Online Forth Compiler Features
Stack-Based Programming Paradigm
- Experience Reverse Polish Notation where 2 3 + means "push 2, push 3, add" using this forth online editor
- Practice stack manipulation with DUP (duplicate), SWAP (exchange), ROT (rotate) operations
- Understand how embedded systems use Forth for firmware due to minimal resource requirements
- Learn computing history—Forth ran on space missions and early boot ROMs
Extensible Through Words
- Define custom operations with : SQUARE DUP * ; to create reusable words in this forth compiler
- Build complex programs by composing simple words—ultimate code reuse
- Test how Forth bootstraps itself from primitive operations to full language
- Perfect for understanding minimalist language design and bootstrapping concepts
Mental Model Training
- Thinking in Forth requires decomposing problems into stack transformations
- Practice factoring large problems into small, testable words
- Understand how constraints (stack-only data) force better program design
- Ideal for programmers exploring alternative paradigms beyond variables and functions
No gforth Installation Needed
- Run Forth code instantly without installing gforth or setting up embedded toolchains
- Share stack-based algorithms, embedded concepts, or Forth idioms via URLs
- Great for learning retrocomputing, embedded programming concepts, or alternative paradigms
- Test word definitions, stack operations, and control structures without local setup
Forth Keyboard Shortcuts
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This entire Forth compiler was built by Replit Agent 3 from a natural language prompt. Replit's environment facilitates rapid development, iteration and testing code for users of any technical ability. Develop software faster and better with Replit’s autonomous AI.
Get started freeFrequently Asked Questions
What is Forth used for?
Forth is used in embedded systems, firmware, and boot ROMs where minimal memory footprint matters. NASA used Forth in space missions. This forth compiler lets you experience stack-based programming that powers critical systems. While niche today, Forth teaches valuable problem decomposition skills.
How does stack-based programming work?
In Forth, all operations work on a data stack. 2 3 + means "push 2, push 3, add". DUP duplicates top stack item. SWAP exchanges top two items. This forth online editor shows how complex programs emerge from simple stack operations—a different mental model than variables.
Why learn Forth in modern times?
Forth teaches alternative computing paradigms and problem decomposition. Thinking in stack operations and word factoring improves design skills applicable to any language. Understanding Forth provides insight into PostScript, Factor, and embedded systems. It's mentally challenging and rewarding.
Can I define my own words in Forth?
Yes! Use : SQUARE DUP * ; to define a word called SQUARE. Then 5 SQUARE . prints 25. This forth playground supports word definitions—the core of Forth's extensibility. You build complex programs by composing simple, tested words.
Can I save Forth code permanently?
Yes! Click Share to generate a permanent URL for your Forth program. Perfect for sharing stack-based algorithms, embedded programming concepts, or demonstrating alternative computing paradigms. Your Forth code stays accessible indefinitely.
What Forth features work in this compiler?
This forth code runner supports core Forth: stack operations (DUP, DROP, SWAP, ROT), arithmetic, word definitions with : and ;, printing with . and emit, conditionals, and loops. Full gforth execution environment without local installation.
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