-- File: TuplesEditorImpl.mesa
-- Created by Donahue November 16, 1982 2:38 pm
-- Last edited by:
-- Donahue, April 14, 1983 10:15 am
-- Cattell, June 24, 1983 3:09 pm

DIRECTORY
Atom USING [GetPropFromList],
BasicTime USING [GMT],
Buttons USING [ButtonProc, ReLabel],
DB,
DBEnvironment,
IO,
Menus USING[ MouseButton ],
Nut,
NutOps,
NutViewer USING [Error, Message],
Rope,
TuplesEditor,
VFonts USING[CharWidth, FontHeight],
ViewerOps USING [AddProp, FetchProp, FetchViewerClass, PaintViewer],
Containers,
ViewerTools USING [GetContents, SetContents, SetSelection],
ViewerClasses, VTables;

TuplesEditorImpl: CEDAR MONITOR
IMPORTS
Atom, Buttons, DB, DBEnvironment, IO, Nut, NutOps,
NutViewer, Rope, VTables, VFonts, ViewerOps, ViewerTools
EXPORTS TuplesEditor =

{ OPEN DB, Rope, Nut, ViewerClasses, VTables;

PosPair: TYPE = RECORD[ row: CARDINAL, col: CARDINAL];

anyErrors: BOOL; -- Set if any procedure discovered user errors in saving the new entries
defaultOld: PUBLIC BOOL← TRUE; -- FALSE => attributes start in NewOrOld mode, else OldOnly
updateList: AttributeValueList;
allFieldsNull: BOOLEAN;
relTable: Viewer;
relRows: CARDINAL;
newRelship, oldRelship: Relship;

DisplayTuples: PUBLIC ENTRY PROC[e: Entity, attrList: AttributeList, parent: Viewer]
RETURNS[ TuplesTable: VTable ] =
-- Main procedure in this module: puts up a subviewer in the parent viewer containing
-- all the tuples that do or could refer to the entity e. Main loop goes through all
-- attributes potentially referencing e's domain, and calls AddRow to add a blank tuple
-- if the tupleList referencing e is empty for that attribute, or the tupleList if it is
-- not empty.
{ ENABLE UNWIND => NULL;
row: CARDINAL ← 0;
TuplesTable ← Create[ parent: parent, rows: Length[attrList]+1, columns: 1 ];
FOR attrL: AttributeList ← attrList, attrL.rest UNTIL attrL = NIL DO
{ tupleList: LIST OF Relship = IF e = NIL THEN NIL ELSE NutOps.GetTuples[e, attrL.first];
relTable: VTable = Create[ rows: 1, columns: 3, parent: TuplesTable ];
IF tupleList = NIL THEN AddRow[ relTable, attrL.first ]
ELSE
FOR tlT: LIST OF Relship ← tupleList, tlT.rest UNTIL tlT=NIL DO
AddRow[ relTable, attrL.first, tlT.first ] ENDLOOP;
SetTableEntry[table: TuplesTable, row: row, flavor: $Viewer,
clientData: relTable, border: NullBorder ];
row ← row+1 }
ENDLOOP;
ViewerOps.AddProp[ TuplesTable, $Entity, e ];
Install[TuplesTable, FALSE] };

AddRow: PROC[ table: VTable, attribute: Attribute, relship: Relship ← NIL ] = {
-- Add a row to the table, where the entity being displayed is assumed to be the value of
-- the attribute supplied. If a relship is supplied, take the values of the other fields from it;
-- otherwise, display empty fields.
row: CARDINAL ← GetRowsAndColumns[table: table].rows-1;
r: Relation = NutOps.GetRelation[attribute];
allAttrs: LIST OF Attribute ← NutOps.AttributesOf[r];
firstRow: BOOLEAN ← TRUE;
displayAttrs: LIST OF Attribute = NutOps.RemoveAttribute[attribute, allAttrs];
howLong: INT = Length[displayAttrs];
howMuchSpace: INT = IF howLong MOD 2 = 0 THEN howLong/2 ELSE (howLong/2)+1;
i: INT ← 1; -- the index of the next column to be updated

-- The structure of the table now is to have three columns; the first is the name of the relation
-- (or blank if in succeeding rows), while the second and third give two attributes of the
-- relation

-- set the first entry
SetTableEntry[ table: table, row: row, column: 0, flavor: $Button, name: GetName[r],
clientData: attribute, proc: RelProc, border: NullBorder ];
{ relViewer: Viewer = GetTableEntry[ table: table, row: row, column: 0 ];
ViewerOps.AddProp[ relViewer, $newLine, NEW[BOOLEAN ← TRUE] ];
ViewerOps.AddProp[ viewer: relViewer, prop: $relShip, val: relship ];
ViewerOps.AddProp[ viewer: relViewer, prop: $r, val: r];
ViewerOps.AddProp[ viewer: relViewer, prop: $a, val: attribute ];
ViewerOps.AddProp[ viewer: relViewer, prop: $row, val: NEW[ INT ← row ] ] };
-- expand the table to contain as many rows as it will need for the display attributes
SetRowsAndColumns[ table: table, rows: row+1+howMuchSpace, columns: 3 ];
FOR da: LIST OF Attribute ← displayAttrs, da.rest UNTIL da = NIL DO
nextAttr: Attribute = da.first;
attrViewer: VTable = Create[ parent: table, columns: 4 ];
ViewerOps.AddProp[ attrViewer, $attr, nextAttr ];
ViewerOps.AddProp[ attrViewer, $which, NEW[ INT← IF defaultOld THEN 2 ELSE 0 ] ];
VTables.SetTableEntry[
table: attrViewer, column: 0, flavor: $Button, proc: AttrProc,
clientData: attrViewer, name: Rope.Cat[DB.NameOf[nextAttr], ":"], border: NullBorder];
IF NutOps.EntityValued[nextAttr] THEN
{ VTables.SetTableEntry[ table: attrViewer, column: 2, name: IF defaultOld THEN "O" ELSE "",
      flavor: $Button, w: VFonts.CharWidth['O]+5, border: NullBorder,
clientData: attrViewer, proc: CycleNewOld ];
VTables.GetTableEntry[ table: attrViewer, column: 2].border ← TRUE };
VTables.SetTableEntry[ table: attrViewer, column: 3, useMaxSize: TRUE, border: NullBorder,
w: 20*VFonts.CharWidth['A], flavor: $Text ];
VTables.GetTableEntry[ table: attrViewer, column: 3 ].scrollable ← TRUE;
IF relship # NIL THEN
ViewerTools.SetContents[ viewer: GetTableEntry[ table: attrViewer, column: 3 ],
contents: GetFS[ relship, nextAttr ], paint: FALSE ];
Install[ attrViewer, FALSE ];
VTables.SetTableEntry[ table: table, row: row, column: i, flavor: $Viewer, clientData: attrViewer,
border: NullBorder, useMaxSize: TRUE ];
i ← (i+1) MOD 3;
IF i = 0 THEN -- it's time for a new row
{ row ← row + 1;
SetTableEntry[ table: table, row: row, column: 0, name: "", border: NullBorder ];
ViewerOps.AddProp[ GetTableEntry[ table, row, 0 ], $newLine, NEW[BOOLEAN ← FALSE] ];
i ← i+1 }
ENDLOOP;
VTables.Install[ table, FALSE ] };

Length: PROC[ l: LIST OF Attribute ] RETURNS[ n: INT ] = {
n ← 0; UNTIL l = NIL DO n ← n+1; l ← l.rest ENDLOOP };

AttrProc: Buttons.ButtonProc = TRUSTED {
viewer: ViewerClasses.Viewer = NARROW[ parent, ViewerClasses.Viewer ];
attrViewer: VTable = NARROW[ clientData, VTable ];
textViewer: Viewer = GetTableEntry[ table: attrViewer, column: 3 ];
attr: Attribute = V2E[ViewerOps.FetchProp[attrViewer, $attr]];
domain: Domain = V2E[GetP[attr, aTypeIs, aTypeOf]];
entity: Entity;
SELECT mouseButton FROM
Menus.MouseButton[red] =>
ViewerTools.SetSelection[ textViewer, NIL ];
Menus.MouseButton[yellow] =>
{ entity ← DeclareEntity[ domain, ViewerTools.GetContents[textViewer], Version[OldOnly] !
DB.Error => { entity ← NIL; CONTINUE } ];
IF entity # NIL THEN [] ← Nut.Display[ entity ]
ELSE NutViewer.Message[viewer, ViewerTools.GetContents[textViewer], " not found!"] };
ENDCASE => ViewerTools.SetSelection[ textViewer, NIL ] };

RelProc: Buttons.ButtonProc = TRUSTED {
viewer: ViewerClasses.Viewer = NARROW[ parent, ViewerClasses.Viewer ];
attribute: Attribute = V2E[clientData];
relTable: VTable ← viewer.parent;
TuplesTable: VTable = relTable.parent;
SELECT mouseButton FROM
Menus.MouseButton[red] =>
{ u: Uniqueness = V2U[GetP[attribute, aUniquenessIs, aUniquenessOf]];
IF u = Key OR u = OptionalKey THEN
{anyErrors← TRUE; NutViewer.Message[viewer, "Only one allowed!"]}
ELSE AddRow[ relTable, attribute ] };
Menus.MouseButton[blue] =>
{ row: INT ← (NARROW[ ViewerOps.FetchProp[ viewer, $row ], REF INT ])^;
newLine: BOOLEAN ← FALSE;
UNTIL newLine DO
FOR i: NAT IN [0..2) DO
{ attrViewer: VTable = GetTableEntry[ relTable, row, i+1 ];
IF attrViewer # NIL THEN
{ textViewer: Viewer ← GetTableEntry[ attrViewer, 0, 3 ];
NewOldButton: Viewer ← GetTableEntry[ attrViewer, 0, 2 ];
TypeLabel: Viewer ← GetTableEntry[ attrViewer, 0, 1 ];
attrButton: Viewer ← GetTableEntry[ attrViewer, 0, 0 ];
xoff, yoff: INTEGER;
text: ROPE = ViewerTools.GetContents[ textViewer ];
textHeight: INT = textViewer.wh;
[xoff, yoff] ← GetEntryOffset[ table: relTable, row: row, column: 0 ];
SetTableEntry[ table: attrViewer, column: 3, flavor: $Text, border: NullBorder,
useMaxSize: TRUE, w: 20*VFonts.CharWidth['A],
h: textHeight+VFonts.FontHeight[]+1 ];
GetTableEntry[ table: attrViewer, column: 3 ].scrollable ← TRUE;
ViewerTools.SetContents[ viewer: GetTableEntry[ table: attrViewer, column: 3 ],
contents: text, paint: FALSE ];
Install[ attrViewer, FALSE ];
SetEntryOffset[ table: relTable, row: row, column: 0,
yoff: GetEntryOffset[ table: attrViewer, column: 0 ].yoff ];
Install[ relTable, FALSE ] } }
ENDLOOP;
row ← row + 1;
IF row = GetRowsAndColumns[relTable].rows-1 THEN EXIT;
{ relViewer: VTable = GetTableEntry[ relTable, row, 0 ];
newLineProp: REF BOOLEAN =
IF relViewer = NIL THEN NIL
ELSE NARROW[ViewerOps.FetchProp[relViewer, $newLine]];
newLine ← IF newLineProp = NIL THEN TRUE ELSE newLineProp^ }
ENDLOOP;
Install[ relTable, FALSE ] };
Menus.MouseButton[yellow] =>
{ row: INT ← (NARROW[ ViewerOps.FetchProp[ viewer, $row ], REF INT ])^;
newLine: BOOLEAN ← FALSE;
UNTIL newLine DO
FOR i: NAT IN [0..2) DO
{ attrViewer: VTable = GetTableEntry[ relTable, row, i+1 ];
IF attrViewer # NIL THEN
{ attr: Attribute = V2E[ViewerOps.FetchProp[attrViewer, $attr]];
type: Entity = V2E[GetP[attr, aTypeIs, aTypeOf]];
SetTableEntry[ table: attrViewer, row: 0, column: 1, name: TypeLabel[type],
border: NullBorder ];
Install[ attrViewer, FALSE ] } }
ENDLOOP;
row ← row + 1;
IF row = GetRowsAndColumns[relTable].rows-1 THEN EXIT;
{ relViewer: VTable = GetTableEntry[ relTable, row, 0 ];
newLineProp: REF BOOLEAN =
IF relViewer = NIL THEN NIL
ELSE NARROW[ViewerOps.FetchProp[relViewer, $newLine]];
newLine ← IF newLineProp = NIL THEN TRUE ELSE newLineProp^ }
ENDLOOP;
Install[ relTable, FALSE ] };
ENDCASE;
InstallAll[ TuplesTable] };

InstallAll: PROC[ viewer: Viewer ] = {
tableClass: ViewerClasses.ViewerClass = ViewerOps.FetchViewerClass[$VTable];
IF viewer = NIL THEN RETURN;
UNTIL viewer.parent = NIL DO
IF viewer.class = tableClass THEN Install[viewer, FALSE]; viewer ← viewer.parent ENDLOOP;
ViewerOps.PaintViewer[viewer, all] };

TypeLabel: PROC[ type: Entity ] RETURNS[ Rope.ROPE ] = {
IF DB.Eq[type, DB.RopeType] THEN RETURN["(String)"]
ELSE IF DB.Eq[type, DB.IntType] THEN RETURN["(Int)"]
ELSE IF DB.Eq[type, DB.BoolType] THEN RETURN["(Bool)"]
ELSE IF DB.Eq[type, DB.TimeType] THEN RETURN["(Time)"]
ELSE RETURN[ Rope.Cat["(", GetName[type], ")"] ] };

CycleNewOld: Buttons.ButtonProc = TRUSTED {
viewer: ViewerClasses.Viewer = NARROW[ parent, ViewerClasses.Viewer ];
Labels: ARRAY[0..3) OF ROPE = ["", "N", "O"];
attrViewer: VTable = viewer.parent;
relRow: VTable = attrViewer.parent;
TuplesTable: VTable = relRow.parent;
EventTable: VTable = TuplesTable.parent;
attr: Attribute = V2E[ ViewerOps.FetchProp[ attrViewer, $attr ] ];
which: REF INT = NARROW[ViewerOps.FetchProp[attrViewer, $which], REF INT];
IF NOT NutOps.EntityValued[attr] THEN RETURN;
which^ ← (which^ + 1) MOD 3;
Buttons.ReLabel[viewer, Labels[which^] ];
ViewerOps.AddProp[attrViewer, $which, which ];
Install[ relRow, FALSE ];
Install[ TuplesTable, FALSE ]; Install[ EventTable, TRUE ] };

SaveTuples: PUBLIC ENTRY PROC[
viewer: VTable, newEntity: Entity ← NIL ] RETURNS [errors: BOOL] = BEGIN
-- Called to update the relationships for an entity. If newEntity is NIL, then destroy
-- all the relationships for the oldEntity (previously associated with $Entity property
-- of the viewer). If oldEntity was NIL, then create a new entity with the relationships
-- that have been filled in by the user. If newEntity=oldEntity, update the relationships
-- that were modified by the user. Finally, if NIL#newEntity#oldEntity#NIL, then
-- copy all of oldEntities relationships to reference newEntity (leaves oldEntity intact).
-- Returns TRUE if any errors were reported to the user as a result of bad entries.
ENABLE UNWIND => NULL;
tupleRows: CARDINAL = GetRowsAndColumns[ viewer ].rows;
oldEntity: DB.Entity = V2E[ViewerOps.FetchProp[viewer, $Entity]];
update: BOOLEAN = NOT DB.Null[oldEntity] AND DB.Eq[oldEntity, newEntity];
destroy: BOOLEAN = NOT DB.Null[oldEntity] AND newEntity = NIL;
create: BOOLEAN = NOT DB.Null[newEntity] AND oldEntity = NIL;
copy: BOOLEAN = NOT (destroy OR create OR update);
parent: Viewer = viewer.parent;
anyErrors← FALSE;

FOR i: CARDINAL IN [0..tupleRows-1) DO
j: CARDINAL ← 0;
relTable ← GetTableEntry[ table: viewer, row: i, column: 0 ];
relRows ← GetRowsAndColumns[ relTable ].rows;
WHILE j < relRows-1 DO
-- The relRows is the number of rows with relationships from relation rel; for each
-- tuple (maybe >1 row), we want to destroy, create, or update the relationship as specified.
relViewer: Viewer = GetTableEntry[relTable, j, 0];
rel: Relation = V2E[ViewerOps.FetchProp[relViewer, $r ] ];
attr: Attribute = V2E[ViewerOps.FetchProp[ relViewer, $a ] ];
oldRelship← V2E[ViewerOps.FetchProp[relViewer, $relShip ] ];
updateList← NIL; allFieldsNull← TRUE; newRelship← NIL;
-- Advance j through attributes of this tuple, AddFields picking off two at a time, to
-- see what the attributes are and which we might have to change.
DO
AddFields[ parent: parent, row: j, copy: NOT (destroy OR create OR update) ];
-- NOTE: AddFields modifies global updateList and allFieldsNull as side effect
IF PastLastRowOfTuple[j← j + 1, relRows, relTable] THEN EXIT;
ENDLOOP;
-- Now we want to either create, destroy, or update the relationship.
IF destroy THEN
-- Destroy this relationship. We've already advanced j to skip over its rows.
{IF NOT DB.Null[oldRelship] THEN DB.DestroyRelship[oldRelship]}
ELSE IF updateList#NIL THEN -- Continue only if user modified something in this tuple..
IF update AND NOT DB.Null[oldRelship] THEN
-- Update mode, and there was an existing relationship: modify or delete it.
IF allFieldsNull THEN DB.DestroyRelship[oldRelship]
ELSE UpdateTuple[oldRelship, updateList]
ELSE IF NOT allFieldsNull THEN {
-- Either we are adding relship to a new entity, or updating old entity with no existing
-- oldRelship: create new tuple, including first attr (that refs entity) in update list.
updateList ← CONS[ AttributeValue[ attribute: attr, lo: newEntity], updateList ];
UpdateTuple[CreateRelship[rel], updateList];
ViewerOps.AddProp[ relViewer, $relShip, newRelship ] };
ENDLOOP;
ENDLOOP;
RETURN[anyErrors]
END;

PastLastRowOfTuple: PROC[
j: CARDINAL, relRows: CARDINAL, relTable: VTable ] RETURNS [BOOL] =
-- Used only by SaveTuples above, to decide when cross tuple boundaries in VTable.
-- Returns TRUE if j has passed the last row in one of the tuples for the given relation relTable.
-- Since $newLine is only attached to the relation button, this is true iff $newLine
-- is attached to this entry, or j is greater than the last row in the relTable.
{RETURN[ j >= relRows-1 OR NARROW[ViewerOps.FetchProp[
GetTableEntry[relTable, j, 0], $newLine], REF BOOL]^]};

UpdateTuple: PROC[ t: Relship, updateList: AttributeValueList ] = {
-- Changes the Relship t as specified by updateList. If ALL of the values in the update list
-- are NILs, then just destroy the whole Relship, 'cause user has left all blanks.
-- First set all of the key values
FOR ul: AttributeValueList ← updateList, ul.rest UNTIL ul = NIL DO
av: AttributeValue = ul.first;
u: Uniqueness = V2U[GetP[av.attribute, aUniquenessIs]];
IF u = Key THEN SetF[ t, av.attribute, av.lo ]
ENDLOOP;
-- Now set all of the non-key attributes
FOR ul: AttributeValueList ← updateList, ul.rest UNTIL ul = NIL DO
av: AttributeValue = ul.first;
u: Uniqueness = V2U[GetP[av.attribute, aUniquenessIs]];
IF u # Key THEN SetF[ t, av.attribute, av.lo ]
ENDLOOP };

PropertyValueList: TYPE = LIST OF PropertyValue;
PropertyValue: TYPE = RECORD[
from: Attribute, -- entity-valued attribute of a relation
avl: AttributeValueList -- value contraints on other attributes of same relation
];

QueryTuples: PUBLIC ENTRY PROC[ viewer: VTable, domain: Domain ]
RETURNS [el: LIST OF Entity] = {
-- Given a table set up by DisplayTuples, finds all the entities in the given domain
-- that satisfy the query filled into the table by the user. Inner loop similar to SaveTuples,
-- but must create PropertyValueList instead of updating tuples.
ENABLE UNWIND => NULL;
tupleRows: CARDINAL = GetRowsAndColumns[ viewer ].rows;
queryList: PropertyValueList← NIL;
parent: Viewer = viewer.parent;

FOR i: CARDINAL IN [0..tupleRows-1) DO
j: CARDINAL ← 0;
relTable ← GetTableEntry[ table: viewer, row: i, column: 0 ];
relRows ← GetRowsAndColumns[ relTable ].rows;
WHILE j < relRows-1 DO
-- The relRows is the number of rows with relationships from relation rel; for each
-- tuple (maybe >1 row), we want to handle the relationship as specified.
relViewer: Viewer = GetTableEntry[relTable, j, 0];
rel: Relation = V2E[ViewerOps.FetchProp[relViewer, $r ] ];
attr: Attribute = V2E[ViewerOps.FetchProp[ relViewer, $a ] ];
updateList← NIL; allFieldsNull← TRUE;
-- Advance j through attributes of this tuple, AddFields picking off two at a time, to
-- see what the attributes are and which we might have to change.
DO
AddFields[ parent: parent, row: j, copy: FALSE ];
-- NOTE: AddFields modifies global updateList and allFieldsNull as side effect
IF PastLastRowOfTuple[j← j + 1, relRows, relTable] THEN EXIT;
ENDLOOP;
IF updateList#NIL AND NOT allFieldsNull THEN
-- Continue only if user modified and put something in this tuple..
queryList← CONS[[from: attr, avl: updateList], queryList];
ENDLOOP; -- WHILE j < relRows-1
ENDLOOP; -- FOR i: CARDINAL
RETURN[EntityQuery[queryList]];
};

EntityQuery: PROC[pvl: PropertyValueList] RETURNS[LIST OF Entity] =
-- A handy procedure for finding all the entities of a domain that have the given
-- property values. Finds all the entities which, for each PropertyValue in the
-- PropertyValueList list, there exists at least one relationship whose
-- "from" attribute equals the entity and whose other attributes satisfy the
-- attribute value list.
BEGIN
f: Attribute← pvl.first.from;
r: Relation← V2E[GetP[f, aRelationIs]];
elNew: LIST OF Entity← NIL;
nestedRS: RelshipSet← RelationSubset[r, pvl.first.avl];
FOR t: Relship← NextRelship[nestedRS], NextRelship[nestedRS] UNTIL t=NIL DO
elNew← CONS[V2E[GetF[t, f]], elNew] ENDLOOP;
ReleaseRelshipSet[nestedRS];
RETURN[NestedEntityQuery[elNew, pvl.rest]]
END;

NestedEntityQuery: PROC[elOld: LIST OF Entity, pvl: PropertyValueList]
RETURNS[LIST OF Entity] = {
-- Finds the entities in elOld that satisfy pvl. We do this recursively as follows.
-- For each entity in elOld, we do a RelationSubset to find the tuples that satisfy pvl.first
-- and also reference the entity. If this list is not empty, we can keep that entity in a
-- new list elNew; otherwise we toss it. When all the entities in elOld that also
-- satisfy pvl.first have been added to elNew in this way, we recursively call
-- NestedEntityQuery, returning the entities in elNew which also satisfy pvl.rest.
IF pvl=NIL THEN RETURN[elOld] ELSE {
f: Attribute← pvl.first.from;
r: Relation← V2E[GetP[f, aRelationIs]];
elNew, elEnd: LIST OF Entity← NIL; -- will equal those in elOld that satisfy pvl.first
FOR elOldT: LIST OF Entity← elOld, elOldT.rest UNTIL elOldT=NIL DO
nestedRS: RelshipSet← RelationSubset[r, CONS[ [f, elOldT.first], pvl.first.avl]];
-- The nestedRS contains tuples that reference e and also satisfy first element of pvl.
-- We can keep elOldT.first in the elNew list iff this list is non-empty.
IF NextRelship[nestedRS] #NIL THEN
IF elNew=NIL THEN elEnd← elNew← CONS[elOldT.first, NIL]
ELSE elEnd← elEnd.rest← CONS[elOldT.first, NIL];
ReleaseRelshipSet[nestedRS];
ENDLOOP;
RETURN[NestedEntityQuery[elNew, pvl.rest]];
}};

AddFields: PROC[parent: Viewer, row: CARDINAL, copy: BOOL] = BEGIN
-- NOTE THIS PROCEDURE UPDATES GLOBAL VARIABLES AS A SIDE EFFECT.
-- THE MONITOR ON THIS MODULE IS TO PROTECT THESE GLOBAL VARIABLES.
-- Adds to updateList the attributes in row that need to be assigned in order to create
-- the relationship. Caller must add the first attribute (that refs the entity),
-- if desired. If the user does not modify a field, it does not appear in the updateList
-- unless there was an existing relationship and we are in "copy" mode.
-- Thus updateList=NIL if the user modified no fields of a tuple. Sets allFieldsNull to
-- FALSE if any of the fields are non-null.
FOR i: INT IN [0..2) DO
attrViewer: VTable = GetTableEntry[relTable, row, i+1];
IF attrViewer # NIL THEN
{ attr: Attribute = V2E[ViewerOps.FetchProp[attrViewer, $attr]];
newOld: INT = NARROW[ViewerOps.FetchProp[attrViewer, $which], REF INT]^;
textViewer: Viewer = GetTableEntry[table: attrViewer, column: 3];
contents: ROPE = ViewerTools.GetContents[textViewer];
type: Entity = V2E[GetP[attr, aTypeIs, aTypeOf]];
value: DB.Value;
IF NOT textViewer.newVersion THEN
-- Skip this guy unless copying and there was an existing relationship
IF oldRelship=NIL OR NOT copy THEN LOOP;
IF NOT Rope.Equal[contents, ""] THEN allFieldsNull← FALSE;
SELECT type FROM
IntType => {
val: INT = IF Rope.Equal[contents, ""] THEN 0 ELSE IO.GetInt[ IO.RIS[contents] ];
value ← I2V[val]};
RopeType =>
value ← S2V[ contents ];
BoolType =>
value ← B2V[ Rope.Equal[contents, "TRUE"] ];
TimeType =>
{ time: DB.GMT;
time.time ← IO.GetTime[IO.RIS[contents] ! IO.Error => TRUSTED {
anyErrors← TRUE;
NutViewer.Error[parent, "Unintelligible time/date: ", contents]}];
value ← T2V[time] };
ENDCASE =>
IF Rope.Equal[contents, ""] THEN value← NIL
ELSE SELECT newOld FROM
0 => -- NewOrOld
{ value ← DeclareEntity[ d: type, name: contents, version: OldOnly ];
IF value = NIL THEN {
NutViewer.Message[parent, "Automatically creating ", contents];
value ← DeclareEntity[ d: type, name: contents ]; } };
1 => -- NewOnly
{ value ← CreateEntity[ d: type, name: contents !
DBEnvironment.Error => TRUSTED {IF code=AlreadyExists THEN {
allFieldsNull← TRUE; -- pretend this tuple didn't happen
anyErrors← TRUE;
NutViewer.Error[parent, " Error: ", contents, " already exists."];
CONTINUE}}]};
2 => -- OldOnly
{ value ← DeclareEntity[ type, contents, Version[OldOnly] ];
IF value = NIL THEN {
allFieldsNull← TRUE; -- pretend this tuple didn't happen
anyErrors← TRUE;
NutViewer.Error[parent, " Error: ", contents, " does not exist."] }};
ENDCASE;
updateList ← CONS[ AttributeValue[attribute: attr, lo: value], updateList ] }
ENDLOOP
END;


}.

Change Log:

Changed by Cattell April 6, 1983 1:12 pm: The CONS in AddRow's first loop was causing it to reverse the order of the attributes to be displayed from the order in the database. Changed loop to destructively modify list, more efficient anyway since no space allocation.

Changed by Cattell April 15, 1983 11:08 am: Numerous changes and bug fixes to SaveTuples. Reduced complexity of inner loop from 22 to 11 lines!