Whitespace checks flexibility

[Gama11]

I'd like to enforce anonymous object declarations that look like this:

{ key: value, key: value }

I think this is currently not possible (except for the space after the comma with WhitespaceAfter and the , token).

• Using the : token in WhitespaceAfter doesn't work, since there is no way to differentiate between object declarations and type hints (I still want name:Type for the latter).
• Using the { token in WhitespaceAfter doesn't work, since it also triggers on empty blocks {} and reification expressions.
• Using the } token in WhitespaceBefore doesn't work, since there is no WhitespaceBefore check yet ;)

[AlexHaxe]

How about writing a generic WhitespaceCheck, that has four modes: NoWhitespace, OnlyBefore, OnlyAfter and WhitespaceAround. It also has a list of tokens like in WhitespaceAround and a scope / context that limits where the mode applies. Possible scopes / contexts are ObjectDecl, FunctionDef, FieldDef, ArrayAccess, etc. Each check instance has one mode, multiple tokens and multiple scopes / contexts.

Depending on coding style WhitespaceCheck would occur multiple times in checkstyle.json, with different mode, token and context combinations, but I think that could cover all cases and we might even incorporate SpacingCheck (by opening up the range of supported tokens).

I have not started development, so if you would like to work on it, go ahead.

[Gama11]

Sounds good to me, I actually had something similar in mind!

For the modes I'd suggest different names: Before, After, Around and None.

[Gama11]

One question is whether the old whitespace checks should be removed when adding this (breaking change).

[AlexHaxe]

Maybe we can keep them (marked as deprecated), but refactor them to use new whitespace check with matching parameters, so they are like dumbed down versions of the full check.

[Gama11]

Seems like a good idea!