Add PostGIS Spatial Operators Support

[maxhelias]

PostGIS provides powerful spatial operators (like <->, &&, @>) that can leverage spatial indexes much more efficiently than equivalent functions. Currently, Doctrine doesn't supports custom operators, which means users cannot take advantage of these performance-critical operators in DQL queries.

PostGIS Operators Overview

Distance Operators (enable KNN queries)

• <-> : Distance operator (used for ORDER BY - K-Nearest Neighbors)
• <#> : Bounding box distance operator
• |=| : Distance operator at their closest point of approach

Bounding Box Relationship Operators (enable efficient spatial filtering)

• && : Overlaps (bounding boxes overlap)
• @> : Contains (A contains B)
• <@ : Contained by (A is contained by B)
• ~= : Same (same geometry)
• << : Is left of
• >> : Is right of
• &< : Overlaps or is left of
• &> : Overlaps or is right of
• <<| : Is below
• |>> : Is above
• &<| : Overlaps or is below
• |&> : Overlaps or is above

Proposed Implementation

Since Doctrine DQL doesn't natively support custom operators, we'll implement them as DQL functions that generate the operator syntax in SQL.

// src/Functions/Operators/
├── DistanceOperator.php           // <->
├── BBoxDistanceOperator.php       // <#>
├── OverlapsOperator.php           // &&
├── ContainsOperator.php           // @>
├── ContainedByOperator.php        // <@
├── SameOperator.php               // ~=
├── LeftOperator.php               // <<
├── RightOperator.php              // >>
├── BelowOperator.php              // <<|
└── AboveOperator.php              // |>>

[maxhelias]

Another proposition here : #15 (comment)