On 14/05/2011 08:53 AM, Warp wrote:
> Invisible<voi### [at] devnull>  wrote:
>> 1. Writing
>
>>     Iterator<Foo>  it = list1.iterator();
>>     ArrayList<Foo>  list2 = new ArrayList<Foo>();
>>     while (it.hasNext()) list2.add(bar(it.next()));
>
>> is way more work than writing
>
>>     list2 = map bar list1
>
>    Argument from verbosity is seldom a good argument in programming.
> Just because something is shorter doesn't necessarily mean it's better.

You don't think the intension of the second example is clearer at a glance?

>    Anyways, many languages have constructs to make that shorter.

Some have a "foreach" construct that can make this kind of thing shorter.

Curiously, Smalltalk had a few library functions to do this kind of 
thing. Then again, in Smalltalk, every block of code is an object. That 
allowed Smalltalk to offer a #do: method for most container classes. 
That means you can then simplement #collect:, #select: and #reject: in 
terms of #do:. For example,

   list2 := map collect: [ x | x bar ]

That's nearly the same level of directness as Haskell.

> Curiously,
> the next C++ standard will introduce constructs that allow you to write:
>
>    for(auto&  v: list1) list2.push_back(v);

And that does what? Copy the list?

-- 
http://blog.orphi.me.uk/
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