Some thoughts:

• as a context, we can either provide a data type ID, or, for convenience, a property ID.

• we need validation, parsing, and formatting. since we often need combinations of these, they could be combined in a module, so these operations can be performed in a single call. Perhaps like this:

• input is either given as JSON, or as a string. In the latter case, it is parsed to get the JSON structure.
• a DataValue is constructed from the JSON structure, based on info from the data type.
• validation is always performed on the DataValue
• the result is the DataValue serialized as JSON (could be omitted if that was the input)
• in addition, a formatted version of the DataValue can be requested as output.

• Note that formatting can depend on a lot of factors: data type, desired output format (html?), current language and variant, user settings (e.g. babel, perhaps even preferred unit system), etc.

Gerard.meijssen wrote:

Being able to easily the #Babel information with an API allows "Reasonator" to apply language fall back.