[Octave-bug-tracker] [bug #65153] Unexpected error when using the ~ palceholder

[Denis Sbragion]

URL:
  <https://savannah.gnu.org/bugs/?65153>

                 Summary: Unexpected error when using the ~ palceholder
                   Group: GNU Octave
               Submitter: dsbragion
               Submitted: Fri 12 Jan 2024 04:01:35 PM UTC
                Category: Interpreter
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Unexpected Error or Warning
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
                 Release: 8.4.0
         Discussion Lock: Any
        Operating System: Microsoft Windows
           Fixed Release: None
         Planned Release: None


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Follow-up Comments:


-------------------------------------------------------
Date: Fri 12 Jan 2024 04:01:35 PM UTC By: Denis Sbragion <dsbragion>
Hello,

a test case for the problem is in the attached ueml.m, which is just the
simple function:


function [ X, Y ] = ueml()
        N = 10;
        X = (1:N)';
        Y = (1:N)';

        [ (1:N)', flipud((1:N)') ]      
endfunction


When called with:


>> ueml();
ans =

    1   10
    2    9
    3    8
    4    7
    5    6
    6    5
    7    4
    8    3
    9    2
   10    1


I get the expected result. When called with:


>> [ ~, Y ] = ueml();
error: undefined element in matrix list
error: called from
    ueml at line 6 column 27


the error happens.

This is caused by flipud returning nothing, not even an empty matrix. It
happens also with some other functions, like circshift. It looks like the ~
placeholder propagates in some way  to the inner function causing it to return
nothing at all.

Tested with the 8.4.0 official Windows release, with 8.4.0 compiled by myself
with the latest Mingw64 and also with 6.4.0 compiled by myself with the
version of Mingw64 availabe when 6.4.0 has been relased. Everything tested
under up to date Windows 10.

Hope it helps.

Bye,

Denis Sbragion






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<http://savannah.gnu.org/bugs/download.php?file_id=55556>

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