guideline, we should enumerate the cases to create consistency.

I suggest we add something like this (text to be defined):

• Around infix operators, whitespace should be used: 1 + 3, not 1+3. This avoids problems like x -1 which is a different expression entirely to x - 1.
• Mention that whitespace following a function identifier can be necessary. myFunction() is different from myFunction (). The advice should be that in general, when it is a .NET member function, no space is used after the identifier. When it is a curried function, or a standard F# function, a space is required. While there are cases where both syntaxes yield the same result, this is the place to give a guideline, which hopefully avoids common pitfalls encountered by newcomers.
• After prefix operators, no space should be used. Good: x = -1, bad: x = - 1.
• In operator definitions, a space should be used. This prevents certain compile errors, and consistency is key here. Good: ( !. ) y = y, bad: (!.) y = y. (i.e., a compile error will happen when an operator starts with a * and you don't use a space).
• Around -> there should always be a space. Good function X -> y, bad: function X->y.

... anything else I've missed?

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Document Details

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• ID: 8c09996f-24ac-cf39-ef43-d7909cbc2b89
• Version Independent ID: 1efdd523-8552-6421-e149-74f76826ef8f
• Content: F# code formatting guidelines
• Content Source: docs/fsharp/style-guide/formatting.md
• Product: dotnet-fsharp
• GitHub Login: @cartermp
• Microsoft Alias: phcart

[cartermp]

@abelbraaksma do you have a good example for the unit guidance?

[cartermp]

@abelbraaksma I'll close this since #9233 addresses everything aside from guidance on passing unit as a parameter to a function or method. But if you have a great motivating example of this, I'll gladly add it and think of what the guidance should be.