rangeP

rangeP is a term used in programming and formal methods to denote a predicate or function that tests whether a value lies within a specified range. It is not a standardized language feature, and its exact form varies across libraries and languages. In general, rangeP expresses the idea of membership within an interval, returning true when the input falls inside the defined bounds.

Semantics and variants overlap across contexts. The typical signature involves a value and two bounds (lower and upper), with optional support for inclusive or exclusive endpoints. A common convention is to use inclusive bounds, so the predicate is true when the value is between or equal to the bounds; some variants allow excluding one or both ends. The concept can be defined over numeric domains such as integers and floating-point numbers, and can be extended to ordered types or discrete domains.

Examples in common languages illustrate the idea. In Python, a simple version is def rangeP(x, lo, hi, inclusive=True): return lo <= x <= hi if inclusive else lo < x < hi. In JavaScript, const rangeP = (x, lo, hi, inclusive=true) => inclusive ? x >= lo && x <= hi : x > lo && x < hi. In Prolog, rangeP(X, Low, High) :- X >= Low, X =< High. In Haskell, rangeP :: Ord a => a -> a -> a -> Bool; rangeP x low high = low <= x && x <= high. Variants may adjust bounds or support multiple intervals.

Applications include input validation, data filtering, and parameter sweeps in algorithms. Performance considerations focus on constant-time comparisons and the cost of bound checks in tight loops. See also: range, interval, predicate, membership test.