*! version 1.0.0 23oct1997   STB-43 dm55
program define _gfill
	version 5.0
	local type "`1'"
	mac shift
	local var1 "`1'"

	mac shift
	mac shift
	
	parse "`*'", parse("( )")
	mac shift
	local lexp ""

	while "`1'" != ")" {
		confirm number `1'
		local lexp "`lexp' `1'"
		mac shift
	}	
	
	mac shift
	parse "`*'"

	local k : word count `lexp'
	local k2 = round(`k'/ 2, 1)
	local k3 = `k2' + 1

	parse "`lexp'", parse(" ")

	local i 1
	quietly generate `type' `var1' = .
	while `i' <= `k' {
		quietly replace `var1' = `1' in `i'
		local i = `i'+1
		mac shift
	}

	tempvar diff
	quietly {
		gen `diff' = `var1'[_n+1] - `var1'[_n]
		replace `diff' = `diff'[_n-`k2'] in `k3'/l
		replace `var1' = `var1'[_n-1] + `diff'[_n-1] in `k3'/l
		drop `diff'
	}
end