Reference Python implementation of Rangeable<Element> — a generic, integer-coordinate, closed-interval set container with first-insert ordered active queries.

Installation

pip install rangeable

Usage

from dataclasses import dataclass
from rangeable import Rangeable

@dataclass(frozen=True, slots=True)
class Strong: pass

@dataclass(frozen=True, slots=True)
class Italic: pass

@dataclass(frozen=True, slots=True)
class Link:
    url: str

r: Rangeable = Rangeable()
r.insert(Strong(), start=2, end=5)
r.insert(Strong(), start=3, end=7)        # merges with [2, 5] → [2, 7]
r.insert(Strong(), start=9, end=11)       # disjoint
r.insert(Italic(), start=3, end=8)

r.get_range(Strong())   # [(2, 7), (9, 11)]
r.get_range(Italic())   # [(3, 8)]

r[4].objs               # (Strong(), Italic())   first-insert order
r[8].objs               # (Italic(),)
r[10].objs              # (Strong(),)

Sweep iteration via transitions

for event in r.transitions(lo=0, hi=15):
    print(event.coordinate, event.kind.value, event.element)

API

Member	Returns	Notes
Rangeable()	constructor	empty container
r.insert(e, *, start, end)	Rangeable (chainable)	raises InvalidIntervalError on start > end
r[i]	Slot[E]	Slot.objs is the active-set tuple
r.get_range(e)	list[tuple[int, int]]	merged disjoint ranges
r.transitions(*, lo, hi)	list[TransitionEvent[E]]	hi=None means +∞
r.count / len(r)	int	distinct elements
r.empty / bool(r)	bool
iter(r)	Iterator[(E, list[(int, int)])]	first-insert order
r.copy()	Rangeable[E]	deep copy
r.version	int	unchanged on idempotent insert

Semantics

• End is inclusive: [a, b] covers a..=b, both ends.
• Same-element merging: equal elements (by __eq__ + __hash__) merge on overlap or integer adjacency. [2, 4] ∪ [5, 7] = [2, 7].
• Idempotent insert: re-inserting a contained interval does not bump version.
• Out-of-order rejected: r.insert(e, start=5, end=2) raises InvalidIntervalError.
• Active-set ordering: deterministic — first-insert order of the element.
• Coordinate sentinel: a close event for an interval ending at the optional int_max sentinel carries coordinate is None (None == +∞ per RFC §4.7). Python ints are unbounded, so this only matters when integrating with bounded-int languages; the fixture does not exercise it.

See RangeableRFC § 4 for normative semantics and § 10 for the 23-case test contract.

Cross-language consistency

This Python implementation joins the Ruby, Swift, JS, Kotlin and Go implementations. All six share a 160-op / 86-probe JSON fixture and produce byte-identical outputs.

See also

• RangeableRFC — normative specification.
• RubyRangeable — Ruby reference (gem install rangeable).
• SwiftRangeable — Swift reference (SPM).
• JSRangeable — TypeScript reference (npm i rangeable-js).
• KotlinRangeable — Kotlin/JVM reference (JitPack).
• GoRangeable — Go reference (go get github.com/ZhgChgLi/GoRangeable).

Development

python -m pip install -e ".[dev]"
pytest -q

The suite covers the full RFC § 10 contract, the cross-language fixture replay, and a property test against a brute-force oracle.

License

MIT (c) ZhgChgLi

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