Red/REBOL are a data format first. Many native data types. Lisp uses Fexpr and Red use a basic token. Each character!

Originally Posted on Hacker News by 9214

Red (and Rebol) are based on research in denotational semantics that Carl Sassenrath did. I'll try to briefly explain the main points.

Everything starts with a UTF-8 encoded string. Each valid token in this string is converted to an internal data representation - a boxed structure 4 machine pointers in size, called a value slot or sometimes a cell.

Value slot is composed of a header and a payload. Header contains various flags and datatype ID, payload specifies exact content of the value. If content doesn't fit in one value slot, then payload contains a pointer to an external buffer (an array of value slots, bytes, or other units + offset and start/end addresses IIRC) with extra data.

So, lexer converts string representation to a tree of value slots (this phase is called loading), which is essentially a concrete syntax tree (CST) — this is the crux of homoiconicity.

https://github.com/red/red/wiki/%5BDOC%5D-How-Red-works,-a-brief-explanation

https://github.com/red/red/wiki/%5BDOC%5D-Guru-Meditations#contexts-and-binding

https://github.com/red/red/wiki/%5BDOC%5D-Function-Evaluation

Who cares if creators cant name things great. Forget names lets use and improve technology.

Also to be fully homoiconic, Meta needs to be able to manipulate its own code. Currently, that is done by REBOL 3. REBOL is homoiconic, and Meta is currently a REBOL 3 format. It will take a lot more to enable Meta to handle its own code, so that will take time. Even though REBOL and Red are homoiconic, they're not implemented in themselves. REBOL has a C interpreter and Red a Red/System interpreter. Meta is two to three orders of magnitude faster and designed to be able to implement itself eventually.