[Jprogramming] Proposed Vocabulary change re. underscore character

[Henry Rich]

Getting a change approved to this part of the Dictionary is not
quite as hard as getting a change to the Space Shuttle approved,
but it's close.  But let us begin.

Unless I'm missing something, I agree with you that the
Dictionary is incomplete.  The statement:

  A verb of rank k applies to each of the k-cells of its argument

does not specify what happens if the argument has rank less
than k.  I think the Dictionary should cover that case, perhaps
by adding "or the the argument in full if it has rank less than k".

The later statement

  The ranks of a verb merely place upper limits on the ranks of
  the cells to which it applies; its domain may include arguments
  of lower rank.

seems to hint at the actual behavior, but the use of 'upper limits'
and 'may' seems almost intended to indicate the absence of a
hard-and-fast rule.

But there is such a rule, so let's state it.  As it is stated now,
if there were a primitive p that worked only on 1- and 3-cells (i. e.
its domain is 1- and 3-cells), the reader would expect that p"2 would
apply p to 1-cells.  Which it won't.

Henry Rich



> -----Original Message-----
> From: programming-bounces at jsoftware.com 
> [mailto:programming-bounces at jsoftware.com] On Behalf Of Tracy Harms
> Sent: Thursday, January 04, 2007 8:22 PM
> To: programming at jsoftware.com
> Subject: [Jprogramming] Proposed Vocabulary change re. 
> underscore character
> 
>  
> 
>  
> 
> As I understand it, symbol _ denotes "unbounded" in the 
> context of rank.
> For example, in the J Vocabulary the explanation of 
> 
> _9: to 9: Constant Functions
> 
>  contains the following two sentences:
> 
>  
> 
> The rank conjunction " applies to any noun to make a constant function
> of specified rank. The particular constant functions illustrated above
> are therefore special cases of the form i"_
> 
>  
> 
> As I studied this use of _ as a right-hand argument, I looked 
> both under
> the definition of rank and the definition of negative 
> sign/infinity, but
> neither entry provided any help in understanding how this 
> symbol applies
> as the right-hand argument to the verb, rank.  I propose that some
> portion of the Vocabulary should note that this symbol 
> functions in this
> manner.  It seems that this would fall under the definition 
> of negative
> sign/infinity, since that section also explains the use of this
> character in name-construction, but some elaboration in the entry for
> rank may also be worthwhile.
> 
>  
> 
> (Part III of the Dictionary explains the use of _ in communicating the
> ranks of functions, but it applies to the text of the 
> dictionary itself,
> and would not necessarily extend to executable code.)
> 
>  
> 
>  
> 
> Tracy Harms
> 
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