这有点令人尴尬，但我已经看过一个OCaml程序，我知道我想做什么，但我找不到文档来帮助我用正确的语法写出我想要的东西，因为我已经从来没有使用过这门语言。
我对程序做了很多工作，这恰好是我需要做的最后一次更改，我无法解决这个问题！
有一个名为caps_default的排序记录（使用的语法让我失望）：
let caps_default =
{
browserName = Firefox ;
version = "" ;
platform = ANY ;
username = "" ;
accessKey = "" ;
javascriptEnabled = true
}
;;
然后定义这些变量以接收命令行参数：
exception Incorrect_cmdline of string option
;;
let browser_name = ref ""
and hub_url_opt = ref ""
and target_url_opt = ref ""
and xml_out_string = ref ""
and user_name = ref ""
and access_key = ref ""
;;
我添加了两个名为＆＃39; username＆＃39;和＆＃39; accessKey＆＃39;我想将它们添加到＆＃34;大写＆＃34;记录的东西。
继续，这里解析命令行参数：
let (target_url, hub_url, caps, xml_out) =
try
parse_cmdline
[
( noshort , "browser-name" , None, (atmost_once browser_name (Incorrect_cmdline (Some "browser-name"))) ) ;
( noshort , "hub-url" , None, (atmost_once hub_url_opt (Incorrect_cmdline (Some "hub-url"))) ) ;
( noshort , "target-url" , None, (atmost_once target_url_opt (Incorrect_cmdline (Some "target-url"))) ) ;
( noshort , "xml-output" , None, (atmost_once xml_out_string (Incorrect_cmdline (Some "xml-output"))) ) ;
( noshort , "username" , None, (atmost_once user_name (Incorrect_cmdline (Some "username"))) ) ;
( noshort , "accessKey" , None, (atmost_once access_key (Incorrect_cmdline (Some "accessKey"))) ) ;
( noshort , "help" , Some (fun s -> raise (Incorrect_cmdline None)) , None );
]
( fun x -> raise (Incorrect_cmdline None)) ;
ignore (List.map
(fun s -> if BatString.is_empty !s then raise (Incorrect_cmdline None) else () )
[ browser_name ; hub_url_opt ; target_url_opt ] );
let target_url =
try
Neturl.parse_url !target_url_opt
with
Neturl.Malformed_URL ->
raise (Incorrect_cmdline (Some ("Invalid target url: " ^ !target_url_opt)))
and hub_url =
try
Neturl.parse_url !hub_url_opt
with
Neturl.Malformed_URL ->
raise (Incorrect_cmdline (Some ("Invalid hub url: " ^ !hub_url_opt)))
and xml_out =
if BatString.is_empty !xml_out_string
then fun s -> ignore s
else
let chan = open_out !xml_out_string in
(fun xml ->
output_string chan (Xml.to_string xml) ;
close_out chan )
(* Continued below *)
我希望将分配给变量username和accessKey的新命令行参数选项user_name和access_key传递给{{1在下面的let assignments中定义的记录：
caps尝试我可以将原作者的--browser-name开关注释掉，并通过放置由花括号包围的庄严线来指定单个值：
(* Continued from above *)
and caps =
{ caps_default with username = !user_name } (* My addition *)
{ caps_default with accessKey = !access_key } (* My addition *)
match !browser_name with (* This switch is original and worked *)
| "firefox" -> { caps_default with browserName = Firefox }
| "chrome" -> { caps_default with browserName = Chrome }
| "html_unit" -> { caps_default with browserName = HtmlUnit }
| "ie" -> { caps_default with browserName = InternetExplorer }
| "iphone" -> { caps_default with browserName = IPhone }
| _ -> raise (Incorrect_cmdline (Some ("Invalid browser name: " ^ !browser_name)))
in
(target_url, hub_url, caps, xml_out)
with
Incorrect_cmdline arg ->
(match arg with | None -> () | Some msg -> print_endline msg) ;
print_synopsis () ;
exit 48
;; (* End of relevant code *)
或
and caps=
{ caps_default with browserName = Chrome } (* Hard-coding a Chrome choice *)
或
and caps=
{ caps_default with username = !user_name } (* Sharing only --username *)
有人能指出我正确的方向吗？我想保留原作者写的开关，但也将and caps=
{ caps_default with accessKey = !access_key } (* Sharing only --accessKey *)
和username字符串传送到accessKey记录。我可以稍后更改caps对象吗？我可以事先修改caps，然后将其复制到default_caps吗？
此代码每次执行只运行一次，因此修改caps对象绝对不会引起关注，即使它不是非常犹豫不决。
感谢您的帮助！
更新
非常感谢斯科菲尔德先生迄今提供的帮助。奇怪的是，我现在遇到了一个稍微不同的错误，抱怨我只能假设类型不匹配。以下是错误的内容：
default_caps第110行
File "tester.ml", line 110, characters 40-47:
Error: This expression has type Selenium.Json_client.capabilities
but an expression was expected of type Selenium.Json_client.browser
在斯科菲尔德先生的代码片段中，40-47为{ caps_default with browserName = browser;
。
browser类型default_caps的定义是这样的：
capabilities类似地，类型type capabilities =
{
browserName : browser ;
version : string ;
platform : platform ;
javascriptEnabled : bool ;
username : string ;
accessKey : string ;
}
：
browser如果重要的话，mli（接口，正确？）定义是相同的。
更新第2部分
仅需要进行小修正以简化代码：
type browser =
Chrome | Firefox | HtmlUnit | InternetExplorer | IPhone
到此：
match !browser_name with
| "firefox" -> { caps_default with browserName = Firefox }
| "chrome" -> { caps_default with browserName = Chrome }
| "html_unit" -> { caps_default with browserName = HtmlUnit }
| "ie" -> { caps_default with browserName = InternetExplorer }
| "iphone" -> { caps_default with browserName = IPhone }
| _ -> raise (Incorrect_cmdline (Some ("Invalid browser name: " ^ !browser_name)))
继续之前：
match !browser_name with
| "firefox" -> Firefox
| "chrome" -> Chrome
| "html_unit" -> HtmlUnit
| "ie" -> InternetExplorer
| "iphone" -> IPhone
| _ -> raise (Incorrect_cmdline (Some ("Invalid browser name: " ^ !browser_name)))
答案 0 :(得分：1)
你可能需要学习一些比你想要的更多的OCaml： - ）
名为caps_default的东西是一条记录，即它有一个记录类型。您将不得不找到此记录类型的定义并向其添加新功能。
<强>更新
好的，你已经修好了记录类型。这是一些代码
and caps =
let browser =
match !browser_name with
| "firefox" -> Firefox
| "chrome" -> Chrome
| "html_unit" -> HtmlUnit
| "ie" -> InternetExplorer
| "iphone" -> IPhone
| _ ->
raise (Incorrect_cmdline
(Some ("Invalid browser name: " ^ !browser_name)))
in
{ caps_default with browserName = browser;
username = !user_name;
accessKey = !access_key;
}
in
(target_url, hub_url, caps, xml_out)
（不用说，这是未经测试的代码。）
更新2
（user_name的固定拼写，谢谢。）