A program with TRAP set and a line that would not parse printed nothing at all
and exited zero. No error line, because akbasic_runtime_error() intercepts for
the trap and deliberately prints nothing; and no handler, because the parse
branch of process_line_run() then set run_finished_mode regardless -- QUIT for a
file -- so the next line boundary the handler would have been entered at never
came. Arming an error handler made errors disappear.
The guard is to set the finished mode only when the error was actually reported.
The runtime path was always right: report_and_reraise() never touched the mode.
The same branch also never recorded the status, so the handler that now runs was
handed ER# 0. It sets lasterrorstatus from the context the way
report_and_reraise() does, and a trapped SCALE with no arguments reports 512.
Found while writing the error-code appendix -- documenting what ER# can hold
means provoking each code, and this is what happened on the way.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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>
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>
Two defects that the same mechanism produced, both found by making the
examples in docs/ actually run.
DLOAD scans the file it reads through the runtime's own scanner, so by the
time it returns, the tokens of the line that invoked it are gone and
hadlinenumber and environment->lineno describe the last line of the *file*.
The REPL carried on parsing what it believed was still its own buffer,
concluded the leftovers were program text because hadlinenumber was now true,
and filed the DLOAD command itself under that line number -- silently
replacing the last line of every program loaded from a prompt. It now
abandons the rest of the line, which is the only thing that can sensibly
follow replacing the whole program.
The second is the same class of oversight one layer up. process_line_run()
has always swallowed the error context after interpret() puts the BASIC-level
line on the sink, with a comment saying that is what goal 3 requires. The
direct-mode branch of process_line_repl() used a bare PASS instead, so
`VERIFY` against a file that did not match -- an ordinary user answer, not a
fault -- came back as a stack trace and terminated the driver. An embedding
host would have gone with it.
Both tests fail when their fix is reverted.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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>
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>
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>
SDL3 has text input off by default and per-window, so without
SDL_StartTextInput() it emits no SDL_EVENT_TEXT_INPUT at all and every
keystroke reaches libakgl's ring with an empty text field. The editor had just
been changed to prefer that composed text over the keycode, so it read every
key as not-a-character: no echo in the window, and nothing on stdout either,
because RUN could never be typed. One cause, both symptoms.
The editor now falls back to the keycode when there is no composed text, so a
host that forgets to start text input gets a worse keyboard rather than none.
The suite missed this because every keyboard test pushes the text-input event
into SDL's queue by hand -- which is what a real keyboard produces, but only
once text input has been started. Synthesising the end of a chain cannot test
the beginning of it. The new test asserts SDL_TextInputActive() directly, and
both halves were checked by reverting each and watching it fail.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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>
The Go reference is deprecated and will not be updated, so the two projects
are no longer required to match. Recorded as TODO.md section 0.1, first thing
in the file, because it silently reverses the premise several later sections
were written on -- an agent reading section 6 without it will park work that
is no longer blocked.
Section 6 item 16 was the item waiting on exactly this and is now fixed: the
keyword tables are searched on the base name with any type suffix stripped, so
PRINT$, LEN# and GOTO% are refused as variable names and the reference's own
diagnostic stops being dead code. It cost the one golden case predicted, and
the cost was nothing -- renaming a variable in strreverse.bas left its expected
output byte-for-byte unchanged.
AKBASIC_KNOWN_FAILING_TESTS is empty as a result and known_reference_defects.c
is gone. Section 6 items 1-9 and 11 are reopened as an ordinary defect list.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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>
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>
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>
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>
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>
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>
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>
Rebasing the defect filing onto libakgl's origin/main brought two upstream
commits with it -- "Consume libakstdlib 0.2.0" and "Bump libakgl to 0.2.0" --
and libakgl's sources now use the 0.2.0 akstdlib API. Our CMakeLists declares
akstdlib::akstdlib from our own tree first, so libakgl was compiling 0.2.0-era
code against 0.1.0 headers and failing on aksl_fwrite, aksl_fread and
aksl_realpath. The two have to move together.
The code change is one call site. aksl_fwrite now takes a required size_t
*nmemb_out and reports a short transfer as AKERR_IO rather than a silent
success, so DSAVE onto a full disk is an error a program sees where before it
reported nothing. The count is passed and discarded on purpose: the library does
the noticing now.
The documentation change is larger, because libakstdlib 0.2.0 fixed all six of
the confirmed defects TODO.md section 1.9 was built around. That section was a
table of bans; leaving it would send an agent around a workaround for functions
that now work. The aksl_ato* family raises AKERR_VALUE on no digits or trailing
junk and ERANGE on overflow -- exactly the contract that section demanded --
aksl_list_append no longer truncates, aksl_list_iterate no longer skips the
first half, AKERR_ITERATOR_BREAK stops a tree traversal, and aksl_realpath no
longer reads uninitialised memory. One caveat survives: aksl_strhash_djb2 still
sign-extends char, which section 1.3 already covers and the symbol tables still
cannot reach.
src/convert.c has therefore outlived its reason, and is deliberately left in
place. Its own note said to delete it when libakstdlib grew the contract, and
that condition is now met -- but doing it touches four call sites, changes the
raised status from AKBASIC_ERR_VALUE to AKERR_VALUE where section 1.8 says
message text is part of the acceptance contract, and would silently gut the CI
mutation job, which is bounded to src/convert.c and src/symtab.c. Section 1.9
now lists all of that. Worth doing on purpose rather than as a side effect of a
version bump.
libakgl defect #14 is closed by its own 1066ac7, which bumped it to 0.2.0 while
this was being written. The requirement is no longer pinned by submodule commit
in the README, because AKGL_VERSION_AT_LEAST(0, 2, 0) finally means something.
70/70 core, 71/71 with libakgl, 70/70 under ASan+UBSan, clean under
-Wall -Wextra, doxygen clean.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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>
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>
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>
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>
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>
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>
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>
