Add CQL2 to Elasticsearch DSL conversion

[Copilot]

Summary

Adds the ability to convert a CQL2 search expression into Elasticsearch Query DSL JSON, addressing the feature request to "add the ability to convert a CQL2 search into Elasticsearch DSL".

Changes

New: ToElasticsearch trait (src/elasticsearch.rs)

A new ToElasticsearch trait with a to_elasticsearch() -> Result<serde_json::Value, Error> method, implemented for Expr. It covers:

Category	Operators
Boolean	AND, OR, NOT
Comparison	=, <>, >, >=, <, <=
Null check	IS NULL
Pattern match	LIKE (converts %→*, _→?; supports casei wrapper via case_insensitive: true)
Membership	IN → terms query
Range	BETWEEN → range query
Spatial	S_INTERSECTS, S_WITHIN, S_CONTAINS, S_DISJOINT, S_EQUALS (bidirectional within+contains), S_TOUCHES/S_OVERLAPS/S_CROSSES (approximated as intersects)
Temporal	T_BEFORE, T_AFTER, T_MEETS, T_METBY, T_DURING, T_CONTAINS, T_STARTS, T_STARTEDBY, T_FINISHES, T_FINISHEDBY, T_OVERLAPS, T_OVERLAPPEDBY, T_EQUALS, T_DISJOINT, T_INTERSECTS, ANYINTERACTS

The property field may be on either side of binary predicates. Both Expr::BBox and the Expr::Operation { op: "bbox" } (from CQL2 text) forms are supported for spatial queries, converted to Elasticsearch envelope shapes.

Updated: src/lib.rs

• Exports ToElasticsearch from the crate root.

Updated: cli/src/lib.rs

• Adds --output-format elasticsearch and --output-format elasticsearch-pretty CLI options.

Examples

echo "eo:cloud_cover < 0.5" | cql2 -o elasticsearch
# {"range":{"eo:cloud_cover":{"lt":0.5}}}

echo "platform = 'landsat-8' AND s_intersects(footprint, {...})" | cql2 -o elasticsearch-pretty
# {
#   "bool": {
#     "must": [
#       {"term": {"platform": "landsat-8"}},
#       {"geo_shape": {"footprint": {"shape": {...}, "relation": "intersects"}}}
#     ]
#   }
# }

use cql2::{Expr, ToElasticsearch};

let expr: Expr = "landsat:scene_id = 'LC82030282019133LGN00'".parse().unwrap();
let dsl = expr.to_elasticsearch().unwrap();
// {"term": {"landsat:scene_id": "LC82030282019133LGN00"}}

Testing

• 45 unit tests in src/elasticsearch.rs covering all supported operators.
• Integration test in tests/elasticsearch_tests.rs following the project's fixture-based pattern (same structure as reduce_tests.rs), with 18 fixture pairs in tests/elasticsearch_expected.txt covering comparisons, boolean operators, LIKE, IN, BETWEEN, IS NULL, and temporal operators.
• All existing 458 tests continue to pass.

[bitner]

Make sure there are tests

[Copilot]

Make sure there are tests

There are 45 unit tests in src/elasticsearch.rs (covering all operators: boolean, comparison, LIKE, IN, BETWEEN, IS NULL, spatial, and temporal) plus a new integration test added in 85ef597:

• tests/elasticsearch_tests.rs — fixture-based integration test following the same pattern as reduce_tests.rs
• tests/elasticsearch_expected.txt — 18 fixture pairs (CQL2 input → expected Elasticsearch DSL) covering the most common query types