cast function in package reshape

Hello R useRs,

I have a function which returns a list of functions :

freq1 <- function(x) {
?lev <- unique(x[!is.na(x)])
?nlev <- length(lev)
?args <- alist(x=)

?if (nlev == 1) {
? ?body <- c("{", "sum(!is.na(x))", "}")
? ?f <- function() {}
? ?formals(f) <- as.pairlist(args)
? ?body(f) <- parse(text = body)
? ?namef <- paste("freq", as.character(nlev), sep = "_")
? ?assign(namef, f)
? ?res <- list(get(namef))
? ?names(res) <- namef
?}
?if (nlev > 1) {
? ?res <- NULL
? ?namesf <- NULL
? ?for (i in 1:nlev) {
? ? ?body <- c("{", paste("sum(x[!is.na(x)] ==", as.character(lev[i]), ")",
sep = " "), "}")
? ? ?f <- function() {}
? ? ?formals(f) <- as.pairlist(args)
? ? ?body(f) <- parse(text = body)
? ? ?namef <- paste("freq", as.character(lev[i]), sep = "_")
? ? ?assign(namef, f)
? ? ?namesf <- c(namesf, namef)
? ? ?res <- c(res, get(namef))
? ?}
? ?names(res) <- namesf
?}
?return(res)
}

df <- data.frame(id = 1:50, x = sample(c(NA, 1), 50, T), y = sample(1:2, 50,
T), z = sample(letters[1:2], 50, T))

freq1(df$x)

$freq_1
function (x)
{
? ?sum(!is.na(x))
}
<environment: 0x03d99684>

freq1(df$y)

$freq_2
function (x)
{
? ?sum(x[!is.na(x)] == 2)
}
<environment: 0x03d6c930>

$freq_1
function (x)
{
? ?sum(x[!is.na(x)] == 1)
}
<environment: 0x03d6c930>


I would like to use this list of functions with cast function (in package
reshape by Hadley Wickham) :

cast(melt(df, id = c("id", "z"), measure = c("x", "y")), variable +

result_variable ~ z, fun = function(x) freq1(x), margins = "grand_col")
Erreur dans freq1(x) : objet "res" non trouv?

Here the result I would like to have :

?variable ? ? ? ? ? ? ? ? ?a ?b (all)
1 ? ? ? ?x ? ? ? ? ?freq_1 10 14 ? ?24
2 ? ? ? ?y ? ? ? ? ?freq_1 18 32 ? ?50
3 ? ? ? ?y ? ? ? ? ?freq_2 ?9 14 ? ?23

I admit it is a bit far-fetched, but is this actually possible ?