convert json to Datatyp at runtime, datatyp to convert at compiler time is unknown ( help)

[bnadem]

i become data json, i have no idea about datatype at compiler time
i must to convert to typedef struct or union maybe nested structure at runtime

{
"type":"struct"
"name:"MyStruct"
"struct": {
"var1":"int",
"var2":float;
"var3":"double"
}
}

convert AT RUNTIME to

typedef struct {
var1:int;
var2:float;
var3:double }MyStruct`

[nlohmann]

Have you looked at https://json.nlohmann.me/features/arbitrary_types/ ?