The LSM Version field was hardcoded and lagged the 0.18.0 bump. Set it to
0.18.0 and have build_pkg.sh rewrite it from the version in include/gwbasic.h
on every build so it can't drift again.
Co-authored-by: Eremey Valetov <evvaletov@users.noreply.github.com>
* tests: automated headless FreeDOS QEMU smoke
Fully-automated counterpart to the manual run_freedos_qemu.sh: overlays the
FreeDOS image (no mutation), stages the interpreter and a SYSTEM-terminated
smoke on C:, injects the run plus poweroff into the image's startup batch,
boots headless, and diffs OUT.TXT against the golden file. Local-dev only
(needs qemu, a FreeDOS qcow2, mtools, nbd, and passwordless sudo); CI keeps
using the DOSBox-X path. Exercises the binary on a real FreeDOS install
rather than DOSBox-X emulation.
* Release 0.18.0
Cross-language linking (link BASIC into C/Fortran, call C from BASIC via
'$EXTERN), the v0.18 codegen/perf batch (paren string-comparison fix,
--no-gc-check/--fast-math, larger 32-bit caps, process-local DATE$/TIME$),
and the automated FreeDOS QEMU smoke. Bumps GW_VERSION and updates the
banners, CHANGES.TXT, and the development history table.
---------
Co-authored-by: Eremey Valetov <evvaletov@users.noreply.github.com>
Add a '$EXTERN NAME(ARGTYPES) AS RET pragma so compiled BASIC can call C
functions directly, the natural follow-up to Level 1 (--emit-obj /
--main-name). The pragma is an apostrophe comment, so the interpreter
ignores it while the compiler registers it.
Map INTEGER/SINGLE/DOUBLE/STRING to int16_t/float/double/const char* at the
boundary: a string argument crosses as a temporary C copy that is freed
after the call, and a string return is copied into the pool. The call name
is matched case-insensitively but emitted as the C symbol with the case
written in the pragma. Names are recognized before parse_var() truncates
identifiers to two significant characters, so multi-character C function
names work.
A string return that aliases a char* argument is copied before the argument
temporaries are freed, which avoids a use-after-free. Over-supplied
arguments are consumed without desyncing the token stream and warn on arity
mismatch.
Docs: getting-started.md "Foreign Functions from BASIC". Test:
tests/run_ffi_test.sh, wired into CI. 63/63 compiler, 72/72 interpreter,
68/68 compat still pass.
Also refile the roadmap "Next Up" backlog as git-bug issues and prune
docs/roadmap.md to point at git-bug as the source of truth for planned work.
Co-authored-by: Eremey Valetov <evvaletov@users.noreply.github.com>
Level 1 of the cross-language linking roadmap entry: produce an
object file with a renamed entry point so a BASIC program can be
linked into a larger C or Fortran build.
- src/compiler_main.c: --emit-obj runs gcc -c (compile-only,
produces prog.o) and skips the runtime link. --main-name NAME
(or --main-name=NAME) is plumbed through codegen_opts_t.
- src/codegen.c: emit `int <name>(int argc, char **argv)` instead
of always emitting `main`. Default unchanged when --main-name
isn't specified.
- include/codegen.h: add main_name to codegen_opts_t.
- docs/getting-started.md: new "Cross-Language Linking" section
with C and Fortran (iso_c_binding) driver examples.
- docs/roadmap.md: three levels of cross-language linking, with
Level 1 marked done, Level 2 (BASIC-side EXTERN declarations)
as the next concrete step, Level 3 (BASIC SUBs as C functions)
deferred. Also added: FORTRAN-style WRITE / C-style PRINTF
formatted I/O extensions, and a NumPy / DataFrame / Matplotlib-
style standard library section as a separate sub-project track.
Verified end-to-end: a BASIC program compiled with --emit-obj
--main-name=run_basic_greet links cleanly with both a C driver
(gcc) and a Fortran driver (gfortran with iso_c_binding), and
prints the BASIC output before returning to the host. All
72 interpreter / 68 compat / 63 compiler tests still pass.
Four roadmap items:
- codegen: fix parenthesized string comparison. emit_atom didn't
consume the body of a string-literal token (`"`), so for
PRINT (A$+B$ < "ZZZ") it emitted a 0 placeholder, advanced one byte,
and left "ZZZ" to be reparsed as a variable + extra trailing tokens
-- the binary then failed to link with `var_ZZ_sng` undeclared.
emit_atom now skips to the closing quote. Separately, the
left_type tracking in emit_num_prec dropped VT_STR after a string +
string concat (becoming VT_SNG), so the string-comparison codepath
skipped when the relational operator arrived. Preserve VT_STR
through TOK_PLUS when both operands are strings. Verified: paren
string-cmp now compiles and produces the same -1 / 0 result as the
interpreter.
- compiler: --no-gc-check and --fast-math optimization flags.
--no-gc-check skips the per-line gwrt_check_line() (no string-pool
GC, no Ctrl+Break trap). --fast-math drops the divide-by-zero
guard on `/`; the divisor still goes through (double) so 10/0
produces inf rather than SIGFPE. Both threaded through
codegen_opts_t and exposed in --help. --inline-arrays from the
roadmap deferred -- larger refactor.
- interp: raise static caps on 32-bit / Linux builds. vars 256
-> 1024, arrays 64 -> 256, MAX_FOR_DEPTH 16 -> 64, MAX_GOSUB_DEPTH
24 -> 128, MAX_WHILE_DEPTH 16 -> 64. Codegen FOR_STACK_MAX 16
-> 64. Analysis-pass caps: MAX_LINES 4096 -> 8192, MAX_VARS 256
-> 1024, MAX_GOTOS 256 -> 1024, MAX_DATA 1024 -> 4096,
MAX_GOSUB_RET 256 -> 1024. 16-bit DOS keeps the original modest
caps via #ifdef _M_I86 -- the MEDIUM model has a single 64KB
DGROUP for all static data and the bumped sizes broke runtime
startup under DOSBox-X. 16-bit binary grew from 128KB to 132KB
from the offset_secs field plus DATE$/TIME$ shift code, well
within the FreeDOS budget.
- interp + codegen: DATE$ / TIME$ assignment via process-local
clock offset. Was a no-op accept-and-ignore. Now sets
gw.time_offset_secs (long), and DATE$ / TIME$ / TIMER readers
apply it to time(NULL) before formatting. The OS clock is
unaffected (would need root). Compiled-binary readers also
reference gw.time_offset_secs since libgwrt shares the gw
struct. Verified: PRINT DATE$; DATE$="12-31-1999"; PRINT DATE$
shows the expected before/after in both interpreter and AOT
paths.
After these changes: 72/72 interpreter tests, 68/68 compat, 63/63
compiler tests, DOS smoke under DOSBox-X all pass. Build clean on
both Linux (cmake) and 16-bit DOS (build_dos.sh 16).
- .github/workflows/ci.yml: the dos-cross-compile job failed on the
first push because build_dos.sh sources $HOME/openwatcom-v2/setvars.sh
if WATCOM is unset, but that file isn't part of the OpenWatcom V2
snapshot — I'd been creating it locally by hand. Add a "Configure
OpenWatcom env" step that generates setvars.sh after extraction (so
build_dos.sh works) AND exports WATCOM/PATH/INCLUDE via $GITHUB_ENV
(so subsequent steps work even if setvars.sh sourcing changes).
Also stash both DOS binaries before the next-mode clean wipes them,
so the artifact upload actually has both .exe files.
- src/codegen.c: switch the four remaining emit_str_atom callers
(CVI/CVS/CVD function args + string-comparison left/right) to
emit_str_expr. Now `CVS(A$+B$)` and `A$+B$ < C$` accept
concatenation in their string operands; previously the atom-level
caller stopped at the first identifier and the trailing `+` confused
downstream parsing. Verified: CVS(MKS$(3.14)+MKS$(0)) round-trips
to 3.14 in both interpreter and compiled binary. All 72 interpreter
+ 63 compiler tests still pass.
- docs/getting-started.md: document that gwbasic-compile auto-numbers
unnumbered direct-mode lines (last_num + 10) so scratchpad-style
programs compile without manual renumbering.
- tests/run_freedos_qemu.sh: helper for going through the manual TUI
checklist on bare FreeDOS. Modern qemu-kvm doesn't expose -fda on
the default machine type and fat:rw: protocol is gone, so a fully
automated FreeDOS smoke isn't tractable from userspace; this script
builds a FAT data image (mtools), attaches it as -hdb to the FreeDOS
qcow2, and points the user at the manual sequence in the script
header. The DOSBox-X harness (run_dos_smoke.sh) remains the
automated DOS smoke.
Three fixes that lift seven test programs from skipped to passing,
bringing the AOT compiler harness from 56/56 to 63/63.
- Unnumbered programs (compiler_main.c): src/compiler_main.c skipped
any line that didn't start with a digit, so direct-mode .bas files
like hello.bas, math_ops.bas, string_ops.bas (no line numbers)
failed with "No program lines found". load_file now auto-assigns
line numbers (last_num + 10) to unnumbered lines, with overflow
protection at line 65520.
- String concatenation in PRINT (codegen.c): emit_str_atom had a
broken concat loop that emitted "; _cat = gw_str_concat(&...
_cat.sval ...)" — _cat was never declared, so any program with a
string-literal concat in PRINT (like PRINT "ABC" + "DEF") failed
to link. Concat is properly handled by emit_str_expr's outer
loop; remove the dead/broken code in the atom. Fixes
string_ops.bas.
- Transcendental result type (codegen.c): peek_expr_type returned
VT_DBL for ATN/LOG/EXP/VAL, so PRINT formatted them with 15-digit
double precision (e.g. 3.141592653589793) while real GW-BASIC and
the interpreter format the single-precision result as 3.141593.
Real GW-BASIC's transcendentals are single-precision; only CDBL
forces double. Demote ATN/LOG/EXP/VAL to VT_SNG; CDBL stays
VT_DBL. Fixes math_ops.bas.
Also: tests/run_compiler_tests.sh now runs the compiled binary from
the project root rather than the tempdir where it was built, so
test programs that reference tests/programs/ via relative paths
(chain_test, common_test, run_file, misc_stmts) resolve their
targets. Earlier I'd misdiagnosed those failures as ON ERROR
divergence — they were just CWD-dependent path lookups.
Doc/test counts: 56 → 63 in README, docs/index.md, docs/development.md,
docs/roadmap.md. Roadmap updated to note the compiler now accepts
unnumbered programs.
- build_dos.sh: Linux-friendly cross-compile to DOS via OpenWatcom V2.
OpenWatcom's wmake on Linux can't apply the .c.obj implicit rule for
subdirectory paths, and Makefile.dos / Makefile.dos16 rely on DOS-
only commands like 'del'. Script invokes wcc / wcc386 directly,
tracks 16-bit vs 32-bit mode via a stamp file (auto-cleans on
switch), generates a wlink directive file (the brace-delimited file
list wouldn't survive shell quoting), and supports clean. The DOS
Makefiles still work on Windows / DOS hosts.
- tests/run_compiler_tests.sh: AOT compiler harness. For each .bas
in tests/programs/, compiles via gwbasic-compile -c, runs the
resulting executable, normalizes output and diffs against the
golden file from tests/expected/. Skip list covers chain/common
multi-file flows, hardware/timing-dependent programs, unnumbered
direct-mode programs (compiler requires line numbers), and
misc_stmts/run_file (interpreter-vs-compiler ON ERROR divergence).
Result: 56/56 pass.
- tests/run_dos_smoke.sh + dos_smoke.bas + expected: runs gwbasic16.exe
under DOSBox-X (flatpak) with a program that exercises arithmetic,
strings, control flow, GOSUB, FOR/NEXT, DATA/READ, DEF FN, OPEN/
PRINT#/CLOSE, and diffs against the interpreter's golden output.
Uses $HOME for the staging dir (DOSBox-X flatpak doesn't see /tmp).
- pkg/GWBASIC.LSM + pkg/build_pkg.sh: FreeDOS submission package.
Produces dist/gwbasic-<VERSION>.zip with the standard FreeDOS
layout (APPINFO/GWBASIC.LSM, BIN/GWBASIC.EXE, DOC/GWBASIC/{README,
CHANGES,LICENSE} with CRLF, SOURCE/GWBASIC/<full source>). Source
tree is filtered through git ls-files to exclude build artifacts.
- docs/Makefile: standard Sphinx Makefile so 'cd docs && make html'
works as documented in README.md.
- .github/workflows/ci.yml: split into two jobs. build-and-test now
also runs the compiler harness. New dos-cross-compile job caches
~/openwatcom-v2, downloads the OpenWatcom V2 snapshot if not
cached, builds both 16-bit and 32-bit DOS binaries, asserts size
bounds, and uploads them as artifacts.
- .gitignore: ignore .dos_build_mode (script's stamp), .link_dir/
(transient wlink directive dir), dist/ (package output).
QA findings from a multi-round review of the FreeDOS submission prep work:
- TUI rendering refactor: src/tui.c emitted ANSI escape sequences via
printf, which displays as raw text on bare FreeDOS (no ANSI.SYS).
Add four HAL ops (tui_enter, tui_leave, render_run, set_cursor_shape)
and route per-cell rendering through them. POSIX backend keeps the
ANSI path; DOS backend drives BIOS INT 10h via the existing
bios_set_cursor / bios_write_char helpers. The TUI's logical cursor
goes through the saved orig_locate to avoid recursing through the
swapped-in gw_hal->locate.
- DOS extended-key mapping: dos_getch returns 0x100 | scancode for
arrows / F-keys; tui_read_key wasn't translating those to its TK_*
constants, so the editor never saw arrow keys or F1-F10 on DOS.
Add a __MSDOS__-conditional translation table in tui_read_key.
- Version banner: GW_VERSION was still 0.16.0 even though the v0.17.0
release prep was already in CHANGES.TXT. Bump.
- Compiler PulseAudio link: gwbasic-compile -c hardcoded
'-lgwrt -lm -lpthread' on the gcc command line. When libgwrt was
built against libpulse-simple (the default on any host with the
PulseAudio dev headers installed), the compile workflow failed with
'undefined reference to pa_simple_drain'. CMake now passes
GWRT_HAS_PULSEAUDIO to gwbasic-compile when libpulse is present, and
the compiler appends -lpulse-simple to the link line.
- FRE("") garbage collection: the interpreter skipped strpool_gc with a
comment 'unsafe during expression eval', but that's exactly what real
GW-BASIC's FRE("") does (and the AOT compiler path already did). Add
the GC call; strpool_pin/unpin is the existing escape hatch if a
caller has live pool pointers on the C stack. Fixes the string_gc
compat test.
- Test harness normalization: run_tests.sh stripped trailing whitespace
on the actual output but not the expected file, causing spurious
mismatches against golden files captured from real GWBASIC.EXE.
Normalize both sides identically. Fixes the peek_gfx mismatch.
- Print_using: snprintf into mantissa[32] with %.*f and an unbounded
dec triggered a -Wformat-truncation warning. Clamp dec to 20 (IEEE
double has at most ~17 significant decimal digits).
- Doc/version consistency: 16-bit binary size reported as 127KB in one
place and 128KB in three; standardize on 128KB. HAL backend count
said '1 file' but is now 2. CI test count said 'all 66 test
programs' but is 72. Add a v0.17.0 row to the development.md table.
Update getting-started.md DOS section to match the BIOS-rendering
reality and add a manual TUI verification checklist.
- dos_init now writes back BIOS-reported cols/rows to dos_hal struct
fields (forward-declared so dos_init can reference it).
After these changes: 72/72 interpreter tests pass, compat 68/68
matched, no warnings on the Linux build.
- Add CHANGES.TXT with full version history (DOS-friendly format)
- Add DOS/FreeDOS section to README.md
- Move compiler memory safety and DOS target to Completed in roadmap
- Add hal_dos.c to architecture.md module map
- Add .tab-color to .gitignore
The 4KB screen buffer (80x25x2 bytes) was allocated from near heap via
calloc(), which exhausted the 64KB data segment on 16-bit DOS. Now uses
_fcalloc()/_ffree() from OpenWatcom's far heap on 16-bit, keeping the
buffer outside DGROUP.
The TUI now works fully on 16-bit FreeDOS: full-screen editor, F-key
bar, cursor positioning, and scroll -- all via BIOS INT 10h through the
DOS HAL, with the screen buffer in far memory.
Changes:
- tui.h: GW_FAR macro (expands to __far on 16-bit, nothing elsewhere),
tui.screen declared as tui_cell_t GW_FAR *
- tui.c: _fcalloc/_ffree for 16-bit, _fmemmove for scroll_up()
- TUI_CELL() macro works unchanged (far pointer dereference is
transparent)
Fix 6 crash paths when TUI screen buffer allocation fails (common on
16-bit DOS due to near-heap exhaustion):
- main.c: REPL and AUTO mode fall back to fgets-based line reader
- tui.c: tui_key_on/off/list return early if tui.screen is NULL
Add DOS build documentation to getting-started.md (16-bit and 32-bit
targets, running on FreeDOS). Fix stale version string (0.14.0 -> 0.16.0).
New Makefile.dos16 builds with OpenWatcom wcc (16-bit, MEDIUM model)
producing a standard MZ executable that runs on any DOS without DOS/4GW.
All 24 source files compile clean; tested on FreeDOS 1.4 via QEMU.
Changes for 16-bit compatibility:
- hal_dos.c: INTX macro selects int86() vs int386() based on _M_I86
- sound.c: reduce stack buffer from 8192 to 512 samples on 16-bit
- tui.c: gracefully disable TUI if screen buffer allocation fails
(near heap exhaustion common on 16-bit), batch mode still works
- .gitignore: add .obj/.exe/.err/.lib for OpenWatcom build artifacts
Size comparison:
- 32-bit DOS/4GW: 175KB + 265KB extender = 440KB total
- 16-bit real-mode: 127KB standalone
The 32-bit build (Makefile.dos) and Linux build are unaffected.
72/72 interpreter tests pass.
1. ABS() now preserves integer argument type in codegen — ABS(int%)
returns int%, uses gw_int_neg in safe mode. Previously always emitted
fabs() returning float, causing ABS(30000)+ABS(30000) to silently
produce 60000.0 instead of raising Overflow.
2. SGN() return type added to VT_INT list in peek_expr_type, so
SGN(A%)+32767 correctly triggers gw_int_add overflow check.
3. gwrt_array_elem() now uses ERR_BS (Subscript out of range) instead
of ERR_FC (Illegal function call) for bounds errors, matching the
safe variant and the interpreter. ON ERROR handlers see ERR=9 in
both modes.
4. COMMON variables now tracked as assigned in analysis warnings,
preventing false "used but never assigned" warnings.
5. IF...THEN followed by inline assignment (IF 1 THEN A=5) now
correctly sets assign_ctx after THEN, preventing false uninitialized
variable warnings.
In the buffered expression path, left_type was set once from
peek_expr_type() and never updated. After I% * 2.5, the intermediate
result is float but left_type stayed VT_INT, causing the subsequent
+ I% to incorrectly use gw_int_add which truncated the float to
int16_t and raised a spurious overflow.
Now left_type is updated after each binary operator based on type
promotion rules: division and power produce VT_DBL, comparisons
produce VT_INT, and mixed int/float operations promote to the wider
type.
1. peek_expr_type() now handles parenthesized expressions — (A%) + (B%)
correctly triggers gw_int_add in --safe mode instead of falling back
to plain C addition.
2. FOR limit and step assignments use gw_cint() for integer variables in
--safe mode, catching out-of-range values (e.g., FOR I% = 1 TO 100000
now raises Overflow instead of silently truncating).
3. SWAP sets multi_assign so both variables are marked as assigned in the
--warn uninitialized variable analysis.
4. Bare NEXT (without variable name) now emits the loop variable increment
from the FOR stack, fixing a pre-existing bug where the loop body
would execute but the variable never advanced.
All 24 source files compile and link for DOS/4GW 32-bit target using
OpenWatcom V2 cross-compiler (wcc386 -bt=dos -mf -za99 -D__MSDOS__).
Platform portability fixes:
- hal_dos.c: use int386() instead of int86() for 32-bit DOS
- interp.c: mkdir() 1-arg on DOS, _dos_findfirst/findnext for FILES,
monotonic_time() portable wrapper for clock_gettime/clock()
- virmem.c: replace clock_gettime with portable time()/localtime()
- graphics.c: define M_PI, avoid non-constant aggregate initializers
- tui.c: guard sys/ioctl.h and sigaction, use signal() on DOS,
use HAL screen size instead of TIOCGWINSZ
Produces: gwbasic.exe (154KB LE executable, requires DOS4GW.EXE)
Linux build and all 72+14+69 tests unaffected.
platform/hal_dos.c: DOS HAL implementation using BIOS INT 10h for
screen/cursor, INT 16h for keyboard, direct character output via
BIOS write-char. Compile-time selection via __MSDOS__ define.
Linux HAL (hal_posix.c) unchanged -- full backward compatibility.
hal.h: add hal_dos_create() declaration under __MSDOS__ guard.
main.c, gwrt.c: select HAL at compile time via #ifdef __MSDOS__.
Makefile.dos: OpenWatcom wmake build file targeting DOS/4GW 32-bit.
Builds GWBASIC.EXE (interpreter), GWBASCOM.EXE (compiler),
GWRT.LIB (runtime library for compiled programs).
All 72 interpreter, 14 kernel, and 69 compiler tests continue to
pass on Linux (no regression).
Remove Unicode em dashes (U+2014) and en dashes (U+2013) from all
Markdown files. Use ASCII -- for parenthetical breaks and - for
hyphenation, matching standard plain-text conventions.
README.md: rewrite with v0.16.0 version, compiler section, Jupyter
kernel section, hardware I/O in statement table, accurate test counts
(72 interpreter + 14 kernel + 69 compiler), build instructions for
all three targets.
docs/roadmap.md: clean up Phase 2 accumulation into single coherent
compiler description. List all language coverage, operators, functions,
and optimizations. Remove stale intermediate progress markers.
docs/development.md: update test counts (72 programs, 68 golden files),
add kernel and compiler test commands.
Constant folding: when both operands of an arithmetic operator are
numeric literals, compute the result at compile time. Eliminates
runtime computation for expressions like 2*3.14 or 4*1024.
FOR step=1 elision: when STEP is omitted (default 1), skip the static
_for_step declaration entirely. NEXT emits var++ instead of
var += _for_step. Reduces generated code by 1-2 lines per FOR loop.
Tracked via has_step flag in FOR stack.
FOR comparison simplification: step=1 emits simple > check instead
of ternary step-sign comparison.
69/69 compiler tests pass (play_scale is audio-timeout flaky).
Selective variable sync in emit_delegate_stmt: scan embedded token bytes
for variable name references, only sync variables that appear. Reduces
generated code by ~50% for PRINT USING and other delegated statements.
DRAW/PLAY use full sync (=variable; string substitution references vars
not visible in tokens). CHAIN uses full sync (passes COMMON vars).
Fast-path expression emitter: skip open_memstream buffering when no
MOD/IDIV/POW/string-comparison operators present (the common case).
Scan ahead for special operators; emit directly to output stream.
FOR loop simplification: when STEP is omitted (default 1), emit simple
> comparison instead of step-sign check. Integer FOR vars use gw_cint().
Division-by-zero check in fast path matches buffered path.
69/69 compiler tests, 72/72 interpreter, 14/14 kernel — all pass.
Fast-path expression emitter: skip open_memstream buffering for the
common case (no MOD/IDIV/POW/string-comparison). Scans ahead for special
operators; if none found, emits directly to the output stream. Reduces
compilation overhead for the majority of expressions.
FOR loop integer rounding: use gw_cint() for integer loop variables
(consistent with scalar assignment rounding).
Division-by-zero in fast path: emit GCC statement expression check
for / operator (matches the buffered path).
Dead code elimination: skip statements after GOTO/END/STOP.
Skip gwrt_check_line() for REM-only lines.
All 69/69 compiler tests, 72/72 interpreter tests, 14/14 kernel tests
continue to pass.
RNG: use gw_rnd() (GW-BASIC's LCG) instead of rand()/RAND_MAX.
RANDOMIZE: set gw_rnd_seed directly instead of srand(). Compiled and
interpreted programs now produce identical random sequences.
Dead code elimination: skip statements after unconditional GOTO/END/STOP
on the same line. Skip gwrt_check_line() for REM-only lines.
69 of 69 eligible compiler tests now pass (100%). Zero failures.
(3 tests without line numbers are skipped by the compiler.)
CHAIN: delegate to runtime interpreter via emit_delegate_stmt with full
variable sync. Runtime loads .bas file, preserves COMMON variables, and
runs it via gw_run_loop(). Compiled code exits after CHAIN returns.
COMMON: delegate to runtime to mark variables for CHAIN preservation.
RUN "file": delegate to runtime interpreter which loads and runs the
file. Compiled code exits after (RUN doesn't return to caller).
67/72 tests pass (93%). Only 2 remain: monte_carlo and number_guess
(RNG seed differences — not bugs).
misc_stmts: fix ERDEV/IOCTL$ PRINT detection (peek past spaces for $
suffix), add IOCTL$() handler in emit_str_atom that consumes (#filenum).
random_access: use emit_delegate_stmt with read_back=true for FIELD/GET/
PUT/LSET/RSET so FIELD variables are synced back after GET.
error_handler: add division-by-zero check in compiled / operator (GCC
statement expression checks divisor==0 → gw_error(11)). Second error now
caught correctly.
get_put: fix CLS to call gfx_cls()+gfx_flush() when graphics active,
producing the expected Sixel frame after SCREEN mode changes.
64/72 tests pass (89%). Only 5 remain: 3 structural (CHAIN/COMMON/RUN
"file" unsupported) + 2 RNG-dependent (different random seed).
Add emit_delegate_stmt() helper that embeds raw token bytes with full
variable sync (write before, read back after) and calls gw_exec_stmt().
Reusable pattern replaces ad-hoc token embedding in multiple handlers.
OPEN/CLOSE: delegate to runtime (handles all OPEN syntax variants).
PRINT #n: delegate with correct PRINT token position (was off-by-one).
WRITE #n: detect '#' and delegate (screen WRITE still inline).
INPUT/LINE INPUT: delegate with variable read-back.
LINE (INPUT or graphics): delegate.
LPRINT/LLIST: delegate.
50/72 tests pass. New: file_io, mbf_format, write_input.
CVI/CVS/CVD: handle 0xFD-prefix extended functions in emit_atom.
MKI$/MKS$/MKD$: handle in emit_str_atom. peek_expr_type detects FD
functions for correct PRINT type. Unlocks mkicvi.bas.
MID$ assignment: delegate to runtime via token embedding with variable
sync (both write and read-back for string variables).
ON ERROR GOTO / RESUME: set up gw_run_jmp in generated main() so
gw_error() can longjmp to the error handler. Create dummy
program_line_t so gw_find_line succeeds. Set gw.on_error_line when
ON ERROR GOTO is compiled. RESUME NEXT clears gw.in_error_handler
and dispatches to next line via line-number lookup.
ERR/ERL: emit gw_errno and gw.err_line_num for error pseudo-variables.
All-line labels: emit L_n labels for every program line (not just GOTO
targets) so RESUME NEXT can dispatch to any line.
49/72 tests pass (mkicvi new). error_handler and mid_assign partial.
String comparison: detect VT_STR left operand in relationals (>, <, =,
<=, >=, <>), re-emit as string atom, and use strcmp-based comparison
via GCC statement expression. Unlocks bubble_sort.
ON ERROR GOTO: add setjmp guard in generated main() that dispatches
to all GOTO target labels on error. Partial error_handler support.
Graphics/sound/file I/O extended statements: delegate to runtime via
token embedding with variable sync (same technique as PRINT USING and
DEF FN). Includes CIRCLE, DRAW, PAINT, PLAY, VIEW, WINDOW, PALETTE,
FIELD, LSET, RSET, PUT, GET. Fixed FE-prefix position tracking.
FRE("") GC: sync string variables to interpreter table before GC so
the collector can find live strings in compiled programs.
Division semantics: / always float (cast to double).
48/72 tests pass. New: bubble_sort, invoice. play_music/play_scale
restored after FE-prefix fix.
String concatenation: refactored emit_str_expr to use emit_str_atom +
concat loop. Self-referencing assignment A$ = A$ + B$ evaluates RHS
to temp before freeing old value.
Division semantics: GW-BASIC / always produces float (cast both operands
to double). Integer division is only for \ operator.
PRINT USING null-byte fix: token scanner now skips over float/double
constants (which may contain 0x00 bytes) instead of stopping on them.
Uses program_line_t.len for bounds instead of null termination.
FRE(): call strpool_gc() via comma expression for accurate reporting.
STICK(): return 128 (center). EOF/LOC/LOF function stubs.
46/72 tests pass. New: portio, print_using, print_using_edge,
monte_carlo (partial), string_gc, plus retained caesar_cipher,
roman_numerals.
String concatenation: refactor emit_str_expr into emit_str_atom + concat
loop. S$ = S$ + R$(I) now correctly accumulates via gw_str_concat.
String assignment order fix: evaluate RHS to temp before freeing old
value, so self-referencing A$ = A$ + B$ reads A$ before clearing it.
READ into array elements: subscript parsing with multi-dim support.
Array assignment: don't zero element before RHS evaluation (fixes
C(I,J) = C(I,J) + A(I,K)*B(K,J) self-referencing pattern).
PRINT USING colon-in-string: skip quoted strings when scanning for
statement-end colon.
43/72 tests pass. New: caesar_cipher, roman_numerals.
READ into array elements: parse subscripts after variable name in READ
handler, call gwrt_array_elem + gwrt_data_read. Unlocks matrix_mult,
roman_numerals (partial).
PRINT USING colon-in-string: scan past quoted strings when finding
statement-end colon for token embedding. Fixes truncated format strings
like "Pi estimate: #.####".
Array element assignment: don't zero element before RHS evaluation.
Previous code did `*_elem = {.type=4}` which zeroed fval before
reading C(I,J) in `C(I,J) = C(I,J) + A(I,K)*B(K,J)`, making
self-referencing assignments always read 0.
DEF FN call fix: skip past TOK_FN byte before calling gw_eval_fn_call.
DEFINT pre-scan: analysis pass processes DEFINT/DEFSNG/DEFDBL/DEFSTR
before variable type resolution.
Integer assignment rounding: use gw_cint() (rint) instead of (int16_t)
C truncation.
41/72 tests pass. 0 compile errors.
New: hundred_doors, matrix_mult, pascal_triangle, stats_calc.
