README.md

@@ -45,6 +45,14 @@ Each lecture has its own screenshot in `docs/images/` (made by `docs/images/capt
 
 ![Lecture 4: __name__ and __main__](docs/images/lecture-04.png)
 
+**Lecture 5: functions are first-class objects.** A function can be passed as an argument (`calculate(add, 2, 3)`), defined inside another function and returned from it. See `flask_day_54.domain.first_class_functions`; run it with `python -m flask_day_54.domain.first_class_functions`.
+
+![Lecture 5: functions as first-class objects](docs/images/lecture-05.png)
+
+**Lecture 6: decorators and the `@` syntax.** `@make_bold` above a function is shorthand for `say_hello = make_bold(say_hello)`. See `flask_day_54.domain.decorators`; run it with `python -m flask_day_54.domain.decorators`.
+
+![Lecture 6: decorators](docs/images/lecture-06.png)
+
 ## 📋 Requirements
 
 - Python 3.13 or newer, because the project sets `requires-python = ">=3.13"` in `pyproject.toml`.

docs/artifact-registry.md

@@ -18,7 +18,7 @@ document of a type. `Primary File` may contain a glob (e.g.
 | ADR | Architecture Decision Record | docs/adr/adr-NNNN-*.md | 0002 |
 | DICT | Domain Dictionary | docs/dictionary.md | 002 |
 | TM | Traceability Matrix | docs/sqa/traceability-matrix.md | 002 |
-| RC | SQA Review Record | docs/sqa/reviews/rc-*.md | 018 |
+| RC | SQA Review Record | docs/sqa/reviews/rc-*.md | 019 |
 
 ## Languages
 

docs/images/sources/lecture-05.html

@@ -0,0 +1,10 @@
+<!doctype html><meta charset='utf-8'><style>
+body{margin:0;background:#1e1e1e;font-family:Consolas,'DejaVu Sans Mono',monospace;color:#d4d4d4}
+.bar{background:#333;color:#ccc;padding:8px 14px;font-size:14px}
+pre{margin:0;padding:16px 18px;font-size:15px;line-height:1.45;white-space:pre-wrap}
+.p{color:#6a9955}.c{color:#9cdcfe}
+</style><div class='bar'>Terminal - lecture 5: functions as first-class objects</div><pre><span class="p">$</span> <span class="c">python -m flask_day_54.domain.first_class_functions</span>
+calculate(add, 2, 3) = 5
+calculate(subtract, 5, 3) = 2
+outer_function() = Hello from the nested function
+returned nested function() = Hello from the nested function</pre>

docs/images/sources/lecture-06.html

@@ -0,0 +1,10 @@
+<!doctype html><meta charset='utf-8'><style>
+body{margin:0;background:#1e1e1e;font-family:Consolas,'DejaVu Sans Mono',monospace;color:#d4d4d4}
+.bar{background:#333;color:#ccc;padding:8px 14px;font-size:14px}
+pre{margin:0;padding:16px 18px;font-size:15px;line-height:1.45;white-space:pre-wrap}
+.p{color:#6a9955}.c{color:#9cdcfe}
+</style><div class='bar'>Terminal - lecture 6: decorators and the @ syntax</div><pre><span class="p">$</span> <span class="c">python -m flask_day_54.domain.decorators</span>
+plain: Hello, World!
+by hand, make_bold(plain_hello)(): &lt;b&gt;Hello, World!&lt;/b&gt;
+@ syntax, say_hello(): &lt;b&gt;&lt;em&gt;&lt;u&gt;Hello, World!&lt;/u&gt;&lt;/em&gt;&lt;/b&gt;
+say_hello.__name__: say_hello</pre>

docs/sqa/reviews/rc-018-code-mil-004-functions-decorators.md

@@ -0,0 +1,61 @@
+# Review of MIL-004
+
+## Metadata
+| Key | Value |
+| --- | --- |
+| ID | RC-018 |
+| CrossReference | [MIL-004], [QC-PY-001] |
+
+## Version History
+| Date | Status | Author | Reviewer | Change | Commit |
+| --- | --- | --- | --- | --- | --- |
+| 2026-11-06 | Proposed | Jens Tirsvad Nielsen | AI as stand-in for S01 | Initial version | pending |
+
+---
+
+## Artifact Under Review
+
+- Instance reviewed: [MIL-004]
+- Checklist used: [QC-PY-001]
+- Scope: full review of the source and tests delivered by MIL-004 (src/, tests/)
+- Language and domain: n/a
+- Language reviewer: none (the reviewer reads English and knows the IT domain)
+- Mode: autonomous, not independent (AI as stand-in for S01)
+
+## Checklist Results
+
+| # | Criterion | Status | Evidence/Notes |
+| --- | --- | --- | --- |
+| 1 | Packages, modules, functions, variables, classes and constants follow PEP 8 casing (`snake_case`, `PascalCase`, `UPPER_SNAKE`) | Pass | Modules, functions and constants use snake_case / UPPER_SNAKE; classes none or PascalCase. |
+| 2 | Names state purpose in the domain's language; no unexplained abbreviations, no single-letter names outside tiny scopes | Pass | Names follow the lecture and the domain dictionary. |
+| 3 | Code is produced by the project's formatter and passes its linter with no unexplained suppressions | Pass | `ruff format` leaves files unchanged and `ruff check` (E, F, I, B, UP) passes; configured in pyproject.toml. |
+| 4 | Every function and method signature is type-annotated, including `-> None` | Pass | Every function signature is annotated, including `-> None`. |
+| 5 | No bare `except:`, no swallowed exceptions; specific exceptions are raised and the cause is kept (`raise ... from`) | Pass | No bare except and no swallowed exception. |
+| 6 | No mutable default arguments and no shadowed builtins | Pass | No mutable defaults; no builtin shadowed. |
+| 7 | Files, locks and connections are managed with context managers | N-A | No file, lock or connection is opened. |
+| 8 | Public modules, classes and functions have docstrings that say what, not how | Pass | Module and public names carry docstrings plus Doxygen comments. |
+| 9 | Logging uses `logging`, not `print`; no secrets or personal data in log output | N-A | Console output of the demo entry points (print under the __main__ guard) is the program's result, not diagnostic logging; no secrets handled. |
+| 10 | Classes and operations trace to the Design Class Diagram they implement; deviations are recorded | N-A | No DCD exists in this project; the layered layout is recorded in ADR-0001. |
+| 11 | Tests exist for new behaviour, are named for the behaviour, and do not depend on order or the network | Pass | pytest tests named for behaviour; no order or network dependence. |
+| 12 | Type checker runs in strict mode without errors; `Any` is justified in a comment | N-A | No type checker is configured (optional criterion). |
+| 13 | Dependencies are declared and pinned in the project's dependency file, none unused | Pass | Dependencies are declared in pyproject.toml; none unused (Flask is the optional `web` extra). |
+| 14 | Each piece of knowledge (a business rule, constant, format, validation or query) is defined in one place; code is merged only where it expresses the same knowledge, not where it merely looks alike | Pass | Each constant is defined once in the constants.py of its layer. |
+| 15 | Imports point inward: business-rule modules import no framework, database, UI or delivery-mechanism code, and there are no import cycles | Pass | `domain` imports no framework or outer layer; imports point inward; no cycles. |
+| 16 | SOLID holds: a class or module has one reason to change; new behaviour is added by extension, not by editing a type test in several places; subclasses honour the contract of their base; protocols are narrow; high-level code depends on protocols or abstract types and receives its implementations | Pass | Small modules with one reason to change; no type tests or subclass hierarchies. |
+| 17 | Source is laid out in the layers and folders of the clean architecture folder structure (`domain`, `application`, `infrastructure`, `presentation` packages under `src/`, and `unit`, `integration` and `e2e` under `tests/`), in `snake_case`, and imports between the layers point inward | Pass | Layers domain, application, infrastructure, presentation under src/flask_day_54; tests in unit and e2e (ADR-0001); no layer merged. |
+| 18 | File and folder names are English, contain no space and no character outside letters, digits, `-`, `_` and `.`, and follow the casing of the language for files | Pass | English snake_case file names without spaces. |
+
+## Overall Verdict
+
+Go — All applicable mandatory criteria pass.
+
+## Action Items
+
+| Action | Owner | Due |
+| --- | --- | --- |
+| None | S01 | - |
+
+---
+
+[MIL-004]: ../../milestones/mil-004-functions-decorators.md
+[QC-PY-001]: ../../../framework/qc/code/qc-programming-python.md