HELP SEETREE R.Evans, March 1984
lib seetree;
seetree(tree);
LIB SEETREE provides an interface to showtree (see *SHOWTREE) which
a) protects you from corrupting the tree
b) makes it easy to explore the tree
c) doesn't require knowledge of VED
To display a tree just do
seetree(tree);
The tree will be displayed, as in showtree, but then the keyboard will
be redefined. Most of the keys produce a BEEP (meaning 'this key doesn't
do anything'), but some of them provide functions for exploring the
tree:
cursor up UP to parent node
cursor down left DOWN to leftmost daughter
cursor down DOWN to middle daughter
cursor down right DOWN to rightmost daughter
cursor left LEFT to sister
cursor right RIGHT to sister
end-of-file EXIT from seetree
refresh-window REFRESH WINDOW
After the EXIT command has been given, the call of seetree exits and
control returns to wherever it was called from as usual.
-- Defining new keys ---------------------------------------------------
The keyboard is redefined in such a way that adding new key functions is
particularly easy. VED's normal keyboard decoder is used to read the
keyboard and produce a procedure that would normally be run (by VED).
This procedure is given to the property SEETREE_COMMAND for translation
to the actual procedure to run - the default is VEDSCREENBELL. The
system sets up the keys given above, but these may be overridden/added
to by modifying the property SEETREE_COMMAND (which is given a procedure
(normally) and MUST return a procedure).
For example, to define the <ENTER> key to produce the message 'DONT
TOUCH THAT!' on the status line, we can proceed as follows:
vedputmessage(%'DONT TOUCH THAT!'%) -> seetree_command(vedenter);
(vedenter is the procedure VED calls when the <ENTER> key is hit - to
find this out we could have used <ENTER> HK).
--- C.all/help/seetree
--- Copyright University of Sussex 1992. All rights reserved. ----------