When comparing Objective-C vs Rebol, the Slant community recommends Rebol for most people. In the question“What is the best programming language to learn first?” Rebol is ranked 49th while Objective-C is ranked 65th. The most important reason people chose Rebol is:
Almost natural language, for example: `write %out.html read http://google.com`.
Ranked in these QuestionsQuestion Ranking
Pro Well Documented
Objective-C's documentation exists on Apple's website, and explains language features in detail.
Pro Develop Apple applications
Similar to C# and Java, but used to develop native applications for Apple hardware.
Pro Objective-C supports an open style of dynamic binding
A style that can accommodate a simple architecture for interactive user interfaces.
Pro Human friendly
Almost natural language, for example:
write %out.html read http://google.com.
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 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 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 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.
Con Odd Syntax
Objective C's syntax is very alien to other languages. Learning Objective-C first will fail to expose you to a syntax style that would be relatively familiar in almost any other language.
Con Might as well learn Swift
Swift works almost anywhere Objective C does, and it was designed to replace Objective C.
Con One of the biggest mistakes ever.
It was meant to be one of the C-style languages, but has such bad syntax design it actually is the odd duck.
Con Apple-centric and obsolete
Con Tied into Apple's eco-system.
Con More Technical
To be able to do basic tasks in Objective-C requires a strong understanding of programming.
Con Requires Understanding of C-language.
Objective-C is built on top of C, and as such, requires at least a basic understanding of how to program in C.
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 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.