What is LC's internal text format?

[Mark Waddingham]

On 2018-11-13 11:06, Geoff Canyon via use-livecode wrote:
> I don't *think* I'm confusing binary string/data with binary numbers -- 
> I
> was just trying to illustrate that when a Latin Small Letter A (U+0061)
> gets encoded, somewhere there is stored (four bytes, one of which is) a
> byte 97, i.e. the bit sequence 1100001, unless computers don't work 
> that
> way anymore.

Yes - a byte is not a number, a char is not a number a bit sequence is 
not a number.

Chars have never been numbers in LC - when LC sees a char - it sees a 
string and so
when such a thing is used in number context it converts it to the number 
it *looks* like
i.e. "1" -> 1, but "a" -> error in number context (bearing in mind the 
code for "1" is not 1).

i.e. numToChar(charToNum("1")) + 0 -> 1

The same is try for 'byte' in LC7+ (indeed prior to that byte was a 
synonym for char).

> What I now see is tripping me up is the implicit cast to a character 
> you're
> saying that charToNum supports, without the corresponding cast to a 
> number
> supported in numToChar -- i.e. this fails:
> 
> put textEncode("a","UTF-32") into X;put numtochar(byte 1 of X)

Right so that shouldn't work - byte 1 of X here is <97> (a byte), bytes 
get converted to native
chars in string context, so numToChar(byte 1 of X) -> numToChar(<97> as 
char) -> numToChar("a")
and "a" is not a number.

You'd get exactly the same result if you did put numToChar(char 1 of 
"a").

As I said, bytes are not numbers, just as chars are not numbers - bytes 
do implicitly convert to
(native) chars though - so when you use a binary string in number 
context, it gets treated as a
numeric string.

Put another way, just as the code for a char is not used in conversion 
in number context, the
code of a byte is not used either.

Warmest Regards,

Mark.

-- 
Mark Waddingham ~ mark at livecode.com ~ http://www.livecode.com/
LiveCode: Everyone can create apps