问题
I'm trying to write a function that takes an input string, a regex (made by std.regex.regex from a rawstring) and an error message string, and attempt to match something from the input string using the regex, displaying the error message if there are no matches. I came up with the following signature so far:
string check_for_match (string input, Regex r, string error_message)
However, this doesn't seem to work, as the compiler complains, saying:
struct std.regex.Regex(Char) is used as a type
So what should I use instead?
回答1:
It'll compile if you change Regex to Regex!char.
The reason is that Regex is a template that can use any character size: char for UTF-8 patterns, wchar for UTF-16, or dchar for UTF-32. The compiler is saying you need to create a type by passing the required Char argument there to use it here.
Since you are working with string, which is made up of chars, Regex!char is the type to use.
string check_for_match (string input, Regex!char r, string error_message) { return null; }
来源：https://stackoverflow.com/questions/24967276/return-value-of-std-regex-regex