Re: st: -syntax , option(varlist min=0)-?

[Jeph Herrin <jeph.herrin@yale.edu>]

Nice.

Nick Winter wrote:
> Even spiffier:
>
>
> program twoopts
>     syntax varlist , [  MYOPTion1 MYOPTion2(varlist)  ]
>     
>     di "varlist:   [`varlist']"
>     di "myoption1: [`myoption1']"
>     di "myoption2: [`myoption2']"
>     
>     if "`myoption1'"!="" local myoption `varlist'
>     else if "`myoption2'"!="" local myoption `myoption2'
>
>     di "myoption: [`myoption']"
>
> end
>
> This gives:
>
> . twoopts mpg price
> varlist:   [mpg price]
> myoption1: []
> myoption2: []
> myoption: []
>
> . twoopts mpg price , myopt(mpg)
> varlist:   [mpg price]
> myoption1: []
> myoption2: [mpg]
> myoption: [mpg]
>
> . twoopts mpg price , myopt
> varlist:   [mpg price]
> myoption1: [myoption1]
> myoption2: []
> myoption: [mpg price]
>
>
>
> This is documented somewhere, i think....
>
> Nick Winter
>
> Jeph Herrin wrote:
> > Thanks for the tip. I knew there must be a trick somewhere.
> > I can even do this, no?
> >
> >   capture syntax varlist, myoption(varname)
> >   if _rc {
> >      syntax varlist, myoption
> >   }
> >
> > cheers,
> > J
> >
> >
> > Sergiy Radyakin wrote:
> > > Dear Jeph,
> > >
> > > try:
> > >
> > > capture syntax varlist, myoption(varname)
> > > if !_rc {
> > >
> > >   //program implementation for syntax1
> > >
> > >   ....
> > >   exit
> > > }
> > >
> > > syntax varlist, myoption
> > > // program implementation for syntax2
> > >
> > > this is often used when there are several distinct syntaxes possible
> > > for a command.
> > > See for example the implementation of -test- in test.ado.
> > >
> > > Best regards, Sergiy Radyakin
> > >
> > >
> > >
> > >
> > >
> > > On Thu, Oct 8, 2009 at 2:13 PM, Jeph Herrin <junk@spandrel.net> wrote:
> > > > I would like a program to take an option which contains
> > > > either a varlist or nothing. Something like
> > > >
> > > >  syntax varlist..., myoption(varlist min=0)
> > > >
> > > > which Stata doesn't like. The idea is that -myoption-
> > > > only applies to the listed variables in the primary varlist;
> > > > unless -myoption()- is specified, then it applies to all
> > > > variables in the primary varlist. This sounds confusing
> > > > even to me, so in pseudo code, I would like to have
> > > >
> > > >  myprogram var1-var10, myoption(var1)
> > > >
> > > > apply the option to only -var1-, but
> > > >
> > > >  myprogram var1-var10, myoption
> > > >
> > > > apply the option to var1-var10. Seems like I have done this
> > > > before, but it escapes me now. Any ideas?
> > > >
> > > >
> > > >
> > > > thanks,
> > > > Jeph
> > > > *
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