Re: [Nmh-workers] The -prefer argument to mhshowsca for versison 1.7

[Ralph Corderoy]

Hi Ken,

> >     mhshow: -prefer text/plain
> >
> > How can I override that to get the default behavior for a single
> > invocation of mhshow?
>
> Hm.  It doesn't look like that is currently possible.  There should
> have been a -noprefer switch that would zero out the current prefer
> list

Or the design should have been the reverse:  Specify the most preferred
last.  Then my ~/.mh_profile of

    mhshow: -prefer text/html -prefer text/rtf -prefer text/plain

can be temporarily overridden with `mhshow -prefer text/html' at the
command line without having to re-specify the relative preference of the
others.

I don't think the man page makes clear how multiple -prefer options
interact?

I've tried some tests.  The email has text/stN in ascending order.
mhlist correctly flips the 42.3.* alternatives around.

    42  multipart/mixed
        1  text/st1
        2  text/st2
        3  multipart/alternative
            1  text/st5
            2  text/st4
            3  text/st3
            4  text/st2
        4 text/st3

So I've two st2, and two st3.

`mhstore', the default, is correct.

    subtype 1
    subtype 2 before
    subtype 5
    subtype 3 after

`mhstore -prefer text/st2' switches st5 for st2, correct.

    subtype 1
    subtype 2 before
    subtype 2 alternative
    subtype 3 after

`mhstore -prefer text/st3' similarly switches st5 for st3, correct.

    subtype 1
    subtype 2 before
    subtype 3
    subtype 3 after

`mhstore -prefer text/st4 -prefer text/st5' has the first preference be
most important;  I get st4.

    subtype 1
    subtype 2 before
    subtype 4
    subtype 3 after

`mhstore -prefer text/st5 -prefer text/st4', the reverse, has st5 win.
Just checking it doesn't matter if it's the default anyway.

    subtype 1
    subtype 2 before
    subtype 5
    subtype 3 after

`mhstore -prefer text/st3 -prefer text/st4' doesn't
mention st5.  The first, st3, still wins.

    subtype 1
    subtype 2 before
    subtype 3
    subtype 3 after

`mhstore -prefer text', with no subtype specified, gives st5.  The
implementation moves matching alternatives, i.e. all, in the order
they're encountered into a new list and then tacks on the non-matching
ones in their original order.  So this moves all of st{5,4,3,2} and
changes nothing.

    subtype 1
    subtype 2 before
    subtype 5
    subtype 3 after

I guess this means `-prefer text' could be used to shuffle whatever text
is available ahead of slow audio/*.

-- 
Cheers, Ralph.
https://plus.google.com/+RalphCorderoy