Joseph Rushton Wakeling:
Can anyone advise why,
map is lazy, like most other ranges.
and whether there's a nice range iteration option to ensure that this function gets called using each element of the filteredRange?
Lazy higher order functions like map/filter should be used only with pure functions. There are bugs/troubles in using them on impure code.
There was a proposal for a "each" function to terminate a range chain with something effectful, but I think it has gone nowhere. This means you have to use a foreach on a range.
Bye, bearophile
