|Perl: the Markov chain saw|
What makes map so special?
Because its name and general usage strongly suggests that it should return something. Take a sub like get_value if you saw that in void context wouldn't you wonder what is going on? Wouldn't it annoy you to discover that in fact the routine has nothing to do with getting a value? Well likewise for me and map. If you want to do some action for each member of a list, then use foreach. If you want to transform each member of a list into something else and get the resulting list back, then use map. The cues in the name help you understand the intent of the author more quickly and with less effort. If someone plays silly bugger and uses map as for then they have just thrown away a useful cue to a future developer as to what was on their mind when they wrote the code.
Think about it for a minute. We do our best to not confuse ourselves and theose that come after us. We don't use $var1 and $var2 for our variable names so that the programmer that follows us (more often than not itll be ourselves a few days or weeks later :-) has a hope in hell of figuring out what it going on. We don't name our subroutines A, B, C etc, for similar reason. We dont use goto's as our primary flow control mechanism etc. All of these things are to provide as much of a cognitive model of what is happening as possible. The same goes for map.
I mean why make life hard? Perl has a hugely expansive vocabulary as far as programming goes. Why waste the expressiveness that it provides? Say what you mean and mean what you say. If you want to map a list then do so, if you want to iterate over the list then do so, but don't pretend to one when you are really doing the other.
First they ignore you, then they laugh at you, then they fight you, then you win.