From d123b9c19665c80a57dc585433ec180c54bb2d0a Mon Sep 17 00:00:00 2001
From: Yusur Princeps <sakuragasaki46@gmail.com>
Date: Fri, 12 Dec 2025 11:03:10 +0100
Subject: [PATCH] 0.12.0a1 add Matrix()

---
 CHANGELOG.md         |   4 ++
 src/suou/__init__.py |   2 +-
 src/suou/mat.py      | 121 +++++++++++++++++++++++++++++++++++++++++++
 tests/test_mat.py    |  47 +++++++++++++++++
 4 files changed, 173 insertions(+), 1 deletion(-)
 create mode 100644 src/suou/mat.py
 create mode 100644 tests/test_mat.py

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b4ba99a..f449db1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog
 
+## 0.12.0
+
+* New module `mat` adds a shallow reimplementation of `Matrix()` in order to implement matrix multiplication
+
 ## 0.11.2
 
 + increase test coverage of `validators`
diff --git a/src/suou/__init__.py b/src/suou/__init__.py
index c3c8724..2d79b4b 100644
--- a/src/suou/__init__.py
+++ b/src/suou/__init__.py
@@ -37,7 +37,7 @@ from .redact import redact_url_password
 from .http import WantsContentType
 from .color import chalk, WebColor
 
-__version__ = "0.11.2"
+__version__ = "0.12.0a1"
 
 __all__ = (
     'ConfigOptions', 'ConfigParserConfigSource', 'ConfigSource', 'ConfigValue',
diff --git a/src/suou/mat.py b/src/suou/mat.py
new file mode 100644
index 0000000..fa60f08
--- /dev/null
+++ b/src/suou/mat.py
@@ -0,0 +1,121 @@
+"""
+Matrix (not the movie...)
+
+*New in 0.12.0*
+
+---
+
+Copyright (c) 2025 Sakuragasaki46.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+See LICENSE for the specific language governing permissions and
+limitations under the License.
+
+This software is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+"""
+
+from __future__ import annotations
+from typing import Collection, Iterable, TypeVar
+from .functools import deprecated
+
+_T = TypeVar('_T')
+
+class Matrix(Collection[_T]):
+    """
+    Shallow reimplementation of numpy's matrices in pure Python.
+
+    *New in 0.12.0*
+    """
+    _shape: tuple[int, int]
+    _elements: list[_T]
+
+    def shape(self):
+        return self._shape
+
+    def __init__(self, iterable: Iterable[_T] | Iterable[Collection[_T]], shape: tuple[int, int] | None = None):
+        elements = []
+        boundary_x = boundary_y = 0
+        for row in iterable:
+            if isinstance(row, Collection):
+                if not boundary_y:
+                    boundary_y = len(row)
+                    elements.extend(row)
+                    boundary_x += 1
+                elif boundary_y != len(row):
+                    raise ValueError('row length mismatch')
+                else:
+                    elements.extend(row)
+                    boundary_x += 1
+            elif shape:
+                if not boundary_x:
+                    boundary_x, boundary_y = shape
+                elements.append(row)
+        self._shape = boundary_x, boundary_y
+        self._elements = elements
+        assert len(self._elements) == boundary_x * boundary_y
+
+    def __getitem__(self, key: tuple[int, int]) -> _T:
+        (x, y), (_, sy) = key, self.shape()
+        
+        return self._elements[x * sy + y]
+
+    @property
+    def T(self):
+        sx, sy = self.shape()
+        return Matrix(
+            [
+                [
+                    self[j, i] for j in range(sx)
+                ] for i in range(sy)
+            ]
+        )
+
+    def __matmul__(self, other: Matrix) -> Matrix:
+        (ax, ay), (bx, by) = self.shape(), other.shape()
+
+        if ay != bx:
+            raise ValueError('cannot multiply matrices with incompatible shape')
+        
+        return Matrix([
+            [
+                sum(self[i, k] * other[k, j] for k in range(ay)) for j in range(by)
+            ] for i in range(ax)
+        ])
+
+    def __eq__(self, other: Matrix):
+        try:
+            return self._elements == other._elements and self._shape == other._shape
+        except Exception:
+            return False
+
+    def __len__(self):
+        ax, ay = self.shape()
+        return ax * ay
+
+    @deprecated('please use .rows() or .columns() instead')
+    def __iter__(self):
+        return iter(self._elements)
+
+    def __contains__(self, x: object, /) -> bool:
+        return x in self._elements
+
+    def __repr__(self):
+        return f'{self.__class__.__name__}({list(self.rows())})'
+
+    def rows(self):
+        sx, sy = self.shape()
+        return (
+            [self[j, i] for j in range(sy)] for i in range(sx)
+        )
+
+    def columns(self):
+        sx, sy = self.shape()
+        return (
+            [self[j, i] for j in range(sx)] for i in range(sy)
+        )
+
+## TODO write tests!
+
+
diff --git a/tests/test_mat.py b/tests/test_mat.py
new file mode 100644
index 0000000..ac1e00c
--- /dev/null
+++ b/tests/test_mat.py
@@ -0,0 +1,47 @@
+
+
+import unittest
+
+from suou.mat import Matrix
+
+
+class TestMat(unittest.TestCase):
+    def setUp(self):
+        self.m_a = Matrix([
+            [2, 2],
+            [1, 3]
+        ])
+        self.m_b = Matrix([
+            [1], [-4]
+        ])
+    def tearDown(self) -> None:
+        ...
+    def test_transpose(self):
+        self.assertEqual(
+            self.m_a.T,
+            Matrix([
+                [2, 1],
+                [2, 3]
+            ])
+        )
+        self.assertEqual(
+            self.m_b.T,
+            Matrix([[1, -4]])
+        )
+    def test_mul(self):
+        self.assertEqual(
+            self.m_b.T @ self.m_a,
+            Matrix([
+                [-2, -10]
+            ])
+        )
+        self.assertEqual(
+            self.m_a @ self.m_b,
+            Matrix([
+                [-6], [-11]
+            ])
+        )
+    def test_shape(self):
+        self.assertEqual(self.m_a.shape(), (2, 2))
+        self.assertEqual(self.m_b.shape(), (2, 1))
+        self.assertEqual(self.m_b.T.shape(), (1, 2))
\ No newline at end of file