DelphiTools.info relocated

The DelphiTools.info website has just been relocated, it also transitioned from a Linux host to a Windows one.

There were a few glitches with WordPress during the transfer, but they should hopefully have been solved, if not, feel free to post about them here!

Christmas present for SynEdit users

SynEdit LogoJust committed to the SynEdit SVN a few enhancements:

  • much improved performance for long & large files, still not quite notepad++-class just yet, but my profiler tells me there are many juicy low-hanging candies left 🙂
  • improvements to the TSynGeneralSyn highlighter (single & double quote mode, token callback, and a few other niceties)
  • DWScript syntax highlighter has been moved to the SynEdit SVN, the copy in the DWScript SVN will no longer be the primary reference

edit 27/12: committed another optimization, AFAICT, when working on large files, SynEdit is now faster than the Delphi IDE code editor and *way* faster than Scintilla/notepad++ 5.9.6.2 (with and without a syntax highlighter like DWS’s)

DWS news + OP4JS aka SmartMobileStudio

A quick news roundup before Christmas.
 

OP4JS Alpha aka SmartMobileStudio is in the wild

We’ve now sent “Smart Mobile Studio” Alpha version to 50 testers.

Did you miss the beta invite?

Visit www.SmartMobileStudio.com to participate.

SmartMobileStudio leverages DWScript’s JavaScript CodeGen.

My first test app with the alpha was a clock, check it in your iOS or Android Browser or in the Android market. Source is included in the alpha. Will be beautified it later on 🙂

I’ve been playing on another one, head over to YouTube to see a small video, you can also get the apk (47 kB), but beware it’s basic, ugly, and definitely early alpha, but it’s coded in Pascal!

Below is a snippet of the source code (using DWS inline implementations for illustration and compactness purposes, most of OP4JS is written in the more classic interface/implementation style), it’s a snip of the root class of the mini-engine of the game (yes, virtual methods are supported):

type
   TEntity = class
      X, Y : Float;

      function Progress : Boolean; virtual;
      begin
         // does nothing by default
      end;

      constructor Create(aX, aY : Float);
      begin
         X := aX;
         Y := aY;
      end;

      function Dist2(entity : TEntity) : Float;
      begin
         Result := Sqr(X-entity.X)+Sqr(Y-entity.Y);
      end;
   end;
 

Other recent changes to the DWScript SVN

  • Added sample/simple IndyWebServer demo, implements basic “pascal server pages” and demonstrates how to use DWS in a multi-threaded environment. Makes use of RTTI Environment class to expose WebRequest & WebResponse. Expect more details in a future post.
  • TTerminatorThread has been replaced by TGuardianThread, which can “guard” multiple executions
  • Dotted unit names are now supported
  • Random no longer uses the Delphi RTL but XorShift
  • unit name symbols are now included in the Symbol Dictionary
  • include references are now included in the Symbol Dictionary
  • TdwsSuggestions can now optionally suggest reserved words (begin, procedure, etc.)
  • fixes for Inc() & Dec() when operating on references with side-effects.
  • improved several error messages related to parameter passing.
  • other misc. fixes and optimizations, more unit tests.

Pimp your random numbers with XorShift!

A 64bit XorShift is now used to generate random numbers in DWScript, and there is a now a separate random number generator per-execution, which is auto-randomized when an execution is created.

Previously, the RTL random generator was used, this was “okay” when you had only one script using random numbers at a time, but multiple scripts running at the same time would interfere (Randomize calls would affect each others f.i.), and Random isn’t really thread-safe.

Performance fo XorShift is roughly comparable to the Delphi RTL’s linear congruential generator, but with much better statistical random properties and a very long period, without the overhead of a Mersenne Twister. For those interested in the mathematical details, see “XorShift RNGs” paper by G. Marsagalia.

As an illustration of the improved random properties, consider filling a bitmap with “random” RGB colors for each pixel:

var x, y : Integer;
for x := 0 to bmp.Width-1 do
   for y := 0 to bmp.Height-1 do
      bmp.Pixel[x, y] := RandomInt($1000000);

Using the Delphi built-in Random, you’ll get something like the image below (generated at 512×512, then halved and downgraded to 4bpp for web consumption)

Delphi RTL Random

Oooh… the horizontal scratch lines! Not so random after all… I don’t know if the Delphi LCG is as biased as RANDU, but visibly, it is probably not something you want to rely upon too much.

And now, the same but with the XorShift implementation now used in DWS:

DWScript XorShift Random

The  XorShift implementation is very simple, fast, and doesn’t require much memory: a single 64bit value is enough to get good random, use two if you want longer periods that won’t have a chance to loop before the universe ends.

Last but not least, 64bit XorShift may be fast in 32bit binaries, but it practically walks on water in 64bit binaries 😉

DWS news roundup

Here is a quick summary of recent additions to DWScript:

  • exit, break and continue are now reserved keyword (and highlighted as such), previously they weren’t (as in Delphi), but having variables or functions named that way just “breaks” (pun intended) those language features (as it does in Delphi)
  • new TdwsRTTIEnvironment, fields and properties of a class exposed this way are directly accessible in scripts, more details on that one in a future post.
  • support passing constant arrays to dynamic array parameters (automatic conversion).
  • improved the language documentation.
  • added ability for custom extension of Abs() special function (now supported by TComplex).
  • added Clamp() floating-point function.
  • added Gcd(), Lcm(), IsPrime() and LeastFactor() integer functions.
  • fixed an issue that prevented conditional directives from being supported in all portions of the code, they can now properly be used anywhere.
  • JavaScript codegen optimization for variable symbol lookup.
  • minor tokenizer speedup, compile speed should now be close to 200k LOC/sec*.
  • more test cases, minor fixes.

*: FWIW since the old benchmark, compile and execution performance almost tripled and memory requirements were cut by approx 30%. At the same time the language became quite a bit richer.