resolving "unknown variable" when using string.gsub()

[JLPLabs]

I'm using the "function" form of string.gsub(s, pattern, repl [, n])

By that I mean repl is a function.

    local sub = function(s: string): string, integer
      return s:gsub("_","")
    end

    blex = blex:gsub("[%d_%.]+", sub(s))

It seems reasonable for Teal to complain about the parameter 's' being passed (as it seems it is created out of thin air). Teal does complain about this. Can you provide any insight into how do I make Teal feel OK about 's'?

Here is the error...

pinoak> cyan build
    Error 1 type error in src/filescanner.tl
      ... src/filescanner.tl 193:38
      ...    193 |     blex = blex:gsub("[%d_%.]+", sub(s))
      ...        |                                      ^
      ...        | unknown variable: s

Many thanks!

[JLPLabs]

Sorry for the noise in your discussion list. I made this harder than it needed to be.

There is an easy answer... just had to tell it the types (consolidating to an anonymous function doesn't change the approach).

    blex = blex:gsub("[%d_%.]+", function(s: string):string, integer 
          return s:gsub("_","") end)