Disornamentation    (see also ornamentation)

Introductory Examples

• Ornamenting nat to list is one of the smallest examples of ornamentation. The code obtained can be disornamented without user interaction: from lists to nat.
• Disornamentation makes it possible to go back and forth between the ornamented and disornamented code. This example demonstrates several features of the new prototype: disornamentation; adding new constructors; edition of the ornamented code and of the disornamented code, while keeping both synchronized. From bare expressions to localized expressions. At this occasion, we introduce the robust patch language.
• From red-black trees to trees without any balancing information. This disornamentation removes data that is used in the computation. Therefore, one needs to supply patches.
• Using an ornament, sets can be converted to maps. Surprisingly, the code of sets can be obtained by ornamentation from maps. Indeed, there is an isomorphism between unit map and set. However, it is more natural to obtain this code with disornamentation. This example demonstrates disornamentation on a larger example: maps to sets by disornamentation.

Other Transformations

• From an interpreter with named variables to a De Bruijn interpreter: this example features a transformation that mixes ornamentation and disornamentation.
• Other transformations can be dealt with in this framework. Adding new independent constructors: an example on a tiny language where we add substraction.

Technical Examples

• Dead code elimination
• Disornaments are implicitly polymorphic as there is no need to constrain the type of variables that are removed. Therefore, we wrote a small example which explains why it is needed and how it works.