math, bigly

Mark Waddingham mark at livecode.com
Wed Aug 9 05:58:14 EDT 2017


On 2017-08-09 11:36, hh via use-livecode wrote:
>> Mark wrote:
>> but I'm annoyed that the IDE doesn't give me an overflow warning if I 
>> try
>> to perform an operation on a number that's bigger than 0xFFFFFFFF.
>> Instead, it just happily trims it down to an unsigned integer and 
>> proceeds
>> to give me a wrong result.
> 
> Hey Mark.
> Don't complain because *you* are easily able to work around your
> "not-reading-the-dictionary" ;-))
> 
> From the baseconvert entry of the dictionary:
> baseConvert(number, originalBase, destinationBase)
> The number must be an integer between zero and 4,294,967,295 (2^32 - 
> 1).

The engine hasn't ever done range checks on integers - mainly because 
numbers are doubles so (in most ases) you just lose accuracy / precision 
as the numbers get larger. In this case it *could* because it is 
actually using integers.

Although, perhaps, baseConvert should be a purely string->string 
operation - I think that can be done relatively easily without ever 
having to convert to an integer. This would mean you would be able to 
base-convert any sized number, although you wouldn't necessarily be able 
to perform non-precision losing arithmetic operations on the result.

Warmest Regards,

Mark.

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




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