bug concatenating vectors in 3.1.51+

[Ben Abbott]

I attempted a fresh build last night. My tip is

changeset:   8210:a10397d26114
tag:         tip
user:        John W. Eaton <jwe at octave.org>
date:        Fri Oct 10 15:10:58 2008 -0400
summary:     graphics.cc (base_graphics_properties::adopt): place new  
child at front of list, not end; make children a column vector instead  
of a row vector

The bug is fairly easy to see

	[ones(1,0); zeros(5,1)]
	error: number of columns must match (1 != 0)

In Matlab

 >> [ones(1,0);zeros(5,1)]

ans =

      0
      0
      0
      0
      0

Presently Octave will not build for me.

if [ -f gplot.eps ] ; then gs -dBATCH -dEPSCrop -dNOPAUSE -q - 
sDEVICE=pdfwrite -sOutputFile=gplot.pdf gplot.eps ; fi
../../run-octave -f -q -H -p . --eval "sparseimages ('grid', 'eps');"
error: number of rows must match (79 != 1) near line 937, column 23
error: called from:
error:   /Users/bpabbott/Development/mercurial/octave-3.1.51/scripts/ 
plot/__go_draw_axes__.m at line 937, column 6
error:   /Users/bpabbott/Development/mercurial/octave-3.1.51/scripts/ 
plot/__go_draw_figure__.m at line 59, column 8
error:   /Users/bpabbott/Development/mercurial/octave-3.1.51/scripts/ 
plot/gnuplot_drawnow.m at line 55, column 7
error:   /Users/bpabbott/Development/mercurial/octave-3.1.51/scripts/ 
plot/print.m at line 447, column 7
error:   /Users/bpabbott/Development/mercurial/octave-3.1.51/doc/ 
interpreter/sparseimages.m at line 231, column 5
error:   /Users/bpabbott/Development/mercurial/octave-3.1.51/doc/ 
interpreter/sparseimages.m at line 33, column 2

make[3]: *** [grid.eps] Error 1
make[2]: *** [interpreter] Error 2
make[1]: *** [doc] Error 2
make: *** [all] Error 2

The offending line in __go_draw_axes__.m is

	kids = [obj.children, kids];

Which with John's change from row to column vector for handles needs  
to be

	kids = [obj.children; kids];

However, in this instance an empty vector with size [1, 0] fails.

I replaced the line with

	  if (isempty (kids))
	    kids = obj.children;
	  elseif (! isempty (obj.children))
	    kids = [obj.children; kids];
	  endif

and "make" and "make check" completed without further problems.

I could offer a changeset to resolve the problem with  
__go_draw_axes__, but expect the the proper solution would to fix the  
concatenation of column vectors.

Might someone with c++ skill take care of this, or if there are  
substantial problem with that, say the word and I'll submit a  
changeset for __go_draw_axes__.

Ben

Ben