Hyphen '-' is not working within GMM equation sequence, any alternative suggestion is highly appreciated

[Rabiul Islam]

I am writing the following program:

clear all
program define svywt
version 15.1
syntax varlist, WTvar(varlist)
    
    gettoken depvar indepvars : varlist
    _fv_check_depvar `depvar'
    
    local k: word count `wtvar'
    
    forvalues i = 2/`k'{
    local 1(1:`:word 1 of `wtvar''/(1+{xb: `wtvar'})) //this equation has been written manually to provide linear combinations xb.
    local `i'(`i':`:word `i' of `wtvar''/(1+{xb: }))
    }
    local last(last:(`depvar' - ({`depvar': `indepvars' _cons}))/    (1+{xb: }))
    local last_inst instruments(last: `indepvars')
    
    gmm `1' `2'``k'' `last', `last_inst' onestep winitial(unadjusted, independent)  //help needed in this part
        
    end

sysuse auto, clear
egen y = mean(price)

gen price_1 = price -y

egen x = mean(mpg)

gen mpg_1=mpg-x

egen z =mean(trunk)

gen trunk_1 = trunk-z

svywt price weight mpg, wtvar(price_1 mpg_1 trunk_1)

I need help to write this:

 gmm `1' `2'``k'' `last', `last_inst' onestep winitial(unadjusted, independent)

in the form

gmm `1' -``k'' `last', `last_inst' onestep winitial(unadjusted, independent)

or some other form that allows me to write "1-k" equations in short so that if I have very large 'k', I do not need to mention all equations one by one.

Thanks in advance for your help.

Rabiul