TEditSelectionAllocImpl.mesa
Copyright © 1985 by Xerox Corporation. All rights reserved.
Edited by Paxton on December 28, 1982 2:01 pm
Doug Wyatt, March 3, 1985 6:28:45 pm PST
DIRECTORY
TEditDocument USING [Selection, SelectionRec],
TEditSelection;
TEditSelectionAllocImpl: CEDAR MONITOR
EXPORTS TEditSelection
= BEGIN OPEN TEditSelection;
pSel: PUBLIC TEditDocument.Selection ← Create[];
sSel: PUBLIC TEditDocument.Selection ← Create[];
fSel: PUBLIC TEditDocument.Selection ← Create[];
oldSel: PUBLIC TEditDocument.Selection ← Create[];
nilSel: PUBLIC TEditDocument.Selection ← Create[];
tSel1, tSel2, tSel3: TEditDocument.Selection; -- cache of temporary selection records
Create:
PUBLIC
PROC
RETURNS [TEditDocument.Selection] = {
RETURN [NEW[TEditDocument.SelectionRec]] };
Alloc:
PUBLIC
ENTRY
PROC
RETURNS [tSel: TEditDocument.Selection] = {
ENABLE UNWIND => NULL;
IF tSel3 # NIL THEN { tSel ← tSel3; tSel3 ← NIL }
ELSE IF tSel2 # NIL THEN { tSel ← tSel2; tSel2 ← NIL }
ELSE IF tSel1 # NIL THEN { tSel ← tSel1; tSel1 ← NIL }
ELSE tSel ← Create[];
};
Free:
PUBLIC
ENTRY
PROC [tSel: TEditDocument.Selection] = {
ENABLE UNWIND => NULL;
IF tSel3 = tSel OR tSel2 = tSel OR tSel1 = tSel THEN ERROR;
IF tSel3 = NIL THEN tSel3 ← tSel
ELSE IF tSel2 = NIL THEN tSel2 ← tSel
ELSE IF tSel1 = NIL THEN tSel1 ← tSel;
};
Copy:
PUBLIC
ENTRY
PROC [source, dest: TEditDocument.Selection] = {
ENABLE UNWIND => NULL;
dest^ ← source^;
};
END.