Feature/blog structure

CONTRIBUTING.md

@@ -17,16 +17,55 @@ broken link fails the build, and it's faster to find out on your machine.
 
 Forgetting step 2 means your page builds but nobody can find it.
 
+### Adding a blog post
+
+Blog posts are the one exception to step 2. Put the file in `docs/blog/posts/` and the blog index
+picks it up, newest first.
+
+```markdown
+---
+date: 2026-10-10
+authors:
+  - xarlos
+description: One sentence.
+categories:
+  - Python releases
+---
+
+# Title
+
+Opening paragraph. This is what the blog index shows. Below a `<!-- more -->` tells the blog home where the preview cuts off and you see `more...`
+
+<!-- more -->
+
+The rest of the post.
+```
+
+`date` and the `<!-- more -->` line are required, and the build fails without them. Reuse an
+existing category before inventing one.
+
+`authors` puts your name and picture on the post. Each entry is a key from `docs/blog/.authors.yml`,
+so add yourself there in the same pull request as your first post:
+
+```yaml
+authors:
+  yourkey:
+    name: Your Name
+    description: A few words about you
+    avatar: https://github.com/your-username.png
+    url: https://github.com/your-username
+```
+
+`name` and `avatar` are required. A key that isn't in the file fails the build. A post written by
+two people lists both keys.
+
 ### Nav conventions
 
 The nav is written out rather than derived from the folder structure. Zensical can derive it, but it
 sorts alphabetically, which puts Projects ahead of Rules.
 
 - Every section's `index.md` comes first in its list.
-- Everything after that goes in reading order — the page a newcomer needs first goes first, not the
-  one that's alphabetically luckiest.
-- Nest a sub-group only when a section has two clear halves. `projects/` does. Nothing else needs
-  to.
+- Everything after that goes in reading order.
 
 ### Front matter
 

docs/blog/.authors.yml

@@ -0,0 +1,6 @@
+authors:
+  xarlos:
+    name: Xarlos
+    description: Zaaar-los. It's like Carlos, but from space.
+    avatar: https://github.com/Xarlos89.png
+    url: https://github.com/Xarlos89

docs/blog/index.md

@@ -0,0 +1,7 @@
+---
+description: Posts about Python and the tech around it, written by the Practical Python community.
+---
+
+# Blog
+
+Posts about Python and the tech around it, written by the community. Newest first.

docs/blog/posts/python-3-15.md

@@ -0,0 +1,170 @@
+---
+date: 2026-10-10
+authors:
+  - xarlos
+description: Python 3.15 is out. Lazy imports, frozendict, unpacking in comprehensions, UTF-8 by default and a new profiler.
+categories:
+  - Python releases
+---
+
+# Python 3.15 is out
+
+Python 3.15.0 was released on 9 October 2026. It adds a `lazy` keyword for imports, a built-in
+`frozendict`, `*` unpacking inside comprehensions, and a new sampling profiler. It also makes UTF-8
+the default text encoding on every platform, which is the change most likely to affect code you have
+already written.
+
+<!-- more -->
+
+Everything below comes from the official
+[What's new in Python 3.15](https://docs.python.org/3.15/whatsnew/3.15.html), which is the full
+list. This is the short one.
+
+## The parts you will notice
+
+### Lazy imports
+
+Put `lazy` in front of an import and the module is not loaded until you first use the name
+([PEP 810](https://peps.python.org/pep-0810/)).
+
+```python
+lazy import json
+lazy from pathlib import Path
+
+print("Starting up...")  # json and pathlib are not fully imported yet
+
+data = json.loads('{"key": "value"}')  # json gets fully imported here
+p = Path(".")  # pathlib gets fully imported here
+```
+
+This is for programs with slow startup, mostly command-line tools that import a lot and use a little
+of it on any one run. The catch: if the module is missing, the error turns up at first use, not on
+the import line. A typo in a lazy import can sit there until that code path runs.
+
+### `frozendict`
+
+A dictionary you can't change, and can therefore hash
+([PEP 814](https://peps.python.org/pep-0814/)). It is a built-in, so there is nothing to import.
+
+```pycon
+>>> a = frozendict(x=1, y=2)
+>>> a
+frozendict({'x': 1, 'y': 2})
+>>> a['z'] = 3
+Traceback (most recent call last):
+  File "<python-input-2>", line 1, in <module>
+    a['z'] = 3
+    ~^^^^^
+TypeError: 'frozendict' object does not support item assignment
+>>> b = frozendict(y=2, x=1)
+>>> hash(a) == hash(b)
+True
+>>> a == b
+True
+```
+
+Being hashable means it can be a dictionary key or a member of a set, which a `dict` can't. It keeps
+insertion order but ignores it when comparing, same as `dict`. It is not a subclass of `dict`, so
+`isinstance(a, dict)` is `False`.
+
+### Unpacking in comprehensions
+
+`*` and `**` now work inside comprehensions and generator expressions
+([PEP 798](https://peps.python.org/pep-0798/)).
+
+```pycon
+>>> lists = [[1, 2], [3, 4], [5]]
+>>> [*L for L in lists]  # equivalent to [x for L in lists for x in L]
+[1, 2, 3, 4, 5]
+
+>>> dicts = [{'a': 1}, {'b': 2}, {'a': 3}]
+>>> {**d for d in dicts}  # equivalent to {k: v for d in dicts for k,v in d.items()}
+{'a': 3, 'b': 2}
+```
+
+Flattening a list of lists is one of the most-asked questions in the server. The old answer was a
+comprehension with two `for` clauses in an order nobody remembers. This one reads the way you would
+say it.
+
+### Error messages
+
+`AttributeError` now recognises method names from other languages and tells you the Python one:
+
+```pycon
+>>> [1, 2, 3].push(4)
+AttributeError: 'list' object has no attribute 'push'. Did you mean '.append'?
+
+>>> 'hello'.toUpperCase()
+AttributeError: 'str' object has no attribute 'toUpperCase'. Did you mean '.upper'?
+
+>>> {}.put("a", 1)
+AttributeError: 'dict' object has no attribute 'put'. Use d[k] = v.
+
+>>> (1, 2, 3).append(4)
+AttributeError: 'tuple' object has no attribute 'append'. Did you mean to use a 'list' object?
+```
+
+If you came to Python from JavaScript or Java, this one is for you.
+
+## The part that can break things
+
+Python now uses UTF-8 whenever you don't pass `encoding`
+([PEP 686](https://peps.python.org/pep-0686/)). So `open("notes.txt")` reads UTF-8 on every
+platform.
+
+On Linux and macOS that was almost always the case already. On Windows the default used to be the
+system code page, so a script that reads a file written by an older Windows program may now raise
+`UnicodeDecodeError`, or quietly read the wrong characters.
+
+| Situation                              | What to do                                         |
+|----------------------------------------|----------------------------------------------------|
+| New code                               | Pass `encoding="utf-8"` anyway. It works on every version |
+| Old file in a legacy encoding          | Name it: `open(path, encoding="cp1252")`           |
+| Need the old behaviour for a whole run | Set `PYTHONUTF8=0` or run with `-X utf8=0`         |
+
+## For people who measure things
+
+There is a new `profiling` package ([PEP 799](https://peps.python.org/pep-0799/)).
+`profiling.tracing` is the deterministic profiler you know as `cProfile`, which stays as an alias.
+`profiling.sampling` is new. It is a sampling profiler called Tachyon that can attach to a process
+that is already running, by PID, and write flame graphs. The pure-Python `profile` module is
+deprecated and goes away in 3.17.
+
+The experimental JIT compiler got a significant upgrade as well. It is still experimental.
+
+## Smaller things
+
+- A `sentinel` built-in for making unique marker values, the job `object()` has been doing
+  ([PEP 661](https://peps.python.org/pep-0661/)).
+- `re.prefixmatch()` is the new name for what `re.match()` does. `re.match()` still works and is
+  soft deprecated, meaning no removal is planned.
+- The `__cached__` module attribute is gone. Use `__spec__.cached`.
+- Typing gained `TypedDict` with typed extra items ([PEP 728](https://peps.python.org/pep-0728/))
+  and `TypeForm` ([PEP 747](https://peps.python.org/pep-0747/)).
+- The official macOS installer now includes the free-threaded build by default.
+
+## Should you upgrade?
+
+| You are                               | Suggestion                                                      |
+|---------------------------------------|-----------------------------------------------------------------|
+| Learning, on your own machine         | Yes. The error messages alone are worth it                      |
+| Working on a project with dependencies | Try it in a fresh virtual environment first. Packages with compiled parts can take a few weeks to publish 3.15 builds |
+| Running something in production       | Wait for 3.15.1 unless you need a feature now                   |
+
+Python 3.14 is supported until October 2030, so nobody has to hurry.
+
+## Trying it
+
+Installers are on [python.org](https://www.python.org/downloads/). With
+[uv](https://docs.astral.sh/uv/), which keeps versions side by side without touching the one you
+already have:
+
+```console
+$ uv self update
+$ uv python install 3.15
+$ uv run --python 3.15 python
+```
+
+Update uv first. A copy from before the release only knows about the release candidates.
+
+Then type `[1, 2, 3].push(4)` and see what it says.

docs/blog/posts/welcome.md

@@ -0,0 +1,41 @@
+---
+date: 2026-10-10
+authors:
+  - xarlos
+description: Why practicalpython.org has a blog now, and what will be posted on it.
+categories:
+  - Site news
+---
+
+# The Practical Python blog!
+
+As a community, we have decided to try our hand at a blog.
+
+<!-- more -->
+
+## What goes here
+
+| Kind of post     | Example                                                          |
+|------------------|------------------------------------------------------------------|
+| Python releases  | For example, Python 5.15 just came out!                          |
+| Tools            | A look at something like uv, ruff or a debugger                  |
+| Things we built  | How a feature of the bot or this site works, and what went wrong |
+| Community news   | Events, Code Adventure, changes to how the server runs           |
+
+## What doesn't
+
+If you have questions go into Discord, where someone can answer them. Anything that should stay true
+for years goes in [Resources](../../resources/index.md) or the
+[tutorial](../../python-tutorial/index.md), where people will look for it. A blog post is allowed to
+go out of date but we should try to keep resources updated.
+
+## Who writes it
+
+The community, same as the rest of the site. A post is a Markdown file and a pull request. If you
+worked something out last week and feel like sharing a win... make a blog post. The
+[page about this site](../../projects/our-projects/this-site.md) covers how to build it locally, and
+`CONTRIBUTING.md` in the repository has the front matter a post needs.
+
+Not sure whether an idea is worth writing up? Ask in the [Discord]({{ discord_invite }}) first.
+
+The first real post is about [Python 3.15](python-3-15.md).

docs/index.md

@@ -52,11 +52,19 @@ A Discord community for people who write Python. {{ member_count }} of us so far
 
     [:octicons-arrow-right-24: Read the rules](rules/index.md)
 
+-   :material-post-outline:{ .lg .middle } __Blog__
+
+    ---
+
+    Posts about Python and the tech around it, written by the community.
+
+    [:octicons-arrow-right-24: Read the blog](blog/index.md)
+
 -   :material-bug:{ .lg .middle } __Found a mistake on the site?__
 
     ---
 
-    Every page here is Markdown in a public repository, written by members. If
+    Every page here is Markdown in a public repository, written by the community. If
   something is wrong, unclear, or missing, open an issue or PR!
 
     [:octicons-arrow-right-24: Contribute!](projects/our-projects/this-site.md)

zensical.toml

@@ -55,6 +55,11 @@ nav = [
   { "Code Adventure" = [
     "code-adventure/index.md",
   ] },
+  # Posts are not listed here. The blog plugin collects them from
+  # docs/blog/posts/ and lists them on the index, newest first.
+  { "Blog" = [
+    "blog/index.md",
+  ] },
 ]
 
 [project.theme]
@@ -111,6 +116,11 @@ toggle.name = "Switch to light mode"
 invalid_links = true
 invalid_link_anchors = true
 
+[project.plugins.blog]
+blog_dir = "blog"
+post_readtime = true
+post_excerpt = "required"
+
 [project.markdown_extensions.zensical.extensions.macros]
 on_undefined = "strict"
 on_error_fail = true