Re: [NTG-context] Checking existence of a macro (control sequence) by Lua - problem after updating MkIV

18 Jun 2020


      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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