From: context@vivaldi.net
To: mailing list for ConTeXt users <ntg-context@ntg.nl>
Subject: Re: Checking existence of a macro (control sequence) by Lua
Date: Thu, 28 May 2020 23:24:42 +0200 [thread overview]
Message-ID: <263ba20f41f00d3da9433eaf9a66e5b7@vivaldi.net> (raw)
In-Reply-To: <e3765ad9-34e4-8e24-e0bb-324078a9267b@xs4all.nl>
Hello,
one more question - why macros \Undefined and \DoNothing show "defined"
although I (tried to) undefine them?
----
\starttext
\def\MyMacro{Ahoj}
\def\MyMac#1#2{Something}
\def\Undefined{}
\let\Undefined\undefined
\def\DoNothing{}
\let\DoNothing\donothing
\startluacode
local str = { [true] = "defined", [false] = "undefined" }
local function whatever(s)
context.type("\\" .. s)
context(" is " .. (tokens.defined(s) and "defined" or
"undefined")) --% Hans' way
context(" and is " .. str[token.is_defined(s)] .. ".") --% Henri's
way
context.par()
end
whatever("MyMacro")
whatever("MyMacroD")
whatever(" ")
whatever("-")
whatever("Undefined")
whatever("DoNothing")
\stopluacode
%\Undefined % Causes "! Undefined control sequence"
\stoptext
----
Gives:
"
\MyMacro is defined and is defined.
\MyMacroD is undefined and is undefined.
\ is defined and is defined.
\- is defined and is defined.
\Undefined is defined and is defined.
\DoNothing is defined and is defined.
"
Lukas
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next prev parent reply other threads:[~2020-05-28 21:24 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-27 22:42 context
2020-05-27 22:49 ` luigi scarso
2020-05-28 7:56 ` Hans Hagen
2020-05-28 6:50 ` Henri Menke
2020-05-28 8:34 ` Hans Hagen
2020-05-28 11:24 ` context
2020-05-28 21:24 ` context [this message]
2020-05-29 7:36 ` Hans Hagen
2020-05-29 21:21 ` context
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