Context

The context holds the variables available when rendering a template. It is a nested key/value data structure.

Building the context

Patterns provide the core context by asking the user a question and associating the answer with a key.

Patterns, Overlays, and Compositions all have extra_context attributes that provide a method to add key/values to the context without prompting the user.

Overlays provide an answer_map attribute to map one pattern key/value to another.

Compositions use merge_keys to merge the values of common pattern keys.

Contexts are built iteratively question by question and pattern by pattern.

The default answer of a question to be the answer to a previous question.

Patterns may have keys that whose answers should be the same, but their keys are different. For example, one pattern might use project_name and another might use library_name. The overlay’s answer_map allows you to map the answer of project_name to answer of library_name.

Patterns that define complex data structures, such as lists or dicts, may be merged between patterns using the composition’s merge_keys attribute. For example, if several patterns define a requirements dict as in their extra_context, you can have the composition merge all the values of requirements.