feat: more expr operators

Added:
- $max
- $min
- $stdDevPop
- $stdDevSamp
- $sum

Author: lsafer-meemer

module-mongokt/src/commonMain/kotlin/expr/_Accumulators.kt

@@ -0,0 +1,86 @@
+@file:OptIn(ExperimentalMongodbApi::class)
+@file:Suppress("FunctionName")
+
+package org.cufy.mongodb.expr
+
+import org.cufy.bson.BsonMarker4
+import org.cufy.bson.array
+import org.cufy.bson.by
+import org.cufy.mongodb.*
+import org.cufy.mongodb.expr.Expr.*
+
+// https://www.mongodb.com/docs/manual/reference/operator/aggregation/#accumulators--in-other-stages-
+
+/* ============= ------------------ ============= */
+
+/** https://www.mongodb.com/docs/manual/reference/operator/aggregation/avg */
+@BsonMarker4
+fun `$avg`(array: Expr<_Array>): Expr<_Number> =
+    Expr { `$avg` by array.element }
+
+/** https://www.mongodb.com/docs/manual/reference/operator/aggregation/avg */
+@BsonMarker4
+fun `$avg`(vararg expressions: Expr<_Number>): Expr<_Number> =
+    Expr { `$avg` by array { expressions.forEach { by(it.element) } } }
+
+/* ============= ------------------ ============= */
+
+/** https://www.mongodb.com/docs/manual/reference/operator/aggregation/max */
+@BsonMarker4
+fun `$max`(array: Expr<_Array>): Expr<_Element> =
+    Expr { `$max` by array.element }
+
+/** https://www.mongodb.com/docs/manual/reference/operator/aggregation/max */
+@BsonMarker4
+fun `$max`(vararg expressions: Expr<_Element>): Expr<_Element> =
+    Expr { `$max` by array { expressions.forEach { by(it.element) } } }
+
+/* ============= ------------------ ============= */
+
+/** https://www.mongodb.com/docs/manual/reference/operator/aggregation/min */
+@BsonMarker4
+fun `$min`(array: Expr<_Array>): Expr<_Element> =
+    Expr { `$min` by array.element }
+
+/** https://www.mongodb.com/docs/manual/reference/operator/aggregation/min */
+@BsonMarker4
+fun `$min`(vararg expressions: Expr<_Element>): Expr<_Element> =
+    Expr { `$min` by array { expressions.forEach { by(it.element) } } }
+
+/* ============= ------------------ ============= */
+
+/** https://www.mongodb.com/docs/manual/reference/operator/aggregation/stdDevPop */
+@BsonMarker4
+fun `$stdDevPop`(array: Expr<_Array>): Expr<_Number> =
+    Expr { `$stdDevPop` by array.element }
+
+/** https://www.mongodb.com/docs/manual/reference/operator/aggregation/stdDevPop */
+@BsonMarker4
+fun `$stdDevPop`(vararg expressions: Expr<_Number>): Expr<_Number> =
+    Expr { `$stdDevPop` by array { expressions.forEach { by(it.element) } } }
+
+/* ============= ------------------ ============= */
+
+/** https://www.mongodb.com/docs/manual/reference/operator/aggregation/stdDevSamp */
+@BsonMarker4
+fun `$stdDevSamp`(array: Expr<_Array>): Expr<_Number> =
+    Expr { `$stdDevSamp` by array.element }
+
+/** https://www.mongodb.com/docs/manual/reference/operator/aggregation/stdDevSamp */
+@BsonMarker4
+fun `$stdDevSamp`(vararg expressions: Expr<_Number>): Expr<_Number> =
+    Expr { `$stdDevSamp` by array { expressions.forEach { by(it.element) } } }
+
+/* ============= ------------------ ============= */
+
+/** https://www.mongodb.com/docs/manual/reference/operator/aggregation/sum */
+@BsonMarker4
+fun `$sum`(array: Expr<_Array>): Expr<_Number> =
+    Expr { `$sum` by array.element }
+
+/** https://www.mongodb.com/docs/manual/reference/operator/aggregation/sum */
+@BsonMarker4
+fun `$sum`(vararg expressions: Expr<_Number>): Expr<_Number> =
+    Expr { `$sum` by array { expressions.forEach { by(it.element) } } }
+
+/* ============= ------------------ ============= */