[q-lang-users] This feels like a dumb question, but...

[Andrew B. <and...@ya...>]

...I'd sure appreciate a bit of help.

I'm trying to write some file test functions, like the -f and -d  
functions in perl or shell scripts.  Here is what I have so far:

-f F = true if (close (open F 0 0)) = ();
        = false otherwise;

Which when run gives me:

==> -f "fetch.q"
true

==> -f "fetch.qaz"
! Error in conditional
   0>  fetch.q, line 11: -f "fetch.qaz"  ==>  true if close (open  
"fetch.qaz" 0 0)=()

As I understand this, it meains that the "if" got something other  
than true/false.  It seems like I could write another function (or  
maybe use a lambda) to include a "catch" clause, but this seems like  
such a simple thing, so I have the feeling that I am missing  
something fundamental.

I understand that when the file does not exist, the "(close (open F 0  
0))" part does not reduce, but why does "= ()" part not look at  
"close (open "fetch.qaz" 0 0)" and say, "nope, not equal"?  "eq" does  
the same thing.  Is there something that will force the equality  
check to happen?

-andrew