Intervals

IntervalsQuery builds positional conditions as a tree. It is useful when phrase and span queries are not expressive enough, such as ordered alternatives, containment, or exclusions within a bounded passage.

Intervals require indexed positions. Every source in one tree must target the same field.

Source types

Source	Meaning
IntervalsTermSource	One exact indexed term
IntervalsPhraseSource	Adjacent ordered terms
IntervalsOrSource	Any child source
IntervalsOrderedSource	Children in order with at most MaxGaps total gaps
IntervalsUnorderedSource	Children in any order with at most MaxGaps total gaps
IntervalsContainingSource	Outer intervals that contain an inner interval
IntervalsContainedBySource	Inner intervals contained by an outer interval
IntervalsNotContainingSource	Outer intervals that contain no matching inner interval

Ordered proximity

Match distributed followed by search, allowing up to three intervening positions:

using Rowles.LeanCorpus.Search.Queries;

var query = new IntervalsQuery(
    new IntervalsOrderedSource(
        maxGaps: 3,
        new IntervalsTermSource("body", "distributed"),
        new IntervalsTermSource("body", "search")));

var results = searcher.Search(query, topN: 20);

MaxGaps counts gaps across the combined interval. Use 0 for adjacency.

Alternatives

Match either quick or fast, followed by search:

var speed = new IntervalsOrSource(
    new IntervalsTermSource("body", "quick"),
    new IntervalsTermSource("body", "fast"));

var query = new IntervalsQuery(
    new IntervalsOrderedSource(
        maxGaps: 2,
        speed,
        new IntervalsTermSource("body", "search")));

Terms are exact indexed terms. Run user input through the same analyser used for the field before constructing leaf sources.

Containment

Match a bounded passage containing a required phrase:

var passage = new IntervalsUnorderedSource(
    maxGaps: 12,
    new IntervalsTermSource("body", "engine"),
    new IntervalsTermSource("body", "index"));

var phrase = new IntervalsPhraseSource("body", "full", "text");

var query = new IntervalsQuery(
    new IntervalsContainingSource(passage, phrase));

Swap the relationship to return the inner interval:

var inner = new IntervalsContainedBySource(phrase, passage);

Exclude an inner match from otherwise acceptable outer intervals:

var query = new IntervalsQuery(
    new IntervalsNotContainingSource(
        passage,
        new IntervalsTermSource("body", "deprecated")));

Choosing intervals or span queries

Use PhraseQuery for a fixed phrase, MultiPhraseQuery for alternatives at phrase positions, and span queries for direct span composition. Use intervals when containment or a deeper positional expression makes the intent clearer.

Broad alternatives and large gap limits increase positional work. Put selective terms low in the tree, avoid unbounded user-generated expansions, and measure against representative position-heavy fields.

See Phrase and proximity for the simpler query forms.