Add simpler branching functions such as 'if' and 'for'

I know 'switch' and 'select' allow to imitate the way 'if' and 'for' work but it would be nice (especially for beginners) to add a 'if' and 'for' functions. They could work like conditional assignment or list comprehension in Python.

yaql> if($.value = 42, then=>$.value/2, else=>$.value*2
21

yaql> if($.value = 42, $.value/2, $.value*2)
21

yaql> for($.i + $.value, i=>[1, 2, 3])
[43, 44, 45]

yaql> for(i=>[1, 2, 3], do=>$.i + $.value + 2)
[45, 46, 47]

yaql> for(i=>[1, 2, 3], j=>[100, 1000, 10000] do=>$.i + $.j + $.value + 2)
[145, 1046, 10047]

We have already implemented them and we would be happy to contribute.