各位大虾好!

我需要 regexp 方面的一些帮助。
refind("[[:space:]]", str)
will find all the text in the var of the str and to exclude HTML code.
What I need is to include the following three sets of special characters:
nr  // for new line and carriage return, want to retain them 
:  // I want to keep this special character in the text returned as well
-- //  I want to keep this special character in the text returned as well

The following attempt did not work.
refind("(nr|:|--|[[:space:]])", str)

Please advise.   请帮忙。

多谢。