GGViewerOpsImpl.mesa
Copyright © 1985 by Xerox Corporation.  All rights reserved.
Last edited by Bier on August 9, 1985 0:02:25 am PDT
Contents:  Utility routines to get and set values from buttons, labels, and text viewers.
 
DIRECTORY
GGModelTypes,
GGViewerOps,
IO,
Rope,
ViewerClasses,
ViewerTools;
 
GGViewerOpsImpl: 
CEDAR 
PROGRAM
IMPORTS IO, Rope, ViewerTools
EXPORTS GGViewerOps =
BEGIN
Point: TYPE = GGModelTypes.Point;
Viewer: TYPE = ViewerClasses.Viewer;
GetReal: 
PUBLIC PROC [textViewer: Viewer, default: 
REAL] 
RETURNS [r: 
REAL] = {
rRope: Rope.ROPE ← ViewerTools.GetContents[textViewer];
IF Rope.Size[rRope] = 0 
THEN r ← default 
ELSE {
r ← IO.GetReal[IO.RIS[rRope]];
};
 
};
 
SetReal: 
PUBLIC PROC [viewer: Viewer, real: 
REAL] = {
realRope: Rope.ROPE;
realRope ← IO.PutFR["%6.2f", [real[real]]];
ViewerTools.SetContents[viewer, realRope];
};
 
GetPoint: 
PUBLIC 
PROC [textViewer: Viewer] 
RETURNS [point: Point, success: 
BOOL] = {
Assumes a rope of the form "[<real1>,<real2>]".
pointRope: Rope.ROPE ← ViewerTools.GetContents[textViewer];
f: IO.STREAM ← IO.RIS[pointRope];
ReadRope[f, "["];
point[1] ← ReadBlankAndReal[f];
ReadRope[f, ","];
point[2] ← ReadBlankAndReal[f];
ReadRope[f, "]"];
success ← TRUE;
};
 
SetPoint: 
PUBLIC PROC [viewer: Viewer, point: Point] = {
pointRope: Rope.ROPE;
pointRope ← IO.PutFR["[%6.2f,%6.2f]", [real[point[1]]], [real[point[2]]]];
ViewerTools.SetContents[viewer, pointRope];
};
 
ReadRope: 
PUBLIC 
PROC [f: 
IO.
STREAM, rope: Rope.
ROPE] = {
Removes the given rope from the top of the stream. Used to remove formatting words and phrases from 3d files.  We are not interested in these strings but only in the data in between them.
Signals RopeNotOnTop if some other rope is on top.
c: CHAR;
endofstream: BOOL ← FALSE;
FOR i: 
INT 
IN[1..Rope.Length[rope]] 
DO
c ← 
IO.GetChar[f
! IO.EndOfStream => {endofstream ← TRUE; CONTINUE}];
IF endofstream 
THEN 
SIGNAL RopeNotOnTop [IO.GetIndex[f], NIL, rope];
 
IF 
NOT c = Rope.Fetch[rope,i-1] 
THEN 
SIGNAL RopeNotOnTop [IO.GetIndex[f], Rope.FromChar[c], rope];
 
 
ENDLOOP;
};
 
RopeNotOnTop: PUBLIC SIGNAL [position: NAT, wasThere: Rope.ROPE, notThere: Rope.ROPE] = CODE;
ReadBlankAndReal: 
PROC [f: 
IO.
STREAM] 
RETURNS [r: 
REAL] = {
A convenience function.  Equivalent to ReadBlank[f]; r ← ReadReal[f];
ReadBlank[f];
r ← ReadReal[f];
};
 
ReadBlank: 
PROC [f: 
IO.
STREAM] = {
Reads, <SPACE>'s, <CR>'s, and <TAB>'s until something else is encountered.  Doesn't mind if no white space characters are found.  Treats comments as white space.
[] ← IO.SkipWhitespace[f, TRUE];
};
 
ReadReal: 
PROC [f: 
IO.
STREAM] 
RETURNS [r: 
REAL] = {
Reads digits up to the next ], <CR>, <SPACE> or <COMMA>.  Leaves these terminators on the stream.
realRope: Rope.ROPE;
end: BOOL ← FALSE;
[realRope, 
----] ← 
IO.GetTokenRope[f, RealBreakProc
!IO.EndOfStream => {end ← TRUE; CONTINUE}];
IF end THEN {r ← 0.0; RETURN};
IF Rope.Find[realRope, ".", 0, FALSE] = -1 THEN realRope ← Rope.Concat[realRope, ".0"];
r ← IO.GetReal[IO.RIS[realRope]];
};
 
RealBreakProc: 
PROC [char: 
CHAR] 
RETURNS [
IO.CharClass] = {
SELECT char 
FROM
'], ', => RETURN [break];
IO.CR =>RETURN [break];
IO.SP => RETURN [break];
ENDCASE => RETURN [other];
 
};
 
END.