sunny friday afternoon update

[Hans Hagen <j.hagen@xs4all.nl>]

Hi,

I uploaded a new version of lmtx and there are some experimental 
features that users cna play with so that we can think about related 
interfacing. (I won't mention soem in the lua department that I'm still 
exploring myself.)

When you use a math symbol its class property determines the spacing. 
One can use \mathopen etc to wrap such a character an dmake it behave 
different. There is a new mechanism to overload that property in a 
different way:

\startlines
$x\mathopen   {!}+123+\mathclose  {!}x$
$x\tomathopen  ! +123+\tomathclose ! x$
$x\mathclose  {!}+123+\mathopen   {!}x$
$x\tomathclose ! +123+\tomathopen  ! x$
$x             ! +123+             ! x$
\stoplines

It uses a low level primitive, for the open case: \Umathclass 4 with the 
number being the desired class.

A more experimental features concerns native prescripts. Consider the 
following input

\blank \hbox{$
     {\tf X}^1_2^^3__4 \quad
     {\tf X}^1  ^^3    \quad
     {\tf X}  _1   __4 \quad
     {\tf X}    ^^3    \quad
     {\tf X}       __4 \quad
     {\tf X}^^3    __4
$} \blank

or with the control sequence variants:

\blank \hbox{
\ruledhbox{${\tf X}\Usuperscript{a} 
             $}
\ruledhbox{${\tf X}                \Usubscript{b} 
             $}
\ruledhbox{${\tf X}\Usuperscript{a}\Usubscript{b} 
             $}
\ruledhbox{${\tf X}\Usuperscript{a}              \Usuperprescript{c} 
             $}
\ruledhbox{${\tf X}                \Usubscript{b} 
\Usubprescript{d}$}
\ruledhbox{${\tf 
X}\Usuperscript{a}\Usubscript{b}\Usuperprescript{c}\Usubprescript{d}$}
\ruledhbox{${\tf X}                              \Usuperprescript{c} 
             $}
\ruledhbox{${\tf X} 
\Usubprescript{d}$}
\ruledhbox{${\tf X} 
\Usuperprescript{c}\Usubprescript{d}$}
}
\blank

A few days ago there was a discussion about tweaking some math 
parameters, like the radical spacing. I made a macro that deals with it:

$\mathopenupparameter\Umathradicalvgap{10.5}\sqrt[3]{x}$

(this one is also in mkiv, be it slightly less efficient because in lmtx 
we can use \Umathparameter to query the state of a variable)

Already present was a variant on \over which normally is used like

{{1}\over{2}}

i.e. the only time when tex looks back and needs to tweak styles. The 
alternative is:

$\Uover{1}{2}$ etc

which looks forward but is otherwise compatible, apart from supporting 
an optional keyword

$\Uover style \scriptscriptstyle{1}{2}$ etc

$\Uover style \textstyle{1}{2}$ etc

At some point I will adapt some context code to this.

Anyway, these are things that low level math users might like to play 
with. There are few more things but those will probably go unnoticed.

Hans

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
        tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
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