add intersection and union function, which take an arbitrary amount o…

…f markers, and move duplicated code into these functions

src/poetry/core/version/markers.py

@@ -437,16 +437,10 @@ def of(cls, *markers: BaseMarker) -> BaseMarker:
  return MultiMarker(*new_markers)
 
  def intersect(self, other: BaseMarker) -> BaseMarker:
- multi = MultiMarker(self, other)
- return dnf(multi)
+ return intersection(self, other)
 
  def union(self, other: BaseMarker) -> BaseMarker:
- union = MarkerUnion(self, other)
- conjunction = cnf(union)
- if not isinstance(conjunction, MultiMarker):
- return conjunction
-
- return dnf(conjunction)
+ return union(self, other)
 
  def union_simplify(self, other: BaseMarker) -> BaseMarker | None:
  """
@@ -612,17 +606,10 @@ def append(self, marker: BaseMarker) -> None:
  self._markers.append(marker)
 
  def intersect(self, other: BaseMarker) -> BaseMarker:
- multi = MultiMarker(self, other)
- return dnf(multi)
+ return intersection(self, other)
 
  def union(self, other: BaseMarker) -> BaseMarker:
- union = MarkerUnion(self, other)
-
- conjunction = cnf(union)
- if not isinstance(conjunction, MultiMarker):
- return conjunction
-
- return dnf(conjunction)
+ return union(self, other)
 
  def validate(self, environment: dict[str, Any] | None) -> bool:
  return any(m.validate(environment) for m in self._markers)
@@ -744,18 +731,13 @@ def _compact_markers(
 
  # Combine the groups.
  sub_markers = [MultiMarker(*group) for group in groups]
- union = MarkerUnion(*sub_markers)
 
  # This function calls itself recursively. In the inner calls we don't perform any
  # simplification, instead doing it all only when we have the complete marker.
  if not top_level:
- return union
-
- conjunction = cnf(union)
- if not isinstance(conjunction, MultiMarker):
- return conjunction
+ return MarkerUnion(*sub_markers)
 
- return dnf(conjunction)
+ return union(*sub_markers)
 
 
 def cnf(marker: BaseMarker) -> BaseMarker:
@@ -790,6 +772,18 @@ def dnf(marker: BaseMarker) -> BaseMarker:
  return marker
 
 
+def intersection(*markers: BaseMarker) -> BaseMarker:
+ return dnf(MultiMarker(*markers))
+
+
+def union(*markers: BaseMarker) -> BaseMarker:
+ conjunction = cnf(MarkerUnion.of(*markers))
+ if not isinstance(conjunction, MultiMarker):
+ return conjunction
+
+ return dnf(conjunction)
+
+
 def _merge_single_markers(
  marker1: SingleMarker,
  marker2: SingleMarker,