Does Appian (7.11 on-premise) have any easy way in an expression/SAIL to perform

Josh, thanks for the suggestion on the change on the cast() function, I'll take a look at it. As for your year() reference, yes, I was having to do something like that. A coworker had made a Java based plugin to calculate company holidays using some preexisting logic another department had built. A second coworker had built a rule in Appian that would take an individual year and spit out the holidays for a few years before & after that years. It used concatenation inside of the rule and I wanted to see if I could rewrite it to allow you to pass in 2 integers for the number of years before & after the current and get the same results. (I didn't test with 0 as you did, thanks). Here is what my replacement looked like, white convoluted:

apply(fn!commerceobservedholidaysforagivenyear,
apply(fn!cast(typeof(123),_),{union(reverse(apply(fn!sum(year(local(now())),_),-1*enumerate(ri!YearsBeforeCurrent+1))),
apply(fn!sum(year(local(now())),_),enumerate(ri!YearsAfterCurrent+1)))}) )

returned value: 1/1/2014; 1/20/2014; 2/17/2014; 5/26/2014; 7/4/2014; 9/1/2014; 10/13/2014; 11/11/2014; 11/27/2014; 12/25/2014; 1/1/2015; 1/19/2015; 2/16/2015; 5/25/2015; 7/4/2015; 9/7/2015; 10/12/2015; 11/11/2015; 11/26/2015; 12/25/2015; 1/1/2016; 1/18/2016; 2/15/2016; 5/30/2016; 7/4/2016; 9/5/2016; 10/10/2016; 11/11/2016; 11/24/2016; 12/26/2016; 1/2/2017; 1/16/2017; 2/20/2017; 5/29/2017; 7/4/2017; 9/4/2017; 10/9/2017; 11/11/2017; 11/23/2017; 12/25/2017

Josh, thanks for the suggestion on the change on the cast() function, I'll take a look at it. As for your year() reference, yes, I was having to do something like that. A coworker had made a Java based plugin to calculate company holidays using some preexisting logic another department had built. A second coworker had built a rule in Appian that would take an individual year and spit out the holidays for a few years before & after that years. It used concatenation inside of the rule and I wanted to see if I could rewrite it to allow you to pass in 2 integers for the number of years before & after the current and get the same results. (I didn't test with 0 as you did, thanks). Here is what my replacement looked like, white convoluted:

apply(fn!commerceobservedholidaysforagivenyear,
apply(fn!cast(typeof(123),_),{union(reverse(apply(fn!sum(year(local(now())),_),-1*enumerate(ri!YearsBeforeCurrent+1))),
apply(fn!sum(year(local(now())),_),enumerate(ri!YearsAfterCurrent+1)))}) )

returned value: 1/1/2014; 1/20/2014; 2/17/2014; 5/26/2014; 7/4/2014; 9/1/2014; 10/13/2014; 11/11/2014; 11/27/2014; 12/25/2014; 1/1/2015; 1/19/2015; 2/16/2015; 5/25/2015; 7/4/2015; 9/7/2015; 10/12/2015; 11/11/2015; 11/26/2015; 12/25/2015; 1/1/2016; 1/18/2016; 2/15/2016; 5/30/2016; 7/4/2016; 9/5/2016; 10/10/2016; 11/11/2016; 11/24/2016; 12/26/2016; 1/2/2017; 1/16/2017; 2/20/2017; 5/29/2017; 7/4/2017; 9/4/2017; 10/9/2017; 11/11/2017; 11/23/2017; 12/25/2017