xplain lets analysts write XML files containing explanation and interpretation texts for R statistical functions, with embedded R code that reacts to the user’s actual output values. Explanations can be layered by language and complexity level, and can iterate over elements of a function’s return object.

What’s covered#

  • Purpose and application – wrapping functions with adaptive contextual explanations
  • xplain XML structure – <xplain>, <package>, <function>, <result>, <title>, <text> elements
  • Main attributes – name, lang, level
  • Attribute inheritance and necessity
  • Including R code – !%% ... %%! delimiter tags with access to the return object via @ and ##
  • Using placeholders – <define> elements and !** ... **! tags
  • Iterating through return objects – foreach attribute for matrices, vectors, and lists
  • Calling xplain – direct call and wrapper function using xplain.getcall