emacs space regex search

I want to search for x spaces at the start of a line, using interactive regular search ^SPC< selects all lines starting with a variable number of spaces. According to emacs wiki

 (setq search-whitespace-regexp " ")

Should solve this, but this reverses behavior: it selects one space when i'm entering multiple spaces in my search. I do n开发者_C百科ot remember this behavior from earlier emacs (using 23.2 now). Is there a way to make interactive search select one space when entered one space and x spaces when entered x spaces?

cheers Jeroen

I think the behavior you observe is the intended one. From the documentation of search-whitespace-regexp:

If non-nil, regular expression to match a sequence of whitespace chars. [...] When you put a space or spaces in the incremental regexp, it stands for this.

Note the second sentence - whenever you put a single (or multiple) space character(s) in your regex, that gets interpreted as if you entered the value of search-whitespace-regexp. Since you defined that variable to be a single space character, one or multiple space character(s) in your regexp will only match a single space character in your buffer.

Probably the easiest way to achieve what you want is thus to simply set the variable to nil, in which case space characters are no longer treated in a special way in interactive regexp searches. A single space character in your regex will only match a single space character in the buffer.

(setq search-whitespace-regexp nil)

You could try ^[ ]\{5\}< to get lines beginning with 5 spaces, followed by a <.