Andrew Kesterson
1da37cf374
The pin moves e4aa6a5 -> 149bee0, which is libakgl 0.8.0. Nothing in this repository changed to accommodate it: both suites pass unmodified, 110 without akgl and 111 with, and both breakout games run forty seconds headless with no error line. **0.8.0 is a whole collision subsystem** -- shapes, pooled proxies, a pluggable broad phase over a uniform grid, a narrowphase answering with a contact carrying a normal and a depth, world box queries, and static proxies for geometry that is not an actor. None of it is called from here yet. This commit is the pull and nothing else, so that if it has to come out it is one revert of one commit. **It adds two submodules of its own**, `deps/libccd` and `deps/tg`, so a tree that updates without `--recursive` configures and then fails compiling libccd. libakgl's own suite was built and run standalone at RelWithDebInfo before akbasic was pointed at it: 33/33. `libakstdlib` and `libakerror` did not move. MAINTENANCE.md requires checking, and the answer this time is that libakgl 0.8.0 pins exactly what this repository already pins -- 669b2b3 and 5eaa956 -- so the pairing rule is satisfied without a bump. Recorded because "we checked and it was already aligned" and "we forgot to check" look identical in a diff. **The version floor moves to 0.8.0** with its paragraph, following the convention in that header of saying what each minor release did and why the floor moved anyway. Worth knowing for whoever reads it next: `akgl_Actor` grew fields, so a translation unit compiled against a 0.7 `actor.h` and linked against 0.8 writes `renderfunc` and `actorData` at the wrong offsets -- and `src/sprite_akgl.c` writes exactly those two. That is the case the soname cannot catch and the guard exists for. **libakgl's reserved status band grew from five codes to six**, gaining `AKGL_ERR_COLLISION` at `AKGL_ERR_BASE + 5`, so it now owns 256-261 and the headroom below akbasic's band starts at 262. Four documents said otherwise: the coordinated range map in MAINTENANCE.md, the comment above the enum in `include/akbasic/error.h`, the file header of `include/akbasic/akgl.h`, and chapter 15. That map is the only coordination there is -- nothing enforces a band boundary at compile time, and the first anybody would know of an overlap is a status printing under the wrong owner's name in a stack trace. Also cleaned on the way past: `deps/libakgl/deps/libakstdlib` was showing dirty in `git status`. It had no local edits -- the checkout was simply one commit behind the gitlink libakgl records -- so `git submodule update` restored it and nothing was lost. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EwxGB6TdoVvZ11KQQME9cL
The akbasic guide
akbasic is a BASIC interpreter in the style of Commodore BASIC 7.0 — the dialect the C128 shipped with — and Dartmouth BASIC. It runs programs from a file or from an interactive prompt, and it is also a C library you can link into a game so that players can script it.
These chapters follow the shape of the C128 Programmer's Reference Guide: the language first, then each hardware area, then the reference sections. If you know BASIC 7.0 you can skip to Chapter 13, which is the list of everything that behaves differently here and why. Chapter 14 is the odd one out: it is about the interpreter rather than the language, for anyone embedding it, debugging it or changing it.
Chapters 17 and 18 are tutorials rather than reference: they build one complete game twice, two different ways, in numbered steps you can type in one at a time. Start with 17 — it needs nothing but the earlier chapters, and 18 assumes it.
Chapters
| 1. Introduction | What akbasic is, what it is not, and how to build it |
| 2. Getting started | The prompt, your first program, saving and loading |
| 3. The language | Variables, types, arrays, operators, expressions |
| 4. Control flow | IF, FOR, DO, GOSUB, labels, ON, error trapping |
| 5. Strings and formatting | String functions, PRINT USING, PUDEF |
| 6. Graphics | GRAPHIC, DRAW, BOX, CIRCLE, PAINT, shapes |
| 7. Sound | SOUND, PLAY, ENVELOPE, VOL, TEMPO |
| 8. Sprites | SPRITE, SPRSAV, MOVSPR, collision |
| 9. Files and disk | Channels, DOPEN, program storage |
| 10. Embedding | Driving the interpreter from C |
| 11. Verb reference | Every statement, alphabetically |
| 12. Function reference | Every function, alphabetically |
| 13. Differences from BASIC 7.0 | What a C128 programmer needs to know |
| 14. Architecture | How the interpreter is put together, how to debug it, how to change it |
| 15. Error codes | Appendix: every value ER# can hold and every error line the interpreter prints |
| 16. Structures | TYPE, records, strict pointers, and sharing a C struct with an embedding host |
| 17. Tutorial: Breakout | Build a whole game out of the text grid and two DATA sprites, in sixteen steps |
| 18. Tutorial: Breakout with artwork | Build it again out of loaded artwork, powerups and a drawn colour HUD, in thirteen |
The shortest possible start
$ cmake -S . -B build && cmake --build build
$ ./build/basic
10 FOR I# = 1 TO 5
20 PRINT "HELLO " + I#
30 NEXT I#
RUN
HELLO 1
HELLO 2
HELLO 3
HELLO 4
HELLO 5
READY
Two things in that program are not Commodore BASIC and will catch you out
immediately: variables carry a type suffix (I# is an integer) and +
concatenates a string with a number. Chapter 3 explains both.
Every example in these chapters is executed by the test suite and its output
compared byte for byte — see MAINTENANCE.md if you are editing them.