Forth is so named because in 1968 "[t]he file holding the interpreter was
labeled FORTH, for 4th (next) generation software — but the IBM 1130 operating
system restricted file names to 5 characters."
A D V E R T I S E M E N T
Moore saw Forth as a successor to compile-link-go third-generation programming
languages, or software for "fourth generation" hardware, not a fourth-generation
programming language as the term has come to be used.
Forth is a high level programming language which operates similarly to an RPN
(Reverse Polish Notation or postfix) calculator. It differs from typical
programming languages like C and Fortran because it is an interactive language.
If you are using Forth, you do not need to recompile your program to add some
new functionality. You can easily define a new command and it will instantly be
available for you to use.
A procedural, stack-oriented and reflective programming language without type
checking, Forth features both interactive execution of commands (making it
suitable as a shell for systems that lack a more formal operating system) and
the ability to compile sequences of commands for later execution. Some Forth
implementations (usually early versions or those written to be extremely
portable) compile threaded code, but many implementations today generate
optimized machine code like other language compilers