3 Commits

Author SHA1 Message Date
16b38c1138 Generate the documentation's figures from the listings they illustrate
Chapters 6 and 8 described what a verb draws in prose. Eight figures now show
it, and each one is produced by running the BASIC listing printed immediately
above it -- so a picture cannot drift away from the code beside it, which is the
way a screenshot goes wrong and the way nothing notices.

tools/screenshot.c is a second SDL host, much smaller than the frontend: dummy
video driver, software renderer, run to completion, read the target back, write
a PNG. It draws no text layer on purpose, so a READY in the corner is not noise
in a figure about BOX and no font has to be resolved.

tools/docs_screenshots.sh reads the new screenshot=NAME fence tag straight out
of the markdown. size=WxH is the second tag, and SCALE's figure uses it: the
point being made is a 320x200 listing filling a larger window, which cannot be
made on a 320x200 surface.

Two gates, answering different questions. docs_examples fails a tagged block
with no image, in both configurations, so a figure cannot be added and
forgotten. docs_screenshots -- a CTest, AKGL build only -- re-renders every
figure and compares byte for byte, so a listing edited without regenerating
fails. Only the second catches a stale picture.

The PNGs are checked in because a reader on the forge has no build tree, and
docs/images/README.md says loudly that they are generated. Regenerating is never
part of a build: the target is run deliberately, so a make cannot put eight
binary diffs in front of whoever ran it.

Drawing the BOX figure caught a defect in TODO.md itself. Deviation 16 claimed
in bold that BOX fills on a negative angle while its own paragraph said the fill
was filed rather than implemented. BOX cannot fill, and filled_rect is reached
by no verb as a result.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-01 07:37:04 -04:00
23ccb66f69 Document the interpreter's architecture as chapter fourteen
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Chapters 1 through 13 describe the language. Nothing described the machine
that runs it, and the answers were spread across header comments, TODO.md
sections written for a different purpose, and the source itself. Somebody
embedding the interpreter, debugging something it did, or adding a verb had
to reconstruct the shape from all three.

docs/14-architecture.md is that shape, and only that: the three targets and
the driver, the single akbasic_Runtime and why nothing is file-scope,
akbasic_runtime_step() unrolled with the reason each stage sits where it
does, the four modes and what set_mode() does beyond assigning, a line's
journey from text through tokens and leaves to a verb handler, the dispatch
table, the pool map with what each exhaustion actually says, environments
doubling as block state, the two kinds of error, devices, and interrupts.

It defers rather than restates. The headers are the authority on every
function's contract and the chapter says so up front; where a rule is subtle
the header comment already states it at more length than a chapter should.
MAINTENANCE.md keeps the conventions and now points here for the mechanism,
so there is still one copy of each.

Two sections are the reason it exists at all. Debugging: reading a TRON trace
as evidence about the loop rather than the lines, reading an akerror stack
trace and what it is not, four breakpoints and the expressions worth printing
at them, narrowing with ctest -R and the mock devices, and a symptom-to-cause
table. Changing it: the verb recipe end to end including the private
src/verbs.h prototype that is easy to miss, the rule that a missing
dependency capability gets filed upstream rather than worked around, and the
five constraints goal 3 puts on any change.

A `text` fence tag comes with it. Every fenced block in docs/ is executed and
an untagged one is a hard error, so six block diagrams had nowhere to live.
The tag means never executed, it is counted in the skip line like `cmake`,
and MAINTENANCE.md documents it -- the alternative was an indented block the
extractor never sees, and a picture nobody decided about is indistinguishable
from a test nobody ran.

tests/docs_examples.sh now makes --root and --basic absolute before it
starts. Both are used from inside a sandbox directory it cd's into, so the
invocation MAINTENANCE.md itself documents -- --root . --basic ./build/basic
-- failed every example with "exited 127" and every setup= with "setup
failed". CTest passes absolute paths and never saw it; running one document
by hand hits it immediately.

Writing the error section turned up a defect and TODO.md section 8 records
it. The ATTEMPT blocks that turn a script's mistake into an error line wrap
parsing and interpretation but not scanning, so a line with more than 32
tokens escapes as an interpreter error: stack trace, exit 1, and at a prompt
the REPL is gone. That is the same shape as section 8 item 2, on a path that
fix did not cover. Not fixed here -- it is a behaviour change and wants its
own tests -- but written down with the three call sites and what would cover
them.

Both configurations stay green: 95/95 and 94/94. docs_examples now runs 37
programs, 9 transcripts, 45 output comparisons, 3 C snippets, 2 excerpts and
2 shell blocks, and skips 9 text blocks.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-07-31 23:14:17 -04:00
342e4c07da Execute every documented example as a test
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docs/ and README.md carry 85 fenced blocks. Every one was checked by hand
exactly once, when it was written, which is not a standard that survives a
changing interpreter -- and four were already wrong: two transcripts showing a
leading space PRINT does not emit, akbasic_TextSink in README.md missing the
two members it had grown hours earlier, and FILTER's refusal quoted with
wording the code does not use.

tests/docs_examples.sh reads a fence-tag vocabulary and runs what it finds.
BASIC programs and transcripts run and are byte-compared against an `output`
block; C snippets compile with -fsyntax-only against the real include path,
which CMake writes out because it is transitive through akerror, akstdlib and
akgl; shell blocks run in a sandbox. Anything that would reconfigure the build
tree, hit the network or re-enter the suite is tagged norun with the reason in
MAINTENANCE.md, and the two cmake blocks stay hand-maintained by decision.

An untagged block is a failure rather than a default, and the pass line
reports what it executed by kind. Both exist because the way a harness like
this dies is by quietly matching nothing and passing -- which it duly did on
the first CTest run, where a generator expression evaluating to nothing still
contributed an empty argument that the script read as a filename. The count is
what caught it.

The excerpt check earns its own mention: a block tagged
`c excerpt=include/akbasic/sink.h` must still appear in that header, comments
and whitespace ignored. Compiling it would only redefine the type, so a
compile check could not have found the stale struct, and did not.

Registered as the CTest case docs_examples in both configurations. Fixing the
four wrong examples turned up two interpreter defects, fixed in the previous
commit and recorded in TODO.md section 8.

MAINTENANCE.md is new: the fence-tag reference, what to do when the case
fails, and the conventions that until now only existed inside source comments
-- the three test lists and how two of them invert "passed", the sorted verb
table, that a golden file is never edited to suit this interpreter, and that a
fix gets mutation-checked with a file copy rather than git checkout.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-07-31 22:41:36 -04:00