Overview

System for filtering trees and nodes generated by zip.clj in
general, and xml trees in particular.

Usage: (ancestors loc)

Returns a lazy sequence of all ancestors of location loc, starting
with loc and proceeding to loc's parent node and on through to the
root of the tree.

Usage: (children loc)

Returns a lazy sequence of all immediate children of location loc,
left-to-right.

Usage: (children-auto loc)

Returns a lazy sequence of all immediate children of location loc,
left-to-right, marked so that a following tag= predicate will auto-descend.

Usage: (descendants loc)

Returns a lazy sequence of all descendants of location loc, in
depth-first order, left-to-right, starting with loc.

Usage: (left-locs loc)

Returns a lazy sequence of locations to the left of loc, starting with loc.

Usage: (leftmost? loc)

Returns true if there are no more nodes to the left of location loc.

Usage: (right-locs loc)

Returns a lazy sequence of locations to the right of loc, starting with loc.

Usage: (rightmost? loc)

Returns true if there are no more nodes to the right of location loc.

clojure.data.zip.xml

Usage: (attr attrname)
       (attr loc attrname)

Returns the xml attribute named attrname, of the xml node at location loc.

Usage: (attr= attrname attrval)

Returns a query predicate that matches a node when it has an
attribute named attrname whose value is attrval.

Usage: (seq-test preds)

Returns a query predicate that matches a node when its xml content

matches the query expresions given.

Usage: (tag= tagname)

Returns a query predicate that matches a node when its is a tag
named tagname.

Usage: (text loc)

Returns the textual contents of the given location, similar to
xpaths's value-of

Usage: (text= s)

Returns a query predicate that matches a node when its textual
content equals s.

Usage: (xml-> loc & preds)

The loc is passed to the first predicate.  If the predicate returns
a collection, each value of the collection is passed to the next
predicate.  If it returns a location, the location is passed to the
next predicate.  If it returns true, the input location is passed to
the next predicate.  If it returns false or nil, the next predicate
is not called.

This process is repeated, passing the processed results of each
predicate to the next predicate.  xml-> returns the final sequence.
The entire chain is evaluated lazily.

There are also special predicates: keywords are converted to tag=,
strings to text=, and vectors to sub-queries that return true if
they match.

See xml_test.clj for examples.

Usage: (xml1-> loc & preds)

Returns the first item from loc based on the query predicates
given.  See xml->