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Forth is an interesting language, it’s not for the average crowd. It encourages minimalism and a personally defined environment. It fits quite comfortably is small CPU environments as it requires few resources and applications are similar in nature.

It has a few concepts that are different from other languages;

  1. The use of the stack to pass information to other functions (WORDS) this allows for a much faster execution while calling other words.
  2. Its use of Reverse Polish Notation RPN in its operation, similar to HP calculators.
  3. A language embodying a simple syntax – words and numbers separated by spaces.
  4. The system is enhanced by creating new WORDS, these new WORDS are treated the same as the built-in language WORDS.
  5. Applications are created by creating new WORDS so when finalize the application is a language tuned to the application desired.
  6. Small words are encouraged to easily debug and because there is a little penalty in using words the system remains fast but simple to debug.
  7. Newly added words can become a permanent part of the software thereby increasing the system’s capability.
  8. Generally, programs are designed TOP DOWN but created and tested BOTTOM UP, simple WORDS are well tested before using them in more complex WORDS, this makes for easier testing of a program.
  9. The software has an interpreter, a compiler, and an assembler built in and all available at any time.
  10. Due to the nature of the language, all these features are accomplished in a very small application.

Forth has very simple concepts. Like a human language, words are text groupings that represent an action taken by the computer and are separated from one another by white-space characters. Words can be user-defined and are no different that built-in words, generally the added words can be saved to become a part of the programming environment.

The philosophy of Forth is to keep things simple and that is one reason why the system uses Reverse Polish Notation or RPN for equations as that eliminates the need for parentheses and order of operator precedence. Words are encouraged to be small so they can easily be tested and added to the repertory of tested words. It is both an interpreter and a compiler at the same time, in embedded systems, it includes, editors, assemblers, and debuggers and it’s usually the OS for the system.

Due to its interactive nature, it’s ideal for embedded applications and working with hardware devices. Depending on the system the compiler portion can generate very efficient code so it is both easy to work with and efficient with limited resources. Also, it encourages to design Top-Down but to code Bottom-Up and build an application on tested WORDS so debugging software is a lot easier.

You end up working with WORDS that have been tested and along with its interactive nature which helps speed up code development and testing.