Boolean operations on posting lists.
Implements efficient set operations using a two-pointer merge algorithm with O(n + m) complexity — identical to how Lucene performs intersections and unions.
Supports:
- AND — intersection of posting lists
- OR — union of posting lists
- NOT — difference of posting lists
Summary
Functions
Computes the AND intersection of multiple posting lists.
Computes the difference: posts in include that are NOT in exclude.
Computes the OR union of multiple posting lists.
Types
@type posting_list() :: [{String.t(), non_neg_integer(), non_neg_integer()}]
Functions
@spec and_intersect([posting_list()]) :: [{String.t(), non_neg_integer()}]
Computes the AND intersection of multiple posting lists.
Uses a two-pointer merge algorithm for each pair of lists.
Example
iex> BooleanEngine.and_intersect([
...> [{"a", 1, 0}, {"b", 1, 1}, {"c", 1, 2}],
...> [{"b", 1, 0}, {"c", 1, 1}, {"d", 1, 2}]
...> ])
[{"b", 1}, {"c", 1}]@spec not_difference(posting_list(), posting_list()) :: [ {String.t(), non_neg_integer()} ]
Computes the difference: posts in include that are NOT in exclude.
Example
iex> BooleanEngine.not_difference(
...> [{"a", 1, 0}, {"b", 1, 1}, {"c", 1, 2}],
...> [{"b", 1, 0}]
...> )
[{"a", 1}, {"c", 1}]@spec or_union([posting_list()]) :: [{String.t(), non_neg_integer()}]
Computes the OR union of multiple posting lists.
Example
iex> BooleanEngine.or_union([
...> [{"a", 1, 0}, {"b", 1, 1}],
...> [{"b", 1, 0}, {"c", 1, 1}]
...> ])
[{"a", 1}, {"b", 1}, {"c", 1}]