Removing the super-table from toToml output

[bradenhilton]

If you use the toToml template function with nested dicts, you may notice the super-table in the output:

❯ chezmoi execute-template '{{ dict "key1" (dict "key2" (dict "values" (list "value1" "value2"))) | toToml }}'
[key1]
[key1.key2]
values = ['value1', 'value2']

The super-table is unnecessary:

You don't need to specify all the super-tables if you don't want to. TOML knows how to do it for you.

# [x] you
# [x.y] don't
# [x.y.z] need these
[x.y.z.w] # for this to work

[x] # defining a super-table afterward is ok

To remove the super-table, you can combine splitList, rest and join like so to remove the super-table line (requires one template action {{ ... }} per super-table dict):

❯ chezmoi execute-template '{{ dict "key1" (dict "key2" (dict "values" (list "value1" "value2"))) | toToml | splitList "\n" | rest | join "\n" }}'
[key1.key2]
values = ['value1', 'value2']

[twpayne]

To remove the super-table, you can combine splitList, rest and join like so:

This removes the first line of the output, not all super-tables.

[bradenhilton]

It's easier in code for sure. For one, I don't think the template functions support capture groups, hence all the intermediate steps. The example I posted doesn't handle .s within quotes ('a.b'.c) as well.

The super-tables also don't alter the functionality of the file, but having the option to remove them can help with modify_ templates. Similarly, also having the ability to select between single and double quotes would be ideal, but I don't think pelletier/go-toml supports either of them.

[halostatue]

pelletier/go-toml explicitly only supports single quotes unless the string requires double quotes (v2 is much more opinionated than the first version). It looks like @twpayne switched to directly using pelletier/go-toml three years ago and removed the previous dependency BurntSushi/toml.

I just tested BurntSushi/toml and it has the same output as pelletier/go-toml, except indented (and it does not appear to have the same configuration flexibility as pelletier/go-toml).

Unless we're going to post-modify TOML output (which I don’t really think is a good idea, despite my suggestions above). The parent keys aren't necessary, but are legitimately in spec.

[twpayne]

Unless we're going to post-modify TOML output (which I don’t really think is a good idea, despite my suggestions above). The parent keys aren't necessary, but are legitimately in spec.

+1 on this.

Note also that the generated config file is for machine consumption, so we shouldn't care too much about removing in-spec behavior. The fromToml / toToml round trip also removes comments so the resulting file isn't particularly human-friendly.

[bradenhilton]

I'm unsure if there is a prevailing impression that I was making a feature request but this is not the case.

This is an extremely niche use-case, and I deliberately posted this in "Show and tell" in the event that anyone else was looking to accomplish the same and didn't know where to start.

[halostatue]

No, I knew that this is musing far more than anything else. But the musing is still interesting.