Re: [bug-gawk] Missing lint warning ?

[Manuel Collado]

El 08/08/2013 7:47, Hermann Peifer escribió:
> Hi,
>
> I just noted that in the below test code, `print undefined' generates a
> lint warning, whereas `x(undefined)' doesn't. Maybe this is a feature
> rather than a small bug.

Probably a feature. A function argument can be a array to be assigned 
(output argument). So it is perfectly normal to pass an uninitialized one.

The fact that the argument is an array instead of a scalar is determined 
when the function call is actually executed. Example:

function y(a, b) {
   if (a) {
      b[1] = 1
      print "b is an array"
   } else {
      b = 1
      print "b is a scalar"
   }
}

So the lint checker cannot determine if the uninitialized argument of the 
function call is intended to be an array or a scalar without actually 
executing the program.

Regards.

> In any case, I found it worth reporting.
>
> Hermann
>
> $ cat test.awk
> BEGIN { print undefined ; x(undefined) }
>
> function x(a)
> {
>      if (a == "" && a == 0) {
>          print "*** argument 'a' has not been given ***"
>      }
> }
>
>
> $ gawk --lint -f test.awk
> gawk: test.awk:1: warning: reference to uninitialized variable `undefined'
>
> gawk: test.awk:5: warning: reference to uninitialized argument `a'
> gawk: test.awk:5: warning: reference to uninitialized argument `a'
> *** argument 'a' has not been given ***


--
Manuel Collado - http://lml.ls.fi.upm.es/~mcollado