[plt-scheme] HTDP 21.1.2

>From: Felix Klock's PLT scheme proxy <pltscheme at pnkfx.org>
>To: "wooks ." <wookiz at hotmail.com>
>CC: plt-scheme at list.cs.brown.edu
>Subject: Re: [plt-scheme] HTDP 21.1.2
>Date: Sat, 15 Jul 2006 03:28:51 -0400
>
>Wooks-
>
>On Jul 14, 2006, at 11:30 PM, wooks . wrote:
>
>>>The names don't matter at all; in fact, we could instead use the   names 
>>>S and T:
>>>
>>>;; fold : forall S, T . S (S T -> T) [Listof S] -> T
>>>
>>
>>Per our agreed correction
>>We mean
>>
>>;fold : (S T -> T) [Listof S] -> T
>
>Well, no, with the correction I wrote earlier, it should be:
>
>; fold : T (S T -> T) [Listof S] -> T
>
>That is, fold takes three arguments: an initial element from T, a  combiner 
>that takes an S and T and produces a T, and a list of S's,  and from these 
>three arguments, fold produces a T.
>

Sheesh ... cognitive dissonance ... and I repeated it when replying to 
Richard Cobbe's post.....slaps head .....but I am intending to change the 
sequence of arguments to fold be in line with convention.

Will come back to this...have some outstanding posts to go through.

<snip>