Re: preliminary patch for zsh/random module

[Clinton Bunch <cdb_zsh@zentaur.org>]

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On 10/24/2022 8:20 AM, Clinton Bunch wrote:
> On 10/23/2022 11:47 PM, Bart Schaefer wrote:
>> On Sun, Oct 23, 2022 at 7:57 PM Clinton Bunch <cdb_zsh@zentaur.org> 
>> wrote:
>>> On 10/23/2022 9:01 PM, Bart Schaefer wrote:
>>>> * Typo in the introductory comment.
>>> I'm pretty sure I've since found and changed all the instances of
>>> Zoltan's name.
>> I was referring to the spelling of "randome".
>>
>>>> Actual question:  What's the use case for returning or printing a
>>>> block of random bytes?  Why does this need to be a builtin?
>>> Mostly because I see constructs like read -k6 -u3 3</dev/urandom
>> ... because?
>
> I did it to seed rand48.  Roman did it to generate a 32-bit random 
> integer.  Both of which are obsoleted by other parts of this module.
>
> I'm sure there are other reasons someone might want to read more or 
> less than 4 bytes of random data.  One that comes to mind is 
> generating a password in a platform-independent way without assuming 
> perl or python.
>
Here's an example:

randpw () {
         local 
chars="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz01234567890@#%&()"
         local tmp
         local -i num
         num=${1:-10}
         getrandom -l $num -s tmp
         for i in {1..${#tmp}..2}
         do
                 print -n ${chars["16#${tmp[$i,$i+1]}"%${#chars}+1]}
         done
         echo
}

>>
>>> it would be nice to initialize an array with random numbers without
>>> having to use a loop to access SRANDOM n times.
>> But you're not filling an array with random numbers, you're filling a
>> string (scalar) with random bytes.
> Actually, it does both.
>>
>>>> Suggestion:  Treat SRANDOM like SECONDS, in that you can change the
>>>> type from integer to floating-point.  Then maybe the zrandom() math
>>>> function isn't needed?
>>> That would seem confusing to me, and too easy to forget which state you
>>> left it in.
>> You make it local so you're not leaving it.
>>
>> () {
>>   print $SECONDS;
>>   () {
>>    local -F SECONDS
>>    print $SECONDS
>>   }
>>   print $SECONDS
>> }
>> 56
>> 0.0000050000
>> 56
> Still seems like something you do because you can rather than because 
> it's intuitive to the user.  Also, your example assumes you'd only 
> want to do this in a function (or wrap it in an anonymous function 
> just for this purpose)
>>
>>> zrandom was meant to be a replacement for rand48
>> OK.
>>
>
>

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