Suggestion: allow use of variables

[gustavofujita]

Something like string interpolation:

key = "value"
another = "The value is %value%"

ip = "10.0.0.1"
server_ip = %ip%
remote_ip = %ip%

[pradyunsg]

I don't think this complexity belongs in TOML -- rather it is better suited for a templating engine or as an application-specific, if it is deemed necessary by the tool authors.

This has been previously brought up in #686, #528, #606 and more. Please read those.

[KOLANICH]

It is a feature of YAML.

[KOLANICH]

(partially, no templating, but pointers reuse are supported)

[marzer]

It is a feature of YAML.

This alone is not really an argument for or against it being a part of TOML (personally I'm very strongly against bringing TOML closer to YAML for many, many reasons); different languages can have different scopes, and that's OK.

[KOLANICH]

I completely aggree. I personally am aginst interpolation in package metadata formats, because package metadata are the thing that must be automatically scannable and indexable. But allowing sharing vars opens it to billion laughs attack.

[Moosems]

I believe that variables in a data-oriented language can still be simplistic and it removes a lot of boilerplate code and repetition.

[eksortso]

This issue was closed months ago. @Moosems If you have an idea for a very simple (and very safe) way to implement variables and string interpolation in TOML without making the standard any less obvious upon first inspection, then go ahead and open a brand new issue. But do read through #686, #528, and #606 first, at least.

I'm personally not against the idea, but if there's any more than one pass of string interpolation in your proposal, consider me out.