Wrong formatting settings clang-tidy in C++ template project

Closes CWG-48

.clang-tidy

-Checks: '-*,clang-diagnostic-*,llvm-*,misc-*,-misc-const-correctness,-misc-unused-parameters,-misc-non-private-member-variables-in-classes,-misc-no-recursion,readability-identifier-naming'
+Checks: '-*,clang-diagnostic-*,llvm-*,misc-*,-misc-const-correctness,-misc-unused-parameters,-misc-non-private-member-variables-in-classes,-misc-no-recursion,readability-identifier-naming,readability-braces-around-statements'
 CheckOptions:
   - key:             readability-identifier-naming.ClassCase
     value:           CamelCase
   - key:             readability-identifier-naming.EnumCase
     value:           CamelCase
+  - key:             readability-identifier-naming.UnionCase
+    value:           CamelCase
+# Within ASTRON no specific casing is used. Feel free to adjust
+# following casings to camelBack for existing projects or 
+# personal/team preferences.
   - key:             readability-identifier-naming.FunctionCase
-    value:           camelBack
+    value:           lower_case
   - key:             readability-identifier-naming.MemberCase
-    value:           CamelCase
+    value:           lower_case
   - key:             readability-identifier-naming.ParameterCase
-    value:           CamelCase
-  - key:             readability-identifier-naming.UnionCase
-    value:           CamelCase
+    value:           lower_case
   - key:             readability-identifier-naming.VariableCase
-    value:           CamelCase
+    value:           lower_case

[Marcel Loose]

It's been a while since I did active C++ development within ASTRON. But we used to have some standards:

• Class names in CamelCase
• (Member) function names in snakeCase
• Class variables start their name with the prefix its (or their for static class variables)

Insights may have changed, though. @wever should now about current SKA conventions (which are not necessarily ASTRON's conventions).

[Mark de Wever]

In team Schaap we use GoogleStyle, which has its own naming conventions. https://google.github.io/styleguide/cppguide.html#Naming

GoogleStyle is on of the SKA style guides too,

[Hannes Feldt]

@wever the google style is using CamelCase (or PascalCase) for methods. I can add that to the comment or even set is as a default if we want to go into that direction.

@loose For function names do you mean snake_case or camelBack (sometimes named camelCase)? About the prefixes: if we wont to go into that direction we ofc can add that as well but probably should first decide on a (common) style.

[Marcel Loose]

I meant camelBack (I thought that was usually referred to as snakeCase).

[Mark de Wever]

I think referring to a style-guide can't hurt. Google's is quite nice. (I really like they provide rationales for their choices, so you can see whether their reasoning applies to your organization.)

If there is no ASTRON sanctioned style we can make the default Google-style and hope others will start to use the same style. I really like it when code has a consistent style, that makes understanding it a lot easier.

[Marcel Loose]

For what it's worth. Here's our (20 year old!) ASTRON coding standard. coding_standard_C++_v2.1.pdf

[Mark de Wever]

Interesting, at that time ASTRON still used CVS ;-) But indeed this document is quite dated and it's not provided to new developers during their onboarding.

I wouldn't be against reviving this document.

[Marcel Loose]

We could pick this up in the CI/CD group. Maybe good to discuss within Team Schaap too.