On 8/18/2025 7:34 PM, Henning Hraban Ramm wrote:
Am 18.08.25 um 18:31 schrieb Hans Hagen via ntg-context:
On 8/18/2025 3:10 PM, Henning Hraban Ramm wrote:
How would you resolve shell/environment variables like $TEXMFHOME or
~ ($HOME) in Lua code?
dir.expandname doesn’t do that.
Search and replace iterating over os.env?
These tex related variables are often encoded in a special way so you
need to do more (and also know how that coding works). Anyway, it's
not the kind of code one sees / uses everyday (but it's nearly 20
years old now so quite stable):
\startluacode
local function whatever(v)
local p = resolvers.expandedpathlistfromvariable(v)
inspect(p)
for i=1,#p do
print(resolvers.resolve(p[i]))
end
for i=1,#p do
print(resolvers.cleanpath(resolvers.resolve(p[i])))
end
end
whatever("TEXMFHOME")
whatever("TEXMF")
\stopluacode
Thank you!
I guess that was what I was asking for, but not what I needed.
I didn’t think of TeX variables containing lists of paths in opposite to
environment/shell variables that resolve to one value (even if it might
be a function).
I can’t iterate over os.env like I hoped, the table is empty. I can only
ask for single values with os.env[] or os.getenv().
This works (in bash), even if the code is ugly:
function os.resolveenv(path)
-- resolve environment variables
path, _ = string.gsub(path, "~", "${HOME}")
-- are there other special characters to resolve?
local patt = "%${?[%a_-]+}?" -- $BLA or ${BLA}
local inpatt = "[%a_-]+" -- just the name
local found = true
while found do
-- there might be several variables in a path
local var = string.match(path, patt)
if var then
local value = os.getenv(string.match(var, inpatt))
if value then
path, _ = string.gsub(path, var, value)
else
logs.report("resolve env", "Couldn’t resolve variable " ..
var .. " in " .. path)
-- if we don’t break here, we get an endless loop;
-- otherwise we would need to track the finds
found = false
end
else
found = false
end
end
logs.report("resolve env", path)
return path
end
os.resolveenv("~/context/")
os.resolveenv("${JAVA_HOME}/something")
>set WHATEVERNAME=foo
>set WHATEVERMORE=oof
>set WHATEVERELSE=oof/{$WHATEVERNAME}
local p = resolvers.expandedpathlistfromvariable("WHATEVERNAME")
inspect(p)
local p = resolvers.expandedpathlistfromvariable("WHATEVERELSE")
inspect(p)
table={
"foo",
}
table={
"oof/foo",
}
so to some extend ...
Hans
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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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