Merge pull request 'A GALAGA tutorial: C/libakgl engine with akbasic embedded as the enemy-behavior engine' (#37) from galaga-tutorial into main

Reviewed-on: #37

.gitea/workflows/ci.yaml

@@ -17,7 +17,7 @@ jobs:
           # Not recursive, deliberately. The top-level build needs
           # deps/libakerror and deps/libakstdlib, via add_subdirectory, and
           # nothing else: the golden corpus and the Commodore font now live in
-          # this repository (tests/reference/ and assets/fonts/), so
+          # this repository (tests/language/ and assets/fonts/), so
           # deps/basicinterpret is no longer a build dependency at all.
           # It does *not* need deps/libakgl, which is guarded behind
           # AKBASIC_WITH_AKGL and defaults OFF -- and recursing into it would
@@ -62,11 +62,9 @@ jobs:
         run: |
           cmake -S . -B build
           cmake --build build --parallel 2
-      # The suite is 78 cases: 41 golden files byte-compared against the Go
-      # reference's own corpus (checked in at tests/reference/, see its README),
-      # 9 local golden cases for verbs the reference never implemented, 25 unit
-      # tests, 2 embedding examples, and 1 known-failing test that asserts the
-      # *correct* contract for defects carried over from the reference (TODO.md
+      # The suite is 112 cases: 65 language files with sibling expectations,
+      # 43 unit tests, 3 embedding examples, and docs_examples.
+      # Some unit tests assert the *correct* contract for known defects (TODO.md
       # section 6). A green run therefore does not mean defect-free -- see
       # AKBASIC_KNOWN_FAILING_TESTS.
       #

CLAUDE.md

@@ -26,7 +26,7 @@ scripting engine for game authors.
 | [the issue tracker](https://source.starfort.tech/andrew/akbasic/issues) | **Outstanding defects and gaps.** Labelled by kind and blast radius; `status::grooming` means the scope is not settled yet |
 | [`TODO.md`](TODO.md) | The record: settled design decisions, the deviation register, defects already fixed, and the reasoning behind the measurements. §0.1 first — it retires the byte-for-byte fidelity constraint several later sections were written on |
 | [`README.md`](README.md) | What the project is and why, for somebody who has not seen it |
-| [`docs/`](docs/README.md) | The language itself: eighteen chapters, verb and function reference. [Chapter 14](docs/14-architecture.md) is the interpreter's architecture — the step loop, the pools, the two kinds of error, and how to debug it. [Chapter 15](docs/15-error-codes.md) is the error-code appendix. [Chapters 17](docs/17-tutorial-breakout.md) and [18](docs/18-tutorial-breakout-artwork.md) are tutorials that build the games in `examples/breakout/` |
+| [`docs/`](docs/README.md) | The language itself: twenty-one chapters, verb and function reference. [Chapter 14](docs/14-architecture.md) is the interpreter's architecture — the step loop, the pools, the two kinds of error, and how to debug it. [Chapter 15](docs/15-error-codes.md) is the error-code appendix. [Chapters 17](docs/17-tutorial-breakout.md) and [18](docs/18-tutorial-breakout-artwork.md) are tutorials that build the games in `examples/breakout/`; [Chapters 20](docs/20-tutorial-galaga.md) and [21](docs/21-tutorial-galaga-enemies.md) build the embedding host in `examples/galaga/` |
 | `deps/libakerror/AGENTS.md` | The `ATTEMPT`/`CLEANUP`/`PROCESS`/`HANDLE`/`FINISH` protocol, authoritatively |
 | `deps/libakerror/UPGRADING.md` | 1.0.0's status registry. Required before writing an error code |
 | `deps/<library>/AGENTS.md` | Per-repo rules. Read the relevant one **before editing a submodule** |
@@ -57,9 +57,9 @@ repeating where you will see them:
   `include/akgl/SDL_GameControllerDB.h`. Change the template or the generator script.
 - **Do not reformat code you are not otherwise changing.** Several files mix tabs and spaces
   and there is no repo-wide formatter; style conversions get their own commit.
-- **Do not edit `tests/reference/`.** Those expectations came from the Go implementation and
-  are never edited to suit this interpreter. A deliberate divergence goes in
-  `tests/reference/README.md`'s divergence table and `docs/13-differences.md`.
+- **Keep `tests/language/` editable.** Its `.bas` programs and sibling `.txt` expectations
+  are changed together when behavior changes. Record deliberate language decisions in
+  `TODO.md` or `docs/13-differences.md`.
 - **Open an issue for outstanding work; do not add it to `TODO.md`.**
   <https://source.starfort.tech/andrew/akbasic/issues>, or `tea issues create --repo
   andrew/akbasic`. Name the file and line, the functional consequence, and what closing it would

CMakeLists.txt

@@ -268,6 +268,69 @@ if(AKBASIC_BUILD_EXAMPLES)
   endforeach()
 endif()
 
+# The galaga example: a C game on libakgl with the interpreter embedded as its
+# enemy-behavior engine. Chapters 20 and 21 build it from an empty file, so it
+# is compiled and run by every AKGL build rather than rotting in a document.
+# The asset, script and font paths are baked in so the smoke test can launch
+# from any working directory; --assets and --script override them at runtime.
+if(AKBASIC_BUILD_EXAMPLES AND AKBASIC_WITH_AKGL)
+  add_executable(akbasic_example_galaga
+    examples/galaga/main.c
+    examples/galaga/script.c
+    examples/galaga/enemies.c
+    examples/galaga/player.c)
+  target_compile_options(akbasic_example_galaga PRIVATE -Wall -Wextra)
+  target_compile_definitions(akbasic_example_galaga PRIVATE
+    GALAGA_ASSET_DIR="${CMAKE_CURRENT_SOURCE_DIR}/examples/galaga/assets"
+    GALAGA_SCRIPT_PATH="${CMAKE_CURRENT_SOURCE_DIR}/examples/galaga/galaga.bas"
+    GALAGA_FONT_PATH="${CMAKE_CURRENT_SOURCE_DIR}/assets/fonts/C64_Pro_Mono-STYLE.ttf")
+  target_link_libraries(akbasic_example_galaga PRIVATE akbasic akgl
+    SDL3::SDL3 SDL3_ttf::SDL3_ttf SDL3_image::SDL3_image)
+  akbasic_instrument(akbasic_example_galaga)
+  # Ten seconds of scripted play under the headless drivers: the script boots,
+  # a wave enters and forms, the autoplay pilot shoots at it, and the program
+  # tears down and exits 0. A tutorial that stops working fails here rather
+  # than in front of a reader.
+  _add_test(NAME example_galaga COMMAND akbasic_example_galaga --frames 600 --autoplay)
+  _set_tests_properties(example_galaga PROPERTIES TIMEOUT 120
+    ENVIRONMENT "SDL_VIDEODRIVER=dummy;SDL_AUDIODRIVER=dummy;SDL_RENDER_DRIVER=software")
+
+  # The boundary's round-trip test: links the real script.c and the real
+  # galaga.bas, and fails the moment the two sides of the interop disagree.
+  add_executable(akbasic_example_galaga_interop
+    examples/galaga/interop_test.c
+    examples/galaga/script.c)
+  target_compile_options(akbasic_example_galaga_interop PRIVATE -Wall -Wextra)
+  target_compile_definitions(akbasic_example_galaga_interop PRIVATE
+    GALAGA_SCRIPT_PATH="${CMAKE_CURRENT_SOURCE_DIR}/examples/galaga/galaga.bas")
+  target_link_libraries(akbasic_example_galaga_interop PRIVATE akbasic akgl
+    SDL3::SDL3 m)
+  akbasic_instrument(akbasic_example_galaga_interop)
+  _add_test(NAME example_galaga_interop COMMAND akbasic_example_galaga_interop)
+  _set_tests_properties(example_galaga_interop PROPERTIES TIMEOUT 120)
+
+  # Regenerating the game figures in docs/ is a deliberate act, never part of
+  # a build, for the same reason docs_screenshots is: the PNGs are checked in.
+  # Wall-clock dt makes each regeneration differ by a few pixels of starfield,
+  # so expect a binary diff every time this runs; commit one only when the
+  # content changed on purpose. (docs_galaga_figures, not docs_game_figures:
+  # the libakgl submodule already owns that target name.)
+  add_custom_target(docs_galaga_figures
+    COMMAND ${CMAKE_COMMAND} -E env SDL_VIDEODRIVER=dummy SDL_AUDIODRIVER=dummy
+            SDL_RENDER_DRIVER=software
+            $<TARGET_FILE:akbasic_example_galaga> --frames 40
+            --screenshot "${CMAKE_CURRENT_SOURCE_DIR}/docs/images/galaga-title.png"
+            --screenshot-frame 30
+    COMMAND ${CMAKE_COMMAND} -E env SDL_VIDEODRIVER=dummy SDL_AUDIODRIVER=dummy
+            SDL_RENDER_DRIVER=software
+            $<TARGET_FILE:akbasic_example_galaga> --autoplay --frames 370
+            --screenshot "${CMAKE_CURRENT_SOURCE_DIR}/docs/images/galaga-wave.png"
+            --screenshot-frame 360
+    DEPENDS akbasic_example_galaga
+    COMMENT "Regenerating the galaga figures in docs/images"
+    VERBATIM)
+endif()
+
 # ---------------------------------------------------------------------------
 # Tests.
 #
@@ -448,7 +511,7 @@ if(AKBASIC_WITH_AKGL)
   # against.
   #
   # **A byte comparison of a rendered PNG is a deliberate bet**, the same bet
-  # tests/reference/ already makes about golden output: that the dummy video
+  # the language corpus makes about golden output: that the dummy video
   # driver and the software renderer are reproducible. They are, run to run and
   # build to build. What is untested is an SDL upgrade that shifts one pixel of
   # a diagonal, and the answer to that is to regenerate the figures in the same
@@ -531,63 +594,20 @@ if(AKBASIC_WILL_FAIL_TESTS OR AKBASIC_KNOWN_FAILING_TESTS)
   )
 endif()
 
-# The reference's own corpus, byte-compared against the sibling .txt. One CTest
-# case per .bas so a failure names the file.
+# The editable language corpus. One CTest case per .bas so a failure names the
+# file. Each program is paired with a sibling .txt expectation; see
+# tests/language/README.md for the editing rule.
 #
-# It used to be driven in place out of deps/basicinterpret, on the reasoning that
-# copying a submodule's corpus guarantees drift. That reasoning was sound and it
-# has been overruled deliberately: the Go dependency is being deprecated, and a
-# build that cannot run its acceptance suite without cloning the implementation
-# it replaced is not finished. The copy is byte-identical to
-# basicinterpreter@d76162c and tests/reference/README.md records
-# where it came from and what the drift now costs.
-file(GLOB_RECURSE AKBASIC_GOLDEN_CASES
-  RELATIVE "${CMAKE_CURRENT_SOURCE_DIR}/tests/reference"
-  "${CMAKE_CURRENT_SOURCE_DIR}/tests/reference/*.bas"
-)
-
-foreach(_case IN LISTS AKBASIC_GOLDEN_CASES)
-  string(REGEX REPLACE "^tests/" "" _name "${_case}")
-  string(REGEX REPLACE "\\.bas$" "" _name "${_name}")
-  string(REPLACE "/" "_" _name "${_name}")
-  _add_test(
-    NAME golden_${_name}
-    COMMAND ${CMAKE_COMMAND}
-            -DBASIC=$<TARGET_FILE:basic>
-            -DCASE=${CMAKE_CURRENT_SOURCE_DIR}/tests/reference/${_case}
-            -P ${CMAKE_CURRENT_SOURCE_DIR}/tests/golden.cmake
-  )
-endforeach()
-
-if(AKBASIC_GOLDEN_CASES)
-  set(AKBASIC_GOLDEN_NAMES)
-  foreach(_case IN LISTS AKBASIC_GOLDEN_CASES)
-    string(REGEX REPLACE "^tests/" "" _name "${_case}")
-    string(REGEX REPLACE "\\.bas$" "" _name "${_name}")
-    string(REPLACE "/" "_" _name "${_name}")
-    list(APPEND AKBASIC_GOLDEN_NAMES golden_${_name})
-  endforeach()
-  _set_tests_properties(${AKBASIC_GOLDEN_NAMES} PROPERTIES TIMEOUT 30)
-  # An AKGL build of `basic` opens a window, and forty-one of them is not what
-  # anybody running the suite wanted. The dummy driver produces the same stdout,
-  # which is the only thing a golden case compares.
-  if(AKBASIC_WITH_AKGL)
-    _set_tests_properties(${AKBASIC_GOLDEN_NAMES} PROPERTIES
-      ENVIRONMENT "SDL_VIDEODRIVER=dummy;SDL_AUDIODRIVER=dummy;SDL_RENDER_DRIVER=software")
-  endif()
-endif()
-
-# The local golden corpus, for verbs the reference never implemented.
+# The corpus includes programs carried over from the deprecated Go implementation
+# and cases written for this interpreter. Their provenance is useful when
+# investigating a regression, but it does not make any case immutable.
 #
-# Still separate now that the reference's corpus lives in this repository too,
-# and the reason changed rather than went away: tests/reference/ is a *record* of
-# what the Go implementation did and nothing in it should ever be edited to suit
-# this one, while tests/language/ is ours to change. Registered under local_ so a
-# failure says at a glance which of the two it came from -- and so a diff that
-# touches tests/reference/ stands out as the thing it is.
+# Programs carried over from the deprecated Go implementation and cases written
+# for this interpreter use the same editable `.bas`/`.txt` contract. Registered
+# under local_ so every failure identifies the program that produced it.
 #
 # Note what this can and cannot cover. The graphics and sound verbs draw and play
-# rather than print, so what a golden file sees of them is their *refusals* and
+# rather than print, so what a golden file sees of them is their refusals and
 # whatever a program can PRINT about the state they changed. The behaviour that
 # reaches a device is asserted against tests/mockdevice.h instead.
 file(GLOB_RECURSE AKBASIC_LOCAL_CASES

MAINTENANCE.md

@@ -88,7 +88,7 @@ source stays readable as documentation of what the original did. Neither is bind
 
 **It is not a build or test dependency.** Both configurations have been configured, built and
 run from scratch with it moved out of the tree. Its acceptance corpus is checked in at
-`tests/reference/` and its Commodore font at `assets/fonts/`.
+`tests/language/` and its Commodore font at `assets/fonts/`.
 
 ```sh norun
 cd deps/basicinterpret
@@ -351,15 +351,10 @@ name. That is not cosmetic: `add_executable` creates a dependency's targets even
 
 ### The golden corpora
 
-`tests/reference/` is the Go implementation's own acceptance suite, byte-compared.
-**Nothing in it is ever edited to suit this interpreter.** If a case fails, either this
-interpreter is wrong or the divergence is deliberate — and a deliberate one goes in
-`tests/reference/README.md`'s divergence table and `docs/13-differences.md`, not into the
-expectation file. `tests/reference/README.md`
-says the same thing at more length.
-
-`tests/language/` is ours and may be changed freely. A new language feature needs a
-`.bas`/`.txt` pair there as well as unit tests.
+`tests/language/` is the editable language corpus. It includes cases carried over from the
+deprecated Go implementation as well as cases written for this interpreter. Every `.bas` file
+has a sibling `.txt` expectation, and a new language feature needs that pair as well as unit
+tests. Change both deliberately in the same commit; provenance does not make a case immutable.