When comparing Rebol vs V, the Slant community recommends V for most people. In the question“What is the best programming language to learn first?” V is ranked 4th while Rebol is ranked 51st. The most important reason people chose V is:
V is easier than C and fast like C.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Very simple syntax
Rebol's name came from "Relative Expression Based Object Language". Rebol is a functional language and everything is an expression that returns a value. Things that have to be baked into the grammar in other languages are simple function calls with block arguments in Rebol.
Pro Homoiconic
Code is data, and data can be code. Rebol is based on a simple block data structure, used both for data and for the code itself. Blocks can be manipulated programmatically, and then evaluated as code. This makes metaprogramming easy in Rebol.
Pro Human friendly
Almost natural language, for example: write %out.html read http://google.com
.
Pro Graphical user interface
Beginners are usually stuck making command-line applications in other languages, because GUIs are too hard. Rebol GUIs are easy enough to start with.
Pro Domain specific languages
Rebol's simple homoiconic syntax makes it easy to create "Rebol dialects"--domain-specific languages optimized for a particular purpose. The Rebol distribution includes many of these, and users are free to create more. These DSLs make tasks that would be complicated to express in other languages easy.
Pro Fast like C
V is easier than C and fast like C.
Pro C Interop
Can import C libraries, structs, and headers.
Pro Cross-platform
Compile to many OSes.
Pro Simplicity
V is simple and powerful.
Pro Can create multi-OS GUIs
Multi-OS GUI creation is more integrated into the language than others.
Pro Clear syntax
Highly understandable language.
Pro Sum types
V has Sum Types.
Pro Generics
V has generics.
Pro Closures
V has closures, which gives the user additional options and usefulness.
Pro Safety
V is very safe.
Pro Single paradigm
Follows the philosophy that there should be only one way to do something, as opposed to multi-paradigm languages like C++.
Pro Supports concurrency and channels
Can run functions concurrently that communicate over channels.
Pro Fast compile times
Compiles programs fast, less waiting around, so more productive and fun.
Pro Friendly and helpful community
Just check the V Discord channel or their GitHub Discussions and you will see by yourself.
Pro Inline assembly
Can add Assembly code.
Cons
Con Not (yet?) Free Software
Rebol 2's core is free (gratis) for commercial use, but the license prohibits modification, a violation of the DFSG. Rebol 3 is Free Software (Apache 2.0), but isn't production ready.
Con Very niche language
Small community.
Con No separators
A function call expression has no parentheses, and there are no separators between sequenced expressions, not even newlines. This means that you have to know the arity of every function in an expression to know how to parse it. It also means you can run into subtle, hard-to-find bugs if you don't provide enough arguments, since the result of the next expression will be passed instead.
Con Rapid changes in a language syntax/features
Since V language under a continuous development and core syntax and features will be "frozen" in a version 1.0.0, updating from older version of a language can cause a code rewrite of previously working program.
Con V 1.0 release was planned for December 2019
The first version of the language was publicly released in June of 2019, version 0.1.x. First beta version of the language was released June of 2022, version 0.3. x. Language has progressed faster than most. Welcomes contributors to join the project.