Thanks , the explanation is good enough.

2009/7/11 Drew Adams <drew.adams@oracle.com>

> >>     `[^\]' (`"[^\\]"' for Lisp string syntax)
>
> >> `[^\]'  or `"[^\\]"' , which is right ?
> >> what is Lisp string syntax for ?
>
> > I try with re-builder ,  find that `"[^\\]"' is corrct .
> > `"[^\]"' can not find anything .
>
> Lisp string syntax is the syntax used in Lisp code when you write a literal
> string (constant). The Lisp reader (part of the Lisp interpreter) reads the
> string syntax you enter and constructs a string constant accordingly.
>
> In Lisp string syntax, you need to double each backslash that you want in
> the
> string. So "\\" is Lisp string syntax for the string that has one
> character, a
> backslash. This doubling is needed because Lisp string syntax uses the
> backslash
> for special escape sequences: for example, \" represents a double-quote
> character.
>
> See the Elisp manual, node `Syntax for Strings'.
>
>