intermediary patch

parsers/nosql/misc_test.go

@@ -186,4 +186,55 @@ func Test_Parse(t *testing.T) {
 			},
 		)
 	})
+
+	t.Run("Should parse SELECT with UDF function", func(t *testing.T) {
+		testQueryParse(
+			t,
+			`SELECT t.name, udf.CalculateTax(t.income, t.category) FROM t`,
+			parsers.SelectStmt{
+				SelectItems: []parsers.SelectItem{
+					testutils.SelectItem_Path("t", "name"),
+					{
+						Type: parsers.SelectItemTypeFunctionCall,
+						Value: parsers.FunctionCall{
+							Type:    parsers.FunctionCallUDF,
+							UdfName: "CalculateTax",
+							Arguments: []interface{}{
+								testutils.SelectItem_Path("t", "income"),
+								testutils.SelectItem_Path("t", "category"),
+							},
+						},
+					},
+				},
+				Table: parsers.Table{SelectItem: testutils.SelectItem_Path("t")},
+			},
+		)
+	})
+
+	t.Run("Should parse WHERE with UDF function", func(t *testing.T) {
+		testQueryParse(
+			t,
+			`SELECT c.id FROM c WHERE udf.IsEligible(c.status) = true`,
+			parsers.SelectStmt{
+				SelectItems: []parsers.SelectItem{
+					testutils.SelectItem_Path("c", "id"),
+				},
+				Table: parsers.Table{SelectItem: testutils.SelectItem_Path("c")},
+				Filters: parsers.ComparisonExpression{
+					Left: parsers.SelectItem{
+						Type: parsers.SelectItemTypeFunctionCall,
+						Value: parsers.FunctionCall{
+							Type:    parsers.FunctionCallUDF,
+							UdfName: "IsEligible",
+							Arguments: []interface{}{
+								testutils.SelectItem_Path("c", "status"),
+							},
+						},
+					},
+					Operation: "=",
+					Right:     testutils.SelectItem_Constant_Bool(true),
+				},
+			},
+		)
+	})
 }

parsers/nosql/nosql.peg

@@ -154,6 +154,14 @@ func createFunctionCall(functionType parsers.FunctionCallType, arguments []inter
     return parsers.FunctionCall{Type: functionType, Arguments: arguments}, nil
 }
 
+func createUDFCall(functionName interface{}, arguments []interface{}) (parsers.FunctionCall, error) {
+    return parsers.FunctionCall{
+        Type: parsers.FunctionCallUDF, 
+        UdfName: functionName.(string),
+        Arguments: arguments,
+    }, nil
+}
+
 func joinStrings(array []interface{}) string {
     var stringsArray []string
     for _, elem := range array {
@@ -511,7 +519,8 @@ BooleanLiteral <- ("true"i / "false"i) {
     return parsers.Constant{Type: parsers.ConstantTypeBoolean, Value: boolValue}, nil
 }
 
-FunctionCall <- StringFunctions
+FunctionCall <- UDFFunction
+    / StringFunctions
     / TypeCheckingFunctions
     / ArrayFunctions
     / ConditionalFunctions
@@ -519,6 +528,20 @@ FunctionCall <- StringFunctions
     / AggregateFunctions
     / MathFunctions
 
+UDFFunction <- "udf"i ws "." ws functionName:Identifier ws "(" ws arguments:UDFArgumentList? ws ")" {
+    if arguments == nil {
+        return createUDFCall(functionName, []interface{}{})
+    }
+    return createUDFCall(functionName, arguments.([]interface{}))
+}
+
+UDFArgumentList <- arg1:SelectItem others:(ws "," ws arg:SelectItem { return arg, nil })* {
+    if others == nil {
+        return []interface{}{arg1}, nil
+    }
+    return append([]interface{}{arg1}, others.([]interface{})...), nil
+}
+
 StringFunctions <- StringEqualsExpression
     / ToStringExpression
     / ConcatExpression