Overview
In many cases, you may need to translate a string from one language to another. For example, when converting Pascal to C or C#, you might need to map the Pascal type integer to int or Int32. Didot provides a feature called mappings, which allows lookup-based translation using a dictionary.
This feature enables the template engine to perform key-based substitution: when rendering a property, the engine checks a predefined dictionary to find a corresponding value for the given key and outputs the mapped result. To register a dictionary, you need to use the method AddMappings from an ITemplateEngine. The arguments correspond to the name of the dictionary and all the keys/values defined in a dictionary.
Registering a Mapping Dictionary
To register a dictionary, use the AddMappings method of an ITemplateEngine. The method requires:
- A dictionary name – the identifier for the mapping.
- Key-value pairs – defining how values should be translated.
Using Mappings in Templates
Once registered, mappings can be applied directly in templates by referencing the dictionary name.
var factory = new FileBasedTemplateEngineFactory();
var engine = factory.GetByTag(tag);
engine.AddMappings("greetings", new Dictionary<object, string>() { {"french", "Bonjour"}, {"english", "Hi"}, {"spanish", "Ola"} })
Assume the model contains a property Language, and a dictionary named greetings has been registered to provide translations. The following examples demonstrate how to apply mappings across different template engines:
Fluid and Scriban
Greetings in {{model.Language}} is {{model.Language | greetings}}
Handlebars
Morestachio
StringTemplate
Greetings in <model.Language> is <greetings.(model.Lang)>
Liquid and SmartFormat
This feature is not supported.
Conclusion
The mappings feature in Didot simplifies value translation using predefined dictionaries, making it particularly useful for language conversions, type mappings, and localization tasks. By leveraging this feature, templates remain clean, dynamic, and easy to maintain.
