`shape_variable()` took the identifier off the leaf and looked the variable up
without ever evaluating the subscript, and both verbs then addressed element
zero with a literal. So `SSHAPE SH$(2), ...` wrote the handle into `SH$(0)` and
`GSHAPE SH$(2)` stamped whatever was in `SH$(0)`.
Ordinary assignment and `PRINT` honour the subscript, which is what made this
expensive: a program keeping several saved shapes in an array got every one of
them resolving to the same element, silently, and the only symptom was that
every stamp came out as the last shape captured. The Breakout in examples/ keeps
its six brick stamps in six separate scalars for exactly this reason.
`SPRSAV` was the counter-example and is the model -- it evaluates its argument
and handles an array element correctly. The subscript resolution itself is now
shared: `collect_subscripts()` comes out of src/environment.c as
`akbasic_environment_collect_subscripts()`, so a verb taking a variable by name
resolves a subscript the same way assignment does rather than each verb deciding
for itself.
tests/graphics_verbs.c covers TODO.md's reduction -- which used to print
"[SHAPE:0] []" and now prints "[] [SHAPE:0]" -- and the case a program actually
wants: two shapes captured into two elements, each stamped back through its own,
asserted against the device log so a fix that merely made the strings look right
would not pass.
Chapter 18's trap 4 becomes history, and Chapter 6 says an array works.
TODO.md section 9 item 6, struck.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
`RGR(1)` and `RGR(2)` gave the window in pixels and nothing gave columns, rows
or the cell size -- so anything placing a character *and* a sprite at the same
spot had to hardcode a number measured by hand against whatever font the host
loaded. The Breakout in examples/ does exactly that, `CW# = 16`, and it is the
one thing in that listing that breaks on a different font or window.
**`RWINDOW` is BASIC 7.0's own answer and had never been implemented here.**
`RWINDOW(0)` is the current text window's rows and `RWINDOW(1)` its columns.
`RWINDOW(2)` reports a C128's 40 or 80 column screen mode, and this interpreter
has neither -- refused by name, because answering 0 would be a plausible lie,
which is worse than a refusal that says why.
The cell size in pixels is `RGR(3)` and `RGR(4)`, beside the surface's own
dimensions rather than on `RWINDOW`. Two reasons: a cell size is a fact about
the surface, and `RWINDOW` reports the *window*, so dividing `RGR(1)` by a
column count stops being right the moment a program calls `WINDOW`.
Both read a new optional `grid` entry point on `akbasic_TextSink` -- columns,
rows, cell width, cell height -- implemented by the akgl sink and forwarded by
the tee, in the shape `moveto` and `window` already had. NULL everywhere else,
so both verbs refuse by name against a sink with no grid. `akbasic_sink_init_
stdio()` clears it for the same reason it now clears the other two.
Measured on the standalone build: `RGR(3)` answers 16 and `RWINDOW` answers 50
columns by 37 rows -- the three numbers the Breakout listing had written out as
constants -- and `RWINDOW` follows a `WINDOW` call while `RGR(3)` does not.
tests/console_verbs.c drives the answers through a stand-in sink with a grid,
since the harness sink is stdio and has none; tests/graphics_verbs.c covers the
new `RGR` fields, their refusal, and the moved range bound. The `c excerpt=`
block in docs/10-embedding.md moves with the header, which is `docs_examples`
doing its job.
TODO.md section 6 item 31's second half, struck.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The graphics verbs documented a coordinate transform that did not exist. With
SCALE off a coordinate went straight to akgl_draw_* as a pixel address, so an
800x600 window drew a C128 listing into its corner and left the rest unused --
while the chapter said coordinates were 320x200 and stretching to fit was the
host's business.
akbasic_GraphicsBackend gains a size entry point, require_graphics() asks it
before every verb that draws so a resized window is honoured between two
statements, and 320x200 becomes the fallback for a backend that leaves it NULL.
It is the record's one optional member, so a host written against the old header
keeps the behaviour it had.
SCALE now maps onto the device, and RGR(1)/RGR(2) report the drawing surface so
a program can use a window whose size it did not choose. RGR(0) is BASIC 7.0's
own field, the GRAPHIC mode.
SCALE also mapped xmax onto the width rather than onto the last pixel, so
SCALE 1, 319, 199 followed by DRAW 1, 319, 199 drew nothing at all -- one pixel
past the surface. Fixed in the same line, because it is what makes "SCALE gives
a C128 listing the whole window" true rather than nearly true.
The akgl test renders against a 128x128 target, deliberately smaller than the
old constants: a SCALE still dividing by them misses it entirely rather than
landing somewhere plausible.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Closes groups A, C, D, E, F, H and J of TODO.md section 4, plus RESTORE and
RENUMBER, and closes section 6 -- all seventeen reference defects. Seven of
those turned out to have been fixed or never ported and nobody had written it
down; the audit records the evidence for each.
Two of the seventeen were real. math_plus mutated its left operand when the
operand was mutable, so A# + 1 could modify A#; it was gated on FOR/NEXT
coverage because NEXT relied on the mutation, so tests/for_next.c came first
and NEXT now writes the counter back itself. And the binary operators summed
both numeric fields of their right operand, which no BASIC program can reach
-- that one needed a test written against the value API.
Writing the tests turned up eight defects nobody had listed. Seven are fixed:
IF A = 2 THEN was a parse error; only == worked
IF ... AND ... was a parse error, because a condition parsed as one relation
IF A = 1 OR B = 2 THEN was silently always false, and so was IF A THEN
EXIT before any NEXT restarted the program and exhausted the variable pool
READ never found a DATA line above it, and swallowed the lines between
PRINT 2 + 2 at the prompt was filed as program text instead of answering
a short read discarded its bytes, so COPY produced empty files
every verb taking an argument list said "peek() returned nil token!" on none
The eighth is not fixed and cannot be quietly: a FOR whose step overshoots
runs its body one extra time, and FOR I = 1 TO 1 runs it zero times. The two
errors cancel for a step of 1, which is why neither was noticed. Correcting
them changes the expected output of a checked-in acceptance file, and
tests/reference/README.md forbids editing one to suit this interpreter. It is
tests/for_semantics.c in AKBASIC_KNOWN_FAILING_TESTS, asserting the correct
contract, and TODO.md items 19 and 20.
Sprites are real libakgl actors with a renderfunc of their own, because
akgl_actor_render draws every sprite square and an actor has no per-axis
scale. Both are filed upstream. SPRSAV takes an image file, an SSHAPE handle
or a 63-element integer array -- a string here cannot hold a zero byte.
Verbs that need hardware that does not exist are refused by name with the
reason rather than faked: SYS, HEADER, COLLECT, BACKUP, BOOT, FILTER, and
DIRECTORY, which is refused for a missing libakstdlib wrapper filed upstream.
94 tests in the default build, 93 with SDL, 94 under ASan and UBSan, doxygen
clean. The Go acceptance corpus stayed green throughout.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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>
