Syntax Error with Embedded Structs

Sherlock has asked for the wisdom of the Perl Monks concerning the following question:

I'm trying to store some data into a rather complex file structure and I'm having a little trouble with the syntax. I have two structs (one embedded within the other) that look like this:

struct Appt => {
   startTime => '$',
   endTime => '$',
};

struct Day => {
   date => '$',
   appts => '@',
   numAppts => '$',
};
[download]

You'll notice that the Day struct contains an array which I intend to be an array of Appt structs. I then have an array of Day structs (and a counter), like this:

my @days;
my $dayCount = 0;
[download]

I seem to be able to add Day structs to my array, days, like this:

sub hdl_start
{
   my ($p, $elt, %atts) = @_;
   if ( $elt eq 'DAY' )
   {
      # Create a new Day struct
      my $temp = Day->new();

      # Set the date element of that struct
      $temp->date($atts{"DATE"});

      # Insert that struct into my array, days
      $days[$dayCount] = $temp;
   }
   $currEle = $elt;
}
[download]

Unfortunately, I'm unable to add any elements to the appts array within the Day struct. This is the code I'm currently trying to use to add a new Appt struct to the appts array:

# Get the number of appointments
my $numAp = $days[$dayCount]->numAppts;

# Create a new Appt struct
my $temp = Appt->new();

# Set the startTime element within my new Appt struct
$temp->startTime("$str");

# Insert my new Appt struct into the appts array
$days[$dayCount]->appts[$numAp] = $temp;
[download]

The error I am given looks like this: syntax error at line 81, near "->appts[". (Line 81 is the final line of code listed above.)

I'm assuming it's just a syntax error, but, unfortunately, I've been unable to track it down. I was hoping one of you could help.

Thanks,
-Sherlock

Comment on Syntax Error with Embedded Structs Select or Download Code

Replies are listed 'Best First'.
Re: Syntax Error with Embedded Structs by princepawn (Parson) on Apr 18, 2001 at 00:50 UTC
I'm not a big fan of Class::Struct... I prefer Class::MethodMaker. But oh well, I would have done this: `# Insert my new Appt struct into the appts array push @{ $days[$dayCount]->appts }, $temp` [download] but I would make sure that `ref($days[$dayCount]->appts) eq 'ARRAY';` [download] before doing so.	[reply] [d/l] [select]
(tye)Re: Syntax Error with Embedded Structs by tye (Sage) on Apr 18, 2001 at 02:56 UTC
`'ARRAY' eq ref $x` is a fragile construct. I think you (and more importantly, other people who want to use your code) will be better off if you use: `UNIVERSAL::isa( $x, 'ARRAY' )` - tye (but my friends call me "Tye")	[reply] [d/l] [select]
Re: Syntax Error with Embedded Structs by arturo (Vicar) on Apr 18, 2001 at 01:00 UTC
I read this and I thought "Struct? Struct? What the heck is up with Structs in perl?" Then it hit me : you're using Class::Struct. That would be a good lead-in to the question =) It seems like overkill and retrograde non-Perlishness to me (I'll confess to not having any use for the module in question). Were it me, I'd use a home-grown data structure and avoid the problem (basic idea: each day would be an anonymous array of appointments, each of which is itself an anonymous array of start and end times; the whole shebang would be an array of days. Sounds complicated, but I think the syntax for dealing with it is less hairy. Still, you've got something different going on here) `$days[$dayCount]->appts[$numAp]` [download] should probably be written `$days[$dayCount]->appts($numAp) = $temp;` [download] Because, near as I can tell from reading the documentation, that there's a function call, not an array index. Update pfeh ... that won't work either, but for a different reason. I'd go with princepawn's suggestion and `push` a value onto that array. But the oddness of this all is what makes me long for a good old fashioned AoAoA =) (3d array ...) Philosophy can be made out of anything. Or less -- Jerry A. Fodor	[reply] [d/l] [select]