Hello,
I need to check within Lua.
My sample cases are very minimalistic - I'm working on more complicated task
actually, where check-for-control-sequence-existence need to be performed
run-time within Lua scope.
Best,
Lukas
---------- Původní e-mail ----------
Od: Hans van der Meer
Komu: NTG ConTeXt
Datum: 18. 6. 2020 12:25:42
Předmět: Re: [NTG-context] Checking existence of a macro (control sequence)
by Lua - problem after updating MkIV
"
Why can you not simply use one of the doifundefined macro's? Something for
example:
\doifundefined{ExitStatus}{\gdef\ExitStatus{0}} % default to ok as in UNIX
dr. Hans van der Meer
"
On 18 Jun 2020, at 10:27, Lukas/ConTeXt wrote:
Hello,
I'm using Hans' macro suggested some time before.
I've just updated Ctx MkIV and my sample code:
----
\starttext
\def\MyMacro{Ahoj}
\def\MyMacWithPars#1#2{Something}
\def\Undefined{}
\let\Undefined\undefined
\def\DoNothing{}
\let\DoNothing\donothing
\startluacode
if CONTEXTLMTXMODE == 0 then
local d = tokens.defined
local c = tokens.create
function tokens.defined(s,b)
if b then
return d(s)
else
return c(s).cmd_name == "undefined_cmd"
end
end
end
--
local defined = tokens.defined
for _, v in ipairs{ "MyMacro", "MyMacWithPars", "Undefined", "DoNothing",
"NonExisting" } do
print(string.format("\letterpercent-12s", v), defined(v), defined(v,
true), defined(v, false))
end
\stopluacode
Aaa
\stoptext
----
gives:
"
MyMacro false false false
MyMacWithPars false false false
Undefined false false false
DoNothing false false false
NonExisting false false false
"
IOW, I'm not able to determine whether a control sequence has not been
defined (or has \undefined value) or not.
Am I doing a trivial mistake or has anything changed?
Thank you for patience...
Lukas________________________
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