Andrew Kesterson
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`SPRHIT n, kind [,x1, y1, x2, y2]` gives a sprite a collision shape: a box, a circle inscribed in it, or a capsule. `RSPHIT(n, f)` reads it back in SPRHIT's own argument order, the way RSPRITE and RSPPOS already do, and needs no device because it answers from interpreter state. The rectangle is two corners measured from the sprite's top-left, in device pixels -- the same `x1, y1, x2, y2` that `BOX` and `SSHAPE` take. A dialect with two spellings for a rectangle is one nobody can write from memory. Omit it and the shape fits whatever the picture turned out to be, which is what a sprite loaded from a file needs: `SPRSAV "ship.png", 1` takes the image's own size and the program never learns what that was. **A sprite nobody has shaped collides with its whole frame, expansion bits included, exactly as before.** That is a promise rather than a convenience, and it has its own test: the same two sprites in the same two places, once with no SPRHIT and once with a four-pixel box, reporting a collision and then not. Named SPRHIT rather than SPRSHAPE because "shape" already means "a region SSHAPE saved" in this dialect, in this very chapter -- `SPRSAV A$, 1` takes one -- and a reader who typed `SPRSHAPE A$, 1` would have had every reason to. Both names, and RSPHIT, were grepped against every label in docs/, examples/ and both corpora first: a bare word is a label here, so a verb and a label share one namespace and taking a name a checked-in listing already uses would break it silently. `SPRHIT n, 0` takes a sprite out of collision while leaving it on the screen -- the ghost, the flashing invulnerable player, the pickup already taken. Hiding it with `SPRITE n, 0` stops it colliding too, and is what you want when it should not be seen either. The circle answers the complaint chapter 8 already ships a figure of. That figure shows two discs whose *boxes* touch at a corner while the artwork is nowhere near, and `BUMP(1)` reporting a collision; two `SPRHIT n, 2` and it stops. The test asserts both halves so the figure's caption stays true. `tests/verbs_table.c` caught RSPHIT filed after RSPPOS rather than before it, which is the sorted-table test doing exactly the job it exists for. Docs: a new section in chapter 8, rows in the verb and function references in alphabetical order, and chapter 13's "collision is by bounding box" becomes "collision is by shape" with the addition named. 111 with akgl, 110 without, and the artwork breakout still runs clean. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01EwxGB6TdoVvZ11KQQME9cL
126 lines
8.6 KiB
Markdown
126 lines
8.6 KiB
Markdown
# 11. Verb reference
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Every statement, alphabetically. This list is generated from the interpreter's own
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dispatch table, so it cannot drift out of step with what the program actually accepts.
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A verb marked **Refused** parses and then reports why it cannot run — see Chapter 13
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for the reasoning in each case.
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| Verb | Form | What it does |
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|---|---|---|
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| `APPEND` | `APPEND n, "name"` | Open a file on channel `n` for writing at its end. |
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| `AUTO` | `AUTO n` | Number lines automatically in steps of `n`. `AUTO 0` turns it off. |
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| `BACKUP` | `BACKUP` | **Refused.** Duplicates one disk onto another; there are no disks. |
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| `BEGIN` | `IF c THEN BEGIN` | Start a block that runs to `BEND`, so an `IF` can span lines. |
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| `BEND` | `BEND` | End a `BEGIN` block. |
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| `BLOAD` | `BLOAD "name", addr, len` | Read a file into memory. The length is required. |
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| `BOOT` | `BOOT` | **Refused.** Loads and runs a boot sector; there is none. |
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| `BOX` | `BOX src, x1, y1, x2, y2 [,angle]` | Outline a rectangle, optionally rotated. |
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| `BSAVE` | `BSAVE "name", from, to` | Write a range of memory to a file. |
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| `CATALOG` | `CATALOG` | **Refused.** The other name for `DIRECTORY`. |
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| `CHAR` | `CHAR col, x, y, "text"` | Put text at a character cell. Needs a sink with a cursor. Terminates the row where it stops, so it erases whatever followed. |
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| `CIRCLE` | `CIRCLE src, x, y, rx, ry [,...]` | Draw an ellipse, arc or polygon. |
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| `CLR` | `CLR` | Drop every variable and function, keeping the program. |
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| `COLLECT` | `COLLECT` | **Refused.** Validates a disk's block allocation map. |
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| `COLLISION` | `COLLISION 1 [,target]` | Call a subroutine when sprites collide. No target disarms it. |
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| `COLOR` | `COLOR src, index` | Bind a colour source to a palette index, 1 to 16. |
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| `CONCAT` | `CONCAT "a", "b"` | Append file `a` to file `b`. |
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| `CONT` | `CONT` | Resume a program stopped by `STOP`. |
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| `COPY` | `COPY "a", "b"` | Copy file `a` to file `b`. |
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| `DATA` | `DATA v [, ...]` | Declare values for `READ`. Collected before the program runs. |
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| `DCLEAR` | `DCLEAR` | Close every open channel. The half of a drive reset that means something. |
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| `DCLOSE` | `DCLOSE [n]` | Close channel `n`, or every channel. |
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| `DEF` | `DEF NAME(args) = expr` | Define a function. Multi-line definitions end in `RETURN`. |
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| `DELETE` | `DELETE [n][-n]` | Delete lines, with the same range forms as `LIST`. |
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| `DIM` | `DIM A#(n [,...])` | Make an array. Subscripts start at zero; `n` is the count. |
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| `DIM` … `AS` | `DIM S@ AS T`, `DIM P@ AS PTR TO T` | Make a structure, or a strict pointer to one. See Chapter 16. |
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| `DIRECTORY` | `DIRECTORY` | **Refused.** Needs a directory-reading wrapper that does not exist yet. |
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| `DLOAD` | `DLOAD "name"` | Load a program from a file. |
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| `DO` | `DO [WHILE c | UNTIL c]` | Start a loop. The condition may be here, on the `LOOP`, or neither. |
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| `DOPEN` | `DOPEN n, "name" [,W]` | Open a file on channel `n`. `W` opens it for writing. |
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| `DRAW` | `DRAW src, x, y [TO x, y ...]` | Plot a point or draw a polyline. |
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| `DSAVE` | `DSAVE "name"` | Save the program to a file. |
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| `DVERIFY` | `DVERIFY "name"` | The other name for `VERIFY`. |
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| `END` | `END` | Stop the program. Does not arm `CONT`. |
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| `ENVELOPE` | `ENVELOPE n, a, d, s, r` | Define one of `PLAY`'s ten envelope presets. |
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| `EXIT` | `EXIT` | Leave the innermost `FOR` or `DO` loop. |
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| `FETCH` | `FETCH count, from, to` | Copy bytes. The same as `STASH`; there is no expansion RAM. |
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| `FILTER` | `FILTER ...` | **Refused.** There is no filter stage in the audio backend. |
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| `FOR` | `FOR V = a TO b [STEP c]` | Start a counted loop, ended by `NEXT`. |
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| `GET` | `GET V` | Take a keystroke if one is waiting, without stopping. |
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| `GETKEY` | `GETKEY V` | Wait for a keystroke, holding the program but not the host. |
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| `GOSUB` | `GOSUB line` | Call a subroutine, returning on `RETURN`. |
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| `GOTO` | `GOTO line` | Jump to a line or a label. |
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| `GRAPHIC` | `GRAPHIC mode | CLR` | Choose a screen mode, or clear it. |
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| `GSHAPE` | `GSHAPE A$, x, y` | Stamp a region saved by `SSHAPE`. |
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| `HEADER` | `HEADER "name"` | **Refused.** Formats a disk. |
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| `HELP` | `HELP` | Re-list the line the last error happened on. |
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| `IF` | `IF c THEN s [ELSE s]` | Branch. Everything after `THEN` belongs to the condition. |
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| `INPUT` | `INPUT ["prompt"] V` | Read a line from the user. |
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| `INPUT#` | `INPUT #n, V` | Read a line from a channel. |
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| `KEY` | `KEY [n, "text"]` | Define a function-key macro, or list them all. |
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| `LABEL` | `LABEL NAME` | Mark this line with a name any branch can use. |
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| `LET` | `LET V = expr` | Assign. Optional; assignment needs no verb. |
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| `LIST` | `LIST [n][-n]` | List the program, or part of it. |
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| `LOAD` | `LOAD "name"` | The other name for `DLOAD`. |
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| `LOCATE` | `LOCATE x, y` | Move the pixel cursor. |
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| `LOOP` | `LOOP [WHILE c | UNTIL c]` | End a `DO` loop. |
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| `MOVSPR` | `MOVSPR n, ...` | Move a sprite. Four forms; see Chapter 8. |
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| `NEW` | `NEW` | Erase the program and every variable. |
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| `NEXT` | `NEXT V` | End a `FOR` loop and advance its counter. |
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| `ON` | `ON e GOTO|GOSUB t [,...]` | Branch to the `e`th target, counting from one. |
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| `PAINT` | `PAINT src, x, y` | Flood-fill the region containing a point. |
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| `PLAY` | `PLAY "notes"` | Queue notes. Does not block. |
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| `POINT` | `POINT P@ AT s@` | Aim a strict pointer at a structure. See Chapter 16. |
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| `POKE` | `POKE addr, byte` | Write a byte to a real address. |
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| `PRINT` | `PRINT [expr]` | Print a value and a newline. |
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| `PRINT#` | `PRINT #n, expr` | Write a line to a channel. |
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| `PUDEF` | `PUDEF "chars"` | Redefine what `PRINT USING` pads and punctuates with. |
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| `QUIT` | `QUIT` | End the interpreter. |
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| `READ` | `READ V [,...]` | Fill variables from the next `DATA` items. |
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| `RECORD` | `RECORD n, r [,pos]` | Position a channel at record `r`. Records are lines. |
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| `RENAME` | `RENAME "a", "b"` | Rename a file. |
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| `RENUMBER` | `RENUMBER [start [,step [,from]]]` | Renumber lines, rewriting every branch to match. |
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| `RESTORE` | `RESTORE [line]` | Reset the `READ` cursor, optionally to a line. |
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| `RESUME` | `RESUME [NEXT | line]` | Return from a `TRAP` handler. |
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| `RETURN` | `RETURN [expr]` | Return from a `GOSUB` or a multi-line `DEF`. |
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| `RUN` | `RUN [line]` | Run the program, optionally from a line. |
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| `SAVE` | `SAVE "name"` | The other name for `DSAVE`. |
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| `SCALE` | `SCALE on [,xmax, ymax]` | Turn user coordinates on or off. |
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| `SCNCLR` | `SCNCLR` | Clear the text screen. |
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| `SCRATCH` | `SCRATCH "name"` | Delete a file. |
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| `SLEEP` | `SLEEP seconds` | Pause. Holds the program, not the host. |
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| `SOUND` | `SOUND v, freq, dur [,...]` | Play a tone on a voice. Does not block. |
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| `SPRCOLOR` | `SPRCOLOR [c1] [,c2]` | Set the two shared multicolour registers. |
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| `SPRHIT` | `SPRHIT n, kind [,x1, y1, x2, y2]` | Give a sprite a collision shape. Kind 0 none, 1 box, 2 circle, 3 or 4 capsule. No rectangle fits the frame. See Chapter 8. |
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| `SPRITE` | `SPRITE n [,on] [,col] [,...]` | Configure a sprite. Omitted arguments are left alone. |
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| `SPRSAV` | `SPRSAV source, n` | Give sprite `n` a picture. Three source forms; see Chapter 8. |
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| `SSHAPE` | `SSHAPE A$, x1, y1 [,x2, y2]` | Save a screen region; `A$` receives a handle. |
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| `STASH` | `STASH count, from, to` | Copy bytes. The same as `FETCH`. |
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| `STOP` | `STOP` | Stop the program; `CONT` resumes it. |
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| `SWAP` | `SWAP A, B` | Exchange two variables of the same type. |
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| `SYS` | `SYS addr` | **Refused.** There is no 6502 and no ROM to call. |
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| `TEMPO` | `TEMPO n` | How fast `PLAY` releases its queue. |
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| `TRAP` | `TRAP [target]` | Send errors to a handler. No target disarms it. |
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| `TROFF` | `TROFF` | Turn line tracing off. |
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| `TRON` | `TRON` | Turn line tracing on; each line prints its number in brackets. |
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| `TYPE` | `TYPE NAME` … `END TYPE` | Declare a record, its fields one per line. See Chapter 16. |
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| `VERIFY` | `VERIFY "name"` | Compare the program in memory against a file. |
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| `VOL` | `VOL n` | Set the overall volume, 0 to 15. |
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| `WAIT` | `WAIT addr, mask [,xor]` | Poll a byte until it matches. Holds the program. |
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| `WIDTH` | `WIDTH 1|2` | How thick a drawn line is. |
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| `WINDOW` | `WINDOW l, t, r, b [,clear]` | Constrain the text area. Needs a sink with a grid. |
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## Words that are not verbs
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`AND`, `ELSE`, `NOT`, `OR`, `REM`, `STEP`, `THEN`, `TO`, `UNTIL`, `USING` and `WHILE`
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are reserved, but none of them is a statement on its own — each is consumed by the verb
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it belongs to.
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## Deliberately absent
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`BANK`, `FAST`, `MONITOR` and `SPRDEF` have no table entry at all. The first three are
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incompatible with a modern machine — there is no bank switching, no CPU speed to
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control, and no machine-language monitor to drop into. `SPRDEF` is an interactive
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full-screen editor rather than a programmable verb.
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