Note that any cache (eg LRU-eviction) is just a specific speculative model for future usage :-)

The cache can be backed by hardware/lookup, or by a cheap computation. The line between functions and data is really blurry.

Would you say it is homoiconic, similar to LISP where the syntax of the language is the AST; so, data can become code (Macros) and code can be data (the S-Expression)?