Plots are not always shown

[woutersj]

Plotting in a session doesn't always work.
If I put these lines in a session

octave>  x = [-pi:0.1:pi];
octave>  hold on;
octave>  plot(x,sin(x));
octave>  plot(x,cos(x))

and repeatedly execute the last two commands, after two times the plot doesn't show up anymore. It seems the method to set TM_OCTAVE_PLOT_DIGEST is not robust.
It seems like if we simply do

    if disp_ans
      tmplot (); ## call TeXmacs plotting interface
      clf()
    endif

in tmrepl.m that plots show as expected, since tmplot() already checks whether the plot is empty or not.

[woutersj]

See this commit

[da-liii]

The digest is for detecting whether the ans is changed. Create PR and I will carefully review the changes.

[da-liii]

How about solving this issue by forcing the display when the last line of the the statements is a plot/imshow/... function call?

[da-liii]

@woutersj How about 00a8f11 ?

Just re-impl the plot part. Have fun!

[woutersj]

Thanks @sadhen! I really like your solution of searching for plot functions.
It seems isplot doesn't work for multiline input. I'll add some tests to plots.tm.

[da-liii]

For multiline input, currently, it is evaled at once. I know the flaws. But I don't want to do more string manipulation on octave code. There seems no official support of meta programming in octave.

[da-liii]

I think detection of plot changes should be provided by octave itself. We need to discuss the details with the octave community.

[woutersj]

I think it should be possible to detect plot changes based on serialize, but we would need to traverse the figure tree instead of serializing the top figure node.
I have been experimenting a bit and I think something like this could work:

function rets = traverse(node,s)
  rets = s;
  if ~isempty(node)
    for i = 1:length(node.children)
      rets = traverse(get(node.children(i)),rets);
    endfor
    rets = strcat(rets,"\n");
  endif
  rets = strcat(rets,serialize(node),"\t");
endfunction

Then we can do traverse(get(get(groot, "currentfigure")),"") to get a string for the entire tree.

However, the tree contains function handles, which serialize.m cannot handle, so there should be some more changes made there. Perhaps the func2str function can be useful.

[woutersj]

It seems this might work to detect any changed figures:

function h = fighash(id)
  fig_struct = hdl2struct (id);
  save_header_format_string("","local")
  h = hash("md5",save("-","-struct","fig_struct"));
endfunction

arrayfun("fighash",get(0,"children"), "UniformOutput", false)