loopsthat

Loopsthat are a class of iterative control structures defined in the recently published Loop Optimization Language (LOL). The term originally derived from the phrase “loop stack trace handling” and is used to denote loops that explicitly manage a manual stack state to emulate recursion with constant memory overhead. Unlike traditional tail‑recursive modules, loopsthat maintain an explicit stack frame list, enabling efficient backtracking and multi‑branch exploration without relying on the call stack. The architecture allows developers to specify guard conditions, stack operations, and branching rules in a declarative manner.

The syntax of loopsthat resembles a standard WHILE loop but includes a stack declaration and a push/pop instruction. A typical example iterates over a graph to generate all simple paths from a source node to a target node while avoiding repeated nodes. When a dead‑end is reached, the loop pops the last node from the stack and continues from the preceding state. This explicit stack handling eliminates possibility of stack overflow on deep recursive graphs.

Practical uses of loopsthat have been reported in compiler literature and in automated theorem proving, where exhaustive search of state spaces requires tight memory control. Implementations are available in the LOL runtime library for platforms including Java, Rust, and Python. While loopsthat are not part of the official ISO standard, several open‑source projects have adopted them for performance‑critical search algorithms.