[plt-scheme] HTDP 21.1.2

From: wooks . (wookiz at hotmail.com)
Date: Sat Jul 15 06:51:55 EDT 2006

>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
>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.


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