Hi Hraban,
On Sun, 2024-06-09 at 22:12 +0200, Henning Hraban Ramm wrote:
> when I define a measure on the TeX side, I used to get at the value in
> Lua with tex.getdim, like:
>
> \definemeasure[Bleed][3mm]
>
> tex.getdimen("Bleed")
>
> But now I get "incorrect dimen name".
> I need it as a dimension, since I do calculations with other dimensions
> like "topspace".
>
> How should I do this correctly?
There doesn't appear to be any official interfaces to get the value of a
measure from Lua, but the following should work okay:
\definemeasure[mymeasure][10pt]
\newdimen\mydimen \mydimen=10pt
\definemeasure[measureexpr][1in + 27.73pt]
\startluacode
-- Returns the unexpanded value of some variable in a namespace.
local function get_variable(namespace, variable)
-- -- Doesn't work since "measure" is defined as a "system
namespace".
-- namespace = interfaces.getnamespace(namespace)
namespace = tokens.getters.macro("??" .. namespace)
return tokens.getters.macro(namespace .. variable)
end
-- Gets the value of a measure and converts it to an integer in sp
units.
local function get_measure(name)
return tex.sp(get_variable("measure", name))
end
-- Gets the \dimexpr-evaluated value of a measure, in sp units.
local function get_measure_expr(name)
local namespace = tokens.getters.macro("??measure")
-- Undocumented, but seems to work as expected.
return tex.getdimensionvalue(namespace .. name)
end
-- Print the values of the lengths.
print(("="):rep(80))
print("mymeasure:" , get_measure("mymeasure") )
print("mydimen:" , tex.dimen["mydimen"] )
print("measureexpr:", get_measure_expr("measureexpr"))
print(("="):rep(80))
\stopluacode
\startTEXpage
\measure{mymeasure}
\the\mydimen
\measure{measureexpr}
\stopTEXpage
Thanks,
-- Max
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