[NTG-context] Formatting numbers in LuaTeX

Andreas Harder aharder at uni-koblenz.de
Mon Feb 15 23:25:44 CET 2010


Am 15.02.2010 um 20:35 schrieb Peter Münster:

> On Sun, Feb 14 2010, Hans Hagen wrote:
> 
>>>   sqrt = math.sqrt
>>>   pi = math.pi
>>>   function my_equation(s, r)
>> 
>> beware, this creates (and possibly overloads) sqrt, pi and my_equation as 
>> gobals
> 
> Indeed...
> 
> The following hack was *not* so quick, but there is a bug somewhere
> (a digit is added at the end):
> 
> \usemodule[calcmath]
> \startluacode
> local exp_replacements = {["*"] = "$·$"}
> local res_replacements = {["sqrt"] = "math.sqrt", ["π"] = "math.pi"}
> userdata = userdata or {}
> function userdata.result_as_string(r)
> 	r = math.floor(1000 * r + 0.5) / 1000
> 	r = tostring(r)
> 	tex.write(r:gsub("%.", ","))
> end
> function userdata.filter_expression(s)
> 	for k, v in pairs(exp_replacements) do
> 		s = s:gsub(k, v)
> 	end
> 	tex.write(s)
> end
> function userdata.filter_result(s)
> 	for k, v in pairs(res_replacements) do
> 		s = s:gsub(k, v)
> 	end
> 	tex.write(s)
> end
> \stopluacode
> \def\calculate#1{%
>  \start
>    \def\Expression{\ctxlua{userdata.filter_expression("#1")}}
>    \def\Result{\ctxlua{userdata.filter_result("#1")}}
>    \calcmath{\Expression=\ctxlua{userdata.result_as_string(\Result)}}
>  \stop
> }
> \starttext
> \startlines
>  \calculate{1+2}
>  \calculate{3/2-1}
>  \calculate{3*2}
>  \calculate{sqrt(2)}
>  \calculate{2*π}
> \stoplines
> \stoptext

I've noticed that one can even use such things as \calculate{3^2},  \calculate{2^3} out of the box and it's easy to add
["e"] = "math.exp(1)", ["sin"] = "math.sin", …

But the "$·$"-construct is problematic. It do not work in display style (\let\calcmath\displaycalcmath) and without the dollar-signs the placement and the spacing are wrong.

Thank you for your elaboration.

Greetings
	Andreas






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