If I understand it correctly, you may need something like this...?

% Protection is key
\protected\def\inner[#1]{\empty}
% \outer is (or was) already defined in \CONTEXT
% Please use another name
\def\Outer{\inner[123] and \inner[some text] etc.}
\startluacode
local implement = interfaces.implement
local argument = tokens.scanners.argument
local function parseinner()
  local r = {}
  local str = argument()
  str = str:gsub("\\inner%s*(%b[])",function(s)r[#r+1] = s:sub(2,#s-1)end)
  context(table.concat(r," ")) -- Change " " by another spacer if needed
end
implement{name = "parseinner", public = true, actions = parseinner}
\stopluacode
\starttext
\parseinner{\Outer}
\stoptext

However, this will only work with very simple cases (no nesting, etc.). Hope this helps.

Best regards,

Jairo

El mar, 16 de nov. de 2021 a la(s) 14:22, Joey McCollum via ntg-context (ntg-context@ntg.nl) escribió:
As the subject of this question suggests, this is really more of a question about expansion control (a topic that is still a bit obscure to me). Suppose I have a macro \inner that expects a single argument or an assignment of parameters in brackets. For my purposes, I don't want this macro to do anything when it is typeset, so I'll just define it as empty:

```
\def\inner[#1]\empty
```

Now suppose I have another macro \outer that invokes this macro with some specific input and sets some plain text after it:

```
\def\outer{\inner[123] etc.}
```

What I'd like to do is parse the argument of \inner in \outer. I was hoping that a string search in Lua would work, but I'm not having any luck. A minimal (non)-working example is included below:

```

\def\inner[#1]\empty

\def\outer{\inner[123] etc.}


\startluacode

local userdata = userdata or {}

function userdata.parseinner(str)

local innerparams = ""

    if string.find(str, "\\inner(%b[])") then

      i, j = string.find(str, "\\inner(%b[])")

      innerparams = string.sub(str, i+1, j-1) -- we just want the content inside the brackets

    end

    context(innerparams)

    return

end

\stopluacode

\def\parseinner#1{\ctxlua{userdata.parseinner([==[#1]==])}}


\starttext

Testing:\blank

\parseinner{\outer}

\stoptext

```

My problem is that when I pass \outer to the \parseinner macro, it gets fully expanded, so there isn't anything left to match "\\inner%b[]". Is there a way to expand \outer when I pass it to the \parseinner macro without also expanding the \inner macro inside it? Or is there some other preferred way of doing this?

Joey
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