Get order of operations the user has entered

[msaron]

Is it possible to get the order of operations the user has entered? I am trying to port the hapijs/Joi object schema validation to Go. Here is how the Joi library in NodeJS is used. Joi modifies and returns the final value as it is being validated; for example, if it says the value has to be in uppercase, the input value is uppercased and if a default value is specified, Joi sets the default value if there is none specified. In NodeJS, I use it for everything including URL query values, form input values, outgoing data, etc. I decided to attempt to port this as I could not find a good solution already available in Go.

var schema = Joi.object().keys({
    username: Joi.string().alphanum().min(3).max(30).required(),
    password: Joi.string().regex(/^[a-zA-Z0-9]{3,30}$/),
    access_token: [Joi.string(), Joi.number()],
    birthyear: Joi.number().integer().min(1900).max(2013),
    email: Joi.string().email()
}).with('username', 'birthyear').without('password', 'access_token');

Joi.validate({ username: 'abc', birthyear: 1994 }, schema, function (err, value) { });  // err === null -> valid