TURBU Tech

Last year when I was at Delphi Live, the event was a bit smaller than it had been the year before.  Less attendees, less sessions, not as nice of a venue, etc.  Kind of to be expected, with the economy in the toilet and all, but still it was sorta sad.  I heard a few  people mention that the way things had gone, they doubted there would be another one this year.

Just yesterday I was thinking back on that, and I figured it was probably right, or we would have heard an announcement about it by now.  And that kinda sucked.  I’d really enjoyed going there the last two years.  Well, I’m glad to be able to say I was wrong about that.

Continue reading ‘Delphi Live 2011 announcement’ »

I wrote my last post about enabling booleans in Firebird after several hours of poking around in database code trying to get my query to execute without errors.  Once it worked, everything seemed great.  But I missed an important step: I hadn’t tried to write anything back to the database yet.

Continue reading ‘Firebird and booleans: one more hurdle’ »

Firebird is a great database, but it’s got one really irritating drawback: no native support for the boolean type.  The standard solution to this issue is to create a BOOLEAN domain as a special restricted version of a smallint, and then make your database driver output the correct type.

The first part is easy.  The second, not so much, if you want to use DBExpress.  This really should be handled internally as a special case inside the DBX driver.  Unfortunately neither Embarcadero nor Chau Chee Yang, maker of the alternative dbExpress Firebird driver, has released the source to their drivers, neither driver handles the BOOLEAN domain, and neither driver has any sort of callback/event handler that you can set up to intercept and modify the schema of a query result.  But I’m not gonna let a little thing like that stop me! Continue reading ‘Adding boolean support to Firebird+DBX’ »

I wrote a compiler at work today.  It took about 5 hours.

Granted, its input is very simple and nowhere near Turing-complete, and its output is in Delphi, not any type of machine language or bytecode.  But it definitely fits Joel Spolsky’s definition of a compiler. Continue reading ‘I built a compiler today’ »

One annoying thing I’ve noticed in building my script compiler is the way the use of generic collections tends to bloat up the size of your EXE.  I use generics for a lot of things; a compiler uses lists, stacks and lookup tables (dictionaries) all over the place.  When I was building it with DeHL, the compiler plus a very simple test frontend compiled into a 36 MB behemoth of a binary, and a quick look at the mapfile shows that the vast majority of that was DeHL collections.  Now that I’ve switched to the more simplified Collections library, it “only” takes 23 MB, a savings of about 33%.  But that’s still huge.  There has to be a better way.

Continue reading ‘Wish list: Generics collapsing’ »

Over the past couple weeks, I’ve been working on refining and testing my RTTI generation and the scripting system I’ve been building on top of it, which I’ve decided to call RTTI Script.  I think I’m finally starting to get something ready for public consumption.  I set up a Google Code repository this morning for RTTI Script, but so far all it contains is the RTTI generation code.  The actual compiler and script executor still need some work. Continue reading ‘RTTI Generation code now available’ »

Just in case you haven’t listened to it yet, Jim McKeeth over at Delphi.org posted a new podcast last week. He did an interview with Allen Bauer that apparently ran for about two hours, so he split it up into two parts.  The second part isn’t up yet, but there’s a lot of interesting stuff in the first one.  But one of the most interesting things actually came in the comments.

Continue reading ‘Run-time stack information?’ »

A few years back, I ran across this post by Hallvard Vassbotn.  (It’s a shame he stopped blogging, because he always had some very interesting stuff about the technical details of how stuff in Delphi works.)  At the bottom was a paragraph that really fascinated me:

On a more technical level it suffices to say that they use custom and extremely compact and fast data structures, tricks and hacks to be able to represent millions and millions of objects within the constraints of a 32-bit Windows system. Throw in the use of Physical Address Extensions, storing per-class information in “virtual” class vars to reduce object instance size, creation of classes and their VMTs dynamically at runtime (!!), pointer packing, multithreading, the list just goes on and on.

Continue reading ‘Dynamic class creation: moving beyond the theoretical’ »

I got an email from Barry Kelly in response to my last post:

I can’t comment on this article as it requires the commenter to be
logged in, and registration is disabled.

There are no plans for a more compact RTTI format. I’d love for there to
be, but the backward compatibility concerns are simply too large.
However, as more code relies on higher-level RTTI constructs, the scope
for freedom there increases incrementally. That’s all I was trying to
say.

— Barry Continue reading ‘Smaller, cleaner RTTI probably NOT coming’ »

One of the biggest complaints about the extended RTTI introduced in Delphi 2010 is the way it adds so much to the size of your EXE.  Well, in a recent StackOverflow answer, Barry Kelly hinted that the format of the basic RTTI structures in TypInfo.pas are “more likely to change from version to version now that it has a much higher level abstraction in the Rtti unit.” Continue reading ‘Smaller, cleaner RTTI coming?’ »