Forth is a stack-based programming language created by Chuck Moore. Its minimalist design and direct hardware control made it popular for embedded systems, astronomical software, and situations requiring maximum efficiency.
Design Philosophy
Forth is radically minimalist:
- Stack-based: Operations work on a stack, no variables needed
- Concatenative: Functions compose by juxtaposition
- Extensible: Define new words (functions) easily
- Interactive: Immediate feedback like REPL
- Tiny: Implementations in kilobytes
How It Works
Forth programs consist of “words” that manipulate a stack:
3 4 + . ( pushes 3, pushes 4, adds, prints 7 )New words are defined in terms of existing words, extending the language.
Applications
Forth excels in constrained environments:
- Embedded systems and microcontrollers
- Astronomical telescope control
- Boot loaders (Open Firmware)
- Real-time systems
Legacy
Forth influenced:
- PostScript (also stack-based)
- Factor and other concatenative languages
- Boot firmware on SPARC and PowerPC
- Minimalist language design philosophy