combining_validations.swift

    //Validate min length
    func minLength(_ value:String, min:Int, fieldName:String) -> Validation<[String], String>{
        if(value.characters.count < min){
            return Validation.Failure(["\(fieldName) must have more than \(min) characters"])
        } else {
            return Validation.Success(value)
        }
    }
    
    //Validate match a regular expression
    func matches(_ value:String, regex:String, errorMessage:String) -> Validation<[String], String>{
        if(value.range(of:regex, options: .regularExpression) == nil){
            return Validation.Failure([errorMessage])
        } else {
            return Validation.Success(value)
        }
    }
    
    //Validate password: concatenation of matches and minLength
    func isPasswordValid(_ password:String) -> Validation<[String], String> {
        return matches(password, regex: "[\\W]", errorMessage: "Password must contain an special character")
            .sconcat(minLength(password, min: 8, fieldName: "Password"))
    }
    
 
    
    //Is password valid is a more complex validation created by combining minLenght and matches validations
    let result = isPasswordValid("A")
    /*  Validation<Array<String>, String>
      ▿ Failure : 2 elements
        - 0 : "Password must contain an special character"
        - 1 : "Password must have more than 8 characters"
    */