In a message of Sun, 10 Apr 2011 14:31:38 EDT, Eugene Toder writes: <snip>

It's well known that minor syntax details cause a lot of disagreement (http://www.haskell.org/haskellwiki/Wadlers_Law), so that's not very surprising. However, are you sure you're not confusing python's with statement and 'with' word in my email, which is simply a placeholder for appropriate keyword to mirror Haskell's 'let'? Or was this just an occasion to complain about with statement abuse, unrelated to list comprehension discussion? <snip> Eugene

I actually had something else in mind. One problem that you get whenever you extend a language 'i.e. make it more expressive' is that it now becomes possible for people to write old things they want to do in new ways. And, of course, this is what you want for the case of <whatever you want the more expressiveness for>, but it is difficult to may a syntax change that doesn't admit a whole lot of other possibilities as well. The argument I have heard around here is 'good programmers don't write unreadable code, as a matter of personal virtue'. This ignores the fact that I have to read a lot of code written by either not-so-good or not-so-virtuous programmers, but I am coming to the conclusion that the problem may be deeper than that. I now believe that some of the hard-to-read stuff I am reading is written by people who actually find this way of writing easier to read and understand than the sort I prefer. Thus I now think that 'expressiveness' is a limited human good, not an absolute one, (like health). You should want you language to be in the golden middle between 'not epressive enough' and 'too expressive'. If your language is sufficiently limited, then idioms will show up, and become widely adopted precisely because they are one of only a few ways (ideally the only way) to do it. This already pleases the people who find this way to do things readable, and those who would naturally pick a different way of doing things are stuck with it, and possibly over time and with familiarity will come to find this way readable as well. But with too much expressibility there comes a danger we will fragment into different sub-communities, those who think that syntax X is more readable than syntax Y and vice versa. There is no reason to believe that these linguistic communities will ever converge. This is the hidden cost of allowing more expressiveness in your language. Laura