Category: Pascal

FreePascal Building

I went to do a little code maintenance on a couple utils I'd written in FreePascal, and they wouldn't build. For a couple years, FPC just didn't work on 64-bit Mac OS, but they finally fixed that. Current fpc 3.2.0 is in MacPorts, I'm not sure what the state of Lazarus is, I quit using it. But the core Pascal is fine for many tasks, and I may do some things in CP/M Pascal when I get my SpecNext (longest wait ever until fall/whenever).

Anyway, the error I got was ld: library not found for -lc and nobody on the Internet has ever posted with that error, that I can find.

And eventually I tracked it down to the SDK not being linked at all. So here's an updated fpc.cfg which goes in your $PPC_CONFIG_PATH, note the DARWIN section. Also that's x86_64 only, I need to add an ARM64 branch at some point.

#IFDEF DEBUG
    #WRITE DEBUG
    -gl
    -Crtoi
#ELSE
    # Strip debuginfo
    -O2
    -Xs
#ENDIF

#IFDEF DARWIN
    #WRITE DARWIN
    # use pipes instead of temporary files for assembling
    -ap
    #DEFINE CPUX86_64
    -Px86_64
    -FD/Library/Developer/CommandLineTools/usr/bin
    -XR/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk
#ENDIF

#IFDEF OBJFPC
    #WRITE OBJFPC
    -Mobjfpc
#ELSE
    #WRITE FPC
    -Mfpc
#ENDIF

# use ansistrings
-Sh

# stop after warnings
-Sew

# don't show Hint: (5023) Unit "X" not used in Y
-vm5023
# don't show Hint: (5024) Parameter "name" not used
-vm5024

#-Fl/usr/X11/lib
#-Fl/usr/local/lib

-Fu/opt/local/libexec/fpc/lib/fpc/$fpcversion/units/$fpctarget
-Fu/opt/local/libexec/fpc/lib/fpc/$fpcversion/units/$fpctarget/*

And a quick hello world/Unicode tester:

{ hello.pas
    Copyright ©2017 by Mark Damon Hughes. Do what thou wilt.
}

program hello;

uses crt, sysutils;

var
    name: utf8string;
    c: widechar;
    i: integer;
begin
    write('What is your name? ');
    readln(name);
    writeln('Hello, ', name, ' from code page ', stringCodePage(name), '!');
    for i := 1 to length(name) do begin
        c := name[i];
        writeln(i, ': ', c, '(', ord(c), ')');
    end;
    readkey();
end.

fpc -dDEBUG hello.pas produces a couple dozen warnings like: ld: warning: object file (/opt/local/libexec/fpc/lib/fpc/3.2.0/units/x86_64-darwin/rtl/baseunix.o) was built for newer macOS version (11.0) than being linked (10.8) and I'd love it if someone could tell me how to get FPC to tell ld to make that STFU.

But it works:

% ./hello
What is your name? Mark
Hello, Mark from code page 65001!
1: M(77)
2: a(97)
3: r(114)
4: k(107)
5: �(239)
6: �(163)
7: �(191)

Tower of Babble

Programmers almost compulsively make new languages; within just a few years of there being computers, multiple competing languages appeared:

It proliferated from there into millions; probably half of all programmers with 10+ years of experience have written one or more.

I've written several, as scripting systems or toys. I really liked my Minimal script in Hephaestus 1.0, which was like BASIC+LISP, but implemented as it was in Java the performance was shitty and I had better options to replace it. My XML game schemas in GameScroll and Aiee! were half programmer humor, but very usable if you had a good XML editor. Multiple apps have shipped with my tiny lisp interpreter Aspic, despite the fruit company's ban on such things at the time. A Brainfuck/FORTH-like Stream, working-but-incomplete tbasic, and a couple PILOT variants (I think PILOT is hilariously on the border of "almost useful").

Almost every new language is invented as marketing bullshit based on a few Ur-languages:

  • C++: Swift
  • Java: Javascript (sorta), C#, Go
  • Awk: Perl, Python, PHP, Julia
  • C: Rust
  • Smalltalk: Objective-C
  • Prolog: Erlang, Elixir
  • ALGOL: C, Pascal, PL/1, Simula, Smalltalk, Java
  • LISP: Scheme, ML, Haskell, Clojure, Racket
  • BASIC: None, other than more dialects of BASIC.
  • FORTRAN: None in decades, but is the direct ancestor of ALGOL & BASIC.
  • COBOL: None in decades.

A few of these improve on their ancestors in some useful way, often performance is better, but most do nothing new; it's plausible that ALGOL 68 is a better language than any of its descendants, it just has mediocre compiler support these days.

Certainly I've made it clear I think Swift is a major regression, less capable, stable, fast, or even readable than C++, a feat I would've called impossible except as a practical joke a decade ago. When Marzipan comes out, I'll be able to rebuild all my 15 years of Objective-C code and it'll work on 2 platforms. The Swift 1.0 app I wrote and painfully ported to 2.0 is dead as a doornail, and current Swift apps will be uncompilable in 1-2 years; and be lost when Apple abandons Swift.

When I want to move my Scheme code to a new version or any other Scheme, it's pretty simple, I made only a handful of changes other than library importing from MIT Scheme to Chez to Chicken 4 to Chicken 5. When I tested it in Racket (which I won't be using) I had to make a handful of aliases. Probably even CLISP (which is the Swift of LISPs, except it fossilized in 1994) would be 20 or 30 aliases; their broken do iterator would be hard but the rest is just naming.

Javascript is a pernicious Herpes-virus-like infection of browsers and desktops, and nothing can ever kill it, so where it fits the problem, there's no reason not to use it. But there's a lot it doesn't do well.

I was leery of using FreePascal because it has a single implementation (technically Delphi still exists, but it's $X,000 per seat on Windows) and minimal libraries, and in fact when it broke on OS X Mojave, I was disappointed but I-told-you-so.

I'm not saying we should quit making new Brainfuck and LOLCODE things, I don't think it's possible for programmers to stop without radical brain surgery. But when you're evaluating a language for a real-world problem, try moving backwards until you find the oldest and most stable thing that works and will continue to work, not piling more crap into a rickety new framework.

The Biblical reference in the title amuses me, because we know now that it requires no malevolent genocidal war deity scared of us invading Heaven to magically confuse our languages and make us work at cross purposes; anyone who can write and think splinters their thought into a unique language and then argues about it.

Software Tools Quote

"Finally, it is a pleasure to acknowledge our debt to the Unix operating system, developed at Bell Labs by Ken Thompson and Dennis Ritchie. We wrote the text, tested the programs, and typeset the manuscript, all within Unix. Many of the tools we describe are based on Unix models. Most important, the ideas and philosophy are based on our experience as Unix users. Of all the operating systems we have used, Unix is the only one that has been a positive help in getting a job done instead of an obstacle to be overcome. The world-wide acceptance of Unix indicates that we are not the only ones who feel this way."
— "Software Tools in Pascal", 1981, by Brian W. Kernighan, P.J. Plauger

As every neckbearded n-gate reader will now rush to well-actually at me, BWK's experience writing this book led to Why Pascal Is Not My Favorite Programming Language, but note this rant is about "standard" ANSI Pascal, not the somewhat improved P-Code Pascal of the '70s or the free-wheeling super-powered Turbo Pascal of the early '80s, and nothing like modern FreePascal. Standard Pascal was a deliberately simplified pedagogical language, not a systems programming language, which the later ones are.

Anyway, the book's interesting as a problem-solving exercise, but the Unix part amused me. And no, Linux is Not Unix. Buy a Mac or install BSD if you want UNIX®.

Debugging Pascal

Having a spare day to actually work on what I want, I get back into my Pascal adventure, and I'm blocked by inobvious bugs.

Thanks to Sierra breaking gdb (unless you disable SIP entirely, which I'm not going to do), Lazarus can't run ggdb, so forget about GUI debugging. I've tried all the code-signing, rebooting suggestions, none of that works.

I'm not a giant fan of the debugger, but even caveman Mark needs a backtrace sometimes. Happily, lldb works from the command line:

lldb -o "breakpoint set -n fpc_raiseexception" -o run foo.app

Then at the lldb prompt after a crash, type 'bt' for backtrace, 'cont' to carry on with the usual exception handling. Most of the lldb tutorial works the same.

TPortableNetworkGraphic

Trying to load a PNG image and display it on the canvas has been… not fun. Delphi only knew about BMP stored in some horrible Microsoft resource format, and so everything FreePascal adds on top is a pile of hacks or undocumented features. The WWW was not especially helpful.

Mostly I'm posting this so someone else might find it in a search.

uses Classes, SysUtils, Controls, Graphics, LCLType, types, contnrs;

{
type
    TSprite = class
    public
        color: integer;
        filename: array of utf8string;
        subrect: array of TRect;
        constructor Create(c: integer; f: utf8string; r: TRect);
    end;
}

var
    imageCache: TFPObjectHashTable;

function getImage(filename: utf8string): TPortableNetworkGraphic;
var
    img: TPortableNetworkGraphic;
begin
    img := imageCache.Items[filename] as TPortableNetworkGraphic;
    if img = nil then begin
        try
            img := TPortableNetworkGraphic.Create();
            img.loadFromFile(filename);
            imageCache.Items[filename] := img;
        except on e: Exception do begin
            LogError(Format('Image %s: %s', [filename, e.message]));
            raise;
        end;
        end; // try
    end;
    Result := img;
end;

procedure drawSprite(canvas: TCanvas; spr: TSprite; srect: TRect; tick: integer);
var
    img: TPortableNetworkGraphic;
    frame, nframes: integer;
begin
    if spr.color <> dawnUndefined then begin
        canvas.Brush.color := spr.color;
        canvas.FillRect(srect);
    end;

    nframes := length(spr.filename);
    if nframes > 0 then begin
        frame := tick mod nframes;
        img := getImage(spr.filename[frame]);
        canvas.CopyRect(srect, img.canvas, spr.subrect[frame]);
    end;
end;

Pascal Learning Curve

What I've learned so far:

  • I spent a while trying graphics libraries (or failing to even compile them) before deciding I don't understand the UI model enough yet, so I'll prototype with some high-level drawing and circle back around to OpenGL or SDL.
  • Build a do-nothing app in Lazarus, make a single form with a default FormCreate method, then quit out and write code starting from there in BBEdit.
    • Part of that is that I'm not going to use a ton of GUI components, and code building is the evil opposite of Interface Builder. In IB, you edit UI and connect it to method names scanned out of the source code, it doesn't touch your code.
    • The Lazarus editor is nightmarishly wrong and keeps inserting stuff in my code which makes me crazy. Maybe there's non-crazy-making settings, and probably it seems fine to masochistic Windows and Linux users, but I make enough problems in my life.
  • Naming conflicts are a giant problem, so my current naming scheme is: For class "foo", it goes in file FooUnit.pas, containing unit FooUnit and type TFoo = class…. I'm naming instance fields _bar and accessors bar() and setBar() as I do in most languages. I've mostly got the compiler to stop screaming at me every build. Not letting you name a unit, class, and field the same thing is infuriating.
  • Build with lazbuild -B --bm=Release whatever.lpi; I wrote a script to choose Debug or Release builds and launch the app if nothing went wrong, which is close enough to hitting Cmd-R.
  • Bookmark the docs for:
    • RunTime Library
    • Free Component Library - in particular unit 'contnrs' wants to buy some vowels but has dictionaries, lists, etc.
    • Lazarus Class Library
    • There's very little explanation, so often I have to go digging in source like /Developer/lazarus/lcl. I lost about 30 minutes today because they didn't document that TCanvas.FillRect uses Brush settings, TCanvas.Rectangle uses Pen settings, and I figured it out by reading the Carbon implementation. ? ☕️ ?
  • Almost always if there's a non-domain-specific type I need it already exists. Batteries are included but mostly they're named badly, or upside down, or hidden in sofa cushions, or the dog buried them and I need a metal detector, or my psycho ex stole them and is holding them hostage for a pity fuck.
  • The actual implementation code isn't much different from any other procedural language. For a guy who codes in Pascal for one year every 10 years, it's rolling along pretty fast. The near-equivalency of records and classes, and of functions, properties, and methods is convenient. Defining vars before using them, like in old-timey K&R C, is not convenient. Inline variable definition would be a gigantic quality of life improvement, which I doubt they'll do.

Pascal

Trying out alternative languages to work around my performance and native binary problems, I've circled back around to the '70s and '80s: Pascal. I used classic Pascal on Atari 800 and TRS-80 back in the day, and did quite a bit with Kylix (Linux version of Delphi) before Borland killed that.

Pro

  • Fast Compiles. FreePascal compiles faster than anything I've used in ages. That was always a major Pascal selling point, and it still is. Optimized for programmer time.
  • Fast Runtime. As close to perfectly optimized machine code as you're going to get. Computer Language Shootout has competitive times with C++ for most benchmarks, and I think the worst-cases are variations in style.
  • Object-Oriented. FreePascal reimplements Delphi-style objects, which are pretty standard Simula-type OOP. I dislike having to tag methods as virtual, like some C++ or Swift peon, but it has everything I'd expect in a modern OOP system.
  • Reference Counting. No GC pausing, no manual memory management. Like Objective-C 1.0, you have to nil-out field references in your destructor, but otherwise you never need to worry about it.
  • Exceptions. Unlike Objective-C and Swift (which relies on Obj-C frameworks), you can throw exceptions and catch them and the program keeps working. Hooray! Flow control that isn't insane! There's no checked exceptions, which is sad, but it works.
  • Cross-Platform. Mac, Linux, Windows, Android, and iOS. Has SDL and OpenGL bindings, and some other options. I'll see how building out UI for each of those works, but it's not trapped on Mac like most other choices.
  • Native Binary. No source code included in the downloaded app. Dynamic language obfuscators are a minor obstacle at best, while machine language is hard enough to decompile. Sure, the other option is to put the program online and just have a thin client in the user's hands, but I'm old-fashioned, I believe in networkless programming and not paying Amazon for server time.
  • Easy Native Library Integration. Pretty much seems to be defining functions as external and calling.
  • Case-Insensitive. I'm usually neurotic about proper capitalization, but here it's a mercy: The classic Pascals were all-uppercase, Delphi CapitalizedEveryWord, but I prefer lazyCaps. FreePascal doesn't care.
  • Real Programs. There's working programmers using FreePascal to keep their (often very expensive) Delphi software running, and writing new code in it. That makes me confident it's not an unsupported toy, and there's current documentation and help.
  • BBEdit. Object Pascal syntax mode works fine.

Con

  • Bondage & Discipline. Not quite as BDSM as Java, Swift, Haskell, or classic ISO Pascal, which in practice have no safewords. You can use dynamic arrays, Variant and OOP types, and even dangerously cast anything to anything or screw around with pointers, but it's not beautiful anarchy like Python or JavaScript.
  • Pascal Syntax. Verbose begin/end pairs everywhere, long words of function, procedure, and such. Semicolon rules are insane (yes, they're terminators not separators; this is not how we use them in any other language, including English), I've taken to just always using begin/end blocks because I don't trust a misplaced semicolon not to terminate the wrong block.
  • Documentation. FPC's docs assume you already know Delphi. I found some decent docs at Borland's site and old Pascal textbooks, but I dunno how a normal person would learn this. Some of the libraries have moved in 3.0, and you're never going to figure this out unless you like digging thru the guts of a language.
  • Configuration. Put this in fpc.cfg somewhere, and export PPC_CONFIG_PATH to the path containing it: 
    #WRITE Compiling with fpc.cfg
-O3
-Xs
-MOBJFPC
-Sh
-Fu/usr/local/lib/fpc/$fpcversion/units/$fpctarget/rtl-console
-Fu/usr/local/lib/fpc/$fpcversion/units/$fpctarget/regexpr

    The write is just a sanity check that I have it configured. Instead of the next two lines, I could put -dDEBUG or -dRELEASE on the fpc command-line, but I'm not currently using gdb (unfrozen caveman Mark debugs by writeln), so this is easier. -MOBJFPC forces modern FreePascal mode, not a compatibility mode. -Sh forces a default string type of ansistring instead of shortstring; but to be precise, I always specify utf8string. The -Fu lines add some paths where libraries have been moved.

    I want to have the local directive {$M+} (reflection support) always turned on, but I can't figure out any command-line option to do that.

  • Look Like a Crazy Person. But sometimes the crazy people are right.

Example

To (re)learn the language, I wrote a 4-function RPN calculator for Mac console: RealCalc

Presumably it compiles just fine on Windows or whatever, but you'll have to customize the fpc.cfg file. I'm a ways from dealing with that.