It annoys me that there's no function to split a string based on a function that examines each character. If there was, you could write it like this:
public static IEnumerable<string> SplitCommandLine(string commandLine)
{
bool inQuotes = false;
return commandLine.Split(c =>
{
if (c == '\"')
inQuotes = !inQuotes;
return !inQuotes && c == ' ';
})
.Select(arg => arg.Trim().TrimMatchingQuotes('\"'))
.Where(arg => !string.IsNullOrEmpty(arg));
}
Although having written that, why not write the necessary extension methods. Okay, you talked me into it...
Firstly, my own version of Split that takes a function that has to decide whether the specified character should split the string:
public static IEnumerable<string> Split(this string str,
Func<char, bool> controller)
{
int nextPiece = 0;
for (int c = 0; c < str.Length; c++)
{
if (controller(str[c]))
{
yield return str.Substring(nextPiece, c - nextPiece);
nextPiece = c + 1;
}
}
yield return str.Substring(nextPiece);
}
It may yield some empty strings depending on the situation, but maybe that information will be useful in other cases, so I don't remove the empty entries in this function.
Secondly (and more mundanely) a little helper that will trim a matching pair of quotes from the start and end of a string. It's more fussy than the standard Trim method - it will only trim one character from each end, and it will not trim from just one end:
public static string TrimMatchingQuotes(this string input, char quote)
{
if ((input.Length >= 2) &&
(input[0] == quote) && (input[input.Length - 1] == quote))
return input.Substring(1, input.Length - 2);
return input;
}
And I suppose you'll want some tests as well. Well, alright then. But this must be absolutely the last thing! First a helper function that compares the result of the split with the expected array contents:
public static void Test(string cmdLine, params string[] args)
{
string[] split = SplitCommandLine(cmdLine).ToArray();
Debug.Assert(split.Length == args.Length);
for (int n = 0; n < split.Length; n++)
Debug.Assert(split[n] == args[n]);
}
Then I can write tests like this:
Test("");
Test("a", "a");
Test(" abc ", "abc");
Test("a b ", "a", "b");
Test("a b \"c d\"", "a", "b", "c d");
Here's the test for your requirements:
Test(@"/src:""C:\tmp\Some Folder\Sub Folder"" /users:""[email protected]"" tasks:""SomeTask,Some Other Task"" -someParam",
@"/src:""C:\tmp\Some Folder\Sub Folder""", @"/users:""[email protected]""", @"tasks:""SomeTask,Some Other Task""", @"-someParam");
Note that the implementation has the extra feature that it will remove quotes around an argument if that makes sense (thanks to the TrimMatchingQuotes function). I believe that's part of the normal command-line interpretation.