what does := means simply?

[bartc]

On 19/05/2018 12:33, Peter J. Holzer wrote:
> On 2018-05-19 11:33:26 +0100, bartc wrote:

>> Not you understand why some of us don't bother with 'text mode' files.
> 
> "Not" or "Now"?

Now.

> Yesterday you claimed that you worked with them for 40 years.

Text files, yes. Not 'text mode' which is something inflicted on us by 
the C library.

(All my current programs can deal with lf or cr/lf line endings. I 
dropped cr-only line endings as I hadn't seen such a file since the 90's.)

>> However if you have an actual EBCDIC system and would to read .ppm files,
>> then you will have trouble reading the numeric parameters as they are
>> expressed using sequences of ASCII digits.

> I think the simplest way would be perform the calculation by hand
> (new_value = old_value * 10 + next_byte - 0x30). At least in a language
> which lets me process individual bytes easily. That would even work on
> both ASCII and EBCDIC based systems (and on every other platform, too).

/The/ simplest? Don't forget the numbers can be several digits each. 
Here's how I read them (NOT Python):

     readln @f, width, height

Would it work in an EBCDIC based system? Probably not. But, who cares? 
(I can't say I've never used such a system, but that was some ancient 
mainframe from the 70s. But I'm pretty certain I won't ever again.)

(Perhaps someone who has access to an EBCDIC system can try a .PPM 
reader to see what happens. I suspect that won't work either.)

-- 
bartc