Hi,
I uploaded a new version that mostly concerns documentation files
(checking them for lmtx and so). I (partly) updated the primitives
manual (for hans vd meer) and added followingup-expressions (for pablo).
The expressions stuff (was already in previous uploads) is a side effect
of finalizing some luametatex code. Part of it had been there in
commented form as I had not yet made up my mind about how much is
needed. In the end I decided to *not* integrate it in the \numexpr an
d\dimexpr primitives because of potential compatibility issues (although
that is unlikely given the way we use them in the core, I don't know to
what extend users use these primitives). The long ago - one of the first
things in luametatex - introtroduced integer division : probably went
unnoticed (of course not by ws) which is an indication that this
extension has been is rather safe.
Anyway, more about expressions can be found in the mentioned documents.
Think of (one can of course also use the usual tex variables):
\starttext
\the\dimexpression 2 * 10pt + 2pt \relax
\the\dimexpression 2 * 10pt > 2pt \relax
\number\dimexpression 2 * 10pt + 2pt \relax
\number\dimexpression 2 * 10pt > 2pt \relax
\ifboolean\dimexpression 2 * 10pt > 2pt \relax yes \else nop \fi
\ifboolean\dimexpression 2 * 10sp > 2pt \relax yes \else nop \fi
\ifdimexpression 2 * 10pt > 2pt \relax yes \else nop \fi
\ifdimexpression 2 * 10sp > 2pt \relax yes \else nop \fi
% alias \ifexpression :
\ifnumexpression (2 * 10) + (3 << 4) > (4 & 5) \relax yes \else no \fi
\stoptext
Performance wise it is comparable to \dimexpr and \numexpr (these are a
bit faster in luametatex than in luatex), the final \relax is mandate
(so no lookahead side effects), and these don't suffer from some of the
somewhat weird properties of their ancestors. The main difference is
that they support comparison and bitwise operators. I can add more but
it probably doesn't make sense. With
\tracingexpressions1 \tracingonline1
you get info like this:
1:4: {dimenexpression rpn: 2 655360 * 131072 +}
1:4: {dimenexpression rpn: 2 655360 * 131072 >}
1:4: {dimenexpression rpn: 2 655360 * 131072 +}
1:4: {dimenexpression rpn: 2 655360 * 131072 >}
1:4: {dimenexpression rpn: 2 655360 * 131072 >}
1:4: {dimenexpression rpn: 2 2 * 131072 >}
1:4: {dimenexpression rpn: 2 655360 * 131072 >}
1:4: {dimenexpression rpn: 2 2 * 131072 >}
1:4: {numexpression rpn: 2 10 * 3 4 << + 4 5 band >}
Of course (maybe for sure) there can be bugs but then, only a few will
ever use this (I bet hvdm is one of them, as he also uses the other new
\if* features).
Other hidden 'pearls' (bachotex speak) will be revealed in due time,
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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