Re: Serious question on using Perl or not...

Gregoire Hostettler wrote:
> Hi!
> 
> I do not know I am on the right mailing list.
> If not, sorry for the burden.
> 
> To say thing briefly:
> I am a programmer for some 25 years using various old and newer languages.
> I have to write some small things in Perl.
> It was fine and fast with some text analysis.
> 
> Now I have to write something using an in-memory "database", i.e. a SINGLE
> table filled with records.
> 
> I am trying to simply add records then retriev them.
> I already spent more than 20 hours for something which should take 30
> minutes....
> 
> Seriousely considering making my customer change his mind and revert to
> plain old C++
> Just to be certain not to miss something simple, I attach a small part of my
> very, very basic trials.
> 
> As you can see when running this small piece of "code", as soon as you push
> a new record, all records already existing become
> filled with the new pushed record and it is impossible to get any other...
> 
> Looks like Perl is not able to handle trivial data structure like an array
> of records (or hashes).
> 
> Thank you for any help!
> 
> 
> Caracal - G. Hostettler
> 6, ch. du Raidillon
> 1522 Lucens
> 

My first bit of advise, don't pass around hashes.  Pass references. 
Second don't declare the @table.  Or rather declare it (with my) but 
don't initialize it.  The assignment make a great comment, but you don't 
declare 'fields' in a hash.  On the push in addrec push a reference.

	push @table, { %lrec};

It's just like an array of pointers in C.  It an array of hash 
references (or pointers).

In getrec, you have an off by 1.  $#table is the last used index in 
@table, not the size.  It's 1 too small. Use scalar(@table to get the 
size or do this

	if (($recnum < 0) or ($recnum > ($#table) )) {

To get you hash back you'd need to dereference it.

	%lrec = %{$table[$recnum]}

Your statements to print the size should look more like:

	print "Added rec. tblsize = ", scalar(@table), "\n";

After all of this, you code is still going to be kind of ugly because 
you pass around the hash in list context.

try something like

	sub addrec { # takes a list of key value pairs
		push @table, { @_ }
	}

	getrec($){ # take an index, returns hash ref or undef on failure
		return $table[shift]; # gets undef() on failure
	}

Dan