Alan BRASLAU
14. September 2015 16:37
On Mon, 14 Sep 2015 16:15:33 +0200

I am not familiar with $\singlebond$ etc.


In ConTeXt, one can also use a different mechanism (chem-str.mkiv):

\chemical{1,SINGLE,2,DOUBLE,3,TRIPLE,4}

Looking at the result of the above, I find that the spacing of DOUBLE
should be modified (to .25ex rather than .5ex), a question of
aesthetics?

Compare this with a third mechanism (mp-chem.mpiv, drawing a chemical
structure rather than writing an inline chemical formula):

\startchemical
\chemical[ONE,Z0,SB1,Z1,MOV1,Z1,DB1,MOV1,Z1,TB1,MOV1,Z1] [1,2,3,4]
\stopchemical

Ignore that the horizontal spacing is different, too, for the structure ONE.
I have no need for the commands, I was only surprised why this happened because
it made no sense when you look at the definition of \singlebond in math-arr.mkiv.

What I noticed now that Hans redefines the command later in math-stc.mkvi where
a number delimiter is missing. When you stop TeX’s number scanner with a \relax
you get the right output even with a number after \singlebond.

-\unexpanded\edef\singlebond{\mathematics{\mathsurround\zeropoint\char\number"002D}}
-\unexpanded\edef\doublebond{\mathematics{\mathsurround\zeropoint\char\number"003D}}
-\unexpanded\edef\triplebond{\mathematics{\mathsurround\zeropoint\char\number"2261}}
+\unexpanded\edef\singlebond{\mathematics{\mathsurround\zeropoint\char\number"002D\relax}}
+\unexpanded\edef\doublebond{\mathematics{\mathsurround\zeropoint\char\number"003D\relax}}
+\unexpanded\edef\triplebond{\mathematics{\mathsurround\zeropoint\char\number"2261\relax}}

Wolfgang