Re: [stack] sweetening concatenative syntax

On Mar 6, 2008, at 8:01 PM, William Tanksley, Jr wrote:

> John Nowak <[email protected]> wrote:
>
>> Lambdas don't have anything to do with
>> it; they just let you write it in a way that makes it look more like
>> pattern matching. You can write it without variables if you prefer.
>> You can even write it with just one variable which is actually nicer:
>>
>>    f map = []
>>            [xs -> f i xs f map cons]
>>          unlist
>
> Okay, so the challenge is to write that entirely without variables
> (i.e. without the benefit of lambdas). Let's try.

You must've missed my response to you earlier where I gave this  
translation:

    map = swap
          []
          [rot dup 2dip swap map cons]
        unlist

> map = [] [ bury over i rot map cons ] unlist

Small point: You forgot the initial swap to put the list on top of the  
stack. The type system would've saved you of course.

> Arguably no worse than yours; the body of my definition contains six
> words, matching yours if we don't count your lambda and its variable
> (beating it otherwise).

This seems like a poor way of measuring how easy it is to read and  
write code. At least in my case, I know I wrote the pointful version  
in about 15 seconds. It took me over a minute to write the pointfree  
version. (Perhaps I just need more practice.) I also think the  
pointful version is easier to read, although we can certainly disagree.

- John