st: Differencing a varlist

[Dani Tilley <tilleydani@yahoo.com>]

Hi,

I'm writing a command that will expect a regressand and possibly several 
regressors. At the beginning of the command, I do this to separate the 
regressand from the regressors: 


token `varlist'
local lefths `1'
mac shift
local righths `*'

So, if a user types -command y x1 x2- varlist will have y, x1 and x2, lefths 
will have the first element of the varlist, y, and righths will have the rest, 
x1 and x2. I can later easily say -reg `lefths' `righths'- if I want a simple 
regression. 


This has worked fine for me until now, when I need to regress the `lefths' on 
the first difference of all the variables in `righths'. I tried, -reg `lefths' 
D1.`righths'- but if righths has more than one variable, only the first is 
differenced and the rest are ignored. Is there a way around this?

Thanks in advance,

DF Tilley



      

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