Fix array access

api/tests/documents_test.go

@@ -65,8 +65,8 @@ func documents_InitializeDb(t *testing.T) (*httptest.Server, *azcosmos.Container
 			Paths: []string{"/pk"},
 		},
 	})
-	repositories.CreateDocument(testDatabaseName, testCollectionName, map[string]interface{}{"id": "12345", "pk": "123", "isCool": false})
-	repositories.CreateDocument(testDatabaseName, testCollectionName, map[string]interface{}{"id": "67890", "pk": "456", "isCool": true})
+	repositories.CreateDocument(testDatabaseName, testCollectionName, map[string]interface{}{"id": "12345", "pk": "123", "isCool": false, "arr": []int{1, 2, 3}})
+	repositories.CreateDocument(testDatabaseName, testCollectionName, map[string]interface{}{"id": "67890", "pk": "456", "isCool": true, "arr": []int{6, 7, 8}})
 
 	ts := runTestServer()
 
@@ -146,6 +146,22 @@ func Test_Documents(t *testing.T) {
 			},
 		)
 	})
+
+	t.Run("Should query array accessor", func(t *testing.T) {
+		testCosmosQuery(t, collectionClient,
+			`SELECT c.id,
+				c["arr"][0] AS arr0,
+				c["arr"][1] AS arr1,
+				c["arr"][2] AS arr2,
+				c["arr"][3] AS arr3
+			FROM c ORDER BY c.id`,
+			nil,
+			[]interface{}{
+				map[string]interface{}{"id": "12345", "arr0": 1.0, "arr1": 2.0, "arr2": 3.0, "arr3": nil},
+				map[string]interface{}{"id": "67890", "arr0": 6.0, "arr1": 7.0, "arr2": 8.0, "arr3": nil},
+			},
+		)
+	})
 }
 
 func Test_Documents_Patch(t *testing.T) {

parsers/nosql/nosql.peg

@@ -251,9 +251,8 @@ DotFieldAccess <- "." id:Identifier {
     return id, nil
 }
 
-ArrayFieldAccess <- "[\"" id:Identifier "\"]" {
-    return id, nil
-}
+ArrayFieldAccess <- "[\"" id:Identifier "\"]" { return id, nil }
+  / "[" id:Integer "]" { return strconv.Itoa(id.(int)), nil }
 
 Identifier <- [a-zA-Z_][a-zA-Z0-9_]* {
     return string(c.text), nil

query_executors/memory_executor/memory_executor.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"reflect"
 	"sort"
+	"strconv"
 	"strings"
 
 	"github.com/pikami/cosmium/internal/logger"
@@ -303,9 +304,18 @@ func (c memoryExecutorContext) getFieldValue(field parsers.SelectItem, row RowTy
 
 	if len(field.Path) > 1 {
 		for _, pathSegment := range field.Path[1:] {
-			if nestedValue, ok := value.(map[string]interface{}); ok {
+
+			switch nestedValue := value.(type) {
+			case map[string]interface{}:
 				value = nestedValue[pathSegment]
-			} else {
+			case []int, []string, []interface{}:
+				slice := reflect.ValueOf(nestedValue)
+				if arrayIndex, err := strconv.Atoi(pathSegment); err == nil && slice.Len() > arrayIndex {
+					value = slice.Index(arrayIndex).Interface()
+				} else {
+					return nil
+				}
+			default:
 				return nil
 			}
 		}