what does := means simply?

[bartc]

On 19/05/2018 01:00, Chris Angelico wrote:
> On Sat, May 19, 2018 at 7:53 AM, bartc <bc at freeuk.com> wrote:
>> I've worked with text files for 40 years. Now Python is telling me I've been
>> doing it wrong all that time!
>>
>> Look at the original code I posted from which this Python was based. That
>> creates a file - just a file - without worrying about whether it's text or
>> binary. Files are just collections of bytes, as far as the OS is concerned.
>>
>> So what could be more natural than writing a byte to the end of a file?
> 
> So, you create a file without worrying about whether it's text or
> binary, and you add a byte to the end of the file. That means you're
> treating it as a binary file, not as a text file. Do you understand
> that?

Well I /don't/ worry about, but the reason is that long ago I switched 
to using binary mode for all files. (My 'createfile' function shown 
after my sig shows how it works. It's a thin wrapper around C's fopen, 
and it's C that has this thing about text and binary files.)

But in Python, even as a binary file I had some trouble writing to it, 
as it's fussy when dealing with strings and bytearrays and bytes and 
array.arrays all with their own rules.

-- 
bartc

global function createfile(name, options="wb") =
     if not name.isstring or name="" then
         return nil
     fi

     return fopen(name,options)
end