Eremey Valetov
5105ecafd6
RND can now be called without parentheses (equivalent to RND(1)), matching real GW-BASIC behavior for legacy code compatibility. Update all Sphinx documentation pages to reflect features added in v0.6.0-0.8.0: DATE$/TIME$/TIMER, FILES/SHELL/CHDIR/MKDIR/RMDIR, AUTO/RENUM/DELETE, COMMON, LPRINT/LLIST with --lpt, --full TUI flag, dynamic screen buffer, 54 tests.
151 lines
5.3 KiB
Markdown
151 lines
5.3 KiB
Markdown
# Language Reference
|
||
|
||
## Data Types
|
||
|
||
| Type | Suffix | Description |
|
||
|------|--------|-------------|
|
||
| INTEGER | `%` | 16-bit signed |
|
||
| SINGLE | `!` | 32-bit float |
|
||
| DOUBLE | `#` | 64-bit float |
|
||
| STRING | `$` | Up to 255 bytes |
|
||
|
||
## Operators
|
||
|
||
`+`, `-`, `*`, `/`, `^`, `\` (integer div), `MOD`, `AND`, `OR`, `XOR`, `EQV`,
|
||
`IMP`, `NOT`, `<`, `=`, `>`, `<=`, `>=`, `<>`
|
||
|
||
## Numeric Functions
|
||
|
||
`SGN`, `INT`, `ABS`, `SQR`, `SIN`, `COS`, `TAN`, `ATN`, `LOG`, `EXP`, `RND`,
|
||
`FIX`, `CINT`, `CSNG`, `CDBL`
|
||
|
||
`RND` can be called with or without parentheses: `RND` is equivalent to `RND(1)`.
|
||
|
||
## String Functions
|
||
|
||
`LEN`, `ASC`, `CHR$`, `VAL`, `STR$`, `LEFT$`, `RIGHT$`, `MID$`, `SPACE$`,
|
||
`STRING$`, `HEX$`, `OCT$`, `INSTR`, `INPUT$`
|
||
|
||
## File Functions
|
||
|
||
`EOF`, `LOC`, `LOF`
|
||
|
||
## Pseudo-variables
|
||
|
||
`ERL`, `ERR`, `CSRLIN`, `INKEY$`, `DATE$`, `TIME$`, `TIMER`, `POS(0)`
|
||
|
||
## Literals
|
||
|
||
Decimal, `&H` hex, `&O` octal, `D` exponent (double), `E` exponent (single),
|
||
type suffixes (`%`, `!`, `#`)
|
||
|
||
## Statements
|
||
|
||
| Category | Statements |
|
||
|----------|------------|
|
||
| Output | `PRINT`, `LPRINT`, `LLIST`, `PRINT USING`, `WRITE`, `CLS` |
|
||
| Variables | `LET`, `DIM`, `ERASE`, `SWAP`, `DEFINT`, `DEFSNG`, `DEFDBL`, `DEFSTR` |
|
||
| Control flow | `GOTO`, `GOSUB`/`RETURN`, `FOR`/`NEXT`, `IF`/`THEN`/`ELSE`, `WHILE`/`WEND`, `ON...GOTO`, `ON...GOSUB` |
|
||
| Input | `INPUT`, `LINE INPUT`, `DATA`/`READ`/`RESTORE`, `INKEY$` |
|
||
| Program control | `RUN`, `RUN "file"`, `CONT`, `STOP`, `END`, `NEW`, `LIST`, `CLEAR`, `AUTO`, `RENUM`, `DELETE` |
|
||
| Sequential I/O | `OPEN`, `CLOSE`, `PRINT#`, `WRITE#`, `INPUT#`, `LINE INPUT#` |
|
||
| Random-access I/O | `FIELD`, `LSET`, `RSET`, `PUT`, `GET`, `CVI`/`CVS`/`CVD`, `MKI$`/`MKS$`/`MKD$` |
|
||
| Program I/O | `SAVE`, `LOAD`, `MERGE`, `CHAIN`, `COMMON` |
|
||
| Error handling | `ON ERROR GOTO`, `RESUME`, `RESUME NEXT`, `RESUME n`, `ERROR`, `ERR`, `ERL` |
|
||
| User functions | `DEF FN`, `RANDOMIZE` |
|
||
| File management | `KILL`, `NAME`, `FILES`, `MKDIR`, `RMDIR`, `CHDIR`, `SHELL` |
|
||
| Date/time | `DATE$`, `TIME$`, `TIMER` |
|
||
| Screen | `LOCATE`, `COLOR`, `WIDTH`, `SCREEN`, `KEY ON`/`OFF`/`LIST`, `KEY n,"string"` |
|
||
| Graphics | `PSET`, `PRESET`, `LINE`, `CIRCLE`, `DRAW`, `PAINT` |
|
||
| Sound | `SOUND`, `BEEP`, `PLAY` (MML parser, PulseAudio backend) |
|
||
| Misc | `POKE`, `KEY`, `TRON`/`TROFF`, `OPTION BASE`, `MID$` assignment |
|
||
| System | `SYSTEM` |
|
||
|
||
## Printer Output (LPRINT / LLIST)
|
||
|
||
`LPRINT` works identically to `PRINT` but sends output to the printer:
|
||
|
||
- **Default:** output is appended to `LPT1.TXT` in the current directory
|
||
- **`--lpt /dev/lp0`** (Linux) or **`--lpt LPT1`** (FreeDOS): send to real hardware
|
||
- **`--lpt report.txt`**: redirect to a custom file
|
||
|
||
`LLIST` lists the program to the printer, with optional line number ranges
|
||
(`LLIST`, `LLIST 10-50`, `LLIST -100`).
|
||
|
||
Both support `PRINT USING`, semicolons, commas, `TAB()`, and `SPC()`.
|
||
|
||
## Graphics
|
||
|
||
Graphics mode is activated with `SCREEN 1` (320x200, 4 colors) or
|
||
`SCREEN 2` (640x200, monochrome). Drawing commands render to an internal
|
||
framebuffer and output via [Sixel graphics](https://en.wikipedia.org/wiki/Sixel),
|
||
which works in terminals like xterm, mlterm, foot, and WezTerm.
|
||
|
||
### Drawing Commands
|
||
|
||
- `PSET (x,y), color` / `PRESET (x,y)` — set/reset individual pixels
|
||
- `LINE (x1,y1)-(x2,y2), color [,B|BF]` — lines, boxes, filled boxes
|
||
- `CIRCLE (cx,cy), r [,color [,start, end [,aspect]]]` — circles and arcs
|
||
- `PAINT (x,y), fill, border` — flood fill
|
||
- `DRAW string` — turtle graphics mini-language (U/D/L/R/E/F/G/H, M, C, S, B, N)
|
||
- `POINT (x,y)` — read pixel color
|
||
- `COLOR fg, bg` — set foreground/background colors
|
||
|
||
### Example
|
||
|
||
```
|
||
SCREEN 1
|
||
LINE (0,0)-(319,199), 1
|
||
CIRCLE (160,100), 80, 2
|
||
PAINT (160,100), 3, 2
|
||
```
|
||
|
||
## Sound
|
||
|
||
- `SOUND frequency, duration` — play a tone (frequency in Hz, duration in clock ticks)
|
||
- `BEEP` — play the default beep
|
||
- `PLAY string` — Music Macro Language (MML) string for melodies
|
||
|
||
Sound output uses PulseAudio when available; commands are silently ignored otherwise.
|
||
|
||
## Full-Screen Editor (TUI)
|
||
|
||
When running interactively, GW-BASIC 2026 presents the authentic full-screen
|
||
editor:
|
||
|
||
- 25×80 screen buffer by default, or full terminal size with `--full`
|
||
- Press Enter on any screen line to re-enter it as BASIC input
|
||
- Insert/Overwrite toggle (Insert key)
|
||
- Home/End/Delete/Backspace/Escape for line editing
|
||
- Ctrl+C interrupts running programs
|
||
- Uses the ANSI alternate screen buffer for clean terminal restore on exit
|
||
|
||
### Function Keys
|
||
|
||
Default F1-F10 bindings match the original GW-BASIC:
|
||
|
||
| Key | Default | Key | Default |
|
||
|-----|---------|-----|---------|
|
||
| F1 | `LIST ` | F6 | `,"LPT1:"` + Enter |
|
||
| F2 | `RUN` + Enter | F7 | `TRON` + Enter |
|
||
| F3 | `LOAD"` | F8 | `TROFF` + Enter |
|
||
| F4 | `SAVE"` | F9 | `KEY ` |
|
||
| F5 | `CONT` + Enter | F10 | `SCREEN 0,0,0` + Enter |
|
||
|
||
- `KEY ON` — show the function key bar on line 25
|
||
- `KEY OFF` — hide the bar
|
||
- `KEY LIST` — display all definitions
|
||
- `KEY n, "string"` — redefine a function key
|
||
|
||
### Piped Mode
|
||
|
||
When stdin is not a terminal (piped input), the TUI is not activated.
|
||
The interpreter reads lines from stdin and writes output directly to stdout,
|
||
suitable for scripting and test harnesses.
|
||
|
||
### Program Editing
|
||
|
||
- `AUTO [start][,increment]` — automatic line numbering mode
|
||
- `RENUM [new][,[old][,increment]]` — renumber program lines (patches all GOTO/GOSUB references)
|
||
- `DELETE range` — delete program lines (`DELETE 10-50`, `DELETE -100`, `DELETE 200-`)
|