Token replacement of {values} in strings?

[subdigital]

I browsed the string parser source and doesn't look like this is supported, and might be a little tricky to implement. I wanted to gather some suggestions before working on a PR to add this.

Our strings have substitutable tokens in them like this:

The farmer has {appleCount} apples in the {placeName}.

Our current code generator (which is showing its age) generates functions for these, and the tokens become the argument names of the function, like this (it's in obj-c, but writing Swift here for simplicity):

func farmerAppleCountMessage(appleCount: String, placeName: String) -> String {
    // ...
}

I know that Swiftgen supports %d and %@, et. al, natively, but given we have thousands of strings and multiple platforms, that part is not really flexible.

I'm wondering if this project would be amenable to a solution like this:

• a new type of metadata for the parser:

extension Strings {
  struct Entry {
    var comment: String?
    let key: String
    let translation: String
    let types: [PlaceholderType]
    let tokens: [String] // ← new
    let keyStructure: [String]
    // ...
  }
}

Then modify the parser to find & fill out this tokens array with any instance of \{[^\}+]\} it finds.

• The next change would require modifying the template to take advantage of this and generate a method that takes these string arguments.

Considerations

• A situation that supported both types and tokens would be a little awkward, but possible.
• Modifying the templates might cause unexpected downstream changes, so perhaps a new template choice could be offered.

Eager to hear the teams thoughts about a solution like this, or if you have any simpler suggestions to achieve the same result.

✌️