TOML file parser

Learning
1

Is there an easy way to read the values from a toml file?

2

I’m using otoml, the library allow you to read the values directly from the toml document, but does not provide any high level function for parsing a whole configuration file (like declaring a field as mandatory, transforming a table into an OCaml record and so one).

For that, I’m using decoders, which gives me what I need to declare my configuration in a verbose way (using a generic decoder):

      let source =
        let* file = D.field "file" S.string
        and* name = D.field "name" S.string
        and* tab = D.field_opt_or ~default:1 "tab" D.int in
        D.succeed { Table.file; name; tab }
3

Please, if you’re writing a new application, consider a nicer configuration format - like JSON5. I’m working (on/off) on a JSON5 parser. But dhall would be even cooler - I am thinking of writing a parser for that, unless someone else has already started?

–
Ian

4

I completely agree, I try to only use scfg nowadays (disclaimer: I wrote the OCaml implementation).

But if you have to stick with toml, I recommend ez_toml.

5

Thank you for that information
I looked at ez_toml and searched for an example without success.
There is example code for scfg.
I would simply like to read a simple config file and save its values in variables.
In golang it’s one line of code and I was hoping it would be just as easy in ocaml.
Overall, I think it would be desirable if the libraries had corresponding examples

6

Did you file an example in the ez_toml repo asking for examples?

Edit: sorry I mean ‘did you file an issue’

7

I would be very grateful for examples

8

I am not sure if this is a good example, but here is a composition over ez_toml:

If you have an example in Golang of how TOML files are accessed in a typed-fashion in a few lines, I would be interested in seeing it to get some inspiration to improve the interface of ez_toml.

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9

I forgot to say, but the main advantage of ez_toml over other implementation of TOML in OCaml is that it also manages comments in the file.

10

FWIW, I updated the README.md with an example similar to the one in OToml: GitHub - OCamlPro/ez_toml: A library to parse and print TOML files

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