It's a way of structuring an interpreter. In forth a word is just a pointer to its definition, which in turn is just a list of pointers to other words, potentially user defined or built in primitives. Execution threads through these pointers, much like making subroutine calls with arguments being passed implicitly on the stack.
It's much more compact and lower overhead than a classic interpreter walking a full Abstract Syntax Tree structure. These days most languages are going to a full native code JIT however.
It's a way of structuring an interpreter. In forth a word is just a pointer to its definition, which in turn is just a list of pointers to other words, potentially user defined or built in primitives. Execution threads through these pointers, much like making subroutine calls with arguments being passed implicitly on the stack.
It's much more compact and lower overhead than a classic interpreter walking a full Abstract Syntax Tree structure. These days most languages are going to a full native code JIT however.