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Dirk Laurie <> wrote:
> APL has an operator "scan" over arrays so that
>    fct / x
> returns the value of a function that can be coded in Lua as
> function scan(fct,x)
>    result = unit(fct)
>    for _,v in ipairs(x) do result = fct(result,v) end
>    return result
> end

I'm sorry if I'm being dense, but what is `unit` there?

> There may well be som such function in Penlight and Microlight.

As Alex Q. says in another reply, scan looks like a fold/reduce. A number
of utility libraries do provide such a function. Penlight and Underscore
definitely do, for example.

We have not been faced with the need to satisfy someone else's
requirements, and for this freedom we are grateful.
    Dennis Ritchie and Ken Thompson, The UNIX Time-Sharing System