In this subsection, ewoc and node stand for the structures described above (see Abstract Display), while data stands for an arbitrary Lisp object used as a data element.
ewoc-createpretty-printer &optional header footer nosep
This constructs and returns a new ewoc, with no nodes (and thus no data
elements). pretty-printer should be a function that takes one
argument, a data element of the sort you plan to use in this ewoc, and
inserts its textual description at point using
insert (and never
insert-before-markers, because that would interfere with the
Ewoc package’s internal mechanisms).
Normally, a newline is automatically inserted after the header,
the footer and every node’s textual description. If nosep
nil, no newline is inserted. This may be useful for
displaying an entire ewoc on a single line, for example, or for
making nodes invisible by arranging for pretty-printer
to do nothing for those nodes.
An ewoc maintains its text in the buffer that is current when
you create it, so switch to the intended buffer before calling
This returns the buffer where ewoc maintains its text.
This returns a cons cell
(header . footer)
made from ewoc’s header and footer.
ewoc-set-hfewoc header footer
This sets the header and footer of ewoc to the strings header and footer, respectively.
These add a new node encapsulating data, putting it, respectively, at the beginning or end of ewoc’s chain of nodes.
ewoc-enter-beforeewoc node data
ewoc-enter-afterewoc node data
These add a new node encapsulating data, adding it to ewoc before or after node, respectively.
These return, respectively, the previous node and the next node of node in ewoc.
This returns the node in ewoc found at zero-based index n.
A negative n means count from the end.
nil if n is out of range.
This extracts the data encapsulated by node and returns it.
This sets the data encapsulated by node to data.
ewoc-locateewoc &optional pos guess
This determines the node in ewoc which contains point (or
pos if specified), and returns that node. If ewoc has no
nodes, it returns
nil. If pos is before the first node,
it returns the first node; if pos is after the last node, it returns
the last node. The optional third arg guess
should be a node that is likely to be near pos; this doesn’t
alter the result, but makes the function run faster.
This returns the start position of node.
These move point to the previous or next, respectively, argth node
ewoc-goto-prev does not move if it is already at
the first node or if ewoc is empty, whereas
moves past the last node, returning
nil. Excepting this special
case, these functions return the node moved to.
This moves point to the start of node in ewoc.
This function regenerates the text of ewoc. It works by deleting the text between the header and the footer, i.e., all the data elements’ representations, and then calling the pretty-printer function for each node, one by one, in order.
ewoc-invalidateewoc &rest nodes
This is similar to
ewoc-refresh, except that only nodes in
ewoc are updated instead of the entire set.
ewoc-deleteewoc &rest nodes
This deletes each node in nodes from ewoc.
ewoc-filterewoc predicate &rest args
This calls predicate for each data element in ewoc and
deletes those nodes for which predicate returns
Any args are passed to predicate.
ewoc-collectewoc predicate &rest args
This calls predicate for each data element in ewoc
and returns a list of those elements for which predicate
nil. The elements in the list are ordered
as in the buffer. Any args are passed to predicate.
ewoc-mapmap-function ewoc &rest args
This calls map-function for each data element in ewoc and
updates those nodes for which map-function returns non-
Any args are passed to map-function.