Re: Test not working so well

On 12/10/23 22:26, William Michels via perl6-users wrote:
> Inline:
> 
>> On Dec 10, 2023, at 12:25, ToddAndMargo via perl6-users 
>> <[email protected]> wrote:
>>
>> On 12/9/23 22:49, William Michels via perl6-users wrote:
>>> f $x.match( / ^ <+[0..9] + [a..z]> ** 7 $ / ) { do something...};
>>
>>
>> What is the difference between
>>
>>    <+[0..9]
>> and
>>   <[0..9]
>>
> 
> Nothing, atm (although there may have been an issue with earlier 
> iterations of Rakudo). Anyway, I find it better to be explicit.
> 
> See:
> 
> https://docs.raku.org/language/regexes#Enumerated_character_classes_and_ranges <https://docs.raku.org/language/regexes#Enumerated_character_classes_and_ranges>
> 
> https://docs.raku.org/syntax/%3C%5B%20%5D%3E 
> <https://docs.raku.org/syntax/%3C%5B%20%5D%3E>
> 
>>
>> And
>>    / ^ <+[0..9] + [a..z]> ** 7 $ /
>>
>> does this mean that both [0..9] AND [a..z] have to
>> be present.  In other words is the an AND or an OR?
>>
> 
> See Kevin Pye's answer. Basically your regex is asking "Starting from 
> the beginning of the string and ending at the end of the string, does 
> the string consist of exactly 7 characters taken from the set of 
> characters including the digits "0"-through-"9" and the lowercase 
> letters "a"-through-"z"? If you satisfy those constraints you're okay 
> (`True`). You could match a string where 1) all 7 characters are digits, 
> 2) all 7 characters are lowercase letters, or 3) a mix of digits and 
> lowercase letters adding up to 7 characters in length.
> 
> HTH, Bill.


Hi Bill,

Yes it does help.  I am slowly getting there.

If I do not know the length of the sting and have to ask
with .chars, is there a way to use a variable in `** 7`

      ** $x.chars   or
      my $xlen = $x.chars; `** $xlen`

or some such?  Is there a special syntax?

Also, must the `**7`  (does it have a name?) always be the length
of the string?

Also, if I do not use ^ and $, what happens?

Yours in confusion,
-T