Re: Recursive anonymous functions?

["Rafael Sabbagh Armony" <sabbagh@...>]

> Although some might call such a function "anonymous", this doesn't
> seem to capture Lua's semantics, In some sense, all Lua objects are
> anonymous (in the sense that no Lua object has an intrinsic name),
> But one could say that a function was anonymous in a compilation unit
> if it had no named reference visible in that compilation unit, which
> would apply, for example, to: (...)

Exactly.
In Lua, what we call the "name" of the function is actually the name of the
variable pointing to it.
Therefore, if there's a variable pointing to a function, it is not
anonymous.

----- Original Message ----- 
From: "Rici Lake" <lua@ricilake.net>
To: "Lua list" <lua@bazar2.conectiva.com.br>
Sent: Thursday, July 22, 2004 5:38 PM
Subject: Re: Recursive anonymous functions?


>
> On 22-Jul-04, at 2:49 PM, Aaron Brown wrote:
>
> > I don't know how deep you'd have to get into the language in
> > question to answer this, but wouldn't the function be
> > considered non-anonymous if a variable contained a reference
> > to it?
>
> I suppose we could distinguish between anonymous functions and
> pronominal functions. The use case, in some hypothetical language,
> would be something like this:
>
> factorials = map(function(i)
>                     if i > 1 then return i * me(i - 1)
>                              else return 1
>                     end
>                   end,
>                   myList)
>
> where me is a pronominal reference to the enclosing function.
>
> I'd be inclined to say that this style of programming is not
> particularly readable, but others may disagree :) In any event,
> the Lua idiom would be:
>
> do
>    local function fact(i) ... end
>    factorials = map(fact, myList)
> end
>
> <digression for="Bennett">
>    This is exactly equivalent to:
>
>    do
>      local fact
>      fact = function(i) ... end
>      factorials = map(fact, myList)
>    end
> </digression>
>
> Although some might call such a function "anonymous", this doesn't
> seem to capture Lua's semantics, In some sense, all Lua objects are
> anonymous (in the sense that no Lua object has an intrinsic name),
> But one could say that a function was anonymous in a compilation unit
> if it had no named reference visible in that compilation unit, which
> would apply, for example, to:
>
>    map(function(i) return i + 1 end, myList)
>
> Clearly, if a function is going to call itself it needs to have a named
> reference to itself, so no recursive function could truly be anonymous
> in that sense; however, the "me" formulation above might be considered
> a halfway house -- hence "pronominal"
>
> The infamous Y combinator is another halfway house, in the sense that
> the function happens to be recursive but doesn't really know that it
> is.
>
> R
>
>
>