Add capsules/turtle.4th, a limited LOGO-style turtle graphics demo capsule

Browse Source

First entry in the "cookbook" track: a demo capsule plus HOWTO, per the
sequencing laid out after the POST-coverage sweep. Built entirely in FORTH
on top of existing primitives -- fabric.4th's LINE (raster Bresenham) and
Q.SIN/Q.COS (Q48.16 trig), plus PLOT/FB-WIDTH/FB-HEIGHT -- no new C words.

FORWARD/BACK/LEFT/RIGHT/PENUP/PENDOWN/HOME/SETXY/SETHEADING/SETCOLOR give
the classic turtle model; POLYGON and STAR compose FORWARD+turn into simple
demo shapes; TURTLE-DEMO is a one-call visual smoke test. Not wired into
init.4th -- REPL-invoked only, matching the original idea's own scope.

Verified: mkcapsule --lint clean, hosted-build logic trace shows zero VM
errors and correct stack balance through the whole vocabulary, zero build
warnings and capsule loads cleanly on all three kernel architectures.
Visual pixel-level confirmation not yet done (needs an interactive
gtk-display session or driving past the ~25-30 min DoE-before-REPL wall),
documented as an open item in the HOWTO.

HOWTO: docs/working/architecture/TURTLE-GRAPHICS-HOWTO-20260819.md

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

...

This commit is contained in:

Robert Allan James

2026-08-19 01:50:54 -04:00

co-authored by Claude Sonnet 5

parent abb858a300

commit e40134da0d

6 changed files with 13242 additions and 2 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download Patch File Download Diff File Expand all files Collapse all files

logs/20260819-014738/amd64/qemu-amd64-20260819-014738.log

+12960

File diff suppressed because it is too large Load Diff