PEP 795: Deep Immutability in Python

.github/CODEOWNERS

@@ -673,6 +673,8 @@ peps/pep-0791.rst  @vstinner
 peps/pep-0792.rst  @dstufft
 peps/pep-0793.rst  @encukou
 peps/pep-0794.rst  @brettcannon
+peps/pep-0795.rst  @mdboom
+# ...
 peps/pep-0798.rst  @JelleZijlstra
 peps/pep-0799.rst  @pablogsal
 peps/pep-0800.rst  @JelleZijlstra

peps/pep-0795/diagram_1.mmd

@@ -0,0 +1,23 @@
+   graph LR
+    subgraph Sub 1
+      A[A]
+      D[D]
+    end
+
+    subgraph Sub 2
+      B[B]
+    end
+
+    C:::imm
+
+    A ----> C
+    B ----> C
+    C ----> D
+    A -. GIL 1 .-> C
+    B -. GIL 2 .-> C
+    C -. GIL 1 .-> D
+    C -. GIL 2 .-> D
+
+    classDef imm fill:#ADD8E6,stroke:#003366,stroke-width:1px,stroke-dasharray: 4 2,color:#003366;
+    linkStyle 4,6 stroke:#f00,stroke-width:2px,color:blue;
+    linkStyle 3,5 stroke:#90f,stroke-width:2px,color:blue;

peps/pep-0795/diagram_10.mmd

@@ -0,0 +1,28 @@
+   graph LR
+     subgraph Sub 1
+       A[A]
+     end
+
+     subgraph Sub 2
+       B[B]
+     end
+
+     C[Cell]:::imm
+     D[Shared field]:::fake_imm
+     E[2]:::imm
+
+     A ----> C
+     B ----> C
+     C ----> D
+     D ----> E
+     A -. GIL 1 .-> C
+     C -. GIL 1 .-> D
+     D -. GIL 1 .-> E
+     B -. GIL 2 .-> C
+     C -. GIL 2 .-> D
+     D -. GIL 2 .-> E
+
+     classDef imm fill:#ADD8E6,stroke:#003366,stroke-width:1px,stroke-dasharray: 4 2,color:#003366;
+     classDef fake_imm fill:#aaa,stroke:#000,stroke-width:1px;
+     linkStyle 4,5,6 stroke:#f00,stroke-width:2px,color:blue;
+     linkStyle 7,8,9 stroke:#90f,stroke-width:2px,color:blue;

peps/pep-0795/diagram_11.mmd

@@ -0,0 +1,32 @@
+   graph LR
+     subgraph Sub 1
+       A[A]
+       D1[interpreter-local storage]
+       E[E]
+     end
+
+     subgraph Sub 2
+       B[B]
+       D2[interpreter-local storage]
+       F[F]
+     end
+
+     C[Prime factoriser]:::imm
+
+     A ----> C
+     B ----> C
+     C ----> D1
+     C ----> D2
+     D1 ----> E
+     D2 ----> F
+     A -. GIL 1 .-> C
+     C -. GIL 1 .-> D1
+     D1 -. GIL 1 .-> E
+     B -. GIL 2 .-> C
+     C -. GIL 2 .-> D2
+     D2 -. GIL 2 .-> F
+
+     classDef imm fill:#ADD8E6,stroke:#003366,stroke-width:1px,stroke-dasharray: 4 2,color:#003366;
+     classDef fake_imm fill:#aaa,stroke:#000,stroke-width:1px;
+     linkStyle 6,7,8 stroke:#f00,stroke-width:2px,color:blue;
+     linkStyle 9,10,11 stroke:#90f,stroke-width:2px,color:blue;

peps/pep-0795/diagram_12.mmd

@@ -0,0 +1,49 @@
+   graph
+     subgraph Module1
+       A[Type1]
+       B[Func1]
+       X[Var1]
+       subgraph Module2
+           C[Type2]
+           D[Func2]
+           Y[Var2]
+       end
+     end
+
+     subgraph Module3
+       E[Type3]
+       EE[Type4]
+       Z[Var3]
+       F[Func3]
+     end
+
+     subgraph Program
+       O1
+       O2
+       x
+       y
+       m3
+       m1
+     end
+
+     A -- calls --> B
+     B -- uses --> C
+     B -- imports --> Module2
+     B -- reads --> X
+     B -- writes --> X
+     C -- calls --> D
+     C -- writes --> Y
+
+     E -- reads --> Z
+     F -- writes --> Z
+
+     F -- imports --> Module2
+
+     EE -- extends --> E
+
+     O1 -- \_\_class__ --> EE
+     O2 -- \_\_class__ --> A
+     x --> O1
+     y --> O2
+     m1 -- imports --> Module1
+     m3 -- imports --> Module3

peps/pep-0795/diagram_2.mmd

@@ -0,0 +1,18 @@
+   graph LR
+     subgraph Sub 1
+       A[A]
+     end
+
+     subgraph Sub 2
+       B[B]
+     end
+
+     C:::imm
+     D:::imm
+
+     A ----> C
+     B ----> C
+     C -- \_\_class__ --> D
+
+    classDef imm fill:#ADD8E6,stroke:#003366,stroke-width:1px,stroke-dasharray: 4 2,color:#003366;
+    linkStyle 2 stroke:#00f,stroke-width:2px,color:blue;

peps/pep-0795/diagram_3.mmd

@@ -0,0 +1,7 @@
+   graph LR;
+     O[Stack frame]-- x -->A
+     A-- f -->B
+     A-- g -->B
+     B-- h -->A
+     B-- j -->C
+     O-- y -->C