Re: Bar lines

[David Kastrup]

Janek Warchoł <address@hidden> writes:

> Hi all,
>
> i was very surprised by Marc's suggestion to revert his barline
> interface commit.  I'm pretty sure that everyone regards Marc's (and
> Harm's) work in this area as very valuable and noone thinks of
> deleting it at all!
>
> What I see are two issues:
>
> a) should we change the character that produces thick barline from .
> to something else?  Personally i've never liked this design choice, so
> i'd be interested in making a simple poll on users- list with various
> options including . I = B U O 0 1 or whatever else may be reasonable.
> Note that this issue is completely independent from Marc's new bar
> line interface.
>
> b) should we define aliases for repeat barlines?  I.e. make \bar ":|"
> a shorthand for \bar ":|." for the sake of user friendliness.  My
> opinion is as follows: if repeat barlines "|:" ":|" (only dots and
> thin line, no thick line at all) aren't used in engraving practice
> (and i guess they aren't), lets make such an alias and mention it in
> the docs.   User can always override it.

If I understand correctly, the barline definition commands basically
have two arguments.  The first part is the name for accessing a bar
line, the second is a breakdown of the look for it in-line, at start of
line, at end of line.

I have no qualms with the breakdown of the look being a very literal
form of WYSIWYG.  For this breakdown of the look, "." is a weird thing
to use.  It is not really WYSIWYG here.

However, the reference string for \bar "xxx" is the user interface.  In
this instance, we should aim for "xxx" being logical.

"|." is logical, "the barline at the end of a sentence".  "|:" and ":|"
are logical.  At the end of the piece, ":|." would also be logical.
":|:" is logical, "||" is logical.  Some variants with additional bars
also make sense, like "||:" to indicate a double bar followed by a
repeat, or a double repeat bar.  Something like ":||:" no longer is
purely logical (as its logical function to separate two repeats from
another is identical to that of ":|:"), but it is a reasonably intuitive
for calling for a visual variant.

I think that if we depart from the notion that the bar name for \bar
should always correspond to the WYSIWYG definition of the in-line
rendition, and thus separate the logical user interface from the purely
visual definition of the resulting look, we will keep the aesthetics of
both users and programmers reasonably unoffended.

-- 
David Kastrup