[Cyan]<PreISLCedar>TempTioga>NodeAddrs.mesa!1

-- NodeAddrs.Mesa

-- written by Paxton. March 1981

-- last written by Paxton. December 28, 1982 10:40 am

-- **** Persistent addressing for characters in text node ****

Last Edited by: Maxwell, January 5, 1983 8:42 am

DIRECTORY

TextNode;

NodeAddrs: CEDAR DEFINITIONS =

BEGIN

Offset: TYPE = TextNode.Offset;

Ref: TYPE = TextNode.Ref;

RefTextNode: TYPE = TextNode.RefTextNode;

RefAddrs: TYPE = REF Body;

Body: TYPE = RECORD [addrs: Pair];

Pair: TYPE = REF PairBody;

PairBody: TYPE = RECORD [

next: Pair,

pinned: BOOL ← FALSE, -- if true, then don't modify location when edits take place

addr: REF,

movedTo: RefTextNode, -- NIL if hasn't been moved

location: Offset ];

AddrsProp: PROC RETURNS [ATOM];

PutTextAddr: PROC [n: RefTextNode, addr: REF, location: Offset];

-- 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: RefTextNode, addr: REF];

-- removes the given addr

-- if addr has been moved, does RemTextAddr on new location also

PinTextAddr: PROC [n: RefTextNode, addr: REF];

-- don't modify location when edits take place

UnpinTextAddr: PROC [n: RefTextNode, addr: REF];

UnpinAll: PROC [n: RefTextNode];

MoveTextAddr: PROC [from, to: RefTextNode, addr: REF, location: Offset];

-- does RemTextAddr[from, addr]; PutTextAddr[to, addr, location];

-- add leaves forwarding address for use by GetTextAddr

GetTextAddr: PROC [n: RefTextNode, addr: REF] RETURNS [node: RefTextNode, location: Offset];

-- generates ERROR TextAddrNotFound if the addr is not in the mapping

-- node may be different than n if addr has been moved

TextAddrNotFound: ERROR;

TryGetTextAddr: PROC [n: RefTextNode, addr: REF]

RETURNS [found: BOOLEAN, node: RefTextNode, location: Offset];

MapTextAddrs: PROC [n: RefTextNode, action: TextAddrsAction]

RETURNS [BOOLEAN];

-- 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: Offset] RETURNS [BOOLEAN];

-- **** notify proc registration ****

AddNotifyProc, RemoveNotifyProc: PROC [proc: AddrNotifyProc];

AddrNotifyProc: TYPE = PROC [node: RefTextNode, new: PROC [old: Offset] RETURNS [Offset]];

-- **** Editing Operations for persistent addrs ****

Replace: PROC [node: RefTextNode, start, len, newlen: Offset];

-- 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: Offset] RETURNS [newLoc: Offset];

-- ***** Initialization

StartNodeAddrs: PROC; -- for initialization only

END.