TASK #1 › Self-descriptive Numbers
Task
Write a script to display the first three self-descriptive numbers.
My solution
say '1210, 2020, 21200'. On to the next task. Not so quickly :) While the above would produce the expected output, that's not the spirit of what the weekly challenge is about.
For this task I ran an incrementing loop that exited once three self-descriptive numbers were found. The main part of the logic appears in the _is_self_descriptive subroutine. I first convert the number into an array of occurrences. For example 12140 would be turned into 1,2,1,0,1,0,0,0,0,0. I then compare this with the digit in the position, and return false undef or true 1 if there is a match.
Example
» ./ch-1.pl
1210, 2020, 21200
TASK #2 › List Methods
Task
Write a script to list methods of a package/class.
My solution
For caveats first.
- In the real world, I would simply use Class::Inspector's
methodsfunction. There is no need to re-invent a perfectly working wheel. - My solution won't list inherited methods. We could walk the
@ISAtree, but this seems more complicated than required for the task. - Likewise it won't show autoloaded methods.
- My code is loosely based on Class::Inspector
And with all of that, there isn't much else to say. I require the package, and then look up everything in its table, and exclude everything that it's a sub-routine (e.g variables).
If a package is not supplied, then Calc is assumed.
Example
» perl -I . ./ch-2.pl
div
new
add
mul
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