what does := means simply?

[bartc]

On 19/05/2018 02:00, Steven D'Aprano wrote:
> On Fri, 18 May 2018 20:42:05 -0400, Dennis Lee Bieber wrote:
> 
>> 	Unfortunately -- in the current era, "text" means "a defined
> encoding",
> 
> Text has ALWAYS meant "a defined encoding". It is just that for a long
> time, people could get away with assuming that the encoding they used was
> the *only* possible encoding, and using it implicitly without even
> thinking about it.
> 
> That One True Encoding is, of course, EBCDIC.
> 
> No, I kid, of course it is Mac-Roman.
> 
> Ha ha, no, just pulling your leg... of course it's ISO 8859-1 (not to be
> confused with ISO-8859-1, yes the hyphen is significant). Except for web
> browsers, which are required to interpret declarations of ISO 8859-1 as
> CP-1252 instead.
> 
> Actually, I'm still kidding around. Everyone knows the One True Encoding
> is ISCII. (That's not a typo.)

The .ppm (really .pbm) file which was the subject of this sub-thread has 
its header defined using ASCII. I don't think an EBCDIC 'P4' etc will work.

-- 
bartc