The most important idea in Forth is factoring. Breaking complex tasks into small pieces. In an ideal Forth codebase, most definitions are about a line long, contain at most one control structure and reference no named variables.<p>Forth&#x27;s stack-oriented semantics make function calls very cheap- a function call and return is literally two instructions, whereas languages which use activation records will turn a function call into dozens of instructions- copying arguments around, backing up registers, etc. Since it&#x27;s computationally inexpensive, you don&#x27;t need to sweat over whether your optimizing compiler will manage to inline a function.<p>Short, simple and mostly pure functions are easy to test in isolation- there aren&#x27;t deeply nested code paths to exercise.<p>Lots of short functions allow your codebase to reuse more of those functions- any redundancy can be collapsed together, both shrinking the codebase and improving test coverage. This effect is magnified in more complex programs.<p>You can do this sort of thing in other languages, but forth&#x27;s syntax <i>and</i> semantics for function definition and invocation are both very lightweight, and this makes it much easier to apply.