/*----------------------------------------------------------------------------
        finddate -- Program to display the period for which data
                    are available.  finddate assumes that the data
                    set is sorted in the order of the date variables.

                    STATA programs called:
                        _voptex

                    Written by Sean Becketti, July 1989.
----------------------------------------------------------------------------*/
program define finddate
version 2.1
quietly {
        if "%_*"=="" {
		di in bl "-> finddate varlist [if] [in], [date(datevars)] [nobs]"
		exit
        }
	mac def _varlist "opt ex"
	mac def _if "opt"
	mac def _in "opt"
	mac def _options "Date(str) Nobs" 
	parse "%_*"
        if "%_if"~="" {
                mac def _if "%_if &"
        }
        if "%_if"=="" {
                mac def _if "if"
        }
	if "%_date"~="" {
                _voptex "%_date", vlist(vLiSt)
                parse "%vLiSt", parse(" ")
                mac def vLiSt
                if "%_4"~="" {
                        di in re "No more than three date variables allowed"
                        exit
                }
                mac def _year  "%_1"
                mac def _ylbl  "%_year"
                mac def _month "%_2"
                mac def _mlbl  "%_month"
                mac def _day   "%_3"
                mac def _dlbl  "%_day"
                mac def _ndates = cond("%_2"=="",1,cond("%_3"=="",2,3))
                conf ex %_year
                cap drop _y_lbl
                cap drop _m_lbl
                cap drop _d_lbl
                cap decode %_year, gen(_y_lbl)
                if ~_rc { 
                        mac def _ylbl "_y_lbl" 
                }
                if (%_ndates>1) {
                        conf ex %_month
                        cap decode %_month, gen(_m_lbl)
                        if ~_rc { 
                                mac def _mlbl "_m_lbl" 
                        }
                }
                if (%_ndates>2) {
                        conf ex %_day
                        cap decode %_day, gen(_d_lbl)
                        if ~_rc { 
                                mac def _dlbl "_d_lbl" 
                        }
                }
        }
        gen int Obs = _n
        if "%_date"=="" {
                mac def _ndates = 1
                mac def _year "Obs"
                mac def _ylbl  "Obs"
        }
        if (%_ndates==1) {
                di in gr _c(11) "First" _c(22) "Last"
                di in gr _c(11) "%_year" _c(22) "%_year"
                di in gr "------------------------------"
        }
        if (%_ndates==2) {
                di in gr _c(16) "First" _c(41) "Last"
                di in gr _c(11) "%_year" _c(22) "%_month" /*
*/                       _c(36) "%_year" _c(47) "%_month"
                di in gr "-------------------------------------------------------"
        }
        if (%_ndates==3) {
                di in gr _c(22) "First" _c(58) "Last"
                di in gr _c(11) "%_year" _c(22) "%_month" _c(33) "%_day" /*
*/                       _c(47) "%_year" _c(58) "%_month" _c(69) "%_day"
                di in gr "-----------------------------------------------------------------------------"
        }
        mac def _S_FN "%S_FN"
        save t_e_m_p, replace
        parse "%_varlist", parse(" ")
        while "%_1"~="" {
                use t_e_m_p, clear
                keep %_if %_1~=. %_in
                if "%_nobs"~="" {
                        mac def _N = Obs[_N] - Obs[1] + 1
                        mac def _n = _N
                        count if Obs-Obs[_n-1]>1 in 2/l
                        mac def _tag = _result(1)
                        mac def _tag "(%_n/%_N/%_tag)"
                }
                if (%_ndates==1) {
                        di in gr "%_1" in ye _c(11) %_ylbl`[1] /*
*/                         _c(22) %_ylbl`[_N] "    %_tag"
                }
                if (%_ndates==2) {
                        di in gr "%_1" in ye _c(11) %_ylbl`[1] /*
*/                         _c(22) %_mlbl`[1] _c(36) %_ylbl`[_N] /*
*/                         _c(47) %_mlbl`[_N] "    %_tag"
                }
                if (%_ndates==3) {
                        di in gr "%_1" in ye _c(11) %_ylbl`[1] /*
*/                         _c(22) %_mlbl`[1] _c(33) %_dlbl`[1] /*
*/                         _c(47) %_ylbl`[_N] _c(58) %_mlbl`[_N] /*
*/                         _c(69) %_dlbl`[_N] "    %_tag"
                }
                mac shift
        }
        use t_e_m_p, clear
        erase t_e_m_p.dta
        mac def S_FN "%_S_FN"
        cap drop Obs
        cap drop _y_lbl
        cap drop _m_lbl
        cap drop _d_lbl
}
end        

capture program drop _voptex
program define _voptex
quietly {
        mac def _varlist "opt ex"
        mac def _options "Vlist(str)"
	parse "%_*"
        if "%_vlist"~="" {
                mac def %_vlist "%_varlist"
        }
}
end