Re: explanation what "error: can't redefine read-only symbol foo" means in detail

[David Bateman]

Andreas Romeyke wrote:
> Hi,
>
> David Bateman wrote:
>   
>> So I don't see what the problem is. Can you give a full example...
>>   
>>     
> The problem is that the original function comes from Matlab and dies on
> Octave with error message above. I do not understand why this message is
> generated, because the function is large but not too complicated.
>
> Therefore it would be helpful to have an example that generates  the
> message above. The function is from the EEGLab toolbox and is called
> eeg_checkset(). The m-file is attached, it dies on line 925.
>
> Here the output:
>
>     Extracting events...
>     Importing data events...
>     Removing event channel...
>     error: can't redefine read-only symbol `eeg_checkset'
>     error: `eeg_checkset' undefined near line 925 column 25
>     error: evaluating switch command near line 837, column 9
>     error: evaluating for command near line 836, column 5
>     error: evaluating if command near line 835, column 1
>     error: called from `eeg_checkset' in file
>     `/SCR/svn_work/eeglab-devel-5.03/eeglab5.03/functions/eeg_checkset.m'
>     error: evaluating assignment expression near line 234, column 9
>     error: evaluating if command near line 226, column 1
>     error: called from `pop_biosig' in file
>     `/SCR/svn_work/eeglab-devel-5.03/eeglab5.03/functions/pop_biosig.m'
>     error: evaluating assignment expression near line 10, column 5
>
> Could it be that the problem depends on type of variable, because the
> EEG-variable is global by default (set in toolbox)?
>
> Any hints?
>
>   
Do you mean eeg_checkset is both a function and a global variable? If so
have you tried changing one of their names?

The error message you are seeing comes from the symbol table code where
the symbol eef_checkset is truly marked as read-only or protected. The
only ways I can see this happening is for built-in mappers  or functions
with a call like "sym_rec->protect()". It can also happen in the
dispatch code. Have you used dispatch?

D.

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