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akbasic/src/runtime.c

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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
/**
* @file runtime.c
* @brief Implements the interpreter core: pools, evaluation and the step loop.
*/
#include <inttypes.h>
#include <stdio.h>
#include <string.h>
#include <akerror.h>
#include <akbasic/error.h>
#include <akbasic/parser.h>
#include <akbasic/runtime.h>
#include <akbasic/scanner.h>
#include <akbasic/verbs.h>
/* ------------------------------------------------------------------ pools -- */
akerr_ErrorContext *akbasic_runtime_new_variable(akbasic_Runtime *obj, akbasic_Variable **dest)
{
PREPARE_ERROR(errctx);
int i = 0;
FAIL_ZERO_RETURN(errctx, (obj != NULL && dest != NULL), AKERR_NULLPOINTER,
"NULL argument in new_variable");
for ( i = 0; i < AKBASIC_MAX_VARIABLES; i++ ) {
if ( !obj->variables[i].used ) {
memset(&obj->variables[i], 0, sizeof(obj->variables[i]));
obj->variables[i].used = true;
*dest = &obj->variables[i];
SUCCEED_RETURN(errctx);
}
}
FAIL_RETURN(errctx, AKBASIC_ERR_BOUNDS, "Maximum runtime variables reached");
}
akerr_ErrorContext *akbasic_runtime_new_function(akbasic_Runtime *obj, akbasic_FunctionDef **dest)
{
PREPARE_ERROR(errctx);
int i = 0;
FAIL_ZERO_RETURN(errctx, (obj != NULL && dest != NULL), AKERR_NULLPOINTER,
"NULL argument in new_function");
for ( i = 0; i < AKBASIC_MAX_FUNCTIONS; i++ ) {
if ( !obj->functions[i].used ) {
memset(&obj->functions[i], 0, sizeof(obj->functions[i]));
obj->functions[i].used = true;
obj->functions[i].leafpool.next = 0;
obj->functions[i].leafpool.capacity = AKBASIC_MAX_LEAVES * 2;
obj->functions[i].leafpool.leaves = obj->functions[i].leafstorage;
*dest = &obj->functions[i];
SUCCEED_RETURN(errctx);
}
}
FAIL_RETURN(errctx, AKBASIC_ERR_BOUNDS, "Maximum function definitions reached");
}
static akerr_ErrorContext *env_acquire(akbasic_Runtime *obj, akbasic_Environment **dest)
{
PREPARE_ERROR(errctx);
int i = 0;
for ( i = 0; i < AKBASIC_MAX_ENVIRONMENTS; i++ ) {
if ( !obj->environments[i].used ) {
obj->environments[i].used = true;
*dest = &obj->environments[i];
SUCCEED_RETURN(errctx);
}
}
FAIL_RETURN(errctx, AKBASIC_ERR_ENVIRONMENT,
"Environment pool exhausted at line %" PRId64 " (%d in use)",
(obj->environment == NULL ? 0 : obj->environment->lineno),
AKBASIC_MAX_ENVIRONMENTS);
}
akerr_ErrorContext *akbasic_runtime_new_environment(akbasic_Runtime *obj)
{
PREPARE_ERROR(errctx);
akbasic_Environment *env = NULL;
FAIL_ZERO_RETURN(errctx, (obj != NULL), AKERR_NULLPOINTER, "NULL runtime in new_environment");
PASS(errctx, env_acquire(obj, &env));
PASS(errctx, akbasic_environment_init(env, obj, obj->environment));
obj->environment = env;
SUCCEED_RETURN(errctx);
}
akerr_ErrorContext *akbasic_runtime_prev_environment(akbasic_Runtime *obj)
{
PREPARE_ERROR(errctx);
akbasic_Environment *popped = NULL;
FAIL_ZERO_RETURN(errctx, (obj != NULL), AKERR_NULLPOINTER, "NULL runtime in prev_environment");
FAIL_ZERO_RETURN(errctx, (obj->environment->parent != NULL), AKBASIC_ERR_ENVIRONMENT,
"No previous environment to return to");
popped = obj->environment;
obj->environment = popped->parent;
/*
* Release it. The reference never does, which is a leak the GC papers over;
* here the pool is finite, so an unreleased environment is a bug that shows
* up as exhaustion a few thousand GOSUBs later.
*/
popped->used = false;
SUCCEED_RETURN(errctx);
}
/* ------------------------------------------------------------- lifecycle -- */
akerr_ErrorContext *akbasic_runtime_zero(akbasic_Runtime *obj)
{
PREPARE_ERROR(errctx);
FAIL_ZERO_RETURN(errctx, (obj != NULL), AKERR_NULLPOINTER, "NULL runtime in zero");
PASS(errctx, akbasic_environment_zero(obj->environment));
SUCCEED_RETURN(errctx);
}
akerr_ErrorContext *akbasic_runtime_init(akbasic_Runtime *obj, akbasic_TextSink *sink)
{
PREPARE_ERROR(errctx);
FAIL_ZERO_RETURN(errctx, (obj != NULL), AKERR_NULLPOINTER, "NULL runtime in init");
FAIL_ZERO_RETURN(errctx, (sink != NULL), AKERR_NULLPOINTER, "NULL text sink in init");
/*
* Claim the status band before anything can raise one of our codes, or the
* first error out of this function prints "Unknown Error". Idempotent, so a
* host that already called it loses nothing.
*/
PASS(errctx, akbasic_error_register());
memset(obj, 0, sizeof(*obj));
obj->sink = sink;
obj->environment = NULL;
obj->autoLineNumber = 0;
obj->eval_clone_identifiers = true;
obj->errclass = AKBASIC_ERRCLASS_NONE;
obj->mode = AKBASIC_MODE_REPL;
obj->run_finished_mode = AKBASIC_MODE_REPL;
obj->inputEof = false;
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
PASS(errctx, akbasic_graphics_state_init(&obj->gfx));
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
PASS(errctx, akbasic_audio_state_init(&obj->audio_state));
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
PASS(errctx, akbasic_valuepool_init(&obj->valuepool));
PASS(errctx, akbasic_value_zero(&obj->staticTrueValue));
PASS(errctx, akbasic_value_zero(&obj->staticFalseValue));
PASS(errctx, akbasic_value_set_bool(&obj->staticTrueValue, true));
PASS(errctx, akbasic_value_set_bool(&obj->staticFalseValue, false));
PASS(errctx, akbasic_runtime_new_environment(obj));
PASS(errctx, akbasic_runtime_zero(obj));
PASS(errctx, akbasic_scanner_zero(obj));
SUCCEED_RETURN(errctx);
}
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
akerr_ErrorContext *akbasic_runtime_set_devices(akbasic_Runtime *obj, akbasic_GraphicsBackend *graphics, akbasic_AudioBackend *audio, akbasic_InputBackend *input)
{
PREPARE_ERROR(errctx);
FAIL_ZERO_RETURN(errctx, (obj != NULL), AKERR_NULLPOINTER,
"NULL runtime in set_devices");
/*
* No validation of the records themselves. A backend with a NULL entry point
* is caught at the call site by the verb that needs it, which can say which
* verb wanted what -- checking every pointer here would only be able to say
* that something, somewhere, was incomplete.
*/
obj->graphics = graphics;
obj->audio = audio;
obj->input = input;
SUCCEED_RETURN(errctx);
}
akerr_ErrorContext *akbasic_runtime_settime(akbasic_Runtime *obj, int64_t timems)
{
PREPARE_ERROR(errctx);
FAIL_ZERO_RETURN(errctx, (obj != NULL), AKERR_NULLPOINTER,
"NULL runtime in settime");
/*
* Deliberately not rejecting a time that moves backwards. A host is free to
* drive this from a paused, scrubbed or replayed clock, and the only thing
* that happens is a note holding longer than it asked to.
*/
obj->timems = timems;
SUCCEED_RETURN(errctx);
}
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
/* ---------------------------------------------------------------- output -- */
akerr_ErrorContext *akbasic_runtime_write(akbasic_Runtime *obj, const char *text)
{
PREPARE_ERROR(errctx);
FAIL_ZERO_RETURN(errctx, (obj != NULL && text != NULL), AKERR_NULLPOINTER,
"NULL argument in write");
PASS(errctx, obj->sink->write(obj->sink, text));
SUCCEED_RETURN(errctx);
}
akerr_ErrorContext *akbasic_runtime_println(akbasic_Runtime *obj, const char *text)
{
PREPARE_ERROR(errctx);
FAIL_ZERO_RETURN(errctx, (obj != NULL && text != NULL), AKERR_NULLPOINTER,
"NULL argument in println");
PASS(errctx, obj->sink->writeln(obj->sink, text));
SUCCEED_RETURN(errctx);
}
static const char *errclass_to_string(akbasic_ErrorClass errclass)
{
switch ( errclass ) {
case AKBASIC_ERRCLASS_IO: return "IO ERROR";
case AKBASIC_ERRCLASS_PARSE: return "PARSE ERROR";
case AKBASIC_ERRCLASS_RUNTIME: return "RUNTIME ERROR";
case AKBASIC_ERRCLASS_SYNTAX: return "SYNTAX ERROR";
default: return "UNDEF";
}
}
akerr_ErrorContext *akbasic_runtime_error(akbasic_Runtime *obj, akbasic_ErrorClass errclass, const char *message)
{
PREPARE_ERROR(errctx);
char line[AKBASIC_MAX_LINE_LENGTH * 2];
FAIL_ZERO_RETURN(errctx, (obj != NULL && message != NULL), AKERR_NULLPOINTER,
"NULL argument in runtime error");
obj->errclass = errclass;
/*
* The format, the trailing \n inside the string, and the second newline
* writeln adds are all part of the acceptance contract --
* tests/language/array_outofbounds.txt ends in 0a 0a. See TODO.md 1.8.
*/
snprintf(line, sizeof(line), "? %" PRId64 " : %s %s\n",
obj->environment->lineno, errclass_to_string(errclass), message);
PASS(errctx, akbasic_runtime_println(obj, line));
SUCCEED_RETURN(errctx);
}
akerr_ErrorContext *akbasic_runtime_set_mode(akbasic_Runtime *obj, int mode)
{
PREPARE_ERROR(errctx);
FAIL_ZERO_RETURN(errctx, (obj != NULL), AKERR_NULLPOINTER, "NULL runtime in set_mode");
obj->mode = mode;
if ( obj->mode == AKBASIC_MODE_REPL ) {
PASS(errctx, akbasic_runtime_println(obj, "READY"));
}
SUCCEED_RETURN(errctx);
}
/* ------------------------------------------------------------ evaluation -- */
/*
* Report a runtime error carrying an akerr message, then re-raise. Used where
* the reference calls basicError() and returns the error: the BASIC-visible line
* goes to the sink and the context keeps propagating.
*/
static akerr_ErrorContext *report_and_reraise(akbasic_Runtime *obj, akerr_ErrorContext *cause)
{
PREPARE_ERROR(errctx);
char message[AKERR_MAX_ERROR_CONTEXT_STRING_LENGTH];
int status = cause->status;
snprintf(message, sizeof(message), "%s", cause->message);
cause->handled = true;
IGNORE(akerr_release_error(cause));
PASS(errctx, akbasic_runtime_error(obj, AKBASIC_ERRCLASS_RUNTIME, message));
FAIL_RETURN(errctx, status, "%s", message);
}
static akerr_ErrorContext *evaluate_identifier(akbasic_Runtime *obj, akbasic_ASTLeaf *expr, akbasic_Value **dest)
{
PREPARE_ERROR(errctx);
akbasic_ASTLeaf *texpr = NULL;
akbasic_Value *tval = NULL;
akbasic_Value *slot = NULL;
akbasic_Value *copy = NULL;
akbasic_Variable *variable = NULL;
int64_t subscripts[AKBASIC_MAX_ARRAY_DEPTH];
int subscriptcount = 0;
/*
* A .right hanging off an identifier is an array subscript only when it is
* an ARRAY_SUBSCRIPT argument list; anything else belongs to the enclosing
* expression and must not be followed.
*/
texpr = expr->right;
if ( texpr != NULL &&
texpr->leaftype == AKBASIC_LEAF_ARGUMENTLIST &&
texpr->operator_ == AKBASIC_TOK_ARRAY_SUBSCRIPT ) {
for ( texpr = texpr->right; texpr != NULL; texpr = texpr->right ) {
FAIL_ZERO_RETURN(errctx, (subscriptcount < AKBASIC_MAX_ARRAY_DEPTH),
AKBASIC_ERR_BOUNDS,
"More than %d array subscripts", AKBASIC_MAX_ARRAY_DEPTH);
PASS(errctx, akbasic_runtime_evaluate(obj, texpr, &tval));
FAIL_NONZERO_RETURN(errctx, (tval->valuetype != AKBASIC_TYPE_INTEGER),
AKBASIC_ERR_TYPE,
"Array dimensions must evaluate to integer (C)");
subscripts[subscriptcount] = tval->intval;
subscriptcount += 1;
}
}
if ( subscriptcount == 0 ) {
subscripts[0] = 0;
subscriptcount = 1;
}
PASS(errctx, akbasic_environment_get(obj->environment, expr->identifier, &variable));
FAIL_ZERO_RETURN(errctx, (variable != NULL), AKBASIC_ERR_UNDEFINED,
"Identifier %s is undefined", expr->identifier);
PASS(errctx, akbasic_variable_get_subscript(variable, subscripts, subscriptcount, &slot));
if ( !obj->eval_clone_identifiers ) {
*dest = slot;
SUCCEED_RETURN(errctx);
}
PASS(errctx, akbasic_environment_new_value(obj->environment, &copy));
PASS(errctx, akbasic_value_clone(slot, copy));
*dest = copy;
SUCCEED_RETURN(errctx);
}
static akerr_ErrorContext *evaluate_binary(akbasic_Runtime *obj, akbasic_ASTLeaf *expr, akbasic_Value **dest)
{
PREPARE_ERROR(errctx);
akbasic_Value *lval = NULL;
akbasic_Value *rval = NULL;
akbasic_Value *scratch = NULL;
PASS(errctx, akbasic_runtime_evaluate(obj, expr->left, &lval));
PASS(errctx, akbasic_runtime_evaluate(obj, expr->right, &rval));
if ( expr->operator_ == AKBASIC_TOK_ASSIGNMENT ) {
PASS(errctx, akbasic_environment_assign(obj->environment, expr->left, rval, dest));
SUCCEED_RETURN(errctx);
}
PASS(errctx, akbasic_environment_new_value(obj->environment, &scratch));
switch ( expr->operator_ ) {
case AKBASIC_TOK_MINUS:
PASS(errctx, akbasic_value_math_minus(lval, rval, scratch, dest));
break;
case AKBASIC_TOK_PLUS:
PASS(errctx, akbasic_value_math_plus(lval, rval, scratch, dest));
break;
case AKBASIC_TOK_LEFT_SLASH:
PASS(errctx, akbasic_value_math_divide(lval, rval, scratch, dest));
break;
case AKBASIC_TOK_STAR:
PASS(errctx, akbasic_value_math_multiply(lval, rval, scratch, dest));
break;
case AKBASIC_TOK_AND:
PASS(errctx, akbasic_value_bitwise_and(lval, rval, scratch, dest));
break;
case AKBASIC_TOK_OR:
PASS(errctx, akbasic_value_bitwise_or(lval, rval, scratch, dest));
break;
case AKBASIC_TOK_LESS_THAN:
PASS(errctx, akbasic_value_less_than(lval, rval, scratch, dest));
break;
case AKBASIC_TOK_LESS_THAN_EQUAL:
PASS(errctx, akbasic_value_less_than_equal(lval, rval, scratch, dest));
break;
case AKBASIC_TOK_EQUAL:
PASS(errctx, akbasic_value_is_equal(lval, rval, scratch, dest));
break;
case AKBASIC_TOK_NOT_EQUAL:
PASS(errctx, akbasic_value_is_not_equal(lval, rval, scratch, dest));
break;
case AKBASIC_TOK_GREATER_THAN:
PASS(errctx, akbasic_value_greater_than(lval, rval, scratch, dest));
break;
case AKBASIC_TOK_GREATER_THAN_EQUAL:
PASS(errctx, akbasic_value_greater_than_equal(lval, rval, scratch, dest));
break;
default:
FAIL_RETURN(errctx, AKBASIC_ERR_SYNTAX,
"Don't know how to perform binary operation %d", (int)expr->operator_);
}
SUCCEED_RETURN(errctx);
}
akerr_ErrorContext *akbasic_runtime_evaluate(akbasic_Runtime *obj, akbasic_ASTLeaf *expr, akbasic_Value **dest)
{
PREPARE_ERROR(errctx);
akbasic_Value *lval = NULL;
akbasic_Value *rval = NULL;
akbasic_Value *scratch = NULL;
const akbasic_Verb *verb = NULL;
FAIL_ZERO_RETURN(errctx, (obj != NULL && dest != NULL), AKERR_NULLPOINTER,
"NULL argument in evaluate");
FAIL_ZERO_RETURN(errctx, (expr != NULL), AKERR_NULLPOINTER, "NULL expression in evaluate");
PASS(errctx, akbasic_environment_new_value(obj->environment, &lval));
PASS(errctx, akbasic_value_zero(lval));
*dest = lval;
switch ( expr->leaftype ) {
case AKBASIC_LEAF_GROUPING:
PASS(errctx, akbasic_runtime_evaluate(obj, expr->expr, dest));
SUCCEED_RETURN(errctx);
case AKBASIC_LEAF_BRANCH:
ATTEMPT {
CATCH(errctx, akbasic_runtime_evaluate(obj, expr->expr, &rval));
} CLEANUP {
} PROCESS(errctx) {
} HANDLE_DEFAULT(errctx) {
PASS(errctx, report_and_reraise(obj, errctx));
} FINISH(errctx, true);
if ( rval->boolvalue == AKBASIC_TRUE ) {
PASS(errctx, akbasic_runtime_evaluate(obj, expr->left, dest));
SUCCEED_RETURN(errctx);
}
if ( expr->right != NULL ) {
/* A false branch is optional for some branching operations. */
PASS(errctx, akbasic_runtime_evaluate(obj, expr->right, dest));
SUCCEED_RETURN(errctx);
}
SUCCEED_RETURN(errctx);
case AKBASIC_LEAF_IDENTIFIER_INT:
case AKBASIC_LEAF_IDENTIFIER_FLOAT:
case AKBASIC_LEAF_IDENTIFIER_STRING:
PASS(errctx, evaluate_identifier(obj, expr, dest));
SUCCEED_RETURN(errctx);
case AKBASIC_LEAF_IDENTIFIER:
/* A bare identifier with no type suffix is a label. */
lval->valuetype = AKBASIC_TYPE_INTEGER;
PASS(errctx, akbasic_environment_get_label(obj->environment, expr->identifier, &lval->intval));
SUCCEED_RETURN(errctx);
case AKBASIC_LEAF_LITERAL_INT:
lval->valuetype = AKBASIC_TYPE_INTEGER;
lval->intval = expr->literal_int;
SUCCEED_RETURN(errctx);
case AKBASIC_LEAF_LITERAL_FLOAT:
lval->valuetype = AKBASIC_TYPE_FLOAT;
lval->floatval = expr->literal_float;
SUCCEED_RETURN(errctx);
case AKBASIC_LEAF_LITERAL_STRING:
lval->valuetype = AKBASIC_TYPE_STRING;
memcpy(lval->stringval, expr->literal_string, sizeof(lval->stringval));
SUCCEED_RETURN(errctx);
case AKBASIC_LEAF_UNARY:
PASS(errctx, akbasic_runtime_evaluate(obj, expr->right, &rval));
PASS(errctx, akbasic_environment_new_value(obj->environment, &scratch));
if ( expr->operator_ == AKBASIC_TOK_MINUS ) {
PASS(errctx, akbasic_value_invert(rval, scratch, dest));
} else if ( expr->operator_ == AKBASIC_TOK_NOT ) {
PASS(errctx, akbasic_value_bitwise_not(rval, scratch, dest));
} else {
FAIL_RETURN(errctx, AKBASIC_ERR_SYNTAX,
"Don't know how to perform operation %d on unary type %d",
(int)expr->operator_, (int)rval->valuetype);
}
SUCCEED_RETURN(errctx);
case AKBASIC_LEAF_FUNCTION:
PASS(errctx, akbasic_verb_lookup(expr->identifier, &verb));
if ( verb != NULL && verb->exec != NULL && verb->tokentype == AKBASIC_TOK_FUNCTION ) {
PASS(errctx, verb->exec(obj, expr, lval, rval, dest));
SUCCEED_RETURN(errctx);
}
PASS(errctx, akbasic_runtime_user_function(obj, expr, dest));
SUCCEED_RETURN(errctx);
case AKBASIC_LEAF_COMMAND_IMMEDIATE:
case AKBASIC_LEAF_COMMAND:
PASS(errctx, akbasic_verb_lookup(expr->identifier, &verb));
FAIL_ZERO_RETURN(errctx, (verb != NULL && verb->exec != NULL), AKBASIC_ERR_UNDEFINED,
"Unknown command %s", expr->identifier);
PASS(errctx, verb->exec(obj, expr, lval, rval, dest));
SUCCEED_RETURN(errctx);
case AKBASIC_LEAF_BINARY:
PASS(errctx, evaluate_binary(obj, expr, dest));
SUCCEED_RETURN(errctx);
default:
SUCCEED_RETURN(errctx);
}
}
akerr_ErrorContext *akbasic_runtime_interpret(akbasic_Runtime *obj, akbasic_ASTLeaf *expr, akbasic_Value **dest)
{
PREPARE_ERROR(errctx);
FAIL_ZERO_RETURN(errctx, (obj != NULL && expr != NULL && dest != NULL), AKERR_NULLPOINTER,
"NULL argument in interpret");
/*
* While an environment is skipping forward to a verb, nothing runs but that
* verb. This is what keeps a zero-iteration FOR body from executing, given
* that the loop condition is evaluated at the bottom of the structure.
*/
if ( akbasic_environment_is_waiting_for_any(obj->environment) ) {
if ( expr->leaftype != AKBASIC_LEAF_COMMAND ||
!akbasic_environment_is_waiting_for(obj->environment, expr->identifier) ) {
*dest = &obj->staticTrueValue;
SUCCEED_RETURN(errctx);
}
}
ATTEMPT {
CATCH(errctx, akbasic_runtime_evaluate(obj, expr, dest));
} CLEANUP {
} PROCESS(errctx) {
} HANDLE_DEFAULT(errctx) {
PASS(errctx, report_and_reraise(obj, errctx));
} FINISH(errctx, true);
SUCCEED_RETURN(errctx);
}
akerr_ErrorContext *akbasic_runtime_interpret_immediate(akbasic_Runtime *obj, akbasic_ASTLeaf *expr, akbasic_Value **dest)
{
PREPARE_ERROR(errctx);
FAIL_ZERO_RETURN(errctx, (obj != NULL && expr != NULL && dest != NULL), AKERR_NULLPOINTER,
"NULL argument in interpret_immediate");
*dest = NULL;
if ( expr->leaftype != AKBASIC_LEAF_COMMAND_IMMEDIATE ) {
SUCCEED_RETURN(errctx);
}
PASS(errctx, akbasic_runtime_evaluate(obj, expr, dest));
SUCCEED_RETURN(errctx);
}
akerr_ErrorContext *akbasic_runtime_user_function(akbasic_Runtime *obj, akbasic_ASTLeaf *expr, akbasic_Value **dest)
{
PREPARE_ERROR(errctx);
akbasic_FunctionDef *fndef = NULL;
akbasic_Environment *targetenv = obj->environment;
akbasic_ASTLeaf *leafptr = NULL;
akbasic_ASTLeaf *argptr = NULL;
akbasic_Value *argvalue = NULL;
akbasic_Value *unused = NULL;
void *fnptr = NULL;
PASS(errctx, akbasic_environment_get_function(obj->environment, expr->identifier, &fnptr));
fndef = (akbasic_FunctionDef *)fnptr;
/*
* The function's environment is owned by the funcdef, not by the pool free
* list: it is reset on every call and outlives any single one. The reference
* holds it by value inside BasicFunctionDef for the same reason.
*/
if ( fndef->environment == NULL ) {
PASS(errctx, akbasic_runtime_new_environment(obj));
fndef->environment = obj->environment;
obj->environment = targetenv;
}
PASS(errctx, akbasic_environment_init(fndef->environment, obj, obj->environment));
/* Bind arguments into the function's scope before entering it. */
leafptr = (expr->right != NULL ? expr->right->right : NULL);
argptr = (fndef->arglist != NULL ? fndef->arglist->right : NULL);
while ( leafptr != NULL && argptr != NULL ) {
akbasic_Environment *callerenv = obj->environment;
PASS(errctx, akbasic_runtime_evaluate(obj, leafptr, &argvalue));
obj->environment = fndef->environment;
PASS(errctx, akbasic_environment_assign(fndef->environment, argptr, argvalue, &unused));
obj->environment = callerenv;
leafptr = leafptr->right;
argptr = argptr->right;
}
obj->environment = fndef->environment;
if ( fndef->expression != NULL ) {
PASS(errctx, akbasic_runtime_evaluate(obj, fndef->expression, dest));
obj->environment = obj->environment->parent;
SUCCEED_RETURN(errctx);
}
/*
* A multi-line subroutine. Hand control to its environment and let the
* caller's step loop run it until RETURN pops back out. The result is the
* value RETURN parked in the child environment.
*/
obj->environment->gosubReturnLine = obj->environment->lineno + 1;
obj->environment->nextline = fndef->lineno;
while ( obj->environment != targetenv && obj->mode == AKBASIC_MODE_RUN ) {
PASS(errctx, akbasic_runtime_process_line_run(obj));
}
*dest = &fndef->environment->returnValue;
SUCCEED_RETURN(errctx);
}
/* ------------------------------------------------------------ line cycle -- */
int64_t akbasic_runtime_find_previous_lineno(akbasic_Runtime *obj)
{
int64_t i = 0;
for ( i = obj->environment->lineno - 1; i > 0; i-- ) {
if ( obj->source[i].code[0] != '\0' ) {
return i;
}
}
return obj->environment->lineno;
}
akerr_ErrorContext *akbasic_runtime_store_line(akbasic_Runtime *obj, int64_t lineno, const char *code)
{
PREPARE_ERROR(errctx);
FAIL_ZERO_RETURN(errctx, (lineno >= 0 && lineno < AKBASIC_MAX_SOURCE_LINES),
AKBASIC_ERR_BOUNDS,
"Line number %" PRId64 " is outside 0..%d",
lineno, AKBASIC_MAX_SOURCE_LINES - 1);
FAIL_ZERO_RETURN(errctx, (strlen(code) < AKBASIC_MAX_LINE_LENGTH), AKBASIC_ERR_BOUNDS,
"Source line exceeds the %d character limit", AKBASIC_MAX_LINE_LENGTH - 1);
strncpy(obj->source[lineno].code, code, AKBASIC_MAX_LINE_LENGTH - 1);
obj->source[lineno].code[AKBASIC_MAX_LINE_LENGTH - 1] = '\0';
obj->source[lineno].lineno = lineno;
SUCCEED_RETURN(errctx);
}
akerr_ErrorContext *akbasic_runtime_process_line_runstream(akbasic_Runtime *obj)
{
PREPARE_ERROR(errctx);
char buffer[AKBASIC_MAX_LINE_LENGTH];
char scanned[AKBASIC_MAX_LINE_LENGTH];
bool eof = false;
PASS(errctx, obj->sink->readline(obj->sink, buffer, sizeof(buffer), &eof));
if ( eof ) {
obj->environment->nextline = 0;
PASS(errctx, akbasic_runtime_set_mode(obj, AKBASIC_MODE_RUN));
SUCCEED_RETURN(errctx);
}
/*
* All this mode does is pick the line number off the front and file the
* source line under it. DLOAD reaches this from REPL mode, where the line
* numbers must be stripped the same way the REPL strips them.
*/
PASS(errctx, akbasic_scanner_scan(obj, buffer, scanned, sizeof(scanned)));
if ( obj->mode == AKBASIC_MODE_REPL ) {
PASS(errctx, akbasic_runtime_store_line(obj, obj->environment->lineno, scanned));
} else {
PASS(errctx, akbasic_runtime_store_line(obj, obj->environment->lineno, buffer));
}
SUCCEED_RETURN(errctx);
}
akerr_ErrorContext *akbasic_runtime_process_line_repl(akbasic_Runtime *obj)
{
PREPARE_ERROR(errctx);
char prompt[32];
char scanned[AKBASIC_MAX_LINE_LENGTH];
akbasic_ASTLeaf *leaf = NULL;
akbasic_Value *value = NULL;
akbasic_Parser parser;
bool eof = false;
if ( obj->autoLineNumber > 0 ) {
snprintf(prompt, sizeof(prompt), "%" PRId64 " ",
obj->environment->lineno + obj->autoLineNumber);
PASS(errctx, akbasic_runtime_write(obj, prompt));
}
PASS(errctx, obj->sink->readline(obj->sink, obj->userline, sizeof(obj->userline), &eof));
if ( eof ) {
obj->inputEof = true;
PASS(errctx, akbasic_runtime_set_mode(obj, AKBASIC_MODE_QUIT));
SUCCEED_RETURN(errctx);
}
if ( obj->userline[0] == '\0' ) {
SUCCEED_RETURN(errctx);
}
obj->environment->lineno += obj->autoLineNumber;
PASS(errctx, akbasic_scanner_scan(obj, obj->userline, scanned, sizeof(scanned)));
PASS(errctx, akbasic_parser_init(&parser, obj));
while ( !akbasic_parser_is_at_end(&parser) ) {
ATTEMPT {
CATCH(errctx, akbasic_parser_parse(&parser, &leaf));
} CLEANUP {
} PROCESS(errctx) {
} HANDLE_DEFAULT(errctx) {
char message[AKERR_MAX_ERROR_CONTEXT_STRING_LENGTH];
snprintf(message, sizeof(message), "%s", errctx->message);
IGNORE(akbasic_runtime_error(obj, AKBASIC_ERRCLASS_PARSE, message));
} FINISH(errctx, false);
if ( obj->errclass != AKBASIC_ERRCLASS_NONE ) {
SUCCEED_RETURN(errctx);
}
PASS(errctx, akbasic_runtime_interpret_immediate(obj, leaf, &value));
if ( value == NULL ) {
/* Not an immediate command, so it is program text: file it. */
PASS(errctx, akbasic_runtime_store_line(obj, obj->environment->lineno, scanned));
} else if ( obj->autoLineNumber > 0 ) {
obj->environment->lineno = akbasic_runtime_find_previous_lineno(obj);
}
}
SUCCEED_RETURN(errctx);
}
akerr_ErrorContext *akbasic_runtime_process_line_run(akbasic_Runtime *obj)
{
PREPARE_ERROR(errctx);
char line[AKBASIC_MAX_LINE_LENGTH];
akbasic_ASTLeaf *leaf = NULL;
akbasic_Value *value = NULL;
akbasic_Parser parser;
if ( obj->environment->nextline >= AKBASIC_MAX_SOURCE_LINES ) {
PASS(errctx, akbasic_runtime_set_mode(obj, obj->run_finished_mode));
SUCCEED_RETURN(errctx);
}
strncpy(line, obj->source[obj->environment->nextline].code, sizeof(line) - 1);
line[sizeof(line) - 1] = '\0';
obj->environment->lineno = obj->environment->nextline;
obj->environment->nextline += 1;
if ( line[0] == '\0' ) {
SUCCEED_RETURN(errctx);
}
PASS(errctx, akbasic_scanner_scan(obj, line, NULL, 0));
PASS(errctx, akbasic_parser_init(&parser, obj));
while ( !akbasic_parser_is_at_end(&parser) ) {
ATTEMPT {
CATCH(errctx, akbasic_parser_parse(&parser, &leaf));
} CLEANUP {
} PROCESS(errctx) {
} HANDLE_DEFAULT(errctx) {
char message[AKERR_MAX_ERROR_CONTEXT_STRING_LENGTH];
snprintf(message, sizeof(message), "%s", errctx->message);
IGNORE(akbasic_runtime_error(obj, AKBASIC_ERRCLASS_PARSE, message));
IGNORE(akbasic_runtime_set_mode(obj, obj->run_finished_mode));
} FINISH(errctx, false);
if ( obj->errclass != AKBASIC_ERRCLASS_NONE ) {
SUCCEED_RETURN(errctx);
}
/*
* The reference discards both results here. An error has already been
* reported to the sink by interpret(); swallowing the context keeps a
* BASIC-level error from tearing down the host, which is the whole point
* of goal 3.
*/
ATTEMPT {
CATCH(errctx, akbasic_runtime_interpret(obj, leaf, &value));
} CLEANUP {
} PROCESS(errctx) {
} HANDLE_DEFAULT(errctx) {
} FINISH(errctx, false);
if ( obj->errclass != AKBASIC_ERRCLASS_NONE ) {
SUCCEED_RETURN(errctx);
}
}
SUCCEED_RETURN(errctx);
}
/* ------------------------------------------------------------- step loop -- */
akerr_ErrorContext *akbasic_runtime_start(akbasic_Runtime *obj, int mode)
{
PREPARE_ERROR(errctx);
FAIL_ZERO_RETURN(errctx, (obj != NULL), AKERR_NULLPOINTER, "NULL runtime in start");
obj->run_finished_mode = (mode == AKBASIC_MODE_REPL ? AKBASIC_MODE_REPL : AKBASIC_MODE_QUIT);
PASS(errctx, akbasic_runtime_set_mode(obj, mode));
SUCCEED_RETURN(errctx);
}
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
akerr_ErrorContext *akbasic_runtime_load(akbasic_Runtime *obj, const char *source)
{
PREPARE_ERROR(errctx);
char line[AKBASIC_MAX_LINE_LENGTH];
char scanned[AKBASIC_MAX_LINE_LENGTH];
const char *cursor = NULL;
const char *eol = NULL;
size_t length = 0;
FAIL_ZERO_RETURN(errctx, (obj != NULL), AKERR_NULLPOINTER, "NULL runtime in load");
FAIL_ZERO_RETURN(errctx, (source != NULL), AKERR_NULLPOINTER, "NULL source in load");
for ( cursor = source; *cursor != '\0'; cursor = (*eol == '\0' ? eol : eol + 1) ) {
eol = strchr(cursor, '\n');
if ( eol == NULL ) {
eol = cursor + strlen(cursor);
}
length = (size_t)(eol - cursor);
if ( length > 0 && cursor[length - 1] == '\r' ) {
length -= 1;
}
FAIL_ZERO_RETURN(errctx, (length < sizeof(line)), AKBASIC_ERR_BOUNDS,
"Source line of %zu characters exceeds the %d character limit",
length, AKBASIC_MAX_LINE_LENGTH - 1);
memcpy(line, cursor, length);
line[length] = '\0';
if ( line[0] == '\0' ) {
continue;
}
/*
* Scanning is what picks the line number off the front and rewrites the
* line to what follows it -- the same path RUNSTREAM takes, so a program
* loaded from memory and one read from a file are filed identically.
*/
PASS(errctx, akbasic_runtime_zero(obj));
PASS(errctx, akbasic_scanner_zero(obj));
PASS(errctx, akbasic_scanner_scan(obj, line, scanned, sizeof(scanned)));
PASS(errctx, akbasic_runtime_store_line(obj, obj->environment->lineno, scanned));
}
obj->environment->nextline = 0;
SUCCEED_RETURN(errctx);
}
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
akerr_ErrorContext *akbasic_runtime_step(akbasic_Runtime *obj)
{
PREPARE_ERROR(errctx);
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
bool blocked = false;
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
FAIL_ZERO_RETURN(errctx, (obj != NULL), AKERR_NULLPOINTER, "NULL runtime in step");
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
/*
* Release the next queued note if its predecessor's time is up. PLAY does not
* block -- section 1.6 forbids it -- so this is what paces a tune, and it
* runs before the QUIT check so a program's last notes still come out while
* a host keeps calling step().
*/
PASS(errctx, akbasic_play_service(obj));
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
if ( obj->mode == AKBASIC_MODE_QUIT ) {
SUCCEED_RETURN(errctx);
}
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
/*
* A GETKEY with nothing typed yet holds the program here. The step still
* returns -- a host keeps its frame rate and a bounded run() still comes
* back -- it simply does not advance, which is what GETKEY means. The note
* queue above is serviced first on purpose: music should keep playing while
* a program waits for a keypress.
*/
PASS(errctx, akbasic_input_service(obj, &blocked));
if ( blocked ) {
SUCCEED_RETURN(errctx);
}
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
PASS(errctx, akbasic_runtime_zero(obj));
PASS(errctx, akbasic_scanner_zero(obj));
switch ( obj->mode ) {
case AKBASIC_MODE_RUNSTREAM:
PASS(errctx, akbasic_runtime_process_line_runstream(obj));
break;
case AKBASIC_MODE_REPL:
PASS(errctx, akbasic_runtime_process_line_repl(obj));
break;
case AKBASIC_MODE_RUN:
PASS(errctx, akbasic_runtime_process_line_run(obj));
break;
default:
break;
}
/*
* The reference never clears runtime.errno, so the first BASIC-level error
* ends the program: in a file run, run_finished_mode is QUIT. Reproduced
* deliberately -- tests/language/array_outofbounds.txt depends on exactly one
* error line being printed and nothing after it.
*/
if ( obj->errclass != AKBASIC_ERRCLASS_NONE ) {
PASS(errctx, akbasic_runtime_set_mode(obj, obj->run_finished_mode));
}
SUCCEED_RETURN(errctx);
}
akerr_ErrorContext *akbasic_runtime_run(akbasic_Runtime *obj, int maxsteps)
{
PREPARE_ERROR(errctx);
int steps = 0;
FAIL_ZERO_RETURN(errctx, (obj != NULL), AKERR_NULLPOINTER, "NULL runtime in run");
while ( obj->mode != AKBASIC_MODE_QUIT ) {
PASS(errctx, akbasic_runtime_step(obj));
steps += 1;
if ( maxsteps > 0 && steps >= maxsteps ) {
break;
}
}
SUCCEED_RETURN(errctx);
}
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