NodeAddrs.mesa
Copyright © 1985, 1986 by Xerox Corporation. All rights reserved.
written by Paxton. March 1981
last written by Paxton. December 28, 1982 10:40 am
Last Edited by: Maxwell, January 5, 1983 8:42 am
Doug Wyatt, September 8, 1986 2:14:17 pm PDT
Persistent addressing for characters in text node.
DIRECTORY
TextNode USING [Node];
NodeAddrs: CEDAR DEFINITIONS
= BEGIN
Node: TYPE = TextNode.Node;
AddrsProp: PROC RETURNS [ATOM];
PutTextAddr:
PROC [n: Node, addr:
REF, location:
INT, pin:
BOOL ←
FALSE];
assigns addr to location in text
ok if addr was previously assigned elsewhere in the text
location automatically updated when text is edited
RemTextAddr:
PROC [n: Node, addr:
REF];
removes the given addr
if addr has been moved, does RemTextAddr on new location also
PinTextAddr:
PROC [n: Node, addr:
REF];
don't modify location when edits take place
UnpinTextAddr:
PROC [n: Node, addr:
REF];
UnpinAll:
PROC [n: Node];
MoveTextAddr:
PROC [from, to: Node, addr:
REF, location:
INT];
does RemTextAddr[from, addr]; PutTextAddr[to, addr, location];
add leaves forwarding address for use by GetTextAddr
GetTextAddr:
PROC [n: Node, addr:
REF]
RETURNS [node: Node, location:
INT];
generates ERROR TextAddrNotFound if the addr is not in the mapping
node may be different than n if addr has been moved
TryGetTextAddr:
PROC [n: Node, addr:
REF]
RETURNS [found:
BOOL, node: Node, location:
INT];
MapTextAddrs:
PROC [n: Node, action: TextAddrsAction]
RETURNS [
BOOL];
apply the action to each addr&location pair for the text
returns true if&when an action returns true
skips pinned or moved addresses
TextAddrsAction:
TYPE =
PROC [addr:
REF, location:
INT]
RETURNS [
BOOL];
Notify proc registration
AddNotifyProc: PROC [proc: AddrNotifyProc];
RemoveNotifyProc:
PROC [proc: AddrNotifyProc];
AddrNotifyProc:
TYPE =
PROC [node: Node, new:
PROC [old:
INT]
RETURNS [
INT]];
Editing Operations for persistent addrs
Replace:
PROC [node: Node, start, len, newlen:
INT];
replace chars in [start..start+len) by newlen chars
addrs that are in the replaced section move to start
add (newlen-len) to addrs that are after the replaced section
Update Functions for persistent addrs
AfterReplace:
PROC [initLoc, start, len, newlen:
INT]
RETURNS [newLoc:
INT];
END.