Such as ... ?
A Forth program is made up of "words." To Forth, a word is
the name for an operation that Forth can perform (e.g. the word to print
spaces to the screen is ... SPACES). To Forth, a word can be any sequence
of letters or symbols, so "+", "-", and "*"
are all considered "words" by Forth. Just like natural languages,
Forth stores all the words it knows about in a "dictionary." Over
time, you can add new words to Forth's dictionary by defining the new words
in terms of the old words (e.g. a "Giant" is a "Large Man").
Forth provides words to:
- do mathy things (add, subtract, etc.)
- make decisions (if these two things are the same, then do this...)
- get input from a human user
- print output to the screen
In short, Forth does everything that other programming languages do.
You do two things with words in a Forth program:
- make new words, which Forth stores in its dictionary
- use the words in the dictionary to do things