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From: oleg@okmij.org
To: 5764c029b688c1c0d24a2e97cd764f@gmail.com
CC: caml-list@inria.fr, gabriel.scherer@gmail.com
In-reply-to: <52985F14.4090508@gmail.com>
Subject: Re: [Caml-list] [batteries] ... how to create (format) directives


> > (* It is possible to avoid s" " below, so to insert interworld space
> >    automatically
> > *)
>
> I do not understand what do you have in mind (above).  (Sometimes
> spaces are desired, sometimes they are undesired.  I do not see a
> general rule that could be embedded to `b' so that it could reliably
> decide in either way.)
>
> > 
> > let ex4 = let open PrintComp in pr
> >   b"mdx" s" " it "command" br
> >   s"Perform a given " it "command" br
> >   s"Section COMMANDS describes all the supported commands."
> >   sprintf

I think there is a rule, but it depends on the context. For example,
in
        br b"xxx"
the 'b' command should not insert the leading white space, but in
        s"yyy" b"xxx"
it has to. It is not that difficult to implement such a
context-sensitive rule since a formatting instruction like 'b' and
's' has access its the context: that's the 'st' parameter being passed
around. So, a formatting command could check what has occurred before
and insert a whitespace as needed. If we do mean that two strings
should be typeset without an intervening space, we should define a
special formatting instruction 'nosp'.

I forgot to mention that the FORTH-like formatter in the previous
message looks quite similar to the one used in BibTeX.