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Lists and tables in Simplemail

1993-04-20 15:10:30
Hi all.

  I was thinking about the generic unfilled line (`:U`) in the
simplemail spec.  One of the primary reasons for including it was to
be able to specify lists of objects:

    :' My least favorite vegetables:
    :'    :u *Broccoli*
    :'    :u Brussels Sprouts
    :'    :u cauliflower

This is actually a special case of a more general ability to include
multi-column tables.  This is quite common in email today and is
usually accomplished by the simple expedient of lining the text up in
columns.

I propose that simplemail include an approximation to such formatting
by treating whitespace as a column separator (in `:U` lines).  As with
paragraph indent, either a tab or four or more spaces would indicate a
column separation:

    :' Some differences between British and American English:
    :'    :u _British_        _American_
    :'    :u  rubber           eraser
    :'    :u  pavement         sidewalk
    :'    :u  lorry            truck

A UA can have a fixed notion of column width or can scan the article
to find the widest entry in each column and adjust column width
accordingly.

In accordance with the simplemail principles, this is the simplest of
table formatting (there is no notion of titles, justification, ruling,
etc.), it mimics current conventions, it is readable by users of plain
UAs, it doesn't introduce new markup characters, and it is easy to
type.

I was originally going to suggest using `:1`, `:2`, `:3`, etc. for
n-column tables, but it's probably best to just have one line type
with the number of columns inferred from the white space.  Perhaps the
prefix should be changed to `:T` (for table) or `:L` (for list) or
something like `:=`. (I find that letters in the prefix are more
intrusive than punctuation marks.)

The one drawback I see with this scheme is that there is no way to
omit an item in a column.  That is,

    :' :u a[1,1]    a[1,2]    a[1,3]
    :' :u a[2,1]              a[2,3]
    :' :u           a[3,2]    a[3,3]

will not do what the user may expect.  People can probably get used to
putting in some placeholder for missing elements.  The alternative
(trying to guess the desired column based on the whitespace) seems
much to difficult (and possibly impossible for the recipient's UA
without information about the sender's UA).

What think you?

Evan Kirshenbaum                       +------------------------------------
    HP Laboratories                    | Whatever it is that the government
    3500 Deer Creek Road, Building 26U | does, sensible Americans would prefer
    Palo Alto, CA  94304               | that the government do it to somebody
                                       | else.
    kirshenbaum(_at_)hpl(_dot_)hp(_dot_)com            |                   P.J. 
O'Rourke
    (415)857-7572

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