Picking TOML vs YAML boils down to personal preference. Both formats work robustly… it’s not “rookieness” to pick TOML. I use the TOML syntax, and prefer it over YAML and JSON.
Like any new syntax you come across, you just have to learn it. I’d suggest quickly skimming through the TOML v0.4 spec/README (v0.4 is used by Hugo, the latest version is 0.5).
The beauty (eye of the beholder) of TOML is that it is not whitespace/indentation sensitive; it is line-position sensitive. While YAML using indentation to define nesting (which I don’t like :)), TOML simple defines a table header, and then all table contents below that header line. I also prefer TOML’s syntax for multi-line strings, which looks like that in Python or Nim.
Sorry, I should have made clear that I do use TOML for the main config file since that is what all of the documentation uses. I use YAML for all my post metadata though - this is also because I converted some of it from a previous Jekyll site which uses YAML as well.
I love the fact that Hugo doesn’t force you to choose one over the other.
As an Information Management specialist, I don’t like tools that apply unnecessary and hidden restrictions. TOML can’t be used easily without knowing that one specific limitation. Hugo happens to be the only tool I’ve ever come across that uses TOML.
You are absolutely correct of course though, this is down to personal preferences.
Also, when getting going with Hugo, it is not clear that you need to know something critical about TOML not to get caught out by this issue. Indeed, if you’ve never come across TOML before, how could you know? I never had to read a manual to use YAML
Interesting that you should mention Python because, of course, YAML is much closer to Python than TOML. Given that Python is indentation-based. As it happened, Python was the first “modern” scripting language I learned (I don’t count PERL as modern). This means that I am much more comfortable with YAML than TOML and I find its terseness a lot more to my liking.
Again, though, just preferences. Depends where you started and the journey you took.
Well, just one last comment. It might be useful to add a footnote to the documentation on the config file about the vertical positioning issue with TOML since this does crop up from time to time.