RegExp "." dos not match any character, as it misses newline

[yidabu]

code:
 import std.stdio;
 import std.regexp;

 void main()
 {
	char[] str = r"a
	b";
	char[] pattern = ".+";
	if ( RegExp(pattern).test(str) ) 
	{
		str = RegExp(pattern).match(str)[0];//无论用什么Attribute,总是只匹配第一行的a,也就是.无法跨行
		writefln(str);
	}	
	else {writefln("failed");}
 }

output:a

seems "." dos not match any character, as it misses newline