[Octave-bug-tracker] [bug #60861] set command sometimes doesn't allow multiple items.

[anonymous]

URL:
  <https://savannah.gnu.org/bugs/?60861>

                 Summary: set command sometimes doesn't allow multiple items.
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Wed 30 Jun 2021 05:05:11 PM UTC
                Category: GUI
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: None
                  Status: None
             Assigned to: None
         Originator Name: Paul Mennen
        Originator Email: paul@mennen.org
             Open/Closed: Open
                 Release: 6.1.0
         Discussion Lock: Any
        Operating System: Microsoft Windows

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Details:

Usually the set command allows multiple items, i.e.


set(handle,prop1,value1,prop2,value2,prop3,value3);


Octave usually permits commands like that, however there are two situations
where this doesn't work. One is where you are setting a single property to
more than one object with different values. (The first set command in the
following script is an example of this. A 2nd one is where you are setting
multiple properties of a single object. (The second set command in the
following script is such an example, and is used to copy both the fontsize and
fontweight properties from one object to another):


figure;
locations = {[2 2 2 1]/20; [2 4 2 1]/20; [2 6 2 1]/20};
txt       = {'ABC'; 'DEF'; 'HIJ'};
props     = {'fontsize' 'fontweight'};
a = [uicontrol uicontrol uicontrol];
set(a,'units','normalized',{'position'},locations,{'string'},txt);
set(a(2),props,get(a(1),props),'backgroundcolor','red');


Although this script runs in Matlab, both of these set commands will produce
an error such as "argument 0 must be a property name".

There is a fairly easy workaround, which is to simply use only one
property/value pair at a time. So if you replace the above two set commands
with the following six set commands, the script runs fine with no errors:


set(a,'units','normalized');
set(a,{'position'},locations);
set(a,{'string'},txt);
set(a(2),props,get(a(1),props)); % copies both fontsize and fontweight
properties from a(1) to a(2)
set(a(2),'backgroundcolor','red');


I suspect this would not be a difficult bug to fix, but if that turns out not
to be the case, I suggest that you at least fix the error message. Almost all
error messages I have seen show the routine and line number where the error
occurred. However for this particular error message, neither the line number
nor the function where the error occurred are displayed. Since my program
contains hundreds of set commands it becomes quite laborious to single step
thru the code trying to find the set command that Octave was (unjustly)
complaining about.





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