Fwd: How the C programming language bridges the man-machine gap

[John W Kennedy]

There were some pre-360 systems, certainly (such as the IBM 650 and 7070), and perhaps, too, the Soviet machines that used trits instead of bits, where it is not correct to assume that '1' + 1 == '2', but I doubt those machines ever ran C. 

But in this age when there are already major languages (e.g., Java and Swift) that support only Unicode, this entire discussion is rather moot. 

-- 
John W. Kennedy
"Compact is becoming contract,
Man only earns and pays."
-- Charles Williams.  "Bors to Elayne:  On the King's Coins"

>>> On Apr 15, 2022, at 2:05 PM, Doug Ewell via Unicode <unicode at corp.unicode.org> wrote:
>>> 
>>> Marius Spix wrote:
>>> 
>>> char literals are not reliable for arithmetic expressions.
>>> '1' - '0' = 1 may be true for Windows-1252 or EBCDIC systems, but you
>>> cannot expect that this works in all character sets.
>> 
>> Modern C language specifications (at least C99) ensure that you can:
>> 
>>> 5.2.1 Character sets
>>> 
>>> Both the basic source and basic execution character sets shall have
>>> the following members: the 26 uppercase letters of the Latin alphabet
>>> 
>>>  A   B   C   D   E   F   G   H   I   J   K   L   M
>>>  N   O   P   Q   R   S   T   U   V   W   X   Y   Z
>>> 
>>> the 26 lowercase letters of the Latin alphabet
>>> 
>>>  a   b   c   d   e   f   g   h   i   j   k   l   m
>>>  n   o   p   q   r   s   t   u   v   w   x   y   z
>>> 
>>> the 10 decimal digits
>>> 
>>>  0   1   2   3   4   5   6   7   8   9
>>> 
>>> the following 29 graphic characters
>>> 
>>>  !   "   #   %   &   '   (   )   *   +   ,   -   .   /   :
>>>  ;   <   =   >   ?   [   \   ]   ^   _   {   |   }   ~
>>> 
>>> [...]
>>> 
>>> In both the source and execution basic character sets, the value of
>>> each character after 0 in the above list of decimal digits shall be
>>> one greater than the value of the previous.
>> 
>> I'm not aware of any character set that meets the repertoire requirement but not the digit-sequencing requirement.
>> 
>> --
>> Doug Ewell, CC, ALB | Lakewood, CO, US | ewellic.org
>> 
>> 
>>