File naming style

[maliberty]

OpenROAD has a mixed of file naming styles for source code. AI summarizes:

┌────────────┬────────────────┬─────┬─────┬─────┬──────┬───────────┬─────┐
│            │                │     │ SWI │     │ Pyth │ Web (JS/C │ Tot │
│   Style    │    Example     │ C++ │ G   │ Tcl │  on  │ SS/HTML)  │ al  │
│            │                │     │ .i  │     │      │           │     │
├────────────┼────────────────┼─────┼─────┼─────┼──────┼───────────┼─────┤
│ lowerCamel │ dbNet.cpp, nes │ 751 │   1 │   2 │    2 │         – │ 756 │
│ Case       │ terovPlace.cpp │     │     │     │      │           │     │
├────────────┼────────────────┼─────┼─────┼─────┼──────┼───────────┼─────┤
│ UpperCamel │ RepairDesign.c │ 667 │  17 │  16 │    – │         – │ 700 │
│ Case       │ c, Resizer.tcl │     │     │     │      │           │     │
├────────────┼────────────────┼─────┼─────┼─────┼──────┼───────────┼─────┤
│ lowercase  │ grid.cpp,      │     │     │     │      │           │     │
│ (single    │ pdnsim.i,      │ 214 │  30 │  20 │    3 │        11 │ 278 │
│ word)      │ main.js        │     │     │     │      │           │     │
├────────────┼────────────────┼─────┼─────┼─────┼──────┼───────────┼─────┤
│ snake_case │ web_gif.cpp,   │ 160 │   1 │  18 │   12 │         – │ 191 │
│            │ run_ext.tcl    │     │     │     │      │           │     │
├────────────┼────────────────┼─────┼─────┼─────┼──────┼───────────┼─────┤
│ kebab-case │ tile-merge.js, │   2 │  28 │   – │    – │        36 │  66 │
│            │  Resizer-py.i  │     │     │     │      │           │     │
├────────────┼────────────────┼─────┼─────┼─────┼──────┼───────────┼─────┤
│ Class_suff │ FlexDR_maze.cp │     │     │     │      │           │     │
│ ix / mixed │ p, OpenRCX_pro │  38 │   – │   1 │    2 │         1 │  42 │
│            │ cess.tcl       │     │     │     │      │           │     │
├────────────┼────────────────┼─────┼─────┼─────┼──────┼───────────┼─────┤
│ Total      │                │ 1,8 │  77 │  57 │   19 │        48 │ 2,0 │
│            │                │  32 │     │     │      │           │  33 │
└────────────┴────────────────┴─────┴─────┴─────┴──────┴───────────┴─────┘

I'd like to pick one style and rename (core code, not third party or submodules). My personal preference is kebab-case for the simple ergonomics of being able to type a filename without needing the shift key. I'd like community input before setting a rule and updating.

Notes:
docs/contrib/CodingPractices.md:66 only says "Don't use prefixes on file names. That's what directories are for."

Class_suffix style (e.g. FlexDR_maze.cpp, FlexPA_init.cpp) is a smell of overly large classes.

[QuantamHD]

Personally I like camel case, but shouldn't we try to minimize the number of renames. I'm not sure what the state of the art is, but my understanding is that if you rename you lose the history of that file

[maliberty]

git can show the history across renames (so long as it is a pure rename)

[maliberty]

git log --follow

[gadfort]

I like camel case, but kebab-case is fine as well if that is what folks prefer.

[jhkim-pii]

I like the camel case. It looks more intuitive because the key class name and file name match.

[maliberty]

db objects break this (e.g. dbNet). Arguable the db prefix shouldn't be there with namespaces but changing it now would be very disruptive.

[vvbandeira]

kebab-case is my personal preference, but it can be a pain with Python if one ever needs to import them.

lowerCamelCase + allowing single word file = more than 50% of the files already comply

[QuantamHD]

@maliberty This is a good point and google does ban - in folder and file names because of it

[maliberty]

https://google.github.io/styleguide/cppguide.html#file-names

Filenames should be all lowercase and can include underscores (_) or dashes (-).

[AcKoucher]

I also like lowerCamelCase and we already have quite some files following it :-)

[bnmfw]

I'm a fan of snake_case, but kebab-case does the work just as well, I like to see words separated, I'm just used to the first.

[maliberty]

Claude also raised this concern:

Case-insensitive filesystems are the biggest risk, and nobody raised it. macOS and Windows treat Resizer.cpp and resizer.cpp as the same file. Any camelCase convention leaves room for collisions that differ only in case. Moving to camelCase would also mean case-only renames like RepairDesign.cc to repairDesign.cc, which git handles badly on those systems. An all-lowercase rule removes this whole class of bugs.

[maliberty]

snake case (or kebab) would avoid this.

[bnmfw]

Did not know that. Good to know

[maliberty]

The python concern argues against kebab case (I'd avoid using different conventions by langauge). The case insensitive issue argues against camel case. It seems like snake_case avoid both. The mapping from class name to file name is pretty simple (FooBar -> foo_bar).

I would do the renaming one tool per PR in bottom up dependency order.

Any further thoughts?

[gadfort]

snake_case seems good to me

[AcKoucher]

that seems fine!