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'end' odds & ends

From: Daniel J Sebald
Subject: 'end' odds & ends
Date: Sat, 29 Jan 2005 15:33:12 -0600
User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.3) Gecko/20041020

There are a few details about using 'end' as the index of a matrix or vector...

The command-line documentation does not mention this use of 'end'. That is, it only says

*** end:

Mark the end of any for, if, do, while, or function block.

Also, it would be good to include comments about 'end' under the 'help -i' documentation for section 10.1 Index Expressions. Furthermore, better organizing the text under 10.1 Index Expressions might make it more clear. There is a discussion of how to generate a vector and matrix using indices, but then after that is a note to not do such a thing.

   Similarly, indexing a scalar with two vectors of ones can be used to
create a matrix.  For example the following statements

    a = 13;
    a ([1, 1], [1, 1, 1])

create a 2 by 3 matrix with all elements equal to 13.

  This is an obscure notation and should be avoided.  It is better to
use the function `ones' to generate a matrix of the appropriate size
whose elements are all one, and then to scale it to produce the desired
result.  *Note Special Utility Matrices::.

Why explain it if it isn't to be recommended? Does the note apply to just generating matrices that way, but vectors are OK? If so, there shouldn't be a new paragraph because that would mean it's talking about something new to come. Also, perhaps put the note up front to give it emphasis. (As it is now, a new user wouldn't read as far as the note and think "oh, that's how I create a matrix".) Now, the second detail about 'end'. The emacs lisp file doesn't recognize 'end' except as the end of a conditional or loop. Therefore, it claims a mismatch and loses track of indentation. (I know zilch about Lisp.) Anyone familiar with Lisp know if this is an easy fix? Or might there be something tricky about it?


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