24 Commits

Author	SHA1	Message	Date
Andrew Kesterson	6a7c8cd920	Add records: TYPE, DIM ... AS, field access, copy on assign ... BASIC 7.0 has no records at all, so none of this is a port. The `@` suffix was not invented either: the Go reference reserved IDENTIFIER_STRUCT and never used it, and src/grammar.c rendered such a leaf as "NOT IMPLEMENTED" until now. Declaring the type is what buys the storage model. A TYPE states its fields, so an instance has a known slot count and is laid out exactly as an array is -- one contiguous run from the same value pool DIM already draws from, with field access as offset arithmetic. No new pool holds data; the only new table holds descriptors. A nested value flattens into its container's run, which is why LINE with two POINTs and a string is five slots rather than three. Each field takes its type from its own suffix, the same rule every other name here follows, so a field list needs no type column. An `@` field is the exception and has to name its type, because three primitive types fit in three suffix characters and N declared types do not fit in one. The declaration is prescanned before the program runs, like labels and DATA and for the same reason: it has to be in effect wherever control goes. Three passes, each for a case the one before cannot do -- names first so a field can refer to a type declared later, then field lists, then sizes by repeated resolution. What never resolves is a cycle of by-value containment, so "a TYPE cannot contain itself by value" is a diagnosis rather than an assumption, and the message says to use PTR TO instead. Assignment copies. That interception is the whole feature and it cannot live in akbasic_value_clone(), which copies one slot -- and one slot holds a *reference* to an instance rather than the instance, so going through it would alias. A structure is intercepted before that path and its slots are copied one at a time, walking the descriptor rather than memcpy-ing the run, because a pointer field must copy its reference where a value field must copy its slots. Two smaller things the work required. All three prescans now sit inside one ATTEMPT: a malformed declaration is the program's mistake, and it was printing a stack trace and taking the driver with it, which is the boundary goal 3 exists to draw. And a fresh variable's structtype is -1 rather than the 0 a memset leaves, because 0 is a valid type index and every new variable was claiming to be the first type declared. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-08-01 11:39:47 -04:00
Andrew Kesterson	3415c9aec6	Take libakgl 0.5.0 and rename every symbol it namespaced ... 0.5.0 gives every exported symbol the akgl_ prefix, which is the first libakgl release to break this project's source rather than only its ABI. The soname goes to libakgl.so.0.5 and include/akbasic/akgl.h asserts the floor. What moved here: akgl_render_bind2d is akgl_render_2d_bind, akgl_sprite_sheet_coords_for_frame is akgl_spritesheet_coords_for_frame, the renderer, camera and window globals carry the prefix, and _akgl_renderer and _akgl_camera are akgl_default_renderer and akgl_default_camera. The renames were applied by site rather than by pattern, because renderer is also a parameter name in src/sprite_akgl.c and a struct member throughout src/frontend_akgl.c -- a substitution would have rewritten both without a word. That is the same trap upstream describes hitting, and it is worth knowing that the defect behind the rename was not cosmetic: an exported global called renderer collided with a test's own variable, the executable's definition preempted the library's, and every texture load in that suite failed while the suite passed. 0.5.0 also fixes libakgl defect 26, which was one of the two reasons src/sprite_akgl.c installs its own renderfunc: akgl_actor_render took its destination height from the sprite's width, drawing a 24x21 Commodore sprite as a 24x24 square. The renderfunc stays, because the other reason has not moved -- an actor carries one scalar scale and SPRITE has separate x- and y-expand bits -- but the comments and TODO.md deviation 40 no longer claim a defect that is fixed. Every documentation figure re-renders byte-identical under the new library, which is what says the sprite and drawing paths did not move underneath them. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-08-01 08:01:43 -04:00
Andrew Kesterson	8077806598	Take libakerror 2.0.1, and guard the exit status it fixes ... 2.0.0 makes the error pool and the status registry thread safe, and it is an ABI break carrying the soname to libakerror.so.2. The break is a quiet one: __akerr_last_ignored became thread-local and akerr_next_error() now returns a context that already holds a reference, so objects compiled against a 1.x header and linked against 2.x count every reference twice and never give a slot back. Nothing about that fails to link, which is exactly what a guard is for -- include/akbasic/error.h feature-tests AKERR_THREAD_SAFE instead of AKERR_FIRST_CONSUMER_STATUS, which 2.0.0 also still defines and which therefore no longer distinguishes anything. 2.0.1 is the release this band needed most. The default unhandled-error handler ended in exit(errctx->status), and a process exit status is one byte: AKBASIC_ERR_BASE is 512, and 512 truncates to 0, so an unhandled AKBASIC_ERR_SYNTAX reported success to anything watching $?. Every other code in the band came out as some unrelated error's number. akerr_exit() substitutes 125 for anything a byte cannot carry, and a probe raising AKBASIC_ERR_DEVICE through FINISH_NORETURN now exits 125 rather than 7. It was latent here rather than live -- src/main.c handles the context and returns EXIT_FAILURE, and every test with a top-level ATTEMPT carries a HANDLE_DEFAULT -- but "no caller relies on it today" is not a property a header can keep true. tests/version_check.c asserts the mapping and fails if AKBASIC_ERR_BASE ever stops truncating to zero, because that is the day this stops being about our base. Chapter 10 gains a threading section: libakerror is safe from any thread now, and this interpreter is not and has no lock anywhere in it. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-08-01 08:00:24 -04:00
Andrew Kesterson	5c5bf63356	Draw into the whole window, not its top-left 320x200 ... The graphics verbs documented a coordinate transform that did not exist. With SCALE off a coordinate went straight to akgl_draw_* as a pixel address, so an 800x600 window drew a C128 listing into its corner and left the rest unused -- while the chapter said coordinates were 320x200 and stretching to fit was the host's business. akbasic_GraphicsBackend gains a size entry point, require_graphics() asks it before every verb that draws so a resized window is honoured between two statements, and 320x200 becomes the fallback for a backend that leaves it NULL. It is the record's one optional member, so a host written against the old header keeps the behaviour it had. SCALE now maps onto the device, and RGR(1)/RGR(2) report the drawing surface so a program can use a window whose size it did not choose. RGR(0) is BASIC 7.0's own field, the GRAPHIC mode. SCALE also mapped xmax onto the width rather than onto the last pixel, so SCALE 1, 319, 199 followed by DRAW 1, 319, 199 drew nothing at all -- one pixel past the surface. Fixed in the same line, because it is what makes "SCALE gives a C128 listing the whole window" true rather than nearly true. The akgl test renders against a 128x128 target, deliberately smaller than the old constants: a SCALE still dividing by them misses it entirely rather than landing somewhere plausible. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-08-01 07:35:20 -04:00
Andrew Kesterson	80b76ad467	Split the documentation by who reads it ... README.md was 577 lines and answered four different questions at once: what the project is, how to build it, every verb and function in the language, and how to maintain the test harness. The verb and function lists had already been written a second time in docs/11 and docs/12, which is how a list of that size goes stale -- there is no way to notice the two have drifted apart. README.md is now 150 lines and holds only what somebody evaluating the project needs: what it is, the quickstart, why it was rewritten in C, the five rules embedding imposes on the design, the two ways to use it, and where everything else lives. Technical detail goes to docs/, maintenance to MAINTENANCE.md. The akbasic_TextSink struct moved to docs/10-embedding.md rather than being deleted. It was the corpus's only `c excerpt=` block -- the check that caught the stale struct two commits ago -- so dropping it with the README would have quietly retired a test. docs/10 also stopped claiming README.md carries the full API surface and the pool limits, which the trim made false. CLAUDE.md went from 458 lines to 62, because almost none of it was agent-specific. The project goals, the Go reference and its architecture, the dependency version and ABI rules, the four ways an embedded build collides, the libakerror convention, the error-code range map and the style rules are all things a maintainer needs, and they are now in MAINTENANCE.md with one copy to keep true. CLAUDE.md points there and keeps only the rules no test enforces: tests in the same commit asserting the correct contract, file a missing dependency capability upstream, do not edit generated output or tests/reference/, co-author your commits. Four claims did not survive the move, having gone stale where nothing could notice: - "The repository is currently empty apart from its submodules -- no commits, no source tree, no build files." There are 43 commits. - libakgl's target_compile_definitions(akerror PUBLIC AKERR_MAX_ERR_VALUE) at deps/libakgl/CMakeLists.txt:44, described as inert but present. It is gone; only a historical mention in a comment remains. - "akbasic_init() claims 512-767." There is no akbasic_init. It is akbasic_error_register(), called from akbasic_runtime_init(). - Time-relative phrasing ("libakgl hit two of them in the last week"). Five places pointed at CLAUDE.md for the range map or the file-it-upstream rule and now point at MAINTENANCE.md: include/akbasic/error.h, src/runtime_disk.c and three entries in TODO.md. Both source changes are comments. deps/libakgl/TODO.md cites it too and is left alone; it is a submodule, and the rule it quotes is still reachable from CLAUDE.md. ctest is green at 95 of 95, docs_examples included: 36 programs, 9 transcripts, 44 output comparisons, 3 C snippets, 1 excerpt. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 22:59:43 -04:00
Andrew Kesterson	9845e77a5c	Finish the language: every remaining verb group, and the defects that blocked them ... Closes groups A, C, D, E, F, H and J of TODO.md section 4, plus RESTORE and RENUMBER, and closes section 6 -- all seventeen reference defects. Seven of those turned out to have been fixed or never ported and nobody had written it down; the audit records the evidence for each. Two of the seventeen were real. math_plus mutated its left operand when the operand was mutable, so A# + 1 could modify A#; it was gated on FOR/NEXT coverage because NEXT relied on the mutation, so tests/for_next.c came first and NEXT now writes the counter back itself. And the binary operators summed both numeric fields of their right operand, which no BASIC program can reach -- that one needed a test written against the value API. Writing the tests turned up eight defects nobody had listed. Seven are fixed: IF A = 2 THEN was a parse error; only == worked IF ... AND ... was a parse error, because a condition parsed as one relation IF A = 1 OR B = 2 THEN was silently always false, and so was IF A THEN EXIT before any NEXT restarted the program and exhausted the variable pool READ never found a DATA line above it, and swallowed the lines between PRINT 2 + 2 at the prompt was filed as program text instead of answering a short read discarded its bytes, so COPY produced empty files every verb taking an argument list said "peek() returned nil token!" on none The eighth is not fixed and cannot be quietly: a FOR whose step overshoots runs its body one extra time, and FOR I = 1 TO 1 runs it zero times. The two errors cancel for a step of 1, which is why neither was noticed. Correcting them changes the expected output of a checked-in acceptance file, and tests/reference/README.md forbids editing one to suit this interpreter. It is tests/for_semantics.c in AKBASIC_KNOWN_FAILING_TESTS, asserting the correct contract, and TODO.md items 19 and 20. Sprites are real libakgl actors with a renderfunc of their own, because akgl_actor_render draws every sprite square and an actor has no per-axis scale. Both are filed upstream. SPRSAV takes an image file, an SSHAPE handle or a 63-element integer array -- a string here cannot hold a zero byte. Verbs that need hardware that does not exist are refused by name with the reason rather than faked: SYS, HEADER, COLLECT, BACKUP, BOOT, FILTER, and DIRECTORY, which is refused for a missing libakstdlib wrapper filed upstream. 94 tests in the default build, 93 with SDL, 94 under ASan and UBSan, doxygen clean. The Go acceptance corpus stayed green throughout. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 21:50:37 -04:00
Andrew Kesterson	df50201121	Own every pixel each frame, and bring the cursor back as a blinking block ... The blinking backspace was not the backspace. The sink skipped rows it believed were already clear, tracked in a drawn[] array, which assumes a frame inherits the frame before it. SDL_RenderPresent swaps buffers, so a frame inherits the one two back: a row erased once is clean in one buffer and dirty in the other, and presenting alternates between them. The first character of a backspaced wrap flickered forever. It reproduces on X11 and never under the dummy driver or a software renderer, which is why the suite stayed green through two rounds of fixing it. The sink now repaints every row it owns every frame -- a frame either owns every pixel it presents or inherits pixels it cannot reason about. Confirmed on real hardware with the reported input: the wrapped tail's row reads zero across five successive captures. The cursor returns as a blinking block, half a second per cycle, off SDL's clock. It sits in the cell after the text rather than under it, which is what made the underscore unreadable, and it wraps to the next row when a line exactly fills one -- where the next character actually lands. The new regression test paints stale pixels by hand, which is what a swapped-in buffer hands back, so the case is covered without real hardware. Every new assertion was checked by reverting the fix and watching it fail. Recorded honestly in TODO.md section 5: the same buffer swap means the graphics verbs were never reliable across frames either. A one-shot DRAW lands in one buffer and the next present shows the other. Making that work needs a persistent surface, which is its own commit. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 15:23:41 -04:00
Andrew Kesterson	acd20eed9a	Erase what the text layer drew: three GUI bugs, one cause ... The sink painted glyphs on top of whatever was already on the renderer and never erased anything, and the host deliberately does not clear the frame so a DRAW survives. The grid was always correct; the screen kept the previous frame. That surfaced as three separate-looking faults: - a backspaced character stayed on screen, including across a line wrap - a scroll left the old rows behind, "papered over with garbage" - the editing cursor smeared an underscore along every column it passed through, which read as an underline under the text being typed render() now fills each row it is about to draw, and each row that has emptied since it last drew, with the background first. Row by row rather than one clear over the whole area: the text layer is authoritative over the rows it occupies and leaves every other pixel alone, so a picture behind the text loses only the strips the text uses instead of all of it. echo_line() also truncates rows that hold nothing but the spaces its own erase pass wrote, which is what backspacing back across a wrap leaves behind. A row of spaces is text as far as render() is concerned, so it would have been repainted forever and kept erasing whatever was under it. The cursor glyph is removed outright, as asked. The smearing was the erase bug rather than the cursor, so one could come back and behave -- a block would read better than an underscore. Four pixel-level tests, because grid assertions could never have caught any of this. Each was checked by reverting the fix and watching it fail; two of them were vacuous when first written and are noted as such where they are fixed. The real-keyboard test also now rubs out a character and scrolls forty lines. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 15:03:37 -04:00
Andrew Kesterson	fca9ad4a89	Consume libakgl 0.3.0: every workaround deleted, two capabilities gained ... 0.3.0 closed all ten API gaps this port had filed. The four workarounds go with them: the CMake block that declared libakgl's vendored dependencies by hand, the akgl/actor.h include in three files, and the six vtable pointers assigned by hand in two more, now akgl_render_bind2d(). Two gaps were capabilities rather than inconveniences, and both are now real: The line editor takes the composed UTF-8 text the ring carries in preference to the keycode, so shifted characters, keyboard layouts, compose keys and dead keys all work. A double quote can be typed, which means a BASIC string literal can be typed -- the sharp end of the old limitation. Letters are no longer folded to upper case. SOUND's dir/min/step reach akgl_audio_sweep instead of being refused. dir 3 sweeps once rather than oscillating and TODO.md section 5 says so. A backend with no sweep still refuses the swept note and plays the held one. The adaptors now carry an AKGL_VERSION_AT_LEAST(0, 3, 0) floor, verified by temporarily demanding 0.4.0 and watching it fire. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 13:25:14 -04:00
Andrew Kesterson	bfac13ff87	Implement the housekeeping verbs, and stop the REPL spinning after an error ... NEW, CLR, CONT, SWAP, TRON, TROFF and HELP. None is in the Go reference, so what each means here is recorded beside it. Testing CONT turned up a hang that predates this: the runtime's error class is deliberately sticky, and with run_finished_mode REPL every later step re-entered REPL and printed READY -- overwriting the QUIT that end of input had just set. An interactive session that hit one runtime error printed READY forever instead of exiting. RESTORE and RENUMBER are deferred with reasons; RESTORE turns out to need a DATA pointer this port does not have, which is a defect in its own right. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 12:07:50 -04:00
Andrew Kesterson	f4007d80d4	Give argument lists their own link, not each argument's .right ... An identifier's subscript list, a unary's operand and a binary's right-hand side all lived in the same field the argument chain used, so ABS(-9), MOD(A#, B# + 12) and any array reference in a parameter list were counted as extra arguments and refused. Subscript lists move to .expr and arguments now chain through a dedicated .next. This is the third time the same collision was fixed; the first two moved it along rather than removing it. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 11:58:15 -04:00
Andrew Kesterson	5b7b7d2ed9	Add akbasic_runtime_global: a host variable lands in the script's root scope ... A host creating a variable while a script was suspended got it in whatever scope was active -- usually a FOR or GOSUB body -- and it died when the body popped, silently. Reaching for the root by hand returned NULL without raising, because environment_get only auto-creates in the active environment. Both are still true of environment_get, which is correct for what the interpreter uses it for. The README and the example now point somewhere else. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 11:53:05 -04:00
Andrew Kesterson	a31058cf37	Consume the COLON token: a line can hold several statements ... The token has existed since the scanner was written and nothing read it, so 10 PRINT A$ : REM ... was a parse error. Leading separators are consumed before each statement and an empty statement yields a NULL leaf rather than an error, so a trailing colon and a run of them are both legal. BASIC 7.0 scopes everything after THEN to the condition, which the reference had no opinion about because it never got here. The rule is not "skip when false": the rest of the line belongs to whichever arm was written last. A whole FOR/NEXT on one line still does not loop -- block skipping works by source line. Recorded in TODO.md as what group A has to fix first. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 11:46:10 -04:00
Andrew Kesterson	1eb8f9ffaa	Fix five defects the port uncovered in the reference parser and scanner ... Chained subtraction and exponentiation fold left instead of abandoning the rest of the line -- `1 - 2 - 3` gave -1 and dropped the `- 3`. A unary leaf's operand moves to .left, so a negative literal is one argument again and a second argument no longer overwrites it. An operator in a line's final column survives. Hex literals reach the parser whole. A leading zero is padding, not a radix. Item 16 stays pinned: the fix works and costs an upstream golden case, which is a decision rather than a defect. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 11:35:14 -04:00
Andrew Kesterson	f24201fdef	Port the standalone SDL frontend, and give the sink a line editor ... An AKGL build of `basic` was a terminal program with unused SDL linked into it. It now opens the reference's 800x600 window, draws BASIC output in the Commodore font, pumps events, lets you type at it, and still mirrors every byte to stdout. The stdout mirror is a composing sink rather than a second write inside the interpreter, and lives in the core library where it needs no SDL. The line editor waits for a typed line by borrowing one frame at a time from the host, so nothing blocks and nothing owns an event loop it should not. The whole golden corpus now runs through the SDL binary as well as the stdio one, byte for byte. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 11:21:39 -04:00
Andrew Kesterson	ecdc6b60ef	Delete src/convert.c: libakstdlib 0.2.0 grew the contract it existed for ... That file wrapped strtoll and strtod because libakstdlib's aksl_ato* family could not report a conversion failure at all -- atoi("not a number") returned success with 0, turning four diagnosable errors into wrong answers. Its own note said what to do when that changed: "When it grows it, delete src/convert.c and switch the call sites over." 0.2.0 grew it, so it is gone. Six call sites go straight to the library now: both literal constructors in src/grammar.c, the line number in src/scanner.c, FunctionVAL in src/runtime_functions.c, INPUT in src/runtime_commands.c, and GSHAPE's handle in src/runtime_graphics.c. aksl_strtoll(str, NULL, base, &dest) rather than aksl_atoll wherever a base is involved, because the ato* forms are base 10 and grammar.c picks base 8 or 16 off the lexeme's prefix; the NULL endptr is what makes trailing junk an error rather than a stopping point. The raised status changed from AKBASIC_ERR_VALUE to AKERR_VALUE, and the message with it -- VAL("garbage") now says `no digits in "garbage"`. Section 1.8 makes message text part of the acceptance contract, so that was checked against the corpus before touching anything: no golden file contained a conversion message, which is also why section 1.9 had been asking for one. Two exist now, so the next change to that text has to move a golden file, and one of them pins the reference's octal-literal defect (section 6 item 10) while it is still deliberately reproduced. tests/convert.c became tests/numeric_contract.c rather than being deleted with the code. The assertions did not stop being worth making when the wrapper went away -- they became assertions about a contract this port depends on and no longer owns, and a regression in it would make four things quietly return zero. Repoints the CI mutation job, which was bounded to src/convert.c and src/symtab.c. src/symtab.c alone measures 74.1% against the gate of 65. src/audio_tables.c was measured as a replacement second file and scored 64.7%: that is a real gap rather than a reason to skip it, since almost every survivor is in akbasic_audio_state_init, where nothing asserts a freshly initialised audio state is actually zeroed -- the same gap this job's history records closing for symtab. Recorded in TODO.md so the file can earn its place back. One thing worth knowing before reading any score here, and now written down: the harness's ICR operator only rewrites the constants 0 and 1, so a lookup table of other values produces no mutants and a high score over one says nothing about whether its entries are right. tests/audio_verbs.c now asserts all 32 ADSR entries against the datasheet anyway, because a hand-edit typo is the real failure mode there -- but that could not and did not move the mutation number, and claiming otherwise would be the kind of thing this file exists to stop. 72/72 core, 73/73 with libakgl, 72/72 under ASan+UBSan, coverage 93.6% line and 97.8% function, clean under -Wall -Wextra, doxygen clean. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 10:28:04 -04:00
Andrew Kesterson	4fc763efb3	Wire the sink and the three devices to libakgl ... src/sink_akgl.c, src/graphics_akgl.c, src/audio_akgl.c and src/input_akgl.c, in the akbasic_akgl target, which is the only thing here that links SDL. -DAKBASIC_WITH_AKGL=ON had never been configured in this repository before, and it now builds and passes. The sink is what section 3 has been waiting on. Its character grid comes from akgl_text_measure(font, "A", &w, &h), the direct equivalent of the reference's font.SizeUTF8("A") and the call that did not exist until 42b60f7. Wrapping is done on the character grid rather than by handing SDL_ttf a wraplength, because the cursor has to land somewhere definite: a program that PRINTs a long string and then PRINTs again expects the second to start on the row after the first ended, and only the code that placed the characters knows which row that is. tests/akgl_backends.c draws into a 128x128 software renderer under the dummy video driver and reads the pixels back -- the pattern deps/libakgl/tests/draw.c established, which needs no display and no offscreen harness. It asserts the seam rather than libakgl's own behaviour: a BASIC line in, a lit pixel of the right colour out. Four things in libakgl had to be worked around to get here. All four are commented at their site with "filed upstream" and recorded in TODO.md section 3: - An embedded libakgl requires SDL, SDL_image, SDL_mixer, SDL_ttf and jansson to be *installed*. It builds its own vendored copies only when it is top-level, and they are sitting right there in deps/libakgl/deps. Every lookup is guarded with if(NOT TARGET ...), so this adds those five subdirectories before add_subdirectory(deps/libakgl) -- the same trick and the same ordering requirement akerror::akerror and akstdlib::akstdlib already need. - akgl/controller.h does not compile on its own: it declares handlers taking an akgl_Actor * and includes nothing that declares the type. - There is no way to attach a 2D backend to a renderer you already have. akgl_render_init2d() installs the vtable but also creates its own window and writes the camera global, so it belongs to the akgl_game_init() path -- which is exactly the path an embedding host is not on. The test assigns the six pointers by hand. - akgl_text_rendertextat() segfaults on a backend whose vtable is empty; it reaches through renderer->draw_texture without checking it. Same class of defect 42b60f7's own commit added a draw test for. The sink's readline reports end of input rather than reading: a drawn text layer is not a source of lines, and INPUT through one wants a line editor built on the keystroke ring. EOF rather than an error is the contract sink.h states, so INPUT already handles it. That editor is the next piece of work there. 70/70 core ctest with no SDL on the include path, 71/71 with the akgl suite, clean under -Wall -Wextra, doxygen clean. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 08:46:53 -04:00
Andrew Kesterson	83185bafa8	Read the keyboard: implement GET, GETKEY and SCNCLR ... The poll_key half of group E, against the akbasic_InputBackend record. The libakgl implementation behind it is akgl_controller_poll_key(), which drains a ring the library fills from SDL events the host pumps -- so the interpreter can answer "is there a key waiting" without owning an event loop, which is what goal 3 requires. GET and GETKEY differ in one way and it is the interesting one. GET takes whatever is there including nothing, and an empty buffer is success with the empty string rather than an error -- that is what happens on most iterations of every GET loop ever written, and upstream is explicit that its poll reports it the same way. GETKEY waits, and since the library may not block, waiting is spelled as holding the step loop: the verb sets a flag and akbasic_runtime_step() declines to advance until a key arrives. Every step still returns and a bounded run() still comes back, so a host keeps its frame rate; the program simply does not move past the GETKEY. The PLAY queue is serviced before that check on purpose -- music should keep playing while a program waits for a keypress. Withdrawing the input device while a GETKEY is holding releases it rather than wedging the script on a device that no longer exists. Both verbs accept an integer variable as well as a string one and give it the raw key code, which is what a program testing for cursor or function keys needs. No key is code zero, matching what a C128 reports. A float variable is refused: it is neither a character nor a code. SCNCLR goes through the text sink rather than a device, because the sink is where PRINT already goes and is the only thing that knows what a screen means for this host. The stdio sink treats it as a no-op; clearing a pipe means nothing. One thing worth knowing before writing any bounded-run test, and now commented in tests/input_verbs.c: source lines are stored indexed by line number and the cursor starts at zero, so a step is spent on each empty slot along the way. A program at line 10 needs eleven steps before it has run anything. 70/70 ctest, clean under -Wall -Wextra, doxygen clean. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 08:35:05 -04:00
Andrew Kesterson	e24926d429	Sound: implement the BASIC 7.0 sound verbs and the PLAY parser ... SOUND, ENVELOPE, VOL, PLAY and TEMPO against the akbasic_AudioBackend record, plus FILTER, which is in the table only so that it can be refused with a reason. The PLAY note-string parser and TEMPO are here rather than in libakgl because that is where its audio commit says they belong: a tone generator synthesises pitches, but deciding that O4CDEFG is five quarter notes starting at middle C is a language question. PLAY does not block. On a C128 it holds the program until the last note ends, which section 1.6 forbids outright, so it parses the string into a fixed queue and returns; akbasic_runtime_step() releases one note at a time against whatever time the host last passed to akbasic_runtime_settime(). The driver now steps one at a time with the clock refreshed in between rather than making a single unbounded run() call -- a tune whose notes all measured themselves against a frozen zero would rush out at once. That loop is its own function because CATCH expands to a break and PASS expands to a return of the context, and main() returns an int; wrapping the loop is what the protocol prescribes for that shape. src/audio_tables.c holds the three conversions, laid out as tables because each is somewhere a wrong constant produces a plausible wrong pitch rather than an error anybody would notice. Two are transcriptions -- the SID frequency formula and its non-linear ADSR rate tables, where decay is exactly three times attack. The third is not: BASIC 7.0 never published what a whole note lasts at a given TEMPO, so 16000 ms at TEMPO 1 is a calibration choice putting a default quarter note at 120 bpm, and it is labelled as a choice where it is made. SOUND's frequency sweep is refused rather than faked, and filed upstream as akgl_audio_sweep. The only way to fake it here is to re-issue tones from step(), which ties audible pitch to how often the host calls us -- a tune that changes key with the frame rate. FILTER is refused for the reason upstream already gave: there is no filter stage and SDL3 has no primitive to build one from. The PLAY parser is tested through akbasic_play_parse() directly rather than through a program, because running one also runs the queue service -- and with the clock at zero every duration has already expired, so the queue empties before an assertion can look at it. Draining is correct behaviour and is tested on its own; the parse tests ask a different question. 68/68 ctest, clean under -Wall -Wextra, doxygen clean. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 08:29:04 -04:00
Andrew Kesterson	9d99d0a67e	Draw: implement the BASIC 7.0 graphics verbs ... GRAPHIC, COLOR, DRAW, BOX, CIRCLE, PAINT, SCALE, SSHAPE, GSHAPE and LOCATE, all against the akbasic_GraphicsBackend record rather than akgl_draw_* directly, so src/runtime_graphics.c includes no SDL and the whole group is testable in a build with no SDL on the machine. The reference lists every one of these as unimplemented, so the semantics come from Commodore BASIC 7.0 rather than from a port, and four places where a modern renderer cannot do what a C128 did are recorded in TODO.md section 5 rather than silently substituted: - CIRCLE is drawn as a polygon of inc-degree segments and akgl_draw_circle is deliberately unused. 7.0's CIRCLE takes two radii, an arc range and a rotation, so the primitive could serve only the fully-defaulted call, and a shape that changed character depending on whether the radii happened to be equal would be worse than one uniformly a polygon. - SSHAPE puts a SHAPE:<n> handle in the string variable rather than the pixels, because a value's string is a fixed 256 bytes and a region is a device surface. GSHAPE refuses a string without that prefix instead of parsing whatever digits it finds and pasting an unrelated slot. - BOX fills on a negative angle; 7.0 puts the fill flag after the rotation, which would make a filled box a seventh argument. - GRAPHIC stores its mode and honours only the one consequence that means anything here -- mode 0 is text -- while still refusing an out-of-range mode, since that is a typo worth catching. PAINT surfaces the flood fill's AKERR_OUTOFBOUNDS as an error rather than success. The device gives up when its span stack runs out having filled *part* of the region, and a program that cannot tell that happened cannot recover from it. Note the shape of that handler: HANDLE sets handled = true on the context, so a FAIL_RETURN from inside the HANDLE block hands the caller something already marked handled, whose FINISH_LOGIC then declines to pass it up and releases it -- the error disappears and PAINT reports success. Flag inside the block, raise after FINISH. COLOR, LOCATE and SCALE need no device on purpose, so a program can set itself up before a host has lent it a renderer. Adds a second golden corpus under tests/language/. The corpus in deps/basicinterpret is a submodule and nothing here may add files to it, but goal 2's new verbs still need the .bas/.txt half of their coverage. Registered under local_ so a failure names which corpus it came from. What it can cover is limited -- these verbs draw rather than print -- so the behaviour that reaches a device is asserted against tests/mockdevice.h instead. 65/65 ctest, clean under -Wall -Wextra, doxygen clean. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 08:17:48 -04:00
Andrew Kesterson	9b9dd09c5a	Reach hardware through backend records, and take the time from the host ... Groups G, I and E are unblocked but cannot be written yet: the core library is free of SDL and builds with no libakgl present, so a graphics verb cannot call akgl_draw_* and a sound verb cannot call akgl_audio_*. This adds what they call instead. Three records of function pointers -- akbasic_GraphicsBackend, _AudioBackend and _InputBackend -- in the same shape as akbasic_TextSink, and the same shape libakgl uses for akgl_RenderBackend. akbasic_runtime_set_devices() attaches any subset; all three may be NULL and that is the standalone driver's normal state, so a runtime with no backends still comes up and still prints. A verb that needs one it was not given raises the new AKBASIC_ERR_DEVICE rather than dereferencing a NULL vtable. Two decisions worth stating. The graphics record has no circle entry point: BASIC 7.0's CIRCLE takes two radii, an arc range, a rotation and a degree increment, which makes it a polygon by definition, so it will be built from line calls rather than from akgl_draw_circle. And coordinates are double rather than an integer pixel address, because SCALE makes them fractional and rounding at each verb rather than once at the backend accumulates drift along a polyline. akbasic_runtime_settime() is how SOUND, PLAY and TEMPO get a clock without the library reading one. Section 1.6 forbids blocking or owning a loop, so the caller that owns the frame owns the time -- which is what libakgl already does, since akgl_actor_logic_changeframe takes curtimems as an argument. Left unset it is zero and every duration expires immediately: audible, but never a hang. AKBASIC_ERR_LAST is a sentinel rather than a status, so tests/error_codes.c walks every code looking for an unnamed one without anybody remembering to widen the loop when a code is added. tests/mockdevice.h records every backend call as a formatted line. The graphics and audio verbs emit nothing a golden file can compare, so that log is where their assertions have to live -- and since it needs no SDL, the whole of groups G, I and E stays testable in the default build. 62/62 ctest, clean under -Wall -Wextra, doxygen clean. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 08:07:23 -04:00
Andrew Kesterson	134ade9392	Document the public API in libakgl's Doxygen style ... Adds a Doxyfile in the shape libakgl uses -- fifteen deliberate lines, including WARN_IF_UNDOCUMENTED and WARN_AS_ERROR=FAIL_ON_WARNINGS -- and fills in the 70 public declarations that had no doc block, bringing include/akbasic to 114 of 114. libakgl is the model rather than libakstdlib. Measured before starting: libakgl documents 122 of 122 public declarations and libakstdlib 3 of 25, and libakstdlib's Doxyfile is the unedited doxygen default, PROJECT_NAME = "My Project" and an empty INPUT. So the house standard is libakgl's, down to the boilerplate phrasing for the recurring parameters -- "Object to initialize, inspect, or modify", "Output destination populated by the function", "`NULL` on success, otherwise an error context owned by the caller". Worth knowing what the gate actually gates. EXTRACT_ALL=YES suppresses doxygen's undocumented-entity warnings, so the rule it enforces is that a *partial* block is an error: document one @param and you must document them all. Verified by deleting a @param and confirming a non-zero exit, then restoring it. Full coverage is therefore a convention this commit adopts rather than something the tool made me do. Where a contract is non-obvious the block says so rather than restating the signature: math_plus explains why it alone mutates its left operand, new_unary notes that hanging the operand on .right is what makes the parser miscount a negative literal argument, leaf_to_string warns that an assignment renders with an empty operator, and stop_waiting records that a verb nobody is waiting for is tolerated. Each cross-references its TODO.md section 6 item. Also records in TODO.md that this repository has no CI, which libakgl and libakstdlib both have -- so ctest, the sanitizer build, coverage and this new doxygen gate are all run by hand today. ctest 61/61; doxygen Doxyfile exits 0; no warnings under -Wall -Wextra. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 07:00:16 -04:00
Andrew Kesterson	cde6fa8f59	Port the README from the Go version and document embedding ... Carries the reference README across, adjusted where C changes the answer: cmake instead of make, the ak* libraries instead of the go-sdl2 bindings, and the limits table now includes the three ceilings the Go version did not need because it called make(). The new "Embedding the interpreter" section is the point of the rewrite, so it states the four rules the library holds to -- nothing terminates the process, nothing calls malloc, no file-scope mutable state, the host owns the loop -- and each was checked against the tree rather than asserted. Adds akbasic_runtime_load(). Writing the section turned up a real gap: a host usually already holds its script as a string and wants the sink reserved for output, and the only path that existed was AKBASIC_MODE_RUNSTREAM reading the program through the sink's readline, which forces a game to point its output device at its source text. The alternative was reaching into the header's "internal API" block for store_line. Neither is something to put in a README. Adds examples/embed.c, which is the code the README quotes -- a custom sink, a bounded per-frame run, and the PASS-not-CATCH rule for a loop inside an ATTEMPT. It is built by every build and registered as a CTest case, so a signature change breaks the build instead of rotting the document. The README's own snippet is compiled separately as a check; both were run before committing. The "What Isn't Implemented / Isn't Working" section leads with the eleven inherited defects rather than burying them, because five of them were found by this port and a reader deserves to know that 1 - 2 - 3 computes 1 - 2 before they hit it. Corrected two claims while verifying: the runtime is 10.1MB rather than the ~8MB first written, and its largest single cost is the environment pool at 4.1MB, not the source table. ctest 60/60; ASan+UBSan 60/60; no warnings under -Wall -Wextra. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-31 06:42:08 -04:00
Andrew Kesterson	f8c15c2f2c	Port the BASIC interpreter from Go to C ... Reproduces deps/basicinterpret in C, in the idiom of the ak* libraries. All 41 .bas files in the reference's corpus produce byte-identical stdout, including the trailing double newline on an error line -- that comes from basicError building a string ending in \n and handing it to Println, and array_outofbounds.txt encodes it. The corpus is driven in place from the submodule as 41 individual CTest cases rather than copied, so it cannot drift from upstream. Eighteen unit tests cover what the corpus cannot reach. Three structural changes carry most of the work. Go's three reflection lookups (Command*, Function*, ParseCommand*) become one sorted dispatch table in src/verbs.c searched with bsearch; adding a verb is a row and two functions. The five Go maps become one fixed open-addressed table over aksl_strhash_djb2. And run(), which owned the process until MODE_QUIT, splits into step() plus a bounded run() -- goal 3 requires a host game to be able to bound execution, and nothing in the library now terminates the process or touches SDL. Output goes through an akbasic_TextSink vtable. src/sink_stdio.c is what makes the corpus runnable with no SDL present; the akgl-backed sink is still to come and is blocked on libakgl having no text-measurement call. src/convert.c exists because libakstdlib's aksl_ato* family cannot report a conversion failure (its TODO.md 2.1.5). The reference checks strconv's error at four sites and turns it into a BASIC error; routing those through aksl_atoi would have turned four diagnosable errors into wrong answers, with VAL("garbage") quietly returning 0. TODO.md 1.9 records which libakstdlib calls are cleared for use here and which are not. Reference defects are reproduced, not fixed: the golden files encode the observed behaviour and a silent correction is a behaviour change. TODO.md section 6 lists sixteen, and tests/known_reference_defects.c asserts the *correct* contract for six of them under AKBASIC_KNOWN_FAILING_TESTS, so a fix shows up as "unexpectedly passed". Five of the sixteen were found by this port and are new: subtraction stops after one operator so 1-2-3 computes 1-2 and abandons the rest of the line (a wrong answer, not a refused one); a unary-minus argument inflates a function's arity so ABS(-9) is rejected; a comparison operator in a line's final column is dropped; hex literals never survive the scanner; and the "Reserved word in variable name" check is dead code. Where the reference reaches undefined behaviour by a route that is defined in Go -- an out-of-range shift, a negative string multiplier, integer division by zero -- this raises instead of inheriting the UB. No golden case exercises any of them. The top-level CMakeLists shadows add_test, set_tests_properties and add_custom_target around all three add_subdirectory calls. Without it libakerror's tests land in our suite as Not Run, and its un-namespaced `coverage` target stops a coverage build from configuring at all. Test targets are akbasic_test_<name>: bare test_<name> collides with libakstdlib's, which is what broke libakgl's configure in c2b16d3. ctest 59/59; ASan+UBSan 59/59; 92.3% line and 96.9% function coverage; no warnings under -Wall -Wextra. Branch coverage is not a target, for the reason libakstdlib and libakgl both record: the akerror macros expand into large branch trees at every call site. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>	2026-07-30 23:53:56 -04:00