QGIS/resources/function_help/json/op_plus

{
  "name": "+",
  "type": "operator",
  "groups": ["Operators"],
  "description": "Addition of two values. If one of the values is NULL the result will be NULL.",
  "arguments": [
        { "arg": "a", "description": "value" },
        { "arg": "b", "description": "value" }
  ],
  "examples": [
	{ "expression":"5 + 4", "returns":"9"},
	{ "expression":"5 + NULL", "returns":"NULL"},
	{ "expression":"'QGIS ' + 'ROCKS'", "returns":"'QGIS ROCKS'"},
	{ "expression":"to_datetime('2020-08-01 12:00:00') + '1 day 2 hours'", "returns":"2020-08-02T14:00:00"}
  ]
}