Multiple inputs to a template (e.g. a "pattern constraint")

[dontlaugh]

Can there be multiple inputs to a template?

// All contexts collected under top-level "contexts:" key
contexts: [Name=_]: #Context & {
    name:        Name
    password:       Name
    favorite_color: #DefaultColor
}

In this template I can provide "Name" like so:

contexts: context_one: {}
contexts: context_two: {}

Is there some way to provide another "parameter" to the template?

[verdverm]

"Templates" have gone through a few names and have also been called "Bulk Optional Fields" and "Pattern Constraints." I believe Pattern Constraints is the correct usage now. (and tour/types/templates/ needs to be updated. See the paragraph before the 3rd code block here: https://cuelang.org/docs/references/spec/#structs

In this sense, you are matching field labels and providing constraints. There are a couple of things you do.

1. Provided more labels and matching

context: [Role=_]: [Name=_]: & {
  name: Name
  role: Role
  foo: "bar"
}

context: {
  admin: {
    bob: _
    mary: _
  }
  user: {
    darth: _
    sue: _
  }
}

This implies nesting your values of interest under more fields.

2. Use the function pattern

#MakeUser: {
  Name: string
  Role: string
  
  Result: {
    name: Name
    role: Role
    foo: "bar"
  }
}

user: (#MakeUser & { Name: "bob", Role: "user" }).Result

You could loop over a list of "inputs" and generate the more complete data this way