DIRECTORYAscii USING [CR, SP, TAB],GetTree USING [],Rope USING [ROPE],RopeEdit USING [Substr],RopeIO USING [FromFile],RopeReader USING [FreeRopeReader, Get, GetIndex, GetRopeReader, ReadOffEnd, Ref, SetPosition],TextNode USING [NewTextNode, Node];GetTreeImpl: CEDAR PROGRAMIMPORTS TextNode, RopeEdit, RopeIO, RopeReaderEXPORTS GetTree= BEGIN OPEN GetTree;ROPE: TYPE = Rope.ROPE;Node: TYPE ~ TextNode.Node;ReadIndent: PUBLIC PROC [fileName: ROPE, tabIndent: NAT _ 4] RETURNS [root: Node] = {input: ROPE _ RopeIO.FromFile[fileName];rdr: RopeReader.Ref _ RopeReader.GetRopeReader[];maxOpen: NAT = 40;openNodes: ARRAY [0..maxOpen] OF Node;openIndents: ARRAY [0..maxOpen] OF INTEGER;level, lvl: NAT;indent: INTEGER;node: Node;noMoreInput: BOOL _ FALSE;ReadLine: PROC RETURNS [ROPE] = { -- read line and set indenttab: CHAR=Ascii.TAB;space: CHAR=Ascii.SP;cr: CHAR=Ascii.CR;start, end: INT _ 0;indent _ 0;DO SELECT RopeReader.Get[rdr ! RopeReader.ReadOffEnd => {noMoreInput _ TRUE; EXIT }] FROMcr => EXIT; -- blank linetab => indent _ indent+tabIndent;space => indent _ indent+1;0C => { noMoreInput _ TRUE; EXIT }; -- stop at first NULL charENDCASE => { -- just saw the first nonblank char on the linestart _ RopeReader.GetIndex[rdr]-1;DO SELECT RopeReader.Get[rdr ! RopeReader.ReadOffEnd => {end _ RopeReader.GetIndex[rdr]; noMoreInput _ TRUE; EXIT }] FROMcr => { end _ RopeReader.GetIndex[rdr]-1; EXIT };0C => { end _ RopeReader.GetIndex[rdr]-1; noMoreInput _ TRUE; EXIT };ENDCASE;ENDLOOP;EXIT };ENDLOOP;RETURN [RopeEdit.Substr[input,start,end-start]] };PlaceNode: PROC = {dest: Node;SELECT lvl FROM< level => { -- insert as sibling of node at lvl+1dest _ openNodes[level _ lvl+1];dest.last _ FALSE; node.next _ dest.next; dest.next _ node };= maxOpen => { -- insert as sibling of node at max leveldest _ openNodes[level]; dest.last _ FALSE;node.next _ dest.next; dest.next _ node };ENDCASE => { -- increase leveldest _ openNodes[level]; node.next _ dest; dest.child _ node;level _ level+1 };node.last _ TRUE; openIndents[level] _ indent; openNodes[level] _ node };RopeReader.SetPosition[rdr,input,0];openNodes[0] _ root _ TextNode.NewTextNode[];root.last _ TRUE;openIndents[0] _ -1; level _ 0;UNTIL noMoreInput DOnode _ TextNode.NewTextNode[];IF (node.rope _ ReadLine[])=NIL THEN indent _ MAX[0,openIndents[level]];FOR lvl _ level, lvl-1 DOIF openIndents[lvl] < indent THEN { PlaceNode[]; EXIT };ENDLOOP;ENDLOOP; RopeReader.FreeRopeReader[rdr];};END.   R  GetTreeImpl.mesaCopyright c 1985, 1986 by Xerox Corporation.  All rights reserved.written by Paxton. May 1981Paxton. August 24, 1982 10:39 amRuss Atkinson, July 26, 1983 5:43 pmDoug Wyatt, August 28, 1986 5:41:07 pm PDTEach line of input file becomes a node (parent for line is the closest previous line with smaller indent).ÊŒ  ˜ codešœ™Kšœ
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