Returns a regexp that matches a nodelist with
respect to a
search list x if the nodelist can be split into sublists
s1, s2,, sn such
that regexpi matches si with respect
to the search list
x for 1 i n and such that si
immediately precedes si+1 with respect to x for 1
i n1.
(regexpor regexp1 regexp2 regexpn)
Returns a regexp that matches a nodelist with respect to a
search list x if, for some i such that 1 i n, the nodelist matches regexpi with respect to x.
(regexpand regexp1 regexp2 regexpn)
Returns a regexp that matches a nodelist with respect
to a search list x if, for every i such that 1 i n, the nodelist matches regexpi with respect to x.
(regexprep regexp)
Returns a regexp that matches a nodelist with respect to a
search list x if the nodelist is empty or if there is some integer
n 1 such that the nodelist can be split into sublists
s1,s2,,sn
such that si matches regexp for each i such that 1
i n and such that si immediately
precedes si+1 with respect to x for each i such that
1 i n1.
(regexpplus regexp)
Returns a regexp that matches a nodelist with
respect to a search list x if there is some integer n 1
such that the nodelist can be split into sublists
s1, s2,,sn such that
si matches regexp for each i such that 1 i n and such that si immediately precedes si+1
with respect to x for each i such that 1 i n1.
(regexpopt regexp)
Returns a regexp that matches a nodelist with respect
to a search list x if either the nodelist is empty or the nodelist
matches regexp with respect to x.
(regexprange regexp k1 k2)
Returns a regexp that matches a nodelist with respect to a
search list x if there is some integer n with k1 n k2 such that the nodelist can be split into sublists
s1,s2,,sn
such that si matches regexp for each i such that 1
i n and such that si immediately
precedes si+1 with respect to x for each i such that
1 i n1. If k1 is zero, then the returned regexp
shall match the empty nodelist.
(string>regexp string)
Returns the regexp represented by string. It shall
be an error if string is not a valid representation of
an extended regular expression as defined in ISO 99452.
A normal character in string matches a node with a char
property whose value is that character.
 This could be implemented in terms of the above primitives. 
