Eremey Valetov
c317d683fb
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.
144 lines
4.1 KiB
Markdown
144 lines
4.1 KiB
Markdown
# GW-BASIC 2026
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A portable C reimplementation of Microsoft GW-BASIC, using the
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[original 8088 assembly source](https://github.com/microsoft/GW-BASIC)
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(released by Microsoft in 2020) as the authoritative reference.
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This is not a transpilation -- it reimplements the algorithms in clean C11
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with modern data structures while targeting bug-compatible behavior.
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## Building
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```bash
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cmake -B build && cmake --build build
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```
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Requires a C11 compiler and CMake 3.10+. PulseAudio (`libpulse-simple`)
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is optional -- detected at build time for `SOUND`/`BEEP`/`PLAY` support.
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Builds three targets:
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- `gwbasic` -- the interpreter
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- `gwbasic-compile` -- the ahead-of-time compiler
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- `libgwrt.a` -- runtime library for compiled programs
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## Usage
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Interactive mode launches the authentic GW-BASIC full-screen editor:
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```
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$ ./gwbasic
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GW-BASIC 2026 0.17.0
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(C) Eremey Valetov 2026. MIT License.
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Based on Microsoft GW-BASIC assembly source.
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Ok
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PRINT 2+2
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4
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Ok
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```
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Run a program file (ASCII or binary tokenized):
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```bash
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./gwbasic tests/programs/prime_sieve.bas
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```
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Compile to a native executable:
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```bash
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./gwbasic-compile tests/programs/fibonacci.bas -c --runtime .
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```
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## Ahead-of-Time Compiler
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`gwbasic-compile` translates BASIC programs to C source, then invokes GCC
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to produce native executables linked against `libgwrt.a`.
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Pipeline: `.bas` → tokenizer → analysis → C codegen → `gcc` → native binary.
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63 of 63 eligible test programs compile via `gwbasic-compile` and produce
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output matching the interpreter's golden files. Run `bash
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tests/run_compiler_tests.sh` to verify.
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```bash
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# Generate C source
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./gwbasic-compile myprog.bas -o myprog.c
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# Compile to executable (automatic)
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./gwbasic-compile myprog.bas -c --runtime /path/to/gw-basic-2026
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```
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## Jupyter Kernel
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A Jupyter notebook kernel for GW-BASIC with inline Sixel graphics
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rendering, INPUT support, and Pygments syntax highlighting.
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```bash
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pip install -e .
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gwbasickernel-install --user
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jupyter notebook # select "GW-BASIC 2026" kernel
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```
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## What Works
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100% token coverage -- all 144 GW-BASIC tokens are implemented.
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**Data types:** INTEGER (%), SINGLE (!), DOUBLE (#), STRING ($)
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**Operators:** `+ - * / ^ \ MOD AND OR XOR EQV IMP NOT < = > <= >= <>`
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**Statements:**
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| Category | Statements |
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|----------|------------|
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| Output | PRINT, LPRINT, LLIST, PRINT USING, WRITE, CLS |
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| Variables | LET, DIM, ERASE, SWAP, DEFINT/SNG/DBL/STR |
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| Control flow | GOTO, GOSUB/RETURN, FOR/NEXT, IF/THEN/ELSE, WHILE/WEND, ON...GOTO/GOSUB |
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| Input | INPUT, LINE INPUT, DATA/READ/RESTORE, INKEY$ |
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| Program | RUN, CONT, STOP, END, NEW, LIST, CLEAR, AUTO, RENUM, DELETE, EDIT |
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| Sequential I/O | OPEN, CLOSE, PRINT#, WRITE#, INPUT#, LINE INPUT# |
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| Random-access I/O | FIELD, LSET, RSET, PUT, GET, CVI/CVS/CVD, MKI$/MKS$/MKD$ |
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| Program I/O | SAVE (binary/ASCII), LOAD (auto-detects), MERGE, CHAIN, COMMON |
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| Event trapping | ON TIMER(n) GOSUB, TIMER ON/OFF/STOP, ON KEY(n) GOSUB |
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| Error handling | ON ERROR GOTO, RESUME, ERROR, ERR, ERL |
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| User functions | DEF FN, RANDOMIZE |
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| File management | KILL, NAME, FILES, MKDIR, RMDIR, CHDIR, SHELL, ENVIRON |
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| Date/time | DATE$, TIME$, TIMER |
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| Screen | LOCATE, COLOR, WIDTH, SCREEN, KEY ON/OFF/LIST |
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| Graphics | PSET, PRESET, LINE, CIRCLE, DRAW, PAINT, GET/PUT (sprites), VIEW, WINDOW, PALETTE, PMAP |
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| Sound | SOUND, BEEP, PLAY (MML) |
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| Memory | DEF SEG, PEEK, POKE, BSAVE, BLOAD |
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| Hardware I/O | OUT, INP, WAIT, MOTOR, STICK, STRIG |
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## Tests
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72 interpreter tests, 14 kernel tests, 63 compiler tests -- all passing.
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```bash
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bash tests/run_tests.sh # interpreter
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python -m gwbasickernel.test_kernel # Jupyter kernel
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```
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## DOS / FreeDOS
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Cross-compiles to DOS with OpenWatcom V2:
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```bash
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wmake -f Makefile.dos16 # 16-bit real-mode (128KB standalone, no extender)
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wmake -f Makefile.dos # 32-bit DOS/4GW (175KB, requires DOS4GW.EXE)
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```
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The 16-bit build runs on FreeDOS, MS-DOS, and compatible systems without
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a DOS extender. See [Getting Started](docs/getting-started.md) for details.
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## Documentation
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Full Sphinx documentation in `docs/`:
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```bash
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cd docs && pip install -r requirements.txt && make html
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```
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## License
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MIT License. See [LICENSE](LICENSE).
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