Message-Id: <199603112107.QAA22282@wilma.cs.utk.edu>
From: Keith Moore <moore@cs.utk.edu>
To: John Gardiner Myers <jgm+@cmu.edu>
cc: drums@cs.utk.edu, moore@cs.utk.edu
Subject: Re: Free insertion of linear-white-space 
In-reply-to: Your message of "Mon, 11 Mar 1996 13:14:13 EST."
             <AlF6ppm00WBw412NlI@andrew.cmu.edu> 
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Date: Mon, 11 Mar 1996 16:07:43 -0500
Sender: moore@cs.utk.edu

> I don't see how the free insertion rule in 3.1.4 could reasonably be
> interpreted to apply to anything but structured field bodies.  Adding
> emphasis:
> 
>         To aid in the creation and reading OF STRUCTURED  FIELDS,  the
>         free  insertion   of linear-white-space (which permits folding
>         by inclusion of CRLFs)  is  allowed  between  lexical  tokens.
>         Rather  than  obscuring  the  syntax  specifications FOR THESE
>         STRUCTURED FIELDS with explicit syntax for this  linear-white-
>         space, the existence of another "lexical" analyzer is assumed.
>         This analyzer does not apply  for  unstructured  field  bodies
>         that  are  simply  strings  of  text, as described above.  The
>         analyzer provides  an  interpretation  of  the  unfolded  text
>         COMPOSING  THE BODY OF THE FIELD as a sequence of lexical sym-
>         bols.
> 
> But anyway, instead of arguing how to interpret this dark corner of
> 822, why don't we take the practical approach.  Existing
> implementations don't generate whitespace between the field-name and
> colon and many existing implementations can't handle whitespace
> between the field-name and colon.  Same thing goes for whitespace
> inside the domain.

Along more general lines, I'd like to see the 822 grammar very clearly
indicate what is and is not a structured field.  The current definition
(whether something is *text or not) is buried within the text and can
easily be missed.

If this means explicitly adding tokens to the grammar that indicate where
white-space and/or comments can be inserted...well, that's ugly, but at
least it's unambiguous.  If someone can figure out a better way, fine.

But the 822 ABNF gets used both for cases where white space and comments are 
legal between tokens and for cases where they are not legal, and having to 
specify which case is which in text is getting to be a pain.

--------
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