    /* Test file for kate's stata syntax highlighting
    */
    *! version 1.2.0 2mar2003 E. Leuven
    program define spellsplit
            version 7
            syntax [anything], spell(varlist min=2 max=2) [ by(varlist)]
            tokenize `spell'
            local date0 `1'
            local date1 `2'
            local f0 : format `date0'
            local f1 : format `date1'

            /* set default statistic */
            local current "mean"

            gettoken left anything : anything, match(prns)
            while "`left'"!="" {
                    if "`prns'"!="" {
                            if !inlist("`left'","mean","sum") {
                                    di as error "Statistic `left' not supported"
                                    exit 198
                            }
                            local current "`left'"
                    }
                    else {
                            local `current'vars  ``current'vars' `left'
                    }
                    gettoken left anything : anything, match(prns)
            }
            if ("`meanvars'"!="") {
                    confirm var `meanvars'
                    unab meanvars : `meanvars'
            }
            if ("`sumvars'"!="") {
                    confirm var `sumvars'
                    unab sumvars : `sumvars'
            }

            quietly {
                    g _count = 1
                    local xvars `meanvars' `sumvars' _count

                    /* create dummy by-var if no by option is specified */
                    if "`by'"=="" {
                            tempvar by
                            g byte `by' = 1
                    }
                    tempvar `xvars' `by'

                    /* create negative for subtraction when spell ends */
                    cap foreach v of varlist `xvars' {
                            g double ``v'' = -`v'
                            local txvars `txvars' ``v''
                    }
                    cap foreach v of varlist `by' {
                            g double ``v'' = `v'
                            local txvars `txvars' ``v''
                    }

                    stack `date0' `xvars' `by' `date1' `txvars', into(`date0' `xvars' `by') clear

                    /* calculate totals per date */
                    cap foreach v of varlist `xvars' {
                            egen double ``v'' = sum(`v'), by(`by' `date0')
                    }

                    /* unique dates only */
                    by `by' `date0', sort: keep if _n==1

                    /* calculate totals (+ when spell starts - when ends) */
                    sort `by'
                    cap foreach v of varlist `xvars' {
                            by `by': replace `v' = sum(``v'')
                    }
                    by `by': g `date1' = `date0'[_n + 1]

                    drop if `date0'>`date1'
                    drop _stack
                    drop if _count==0
                    order `by' `date0' `date1' `xvars'
                    format `date0' `f0'
                    format `date1' `f1'

                    cap for var `meanvars': replace X = X/_count

                    compress
            }

    end