Re: st: -args- how to flag when missing or too many arguments

[Austin Nichols <austinnichols@gmail.com>]

John Antonakis <John.Antonakis@unil.ch>:
You might also want to step through various conditions and then issue
a more informative error message at the end, e.g. consider adapting
this approach:

cap prog drop john
prog john, rclass
 version 12
 loc err 0
 args no_vars df N chi
 loc w: word count `no_vars' `df' `N' `chi'
 if `w'>4 {
  loc err 1
  di in red "More than 4 arguments given"
  }
 foreach v in no_vars df N chi {
  cap confirm integer number `=``v'''
  if _rc!=0 {
   loc err 1
   di in red "Arguments must be integers."
   }
  else if ``v''<0 {
   loc err 1
   di in red "Arguments must be positive integers."
   }
  }
 if `err'==1 {
  di in red "Please enter data after the command" _c
  di in red " john as follows: vars df N chi"
  exit 198
  }
end

On Thu, Mar 21, 2013 at 5:49 PM, daniel klein <klein.daniel.81@gmail.com> wrote:
> John,
>
> I think I would address this with something like this
>
> cap pr drop john
> pr john
>         vers 12.1
>
>         args a b c d
>         if !inrange(`: word count `0'', 1, 4) {
>                 di as err "Please enter data after " ///
>                 "the command john as follows: vars df N chi"
>                 e 198
>         }
>         numlist "`0'" ,int r(>0)
>
> end
>
> Best
> Daniel
> --
> Hi:
>
> I am writing a program and would like Stata to return an error if an
> argument is missing or there are too many of them.
>
>
> For example, if an argument is not an integer, the below will return an error:
>
>
>   program define john, rclass
>   version 12
>   args no_vars df N chi
>
>   if `no_vars'<0 | `df'<0 | `N'<0 | `chi'<0 {
>   di in red "You have to use integers."
>   exit 498
>   }
> end
>
> Now, how do I make Stata display:
>
> di in red "Please enter data after the command john as follows: vars df N chi"
>
>
> .....in cases where (a) there is a missing value (i.e., the user
> missed putting 4 numbers) and (b) if the user provides too many
> numbers (i.e., 5 instead of 4).
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