[Pixel]<Tioga>TBase>EditSpanImpl.mesa!1

-- EditSpanImpl.mesa

-- written by Bill Paxton, June 1981

-- last edit by Bill Paxton, December 23, 1982 2:47 pm

Last Edited by: Maxwell, January 5, 1983 12:46 pm

DIRECTORY

EditSpan,

EditSpanSupport,

EditNotify,

NodeProps,

Rope,

UndoEvent,

TextEdit,

TextLooks,

TextNode;

EditSpanImpl: CEDAR PROGRAM

IMPORTS NodeProps, TextEdit, TextNode, UndoEvent, EditSpan, EditSpanSupport, EditNotify

EXPORTS EditSpan =

BEGIN

OPEN EditSpan, EditSpanSupport, EditNotify;

CannotDoEdit: PUBLIC ERROR = CODE;

afterMoved1, afterMoved2: PUBLIC Location;

-- ***** Editing operations on spans

CheckForNil: PROC [span: Span] RETURNS [BOOLEAN] = INLINE {

RETURN [span.start.node = NIL OR span.end.node = NIL] };

Replace: PUBLIC PROC [destRoot, sourceRoot: Ref, dest, source: Span, words: BOOLEAN ← FALSE, saveForPaste: BOOLEAN ← TRUE, event: Event ← NIL]

RETURNS [result: Span] = {

-- replace dest span by copy of source span

-- result is the new copy of source

newDest: Span;

IF TextSpans[dest,source] THEN { -- pure text replace

RETURN [TwoSpanText[destRoot,sourceRoot,dest,source,words,saveForPaste,

TextEdit.ReplaceWords,TextEdit.ReplaceText,event]] };

source ← CopySpan[source];

sourceRoot ← TextNode.Root[source.start.node];

sourceRoot.deleted ← TRUE;

[result,newDest] ← Transpose[sourceRoot,destRoot,source,dest,words,event];

IF saveForPaste THEN SaveSpanForPaste[newDest,event] };

TextSpans: PROC [dest, source: Span] RETURNS [BOOLEAN] = {

RETURN [dest.start.node = dest.end.node AND

dest.start.where # NodeItself AND dest.end.where # NodeItself AND

source.start.node = source.end.node AND

source.start.where # NodeItself AND source.end.where # NodeItself] };

TwoSpanText: PROC [destRoot, sourceRoot: Ref, dest, source: Span,

words, saveForPaste: BOOLEAN,

wordProc, textProc: TextEdit.TwoSpanProc, event: Event]

RETURNS [result: Span] = {

destNode: RefTextNode ← TextNode.NarrowToTextNode[dest.start.node];

sourceNode: RefTextNode ← TextNode.NarrowToTextNode[source.start.node];

destStart: Offset ← dest.start.where;

destLen: Offset ← dest.end.where - destStart + 1;

sourceStart: Offset ← source.start.where;

sourceLen: Offset ← source.end.where - sourceStart + 1;

resultStart, resultLen: Offset;

editProc: TextEdit.TwoSpanProc ← IF words THEN wordProc ELSE textProc;

IF saveForPaste THEN SaveTextForPaste[destNode,destStart,destLen,event];

[resultStart,resultLen] ← editProc[destRoot,sourceRoot,

destNode,destStart,destLen,sourceNode,sourceStart,sourceLen,event];

RETURN [[[destNode,resultStart],[destNode,resultStart+resultLen-1]]] };

SaveForPaste: PUBLIC PROC [span: Span, event: Event ← NIL] = {

IF CheckForNil[span] THEN RETURN;

IF span.start.node = span.end.node AND

span.start.where # NodeItself AND span.end.where # NodeItself THEN { -- pure text

node: RefTextNode ← TextNode.NarrowToTextNode[span.start.node];

start: Offset ← span.start.where;

len: Offset ← span.end.where-span.start.where+1;

SaveTextForPaste[node,start,len,event] }

ELSE SaveSpanForPaste[CopySpan[span],event] };

Delete: PUBLIC PROC [root: Ref, del: Span, event: Event ← NIL, saveForPaste: BOOLEAN ← TRUE] = {

IF CheckForNil[del] THEN RETURN;

IF del.start.node = del.end.node AND

del.start.where # NodeItself AND del.end.where # NodeItself THEN { -- pure text

node: RefTextNode ← TextNode.NarrowToTextNode[del.start.node];

start: Offset ← del.start.where;

len: Offset ← del.end.where-del.start.where+1;

IF saveForPaste THEN SaveTextForPaste[node,start,len,event];

TextEdit.DeleteText[root,node,start,len,event] }

ELSE {

d: Span ← MoveToLimbo[root,del,event];

IF saveForPaste THEN SaveSpanForPaste[d,event] }};

paste: REF Change;

--really REF ChangingTextForPaste Change OR ChangingSpanForPaste Change

SaveTextForPaste: PROC [node: RefTextNode, start, len: Offset, event: Event] = {

SaveOldPaste[event];

paste ← TextNode.pZone.NEW[ChangingTextForPaste Change ←

[ChangingTextForPaste[node.rope, node.runs, start, len]]];

};

SaveSpanForPaste: PROC [span: Span, event: Event] = {

SaveOldPaste[event];

paste ← TextNode.pZone.NEW[ChangingSpanForPaste Change ←

[ChangingSpanForPaste[span]]];

};

SaveOldPaste: PROC [event: Event] = {

UndoEvent.Note[event, RestorePaste, paste]; paste ← NIL };

RestorePaste: PROC [undoRef: REF Change, currentEvent: UndoEvent.Ref] = {

SaveOldPaste[currentEvent]; paste ← undoRef };

SavedForPaste: PUBLIC PROC RETURNS [span: Span] = TRUSTED {

savedPaste: REF Change ← paste;

IF savedPaste=NIL THEN RETURN [TextNode.nullSpan];

WITH x: savedPaste SELECT FROM

ChangingTextForPaste => { -- convert saved text to a span

node: RefTextNode;

span: Span;

IF x.len <= 0 THEN RETURN [TextNode.nullSpan];

node ← TextNode.NewTextNode[];

[] ← TextEdit.ReplaceByText[root: node, dest: node,

sourceRope: x.rope, sourceRuns: x.runs,

sourceStart: x.start, sourceLen: x.len];

span ← [[node,0],[node,x.len-1]];

paste ← TextNode.pZone.NEW[ChangingSpanForPaste Change ←

[ChangingSpanForPaste[span]]];

RETURN [span] };

ChangingSpanForPaste => RETURN [x.span];

ENDCASE => ERROR;

};

MoveToLimbo: PROC [root: Ref, span: Span, event: Event] RETURNS [result: Span] = INLINE {

RETURN [Move[NIL,root,TextNode.nullLocation,span,FALSE,after,1,event]] };

Copy: PUBLIC PROC [destRoot, sourceRoot: Ref, dest: Location, source: Span, words: BOOLEAN ← FALSE,

where: Place ← after, nesting: INTEGER ← 0, event: Event ← NIL]

RETURNS [result: Span] = {

-- result is the new copy of source

IF CheckForNil[source] OR dest.node=NIL THEN RETURN [TextNode.nullSpan];

IF TextLocationAndSpan[dest,source] THEN -- pure text copy

RETURN [DestSpanText[destRoot,sourceRoot,dest,source,words,

TextEdit.CopyWords,TextEdit.CopyText,event]];

source ← CopySpan[source];

sourceRoot ← TextNode.Root[source.start.node];

sourceRoot.deleted ← TRUE;

result ← Move[destRoot,sourceRoot,dest,source,words,where,nesting,event] };

TextLocationAndSpan: PROC [dest: Location, source: Span] RETURNS [BOOLEAN] = {

RETURN [dest.where # NodeItself AND

source.start.node = source.end.node AND

source.start.where # NodeItself AND source.end.where # NodeItself] };

DestSpanText: PROC [destRoot, sourceRoot: Ref, dest: Location, source: Span, words: BOOLEAN,

wordProc, textProc: TextEdit.DestSpanProc, event: Event]

RETURNS [result: Span] = {

destNode: RefTextNode ← TextNode.NarrowToTextNode[dest.node];

sourceNode: RefTextNode ← TextNode.NarrowToTextNode[source.start.node];

destLoc: Offset ← dest.where;

sourceStart: Offset ← source.start.where;

sourceLen: Offset ← source.end.where - sourceStart + 1;

resultStart, resultLen: Offset;

editProc: TextEdit.DestSpanProc ← IF words THEN wordProc ELSE textProc;

[resultStart,resultLen] ← editProc[destRoot,sourceRoot,

destNode,destLoc,sourceNode,sourceStart,sourceLen,event];

RETURN [[[destNode,resultStart],[destNode,resultStart+resultLen-1]]] };

Move: PUBLIC PROC [destRoot, sourceRoot: Ref, dest: Location, source: Span,

words: BOOLEAN ← FALSE, where: Place ← after, nesting: INTEGER ← 0, event: Event ← NIL]

RETURNS [result: Span] = {

-- dest cannot be within source

-- result is moved span

sBefore, sAfter, sTop, sBottom, dBefore, dAfter: Slice;

sNesting, dNesting: INTEGER;

sDepth: NAT;

beforeSource, afterSource: Ref; -- nodes adjacent to source after do splits

afterLoc: Location;

FreeSlices: PROC = {

FreeSlice[sBefore]; FreeSlice[sAfter]; FreeSlice[sTop]; FreeSlice[sBottom];

FreeSlice[dBefore]; FreeSlice[dAfter];

sBefore ← sAfter ← sTop ← sBottom ← dBefore ← dAfter ← NIL };

ForcedUnNest: PROC [afterNode: Ref] = {

span: Span = TextNode.MakeNodeSpan[afterNode,TextNode.LastWithin[afterNode]];

FreeSlices[];

[] ← UnNest[TextNode.Root[afterNode],span,event] };

ForcedNest: PROC = {

span: Span ← TextNode.MakeNodeSpan[sTop[sDepth],TextNode.LastWithin[sBottom[sDepth]]];

IF SliceLength[sTop] = sDepth+1 THEN { -- can't do it by calling Nest

IF nesting >= 1 THEN ERROR;

nesting ← nesting+1; -- move to a deeper position

FreeSlices[];

RETURN };

FreeSlices[];

[] ← Nest[TextNode.Root[span.start.node],span,event] };

IF CheckForNil[source] THEN RETURN [TextNode.nullSpan];

IF TextLocationAndSpan[dest,source] THEN -- pure text move

RETURN [DestSpanText[destRoot,sourceRoot,

dest,source,words,TextEdit.MoveWords,TextEdit.MoveText,event]];

IF where=child THEN { where ← after; nesting ← nesting+1 }

ELSE IF where=sibling THEN {

newDest: Ref = TextNode.LastWithin[dest.node];

where ← after;

nesting ← nesting + TextNode.Level[dest.node] - TextNode.Level[newDest];

dest ← [newDest, NodeItself];

};

-- split source and dest, if necessary, so can deal with entire nodes

[dest,source,where,nesting] ← DoSplits2[dest,source,where,nesting,event];

beforeSource ← TextNode.StepBackward[source.start.node];

afterSource ← TextNode.StepForward[source.end.node];

afterLoc ← [afterSource,0];

{ -- for exits

-- check for dest already in correct position

IF dest # TextNode.nullLocation AND

((where = after AND (dest.node = beforeSource OR dest.node = source.end.node))

OR (where = before AND (dest.node = afterSource OR dest.node = source.start.node)))

THEN { -- not going anywhere, but might be changing nesting

IF nesting > 0 THEN

FOR i:INTEGER IN [0..nesting) DO

[] ← Nest[sourceRoot,NodeSpan[source],event];

ENDLOOP

ELSE IF nesting < 0 THEN

FOR i:INTEGER IN [nesting..0) DO

[] ← UnNest[sourceRoot,NodeSpan[source],event];

ENDLOOP }

ELSE DO -- repeat this loop only if have forced nest or unnest or source and dest in same tree

--check for dest inside source

[sBefore,sAfter,sTop,sBottom,sNesting,sDepth] ←

DescribeBand[source.start.node,source.end.node ! BadBand =>

{ source ← TextNode.nullSpan; GOTO ErrorReturn } ];

IF dest = TextNode.nullLocation THEN { -- moving to limbo

dest ← CreateDest[SliceLength[sTop]-sDepth];

destRoot ← TextNode.Root[dest.node];

destRoot.deleted ← TRUE; -- so will free this when it falls off the edit history list

where ← after; nesting ← 1 };

[dBefore,dAfter,dNesting] ← DestSlices[dest.node,where];

IF CompareSliceOrder[dBefore,sBefore]=after AND

CompareSliceOrder[dBefore,sBottom]=before THEN GOTO ErrorReturn;

-- dest inside source

IF dBefore[0] = sBefore[0] THEN { -- source and dest in same tree

span: Span = TextNode.MakeNodeSpan[source.start.node,source.end.node];

FreeSlices[];

[] ← MoveToLimbo[sourceRoot,span,event];

LOOP };

dNesting ← dNesting + nesting;

SELECT NeedNestingChange[dBefore,dAfter,sTop,sBottom,dNesting,sDepth] FROM

needUnNest => { ForcedUnNest[LastOfSlice[dAfter]]; LOOP };

needNest => { ForcedNest[]; LOOP };

ENDCASE;

IF SliceLength[sAfter] > SliceLength[sBefore]+1 THEN {

ForcedUnNest[LastOfSlice[sAfter]]; LOOP }

ELSE { -- do it

notify: REF MovingNodes Change;

notify ← TextNode.pZone.NEW[MovingNodes Change ← [MovingNodes[

destRoot,sourceRoot,dest.node,source.start.node,source.end.node,

LastOfSlice[sBefore],sNesting,(where # before)]]];

Notify[notify,before];

DeletePrefix[sTop,sDepth]; DeletePrefix[sBottom,sDepth];

ReplaceBand[dBefore,dAfter,sTop,sBottom,dNesting,event];

Splice[sBefore,sAfter];

FreeSlices[];

Notify[notify,after];

UndoEvent.Note[event,UndoMoveNodes,notify] };

EXIT;

ENDLOOP;

IF dest.where # NodeItself THEN { -- undo prior splits

start, end: BOOLEAN ← FALSE;

IF source.start.where # NodeItself THEN { -- merge start of source with front of dest

start ← TRUE;

[source,] ← ReMerge[source,nullSpan,source.start.node,event] };

IF source.end.where # NodeItself THEN { -- merge end of source with tail of dest

end ← TRUE;

[source,] ← ReMerge[source,nullSpan,source.end.node,event,TRUE] };

IF start AND end THEN { -- merge before source with after source

afterLoc ← Merge[TextNode.Root[afterSource],afterSource,event] }}

ELSE IF source.start.where # NodeItself AND source.end.where # NodeItself THEN {

afterLoc ← Merge[TextNode.Root[afterSource],afterSource,event] };

IF words THEN [source,] ← FixWordSpans[source,nullSpan,event];

afterMoved2 ← afterMoved1; -- save previous hint

afterMoved1 ← IF afterSource=NIL THEN [beforeSource,0] ELSE afterLoc; -- hint for repaint

RETURN [source];

EXITS ErrorReturn => {

FreeSlices[];

[,source] ← UndoSplits2[dest,source,event];

ERROR CannotDoEdit }}};

UndoMoveNodes: PROC [undoRef: REF, currentEvent: Event] = TRUSTED {

saved: REF Change ← NARROW[undoRef];

WITH x:saved SELECT FROM

MovingNodes => {

[] ← Move[x.sourceRoot, x.destRoot,

TextNode.MakeNodeLoc[x.pred], TextNode.MakeNodeSpan[x.first,x.last],

FALSE, after, x.nesting, currentEvent] };

ENDCASE => ERROR };

Transpose: PUBLIC PROC [alphaRoot, betaRoot: Ref,

alpha, beta: Span, words: BOOLEAN ← FALSE, event: Event ← NIL]

RETURNS [newAlpha, newBeta: Span] = {

-- newAlpha is new location of alpha span; ditto for newBeta

aBefore, aAfter, aTop, aBottom, bBefore, bAfter, bTop, bBottom: Slice;

aNesting, bNesting: INTEGER;

aDepth, bDepth: NAT;

beforeAlpha, afterAlpha, beforeBeta, afterBeta: Ref; -- nodes adjacent after do splits

afterAlphaLoc, afterBetaLoc: Location;

FreeSlices: PROC = {

FreeSlice[aBefore]; FreeSlice[aAfter]; FreeSlice[aTop]; FreeSlice[aBottom];

FreeSlice[bBefore]; FreeSlice[bAfter]; FreeSlice[bTop]; FreeSlice[bBottom];

aBefore ← aAfter ← aTop ← aBottom ← bBefore ← bAfter ← bTop ← bBottom ← NIL };

{ -- for exit

IF CheckForNil[alpha] OR CheckForNil[beta] THEN

RETURN [TextNode.nullSpan, TextNode.nullSpan];

IF TextSpans[alpha,beta] THEN { -- pure text transpose

alphaNode: RefTextNode ← TextNode.NarrowToTextNode[alpha.start.node];

betaNode: RefTextNode ← TextNode.NarrowToTextNode[beta.start.node];

alphaStart: Offset ← alpha.start.where;

alphaLen: Offset ← alpha.end.where - alphaStart + 1;

betaStart: Offset ← beta.start.where;

betaLen: Offset ← beta.end.where - betaStart + 1;

alphaResultStart, alphaResultLen, betaResultStart, betaResultLen: Offset;

editProc: TextEdit.TransposeProc ←

IF words THEN TextEdit.TransposeWords ELSE TextEdit.TransposeText;

[alphaResultStart,alphaResultLen,betaResultStart,betaResultLen] ← editProc[

alphaRoot,betaRoot,alphaNode,alphaStart,alphaLen,betaNode,betaStart,betaLen,event];

newAlpha ← [[betaNode,alphaResultStart],[betaNode,alphaResultStart+alphaResultLen-1]];

newBeta ← [[alphaNode,betaResultStart],[alphaNode,betaResultStart+betaResultLen-1]];

RETURN };

[alpha,beta] ← DoSplits[alpha,beta,event]; -- so can deal with entire nodes

beforeAlpha ← TextNode.StepBackward[alpha.start.node];

afterAlpha ← TextNode.StepForward[alpha.end.node];

afterAlphaLoc ← [afterAlpha,0];

beforeBeta ← TextNode.StepBackward[beta.start.node];

afterBeta ← TextNode.StepForward[beta.end.node];

afterBetaLoc ← [afterBeta,0];

-- now check for alpha beta adjacent or overlapping as special cases

IF afterAlpha = beta.start.node THEN { -- alpha just before beta

-- move beta nodes to before alpha nodes

[] ← Move[alphaRoot,betaRoot,NodeLoc[alpha.start],NodeSpan[beta],FALSE,before,0,event] }

ELSE IF afterBeta = alpha.start.node THEN { -- beta just before alpha

-- move alpha nodes to before beta nodes

[] ← Move[betaRoot,alphaRoot,NodeLoc[beta.start],NodeSpan[alpha],FALSE,before,0,event] }

ELSE { -- get slices describing the bands of nodes to be transposed

overlap: BOOLEAN;

head, tail: Span; -- sections of alpha or beta before and after the overlap

startOrder, endOrder: NodeOrder;

[aBefore,aAfter,aTop,aBottom,aNesting,aDepth] ←

DescribeBand[alpha.start.node,alpha.end.node ! BadBand =>

{ alpha ← beta ← TextNode.nullSpan; GOTO ErrorReturn }];

[bBefore,bAfter,bTop,bBottom,bNesting,bDepth] ←

DescribeBand[beta.start.node,beta.end.node ! BadBand =>

{ alpha ← beta ← TextNode.nullSpan; GOTO ErrorReturn }];

-- check for overlap

[overlap,head,tail,startOrder,endOrder] ←

SliceOrder[alpha,beta,aBefore,aBottom,bBefore,bBottom];

IF overlap THEN { -- bands overlap

FreeSlices[];

IF head = TextNode.nullSpan AND tail = TextNode.nullSpan THEN NULL

ELSE IF head = TextNode.nullSpan THEN { --move tail to before alphastart

[] ← Move[alphaRoot,betaRoot,

NodeLoc[alpha.start],NodeSpan[tail],FALSE,before,0,event];

IF endOrder=before THEN { -- alpha end before beta end

beta.start ← tail.start; beta.end ← alpha.end }

ELSE { -- beta end before alpha end

alpha.start ← tail.start; alpha.end ← beta.end }}

ELSE IF tail = TextNode.nullSpan THEN { --move head to after alphaend

[] ← Move[alphaRoot,betaRoot,

NodeLoc[alpha.end],NodeSpan[head],FALSE,after,0,event];

IF startOrder=before THEN { -- alpha start before beta start

alpha.start ← beta.start; alpha.end ← head.end }

ELSE { -- beta start before alpha start

beta.start ← alpha.start; beta.end ← head.end }}

ELSE IF startOrder # endOrder THEN NULL -- one contained in the other

ELSE { --transpose head and tail

[] ← Transpose[alphaRoot,betaRoot,

NodeSpan[head],NodeSpan[tail],FALSE,event];

IF startOrder=before THEN { -- alpha start before beta start

alpha.start ← beta.start; alpha.end ← head.end;

beta.start ← tail.start; beta.end ← alpha.end }

ELSE { -- beta start before alpha start

beta.start ← alpha.start; beta.end ← head.end;

alpha.start ← tail.start; alpha.end ← beta.end }}}

ELSE { -- do transpose as two moves

aSpan, bSpan: Span;

after1, after2: Location;

bLoc: Location ← TextNode.MakeNodeLoc[LastOfSlice[bBefore]];

aLoc: Location ← TextNode.MakeNodeLoc[LastOfSlice[aBefore]];

FreeSlices[];

aSpan ← TextNode.MakeNodeSpan[alpha.start.node,alpha.end.node];

bSpan ← TextNode.MakeNodeSpan[beta.start.node,beta.end.node];

[] ← MoveToLimbo[alphaRoot,aSpan,event]; after1 ← afterMoved1; -- repaint hints

[] ← MoveToLimbo[betaRoot,bSpan,event]; after2 ← afterMoved1;

[] ← Move[betaRoot,TextNode.Root[aSpan.start.node],

bLoc,aSpan,FALSE,after,bNesting,event];

[] ← Move[alphaRoot,TextNode.Root[bSpan.start.node],

aLoc,bSpan,FALSE,after,aNesting,event];

afterMoved1 ← after1; afterMoved2 ← after2 }};

IF alpha.start.where # NodeItself AND beta.start.where # NodeItself THEN { -- remerge starts

[alpha,beta] ← ReMerge[alpha,beta,alpha.start.node,event];

[alpha,beta] ← ReMerge[alpha,beta,beta.start.node,event] };

IF alpha.end.where # NodeItself AND beta.end.where # NodeItself THEN { -- remerge ends

[alpha,beta] ← ReMerge[alpha,beta,alpha.end.node,event,TRUE];

[alpha,beta] ← ReMerge[alpha,beta,beta.end.node,event,TRUE];

afterAlphaLoc ← beta.end; afterBetaLoc ← alpha.end };

IF words THEN [alpha,beta] ← FixWordSpans[alpha,beta,event];

afterMoved1 ← IF afterAlphaLoc.node=NIL THEN [beforeAlpha,0] ELSE afterAlphaLoc; -- hint for repaint

afterMoved2 ← IF afterBetaLoc.node=NIL THEN [beforeBeta,0] ELSE afterBetaLoc;

RETURN [alpha,beta];

EXITS ErrorReturn => {

FreeSlices[]; [alpha,beta] ← UndoSplits[alpha,beta,event];

ERROR CannotDoEdit }}};

MoveOnto: PUBLIC PROC [destRoot, sourceRoot: Ref, dest, source: Span,

words: BOOLEAN ← FALSE, saveForPaste: BOOLEAN ← TRUE, event: Event ← NIL]

RETURNS [result: Span] = {

-- like Replace, but moves source instead of copying it

-- result is moved span

overlap: BOOLEAN;

head, tail, newDest: Span; -- sections of alpha or beta before and after the overlap

startOrder, endOrder: NodeOrder;

aBefore, aAfter, aTop, aBottom, bBefore, bAfter, bTop, bBottom: Slice;

aNesting, bNesting: INTEGER;

aDepth, bDepth: NAT;

FreeSlices: PROC = {

FreeSlice[aBefore]; FreeSlice[aAfter]; FreeSlice[aTop]; FreeSlice[aBottom];

FreeSlice[bBefore]; FreeSlice[bAfter]; FreeSlice[bTop]; FreeSlice[bBottom];

aBefore ← aAfter ← aTop ← aBottom ← bBefore ← bAfter ← bTop ← bBottom ← NIL };

{ -- for exit

IF CheckForNil[source] OR CheckForNil[dest] THEN RETURN [TextNode.nullSpan];

IF TextSpans[dest,source] THEN { -- pure text move

RETURN [TwoSpanText[destRoot,sourceRoot,dest,source,words,saveForPaste,

TextEdit.MoveWordsOnto,TextEdit.MoveTextOnto,event]] };

[dest,source] ← DoSplits[dest,source,event];

[aBefore,aAfter,aTop,aBottom,aNesting,aDepth] ←

DescribeBand[dest.start.node,dest.end.node ! BadBand =>

{ dest ← source ← TextNode.nullSpan; GOTO ErrorReturn }];

[bBefore,bAfter,bTop,bBottom,bNesting,bDepth] ←

DescribeBand[source.start.node,source.end.node ! BadBand =>

{ dest ← source ← TextNode.nullSpan; GOTO ErrorReturn }];

-- get slices for dest and source

[overlap,head,tail,startOrder,endOrder] ←

SliceOrder[dest,source,aBefore,aBottom,bBefore,bBottom];

FreeSlices[];

-- check for overlap

IF overlap THEN { -- bands overlap. modify dest so doesn't overlap

IF head = TextNode.nullSpan AND tail = TextNode.nullSpan THEN GOTO ErrorReturn;

IF head = TextNode.nullSpan THEN { -- source start = dest start

IF endOrder=before THEN GOTO ErrorReturn -- dest end before source end

ELSE dest.start ← tail.start }

ELSE IF tail = TextNode.nullSpan THEN { --source end = dest end

IF startOrder=before THEN

dest.end ← head.end -- dest start before source start

ELSE GOTO ErrorReturn } -- source start before dest start

ELSE { -- have both head and tail

IF startOrder=before AND endOrder=after THEN {

[] ← Delete[destRoot,tail,event]; dest.end ← head.end }

ELSE IF startOrder=before THEN dest.end ← head.end

ELSE IF endOrder=after THEN dest.start ← tail.start

ELSE GOTO ErrorReturn }};

[dest,source] ← UndoSplits[dest,source,event];

source ← MoveToLimbo[sourceRoot,source,event];

sourceRoot ← TextNode.Root[source.start.node];

[result,newDest] ← Transpose[sourceRoot,destRoot,source,dest,words,event];

IF saveForPaste THEN SaveSpanForPaste[newDest,event];

RETURN;

EXITS ErrorReturn => {

[dest,source] ← UndoSplits[dest,source,event]; ERROR CannotDoEdit }}};

-- ***** Nesting

ChangeNesting: PUBLIC PROC [root: Ref, span: Span, change: INTEGER, event: Event ← NIL]

RETURNS [new: Span] = {

-- moves span to a deeper nesting level in tree

before, after, top, bottom: Slice;

nesting: INTEGER;

depth: NAT;

FreeSlices: PROC = {

FreeSlice[before]; FreeSlice[after]; FreeSlice[top]; FreeSlice[bottom];

before ← after ← top ← bottom ← NIL };

{ -- for exit

IF CheckForNil[span] THEN RETURN [TextNode.nullSpan];

[span,] ← DoSplits[span,nullSpan,event]; -- so can deal with entire nodes

DO -- only repeat this loop if have forced nest/unnest

[before,after,top,bottom,nesting,depth] ←

DescribeBand[span.start.node,span.end.node ! BadBand =>

{ span ← nullSpan; GOTO ErrorReturn } ];

IF nesting+change > 1 THEN GOTO ErrorReturn; -- cannot do it

SELECT NeedNestingChange[before,after,top,bottom,nesting+change,depth] FROM

needUnNest => {

afterNode: Ref = LastOfSlice[after];

span: Span = TextNode.MakeNodeSpan[afterNode,TextNode.LastWithin[afterNode]];

FreeSlices[];

[] ← UnNest[root,span,event];

LOOP };

needNest => {

span: Span = TextNode.MakeNodeSpan[top[depth],TextNode.LastWithin[bottom[depth]]];

IF SliceLength[top] = depth+1 THEN GOTO ErrorReturn;

FreeSlices[];

[] ← Nest[root,span,event];

LOOP };

ENDCASE => { -- do it

notify: REF NodeNesting Change;

notify ← TextNode.pZone.NEW[NodeNesting Change ← [NodeNesting[

root, span.start.node, span.end.node, change]]];

Notify[notify,before];

DeletePrefix[top,depth];

DeletePrefix[bottom,depth];

ReplaceBand[before,after,top,bottom,nesting+change,event];

FreeSlices[];

Notify[notify,after];

UndoEvent.Note[event,UndoChangeNesting,notify] };

EXIT;

ENDLOOP;

RETURN [span];

EXITS ErrorReturn => {

FreeSlices[]; [span,] ← UndoSplits[span,nullSpan,event]; ERROR CannotDoEdit }}};

UndoChangeNesting: PROC [undoRef: REF, currentEvent: Event] = TRUSTED {

saved: REF Change ← NARROW[undoRef];

WITH x:saved SELECT FROM

NodeNesting => {

[] ← ChangeNesting[x.root,TextNode.MakeNodeSpan[x.first,x.last],-x.change,currentEvent] };

ENDCASE => ERROR };

-- ***** New nodes; split & merge

Insert: PUBLIC PROC [root, old: Ref, where: Place ← after, event: Event ← NIL]

RETURNS [new: Ref] = TRUSTED {

-- empty copy of old node is inserted in tree in position determined by "where"

IF old=NIL THEN RETURN [NIL];

WITH x:old SELECT FROM

text => new ← TextNode.NewTextNode[];

other => new ← TextNode.NewOtherNode[];

ENDCASE => ERROR;

Inherit[old,new];

DoInsertNode[root,old,new,where,event] };

InsertTextNode: PUBLIC PROC

[root, old: Ref, where: Place ← after, inherit: BOOLEAN ← FALSE, event: Event ← NIL]

RETURNS [new: RefTextNode] = {

-- empty text node is inserted in tree

IF old=NIL THEN RETURN [NIL];

new ← TextNode.NewTextNode[];

IF inherit THEN Inherit[old,new];

DoInsertNode[root,old,new,where,event] };

InsertOtherNode: PUBLIC PROC

[root, old: Ref, where: Place ← after, inherit: BOOLEAN ← FALSE, event: Event ← NIL]

RETURNS [new: RefOtherNode] = {

-- empty "other" kind of node is inserted in tree

IF old=NIL THEN RETURN [NIL];

new ← TextNode.NewOtherNode[];

IF inherit THEN Inherit[old,new];

DoInsertNode[root,old,new,where,event] };

Inherit: PUBLIC PROC [old, new: Ref, allprops: BOOL ← FALSE] = {

newtxt, oldtxt: RefTextNode;

CopyProp: PROC [name: ATOM, value: REF] RETURNS [BOOL] = {

newvalue: REF;

IF ~allprops THEN SELECT name FROM

$Prefix, $Postfix, $StyleDef => NULL; -- these control formatting

ENDCASE => RETURN [FALSE]; -- don't copy anything else

IF (newvalue ← NodeProps.CopyInfo[name,value]) # NIL THEN

NodeProps.PutProp[new,name,newvalue];

RETURN [FALSE] };

new.typename ← old.typename;

IF allprops OR old.hasprefix OR old.haspostfix OR old.hasstyledef THEN

[] ← NodeProps.MapProps[old, CopyProp, FALSE, FALSE];

IF (newtxt ← TextNode.NarrowToTextNode[new]) # NIL AND

(oldtxt ← TextNode.NarrowToTextNode[old]) # NIL THEN

newtxt.comment ← oldtxt.comment };

DoInsertNode: PROC [root, old, new: Ref, where: Place, event: Event] = {

dest, parent: Ref;

child: BOOLEAN;

notify: REF InsertingNode Change;

IF new = NIL OR old = NIL THEN RETURN;

parent ← IF where = child THEN old ELSE TextNode.Parent[old];

IF where = sibling THEN { dest ← TextNode.LastWithin[old]; child ← FALSE }

ELSE IF where = after THEN { dest ← old; child ← FALSE }

ELSE IF where = child THEN { dest ← old; child ← TRUE }

ELSE {

IF parent.child = old THEN { dest ← parent; child ← TRUE }

ELSE { dest ← TextNode.LastWithin[TextNode.Previous[old,parent]]; child ← FALSE }};

notify ← TextNode.pZone.NEW[InsertingNode Change ← [InsertingNode[root,new,dest]]];

Notify[notify,before];

IF child THEN { -- insert as first child of dest

IF dest.child # NIL THEN { new.next ← dest.child; new.last ← FALSE }

ELSE { new.next ← dest; new.last ← TRUE };

dest.child ← new }

ELSE IF where = sibling THEN { -- insert as next sibling of old; don't adopt children

new.next ← old.next; new.last ← old.last;

old.last ← FALSE; old.next ← new }

ELSE { -- insert as next sibling of dest

new.next ← dest.next; new.last ← dest.last;

dest.last ← FALSE; dest.next ← new;

IF where = after AND (new.child ← dest.child) # NIL THEN { -- adopt dest's children

TextNode.LastSibling[new.child].next ← new;

dest.child ← NIL }};

Notify[notify,after];

UndoEvent.Note[event,UndoInsertNode,notify] };

UndoInsertNode: PROC [undoRef: REF, currentEvent: Event] = TRUSTED {

saved: REF Change ← NARROW[undoRef];

WITH x:saved SELECT FROM

InsertingNode => { [] ← Delete[x.root,TextNode.MakeNodeSpan[x.new,x.new],currentEvent] };

ENDCASE => ERROR };

Split: PUBLIC PROC [root: Ref, loc: Location, event: Event ← NIL] RETURNS [new: Ref] = {

-- inserts copy of loc.node is inserted directly after loc.node (as sibling)

-- new adopts children of old (if any)

-- if loc.where # NodeItself and loc.node is a text node, then

-- text after loc.where moves to new node

-- text before loc.where stays in old node

-- returns the new node

old: Ref ← loc.node;

oldTxt, newTxt: RefTextNode;

IF old=NIL THEN RETURN [NIL];

new ← Insert[root,old,after,event];

IF loc.where # NodeItself AND (oldTxt ← TextNode.NarrowToTextNode[old]) # NIL THEN {

newTxt ← TextNode.NarrowToTextNode[new];

[] ← TextEdit.MoveText[destRoot: root, sourceRoot: root, dest: newTxt, destLoc: 0,

source: oldTxt, start: loc.where, event: event] }};

Merge: PUBLIC PROC [root, node: Ref, event: Event ← NIL] RETURNS [loc: Location] = {

-- copies text of node to end of previous node

-- then deletes node

-- returns location of join in the merged node

pred: RefTextNode ← TextNode.NarrowToTextNode[TextNode.StepBackward[node]];

txt: RefTextNode ← TextNode.NarrowToTextNode[node];

start: Offset;

IF pred = NIL OR TextNode.Parent[pred] = NIL OR txt = NIL THEN ERROR CannotDoEdit;

[start,] ← TextEdit.CopyText[root,root,pred,MaxLen,txt,0,MaxLen,event];

[] ← Delete[root,TextNode.MakeNodeSpan[txt,txt],event];

RETURN [[pred,start]] };

-- **** Change looks ****

ChangeLooks: PUBLIC PROC [root: Ref, span: Span, remove, add: Looks, event: Event ← NIL] = {

DoChange: PROC [node: RefTextNode, start, len: Offset] RETURNS [stop: BOOLEAN] = {

TextEdit.ChangeLooks[root,node,remove,add,start,len,event]; RETURN [FALSE] };

Apply[span,DoChange] };

-- ***** Cap's and Lowercase

ChangeCaps: PUBLIC PROC [root: Ref, span: Span, how: TextEdit.CapChange ← allCaps, event: Event ← NIL] = {

DoChange: PROC [node: RefTextNode, start, len: Offset] RETURNS [stop: BOOLEAN] = {

TextEdit.ChangeCaps[root,node,start,len,how,event]; RETURN [FALSE] };

IF CheckForNil[span] THEN RETURN;

Apply[span,DoChange] };

-- ***** Initialization

Start: PUBLIC PROC = {}; -- for initialization only

END.