¶ Rebol
¶ Programming Languages
If you’ve ever felt that programming languages tend to fall into the same predictable patterns—syntax-heavy, rigid, endlessly verbose, and too often dictated by trends rather than vision—then exploring Rebol will feel like stepping into a different universe. A quieter, more thoughtful universe. One where expressiveness matters more than ceremony, where programs read more like ideas than machinery, and where the guiding philosophy is not “add more features” but “capture human intent as simply as possible.”
This introduction begins a long journey: one hundred articles devoted to understanding Rebol—not just how it works, but why it works the way it does, why it feels so different from mainstream languages, and why people who truly learn it often speak of it with an almost artistic appreciation. Rebol is not the biggest language, nor the most marketed, nor the most academically praised. Yet it remains one of the most uniquely designed programming languages ever created, with a clarity of purpose and boldness of experimentation that very few languages have dared to pursue.
Before diving into the deep waters, it’s worth taking a moment to set the stage for what makes Rebol worth studying with this much depth.
Rebol was created by Carl Sassenrath, the architect behind the original AmigaOS kernel—one of the most elegant operating system designs of its time. When you approach Rebol with that bit of history, its design suddenly makes sense: this is a language built by someone who cares deeply about making systems powerful and human-friendly. Someone who believes computers shouldn’t require humans to constantly contort their thinking into rigid syntactic structures. Someone who clearly asked, “What if programming could feel more like expressing ideas and less like writing machine-oriented instructions?”
Rebol answers that question with its core principle: express code as data, and data as code, with as little friction as possible. It’s a language built around the idea of dialects—small, purpose-built mini-languages embedded within Rebol itself. These dialects let you create expressive, compact domain-specific languages with astonishing ease. Instead of forcing every problem into the same mold, Rebol lets the language shape itself around your intent. Very few languages have this kind of flexibility baked into their foundations.
But this course isn’t just about what Rebol can do—it’s about how it changes the way you think about programming. When you learn Rebol deeply, you begin to see that many tasks programmers treat as “complex” are only complex because the languages they’re written in impose unnecessary complexity. You begin to appreciate how a tighter focus on human expression, less on compiler convenience, can reshape the entire programming experience. You begin to understand that minimalism doesn’t mean limitation; it means clarity, precision, and a kind of linguistic elegance that lets ideas flow without friction.
Rebol is often described as “tiny,” but don’t mistake that for shallow. Rebol is tiny in the way a well-crafted tool is tiny: everything extraneous stripped away, everything essential sharpened. You won’t find redundant syntax, needless punctuation, sprawling keywords, or heavy scaffolding. What you will find is intentionality. Rebol asks you to care about clarity. It pushes you to think about the shape of your data. It invites you to build abstractions that fit the problem rather than bending the problem to fit someone else’s abstraction.
As you progress through the coming articles, you’ll notice a shift in your thinking—often subtle at first. You’ll start writing shorter code without even trying. You’ll start finding yourself annoyed at languages that force you to type symbols that don’t matter. You’ll become more aware of the difference between language complexity and problem complexity. It’s not that Rebol magically removes all difficulty—no language could—but it gives you tools that align with the natural ways humans reason about tasks.
Let’s take a moment to talk about what makes Rebol different from languages you might already know. Many languages try to solve the “everything is text” problem by piling on abstractions, macros, elaborate syntax, complex type systems, or huge frameworks. Rebol approaches it differently: by embracing simplicity and unifying code and data into a single coherent model. Instead of having one mechanism for structuring data, another for defining code, and still another for configuration, Rebol treats everything as a series of human-readable values. This means you’re always speaking the same language—whether you’re describing logic, data, or structure.
As a result, Rebol scripts often look like small narratives, almost prose-like in places. They don’t overwhelm you with punctuation. They don’t bury logic under layers of syntactic rules. They don’t force you into rigid structural molds. This freedom isn’t chaos, though—the language is carefully designed so that its flexibility doesn’t erode clarity. That balancing act is one of the most impressive things you’ll discover: how Rebol remains both expressive and disciplined.
One of the most surprising aspects of Rebol—especially to newcomers—is just how small the language is. The core concepts can be explained in a single sitting. But mastering what the language enables? That’s a longer, more rewarding journey. This course embraces that journey fully. We’ll explore the deep ideas behind series, paths, contexts, blocks, words, binding, evaluation, dialects, and Rebol’s unique dataflow model. We’ll look at how something so small can create such rich behaviors. We’ll explore examples that show how little code you actually need to express meaningful, complex ideas.
Rebol encourages you to think about data in ways that feel natural. You’ll find yourself crafting solutions where the code mirrors your mental model almost exactly. This is one of the biggest differences between Rebol and traditional languages: the distance between thought and implementation is dramatically smaller.
But Rebol isn’t just a language—it’s a philosophy. It’s a reminder that programming languages don’t all have to chase bigger toolchains, more features, more syntactic sugar, or endless layers of abstraction. Sometimes the best improvement is subtraction. Sometimes the best innovation is returning to fundamentals and asking, “What truly matters?” Rebol is that kind of innovation—a language that tries to make programming simpler by treating humans as first-class participants in the process.
Over the years, many who’ve learned Rebol deeply report something unexpected: after spending enough time with it, going back to other languages often feels cumbersome, almost archaic. Rebol trains your brain to seek simplicity and clarity. It teaches you to strip problems to their essence. It encourages you to build mini-languages that match your domain instead of bending your domain around a generic programming model. And once you’ve learned to think this way, you don’t easily unlearn it.
Yet Rebol is not a language that screams for attention. It doesn’t demand you follow an ecosystem. It doesn’t need endless frameworks to feel complete. It doesn’t require ceremony. It quietly offers power, and trusts you to use it thoughtfully.
This course is designed for people who want to understand Rebol at that deeper level—not just how to write scripts, but how to appreciate the design behind them. We’ll explore Rebol’s series model, which is one of the most beautifully consistent models in any programming language. We’ll look at Rebol’s evaluation rules, which give it a Lisp-like depth without Lisp’s heavyweight parentheses. We’ll explore binding, which gives Rebol its dynamic flexibility. We’ll explore contexts, which provide structure without rigidity. We’ll explore how Rebol builds entire domain-specific languages inside itself using blocks as malleable building material.
And of course, we’ll explore dialects—the crown jewel of Rebol. Dialects are what let you write expressive, almost poetic mini-languages for everything from UI layout to drawing to configuration to parsing to network protocols. If you’ve ever wished you could express a task in a small, custom mini-language rather than in verbose general-purpose code, Rebol makes that wish effortless. It’s one of the few languages where fully custom micro-syntax is not a hack but a core design feature.
Throughout these articles, we’ll also look at real-world tasks: building network clients and servers, processing structured data, crafting user interfaces, performing computations, and creating tools that feel tailored to the problem at hand. You’ll see how Rebol thrives in tasks that require flexibility, expressiveness, and human readability. You’ll see how it gracefully adapts to both simple scripts and deeply structured systems.
Rebol also invites a stillness that few languages do. When you write Rebol, you’re not constantly bombarded with noise. You’re not juggling ten layers of abstraction. You’re not fighting the compiler. You’re not scanning lines of syntax. Instead, you’re often shaping small, elegant blocks of values that align closely with the ideas you’re expressing. It’s a calm experience—something programming rarely provides these days.
You’ll see how Rebol encourages exploration. You’ll find yourself experimenting inside the interpreter, trying small expressions, shaping blocks on the fly, building concepts incrementally. Rebol is interactive in the most human-friendly way: it lets you test ideas quickly, revise freely, and build understanding organically.
This approach makes learning Rebol not only informative but genuinely enjoyable. At times it feels almost meditative. The clarity of the language helps you focus on the essence of the task. And as you get better, you’ll find yourself solving problems with fewer lines, fewer concepts, and fewer moving parts.
As we move through this long course, think of it as learning a new way to think, not just a new syntax to memorize. Rebol asks you to think clearly about values, about evaluation, about structure, about the relationship between code and data. It teaches you to write code that reflects human reasoning instead of machine language expectations. It encourages you to craft solutions that feel natural instead of forced.
And perhaps most importantly, Rebol reminds you that programming can be elegant. It can be expressive. It can be humane. It can even be beautiful.
This introduction is your first step into that world. Ahead lie many articles, each exploring a different facet of Rebol’s design, behavior, or philosophy. By the end of it, you won’t just know how to write Rebol code—you’ll understand why Rebol is shaped the way it is, and why so many people who discover it keep returning to it even after exploring countless other languages.
Rebol is a language worth knowing. Worth studying deeply. Worth appreciating with patience and curiosity.
¶ Rebol
¶ Beginner Level
1. Introduction to Rebol: A Simple and Powerful Language
2. Setting Up Your Rebol Environment
3. Your First Rebol Program: "Hello, World!"
4. Understanding Rebol’s Syntax and Structure
5. Rebol's Data Types: Atoms, Strings, and Booleans
6. Working with Numbers in Rebol
7. Creating and Manipulating Strings in Rebol
8. Introduction to Lists and Blocks in Rebol
9. Tuples and Paren Expressions in Rebol
10. Understanding Rebol's Unique Data Types: Sets and Rebol Objects
11. Variables and Binding in Rebol
12. Basic Arithmetic and Operators in Rebol
13. Control Flow: Using if, else, and switch in Rebol
14. Working with Loops in Rebol: foreach, while, and for
15. Using Functions in Rebol: Creating Your First Function
16. Understanding return and exit in Functions
17. Creating and Working with Blocks in Rebol
18. Conditionals and Logical Operators in Rebol
19. Using probe and print for Debugging in Rebol
20. Handling Errors and Exceptions in Rebol
¶ Intermediate Level
21. Advanced Data Types: Using Rebol’s Objects and Refs
22. Creating and Managing Functions with func
23. Working with Rebol’s Native Functions
24. Accessing and Modifying Data in Rebol Objects
25. Managing Scope with local and global
26. The Power of Block Manipulation in Rebol
27. Pattern Matching and Parsing in Rebol
28. Using parse to Process Text and Data in Rebol
29. Introducing and Using with for Scoping
30. Working with Rebol’s catch and throw for Error Handling
31. Using do for Evaluating Code Dynamically
32. Understanding Rebol’s Garbage Collection
33. Working with Rebol’s Built-In Functions and Libraries
34. Rebol as a Lightweight Scripting Language
35. Advanced String Manipulations and Regular Expressions in Rebol
36. Creating Simple Games with Rebol
37. Using rebol/view for GUI Programming
38. Introduction to Rebol’s Networking Capabilities
39. Building and Parsing JSON in Rebol
40. Working with Dates and Times in Rebol
41. Rebol’s Event Loop and Asynchronous Programming
42. Creating Rebol Scripts for Automation
43. Using Rebol to Interact with Files and Directories
44. Advanced Loops and Iteration in Rebol
45. Modularizing Your Code with Rebol’s include and import
46. Creating Custom Data Types and Structures in Rebol
47. Handling User Input in Rebol
48. Manipulating Data: reduce, map, and filter
49. Building Rebol Applications with Custom User Interfaces
50. Using time and timer to Create Time-Dependent Code
¶ Advanced Level
51. Metaprogramming in Rebol: Code as Data
52. Using Rebol’s make for Creating Objects Dynamically
53. Advanced Block and Function Manipulation in Rebol
54. Building and Using Rebol’s Native Extensions
55. Networking in Rebol: Sockets and HTTP Requests
56. Working with Threads in Rebol: Parallel Programming
57. Writing a Web Server in Rebol
58. Creating a Rebol REST API
59. Database Connectivity in Rebol
60. Advanced Error Handling in Rebol: try and catch
61. Building a Command-Line Application in Rebol
62. Creating Complex Systems with Rebol Objects
63. Using serialize and unserialize in Rebol
64. Creating and Managing Complex GUI Applications with Rebol/View
65. Rebol and Web Technologies: Building Web Applications
66. Integrating Rebol with External Systems Using JSON and XML
67. Rebol for IoT: Interfacing with Hardware
68. Building Dynamic Dashboards with Rebol
69. Building a Game Engine in Rebol
70. Advanced Object-Oriented Techniques in Rebol
71. Optimizing Performance: Profiling and Debugging in Rebol
72. Advanced Parsing Techniques in Rebol
73. Using Custom Functions and Metafunctions in Rebol
74. Creating Complex Event-Driven Systems in Rebol
75. Advanced File I/O Operations in Rebol
76. Handling and Manipulating Large Datasets in Rebol
77. Creating a Graphical User Interface with Rebol/View
78. Understanding and Using Rebol’s Special Forms
79. Rebol and Web Scraping: Fetching Data from the Web
80. Building Cross-Platform Rebol Applications
81. Optimizing Memory Management in Rebol
82. Implementing Cryptography and Security in Rebol
83. Creating Custom Extensions with Rebol
84. Using Rebol for Real-Time Applications
85. Creating a Dynamic Template System in Rebol
86. Using Rebol’s find and insert for Data Search and Insertion
87. Creating and Managing Large-Scale Rebol Projects
88. Advanced File System Operations in Rebol
89. Building a Rebol-based Web Scraper
90. Rebol for Data Visualization and Analysis
91. Creating an Interactive Chatbot with Rebol
92. Building Complex Command-Line Tools with Rebol
93. Implementing Security Features in Rebol Applications
94. Creating a Full-Stack Application with Rebol
95. Understanding and Using Rebol’s Reflection Capabilities
96. Building and Deploying Rebol Applications
97. Deploying Rebol Applications to the Web
98. Rebol and Mobile Development: Building Mobile Apps
99. Using Rebol for Machine Learning and AI Applications
100. The Future of Rebol: Community, Tools, and Ecosystem Growth