#gw-basic

Post #19: Einfaches Programmierbeispiel

TLDR; Downgraded MacOS 26 to Sequoia.

And it feels faster, more usable (I couln't stand the rounded corner salad), and I've lost nothing since XCode 26 runs on it, as well as Safari 26, even if I'm now a Chrome guy because of profiles!

Also in the works... I'm trying to replace my 5 yo M1 Macbook Air with a slim, and decent Linux notebook (wasn't too convinced with the Framework), for my hobby C++ development.

Speaking of which, my GW-BASIC interpreter is very much stronger than before, now with a full OpenGL screen backend in preperation of the graphics primitives, and also so that I can use the GW-BASIC font and get a much more natural feel.

As stated in the README, it doesn't try to emulate an 8 bit computer, it actually uses C++ standard libraries to implement the language, and it just tries to execute the same code, even if with a different "taste".

I find it amusing that some BASIC programs that seemed to run fine on a real MSX computer, failed on the interpreter: Doing a READ past the end of da DATA segment should issue an Out of Data error, but not on the MSX! It turns out, this was by design and the way the MSX-BASIC treats DATA and returns 0 or "" if it goes after the end of the DATA segment. A lot more forgiving, but I think that issuing the Out of Data is better.

End-of-year Special Blog Post.

I've began implementing a REPL GW-BASIC interpreter in C++, available on GitHub.

Why BASIC? or why C++? BASIC was everyone's first love in computing if you grew up in the 80's. I still maintain a working MSX which runs GW-BASIC and I wanted to see how far along I could go in modern C++. If you've been away from C++, at least check this Youtube channel from Jason Turner!

Modern C++ is pretty good! I don't understand why so many seem to like Rust when C++ has been modernized to the point you barely see a pointer anymore. If you're writing Rust, and then litter it with unsafe code, you might as well stick with good old technologies like C++.

I also don't approve Apple's decision to start a language like Swift when you could just have it all with a modernized version of Obj-C or just use C++ FFS.

As for this project, I'm not gonna lie, I did started it in ChatGPT just to see if could run anything. I then structured it and added some features as well as fixed some bugs, and am now writing most of the new code.

One of the things I wanted to have was a built in editor, at least like Nano, so that having to do LIST and edit lines the old way would not be necessary.

Now there's a lot I'm missing in this first MVP like app. Like there's no graphics code, sound and other nice things you could do with a couple of lines in BASIC, but I'm confident about the progress done and I'm sure I'll add a lot of that in 2026, as a hobby thing, of course!

So, to sum it up, I like C++, I'm surprised you can still write all of this in XCode and get a good terminal app running in 2025. I guess Apple didn't ruin everything yet!

Here's to learning new stuff, and having fun with computers in 2026.

1. Für welche Variablentypen gab es Typenbezeichnungen bei GW-BASIC?

A – Integer: % B - Boolean: § C - Float simple: ! D - Float double: # E - String: $ F - Byte: &

2. Gab es bei GW-BASIC folgende wissenschaftliche Built-In-Funktionen: SIN(x), COS(x), TAN(x), ATN(x), EXP(x), LOG(x) und SQR(x)?

A – Ja B - Nein

3. Bei welchem Bildschirmmodi wurde mit SCREEN in den Textmodus gewechselt?

A – 2 B - 9 C - 0 D - 7 E - 10 F - 1 G - 8

Lösungen: 1. Chr$(65), Chr$(67), Chr$(68), 2. Chr$(65), 3. Chr$(67)

„Da IBM den Einsatz von BASICA-ROM-Chips den allerorten zahlreichen auftauchenden Herstellern von PC-Nachbauten (Clones) nicht gestattete, entwickelte der amerikanische Software-Hersteller MICROSOFT einen eigenen, zu BASICA (Advanced BASIC) in hohem Maße kompatiblen BASIC-Interpreter, der von der Diskette oder Festplatte geladen werden konnte: das GW-BASIC. Bis heute befindet sich das erstmals 1983 erschienene Programm GW-BASIC.EXE stets im Lieferumfang aller Versionen des Betriebssystems MS-DOS. Die letzte Version von GW-BASIC erschien mit der Versionsnummer 3.23 im Jahre 1988.

Bereits im Jahre 1985 bracht Microsoft ein völlig neu konzipiertes BASIC auf den Markt: QUICK-BASIC. QUICK-BASIC ist mit einem Compiler ausgestattet, der die Programmanweisungen in Maschinencode übersetzen kann. Dadurch lassen sich Programme erzeugen, die unmittelbar von der DOS-Ebene aus gestartet werden können - sogenannte EXE-Dateien. Der maschinennahe Programmcode der selbstständig laufenden EXE-Dateien wird vom Computer sehr schnell verarbeitet. Neben vielen anderen Vorteilen hat dies eine schnellere Programmausführung zur Folge. Im Gegensatz dazu mussten die Interpretersprachen BASICA und GW-BASIC jeden einzelnen Befehlt der Reihe nach lesen, analysieren und schließlich durch ein entsprechendes Maschinenprogramm abarbeiten. Die Ausführungszeiten von Programmen sind dadurch entsprechend lange.

Eine wesentliche Neuerung gegenüber den Basic-Vorgängern stellt die Programmiersprache von QUICK-BASIC selbst dar. Sie ist gegenüber den herkömmlichen BASIC-Dialekten um viele leistungsstarke Befehle und Funktionen bereichert worden. Mit QUICK-BASIC lassen sich sowohl alle klassischen Basic-Befehle ausführen, als auch eine große Anzahl von Anweisungen zur strukturierten Programmierung, wie man sie bisher nur von den Programmiersprachen PASCAL oder C kannte. Damit hat das außerordentlich flexible QUICK-BASIC mehr als jede andere Computersprache das Zeug zur Allroundsprache. Bei allem Leistungszuwachs ist QUICK-BASIC dennoch weiterhin eine unkomplizierte, leicht verständliche Computersprache geblieben.

QBASIC wird von Microsoft mit dem MS-DOS-Betriebssystem ab Version 5.0 mitgeliefert. Auf den ersten Blick ist QBASIC dem QUICK-BASIC in seiner letzten Version 4.5 zum Verwechseln ähnlich. Tatsächlich handelt es sich auch bei QBASIC um eine vollwertige Version des QUICK -BASIC 4.5, bei der lediglich der in QUICK-BASIC implementierte Compiler weggelassen wurde. Das bedeutet, dass man mit QBASIC im Unterschied zu QUICK-BASIC 4.5 keine selbstständig ablaufenden EXE-Dateien generieren kann.

In den wesentlichen Eigenschaften ist QBASIC 1.1 nahezu identisch mit der vollständigen Version von QUICK-BASIC 4.5 geblieben. So ist der Befehlssatz von QUICK-BASIC 4.5 bis auf einige wenige Einschränkungen vollständig in QBASIC übernommen worden. Das bedeutet, dass nahezu alle QBASIC-Programme auch unter QUICK-BASIC 4.5 lauffähig sind und umgekehrt. Ebenso ist die Programmierumgebung (IDE) von QBASIC bis auf die Menüpunkte zur Steuerung der Kompilation nahezu identisch mit der Programmierumgebung von QUICK-BASIC.“

From BASICA and GW-BASIC to QBASIC

"Since IBM did not allow the numerous manufacturers of cloned PCs that were appearing everywhere to use BASICA ROM chips, the American software manufacturer MICROSOFT developed its own BASIC interpreter, which is highly compatible with BASICA (Advanced BASIC), which could be loaded from floppy or hard disk: the GW-BASIC. To this day, the GW-BASIC.EXE program, which first appeared in 1983, is always included with all versions of the MS-DOS operating system. The last version of GW-BASIC appeared with version number 3.23 in 1988. As early as 1985, Microsoft launched a completely newly designed BASIC: QUICK-BASIC. QUICK-BASIC is equipped with a compiler that can translate program instructions into machine code. This allows programs to be created that can be started directly from the DOS level - so-called EXE files. The low-level program code of the independently running EXE files is processed very quickly by the computer. Among many other advantages, this results in faster program execution. In contrast to this, the interpreter languages BASICA and GW-BASIC had to read each individual command in turn, analyze them and finally process them using a corresponding machine program. The execution times of programs are correspondingly long.

The programming language of QUICK-BASIC itself represents a major innovation compared to the BASIC predecessors. Compared to the conventional BASIC dialects, it has been enriched with many powerful commands and functions. With QUICK-BASIC, all classic Basic commands can be executed, as well as a large number of instructions for structured programming, previously only known from the programming languages PASCAL or C. This means that the extraordinarily flexible QUICK-BASIC has what it takes to become an all-round language more than any other computer language. With all the increase in performance, QUICK-BASIC has remained an uncomplicated, easy-to-understand computer language.

QBASIC is supplied by Microsoft with the MS-DOS operating system from version 5.0. At first glance, QBASIC is confusingly similar to QUICK-BASIC in its last version 4.5. In fact, QBASIC is also a fully-fledged version of QUICK-BASIC 4.5, in which only the compiler implemented in QUICK-BASIC has been left out. This means that with QBASIC, in contrast to QUICK-BASIC 4.5, you cannot generate any independently running EXE files.

QBASIC 1.1 has remained almost identical to the complete version of QUICK-BASIC 4.5 in its essential features. The command set from QUICK-BASIC 4.5 has been completely taken over into QBASIC with a few restrictions. This means that almost all QBASIC programs can also be run under QUICK-BASIC 4.5 and vice versa. Likewise, the programming environment (IDE) of QBASIC is almost identical to the programming environment of QUICK-BASIC, except for the menu items for controlling the compilation.”

Front page of the book ...

Back side of the book ...

Post #106: Buchtipp für Retrofans #19, Bob Albrecht, Teach Yourself GW-BASIC, Also Covers BASICA & BASIC on Tandy Computers, Osborne McGraw-Hill Inc., Berkeley, California, USA, 408 pages, 1990.

Post #96: Buchtipp für Retrofans #17, Manahar Lotia, Pradeep Nair, Payal Lotia, Modern All About GW-BASIC For School & College, BPB Publications, New Delhi, First Edition 1995, Reprinted 2009.

Der Quelltext des Programms ...

Das eingegebene Programm im Interpreter und die Ausgabe am Monitor ...