From 00997d3c90a71d0d6babf9967d5e73d950895c0c Mon Sep 17 00:00:00 2001
From: Simon Brooke <simon@journeyman.cc>
Date: Sun, 29 Mar 2026 11:07:30 +0100
Subject: [PATCH] Down to to compilation errors. Had to reinstate individual
 size-class headers.

---
 docs/Nodes-threads-locks-links.md |   2 +-
 src/c/memory/pso.h                | 428 +++++++++++++++---------------
 src/c/memory/pso2.h               |  53 ++++
 src/c/memory/pso3.h               |  37 +++
 src/c/memory/pso4.h               |  34 +++
 src/c/memory/pso5.h               |  32 +++
 src/c/memory/pso6.h               |  32 +++
 src/c/memory/pso7.h               |  32 +++
 src/c/memory/pso8.h               |  32 +++
 src/c/memory/pso9.h               |  32 +++
 src/c/memory/psoa.h               |  32 +++
 src/c/memory/psob.h               |  32 +++
 src/c/memory/psoc.h               |  32 +++
 src/c/memory/psod.h               |  32 +++
 src/c/memory/psoe.h               |  32 +++
 src/c/memory/psof.h               |  32 +++
 src/c/payloads/function.h         |   4 +-
 src/c/payloads/hashtable.h        |   6 +-
 src/c/payloads/namespace.h        |  10 +-
 src/c/payloads/read_stream.h      |   3 +-
 src/c/payloads/special.h          |  41 +--
 src/c/payloads/stack.c            |   3 +
 src/c/payloads/stack.h            |   2 +
 src/c/payloads/time.h             |   2 +
 src/c/payloads/vector_pointer.h   |   1 +
 src/c/payloads/write_stream.h     |   1 +
 26 files changed, 733 insertions(+), 246 deletions(-)
 create mode 100644 src/c/memory/pso2.h
 create mode 100644 src/c/memory/pso3.h
 create mode 100644 src/c/memory/pso4.h
 create mode 100644 src/c/memory/pso5.h
 create mode 100644 src/c/memory/pso6.h
 create mode 100644 src/c/memory/pso7.h
 create mode 100644 src/c/memory/pso8.h
 create mode 100644 src/c/memory/pso9.h
 create mode 100644 src/c/memory/psoa.h
 create mode 100644 src/c/memory/psob.h
 create mode 100644 src/c/memory/psoc.h
 create mode 100644 src/c/memory/psod.h
 create mode 100644 src/c/memory/psoe.h
 create mode 100644 src/c/memory/psof.h

diff --git a/docs/Nodes-threads-locks-links.md b/docs/Nodes-threads-locks-links.md
index 1f2a9dd..8108168 100644
--- a/docs/Nodes-threads-locks-links.md
+++ b/docs/Nodes-threads-locks-links.md
@@ -119,7 +119,7 @@ We don't currently have any other mutable objects, but in future at least lazy o
 
 Secondly, reading from a namespace does not happen in a single clock tick, it takes quite a long time. So it's no good setting a lock bit on the namespace object itself and then immediately assuming that it's now mutable. A reading process could already have started, and be proceeding.
 
-So what I think is, that we have a single top level function, `(::substrate:search-store key store return-key?)` (which we already sort of have in the 0.0.6 prototype, [here](https://www.journeyman.cc/post-scarcity/doc/html/intern_8c.html#a2189c0ab60e57a70adeb32aca99dbc43)). This searches a store (hashmap, namespace, association list, or hybrid association list) to find a binding for a key, and, having found that binding, then, if there is a namespace on the search path, checks whether the lock on the any namespace on the search path is set, and it it is, aborts the search and tries again; but otherwise returns either the key found (if `return-key?` is non-`nil`), or the value found otherwise.
+So what I think is, that we have a single top level function, `(::substrate:search-store key store return-key?)` (which we already sort of have in the 0.0.6 prototype, [here](https://www.journeyman.cc/post-scarcity/doc/html/intern_8c.html#a2189c0ab60e57a70adeb32aca99dbc43)). This searches a store (hashmap, namespace, association list, or hybrid association list) to find a binding for a key, and, having found that binding, then, if there is a namespace on the search path, checks whether the lock on the any namespace on the search path is set, and if it is, aborts the search and tries again; but otherwise returns either the key found (if `return-key?` is non-`nil`), or the value found otherwise.
 
 This function implements the user-level Lisp functions `assoc`, `interned`, and `interned?`. It also implements *hashmap-in-function-position* and *keyword-in-function-position*, in so far as both of these are treated as calls to `assoc`.
 
diff --git a/src/c/memory/pso.h b/src/c/memory/pso.h
index 9fd7cc1..5f91bca 100644
--- a/src/c/memory/pso.h
+++ b/src/c/memory/pso.h
@@ -14,234 +14,234 @@
 
 #include "memory/header.h"
 #include "memory/pointer.h"
-#include "payloads/cons.h"
-#include "payloads/exception.h"
-#include "payloads/free.h"
-#include "payloads/function.h"
-#include "payloads/hashtable.h"
-#include "payloads/integer.h"
-#include "payloads/keyword.h"
-#include "payloads/lambda.h"
-#include "payloads/mutex.h"
-#include "payloads/namespace.h"
-#include "payloads/nlambda.h"
-#include "payloads/read_stream.h"
-#include "payloads/special.h"
-#include "payloads/stack.h"
-#include "payloads/string.h"
-#include "payloads/symbol.h"
-#include "payloads/time.h"
-#include "payloads/vector_pointer.h"
-#include "payloads/write_stream.h"
+// #include "payloads/cons.h"
+// #include "payloads/exception.h"
+// #include "payloads/free.h"
+// #include "payloads/function.h"
+// #include "payloads/hashtable.h"
+// #include "payloads/integer.h"
+// #include "payloads/keyword.h"
+// #include "payloads/lambda.h"
+// #include "payloads/mutex.h"
+// #include "payloads/namespace.h"
+// #include "payloads/nlambda.h"
+// #include "payloads/read_stream.h"
+// #include "payloads/special.h"
+// #include "payloads/stack.h"
+// #include "payloads/string.h"
+// #include "payloads/symbol.h"
+// #include "payloads/time.h"
+// #include "payloads/vector_pointer.h"
+// #include "payloads/write_stream.h"
 
-/**
- * @brief A paged space object of size class 2, four words total, two words
- * payload.
- * 
- */
-struct pso2 {
-    struct pso_header header;
-    union {
-        char bytes[16];
-        uint64_t words[2];
-        struct cons_payload cons;
-        struct free_payload free;
-        struct function_payload function;
-        struct integer_payload integer;
-        struct lambda_payload lambda;
-        struct special_payload special;
-        struct stream_payload stream;
-        struct time_payload time;
-        struct vectorp_payload vectorp;
-    } payload;
-};
+// /**
+//  * @brief A paged space object of size class 2, four words total, two words
+//  * payload.
+//  * 
+//  */
+// struct pso2 {
+//     struct pso_header header;
+//     union {
+//         char bytes[16];
+//         uint64_t words[2];
+//         struct cons_payload cons;
+//         struct free_payload free;
+//         struct function_payload function;
+//         struct integer_payload integer;
+//         struct lambda_payload lambda;
+//         struct special_payload special;
+//         struct stream_payload stream;
+//         struct time_payload time;
+//         struct vectorp_payload vectorp;
+//     } payload;
+// };
 
-/**
- * @brief A paged space object of size class 3, 8 words total, 6 words
- * payload.
- * 
- */
-struct pso3 {
-    struct pso_header header;
-    union {
-        char bytes[48];
-        uint64_t words[6];
-        struct exception_payload exception;
-        struct free_payload free;
-        struct mutex_payload mutex;
-    } payload;
-};
+// /**
+//  * @brief A paged space object of size class 3, 8 words total, 6 words
+//  * payload.
+//  * 
+//  */
+// struct pso3 {
+//     struct pso_header header;
+//     union {
+//         char bytes[48];
+//         uint64_t words[6];
+//         struct exception_payload exception;
+//         struct free_payload free;
+//         struct mutex_payload mutex;
+//     } payload;
+// };
 
-/**
- * @brief A paged space object of size class 4, 16 words total, 14 words
- * payload.
- * 
- */
-struct pso4 {
-    struct pso_header header;
-    union {
-        char bytes[112];
-        uint64_t words[14];
-        struct free_payload free;
-        struct stack_frame_payload stack_frame;
-    } payload;
-};
+// /**
+//  * @brief A paged space object of size class 4, 16 words total, 14 words
+//  * payload.
+//  * 
+//  */
+// struct pso4 {
+//     struct pso_header header;
+//     union {
+//         char bytes[112];
+//         uint64_t words[14];
+//         struct free_payload free;
+//         struct stack_frame_payload stack_frame;
+//     } payload;
+// };
 
-/**
- * @brief A paged space object of size class 5, 32 words total, 30 words
- * payload.
- * 
- */
-struct pso5 {
-    struct pso_header header;
-    union {
-        char bytes[240];
-        uint64_t words[30];
-        struct free_payload free;
-    } payload;
-};
+// /**
+//  * @brief A paged space object of size class 5, 32 words total, 30 words
+//  * payload.
+//  * 
+//  */
+// struct pso5 {
+//     struct pso_header header;
+//     union {
+//         char bytes[240];
+//         uint64_t words[30];
+//         struct free_payload free;
+//     } payload;
+// };
 
-/**
- * @brief A paged space object of size class 6, 64 words total, 62 words
- * payload.
- * 
- */
-struct pso6 {
-    struct pso_header header;
-    union {
-        char bytes[496];
-        uint64_t words[62];
-        struct free_payload free;
-        struct hashtable_payload hashtable;
-        struct namespace_payload namespace;
-    } payload;
-};
+// /**
+//  * @brief A paged space object of size class 6, 64 words total, 62 words
+//  * payload.
+//  * 
+//  */
+// struct pso6 {
+//     struct pso_header header;
+//     union {
+//         char bytes[496];
+//         uint64_t words[62];
+//         struct free_payload free;
+//         struct hashtable_payload hashtable;
+//         struct namespace_payload namespace;
+//     } payload;
+// };
 
-/**
- * @brief A paged space object of size class 7, 128 words total, 126 words
- * payload.
- * 
- */
-struct pso7 {
-    struct pso_header header;
-    union {
-        char bytes[1008];
-        uint64_t words[126];
-        struct free_payload free;
-    } payload;
-};
+// /**
+//  * @brief A paged space object of size class 7, 128 words total, 126 words
+//  * payload.
+//  * 
+//  */
+// struct pso7 {
+//     struct pso_header header;
+//     union {
+//         char bytes[1008];
+//         uint64_t words[126];
+//         struct free_payload free;
+//     } payload;
+// };
 
-/**
- * @brief A paged space object of size class 8, 256 words total, 254 words
- * payload.
- * 
- */
-struct pso8 {
-    struct pso_header header;
-    union {
-        char bytes[2032];
-        uint64_t words[254];
-        struct free_payload free;
-    } payload;
-};
+// /**
+//  * @brief A paged space object of size class 8, 256 words total, 254 words
+//  * payload.
+//  * 
+//  */
+// struct pso8 {
+//     struct pso_header header;
+//     union {
+//         char bytes[2032];
+//         uint64_t words[254];
+//         struct free_payload free;
+//     } payload;
+// };
 
-/**
- * @brief A paged space object of size class 9, 512 words total, 510 words
- * payload.
- * 
- */
-struct pso9 {
-    struct pso_header header;
-    union {
-        char bytes[4080];
-        uint64_t words[510];
-        struct free_payload free;
-    } payload;
-};
+// /**
+//  * @brief A paged space object of size class 9, 512 words total, 510 words
+//  * payload.
+//  * 
+//  */
+// struct pso9 {
+//     struct pso_header header;
+//     union {
+//         char bytes[4080];
+//         uint64_t words[510];
+//         struct free_payload free;
+//     } payload;
+// };
 
-/**
- * @brief A paged space object of size class a, 1024 words total, 1022 words
- * payload.
- * 
- */
-struct psoa {
-    struct pso_header header;
-    union {
-        char bytes[8176];
-        uint64_t words[1022];
-        struct free_payload free;
-    } payload;
-};
+// /**
+//  * @brief A paged space object of size class a, 1024 words total, 1022 words
+//  * payload.
+//  * 
+//  */
+// struct psoa {
+//     struct pso_header header;
+//     union {
+//         char bytes[8176];
+//         uint64_t words[1022];
+//         struct free_payload free;
+//     } payload;
+// };
 
-/**
- * @brief A paged space object of size class b, 2048 words total, 2046 words
- * payload.
- * 
- */
-struct psob {
-    struct pso_header header;
-    union {
-        char bytes[16368];
-        uint64_t words[2046];
-        struct free_payload free;
-    } payload;
-};
+// /**
+//  * @brief A paged space object of size class b, 2048 words total, 2046 words
+//  * payload.
+//  * 
+//  */
+// struct psob {
+//     struct pso_header header;
+//     union {
+//         char bytes[16368];
+//         uint64_t words[2046];
+//         struct free_payload free;
+//     } payload;
+// };
 
-/**
- * @brief A paged space object of size class c, 4096 words total, 4094 words
- * payload.
- * 
- */
-struct psoc {
-    struct pso_header header;
-    union {
-        char bytes[32752];
-        uint64_t words[4094];
-        struct free_payload free;
-    } payload;
-};
+// /**
+//  * @brief A paged space object of size class c, 4096 words total, 4094 words
+//  * payload.
+//  * 
+//  */
+// struct psoc {
+//     struct pso_header header;
+//     union {
+//         char bytes[32752];
+//         uint64_t words[4094];
+//         struct free_payload free;
+//     } payload;
+// };
 
-/**
- * @brief A paged space object of size class d, 8192 words total, 8190 words
- * payload.
- * 
- */
-struct psod {
-    struct pso_header header;
-    union {
-        char bytes[65520];
-        uint64_t words[8190];
-        struct free_payload free;
-    } payload;
-};
+// /**
+//  * @brief A paged space object of size class d, 8192 words total, 8190 words
+//  * payload.
+//  * 
+//  */
+// struct psod {
+//     struct pso_header header;
+//     union {
+//         char bytes[65520];
+//         uint64_t words[8190];
+//         struct free_payload free;
+//     } payload;
+// };
 
-/**
- * @brief A paged space object of size class e, 16384 words total, 16382 words
- * payload.
- * 
- */
-struct psoe {
-    struct pso_header header;
-    union {
-        char bytes[131056];
-        uint64_t words[16382];
-        struct free_payload free;
-    } payload;
-};
+// /**
+//  * @brief A paged space object of size class e, 16384 words total, 16382 words
+//  * payload.
+//  * 
+//  */
+// struct psoe {
+//     struct pso_header header;
+//     union {
+//         char bytes[131056];
+//         uint64_t words[16382];
+//         struct free_payload free;
+//     } payload;
+// };
 
-/**
- * @brief A paged space object of size class f, 32768 words total, 32766 words
- * payload.
- * 
- */
-struct psof {
-    struct pso_header header;
-    union {
-        char bytes[262128];
-        uint64_t words[32766];
-        struct free_payload free;
-    } payload;
-};
+// /**
+//  * @brief A paged space object of size class f, 32768 words total, 32766 words
+//  * payload.
+//  * 
+//  */
+// struct psof {
+//     struct pso_header header;
+//     union {
+//         char bytes[262128];
+//         uint64_t words[32766];
+//         struct free_payload free;
+//     } payload;
+// };
 
 struct pso_pointer allocate( char* tag, uint8_t size_class);
 
diff --git a/src/c/memory/pso2.h b/src/c/memory/pso2.h
new file mode 100644
index 0000000..9e838c4
--- /dev/null
+++ b/src/c/memory/pso2.h
@@ -0,0 +1,53 @@
+/**
+ *  memory/pso2.h
+ *
+ *  Paged space object of size class 2, four words total, two words payload.
+ *
+ *  (c) 2026 Simon Brooke <simon@journeyman.cc>
+ *  Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#ifndef __psse_memory_pso2_h
+#define __psse_memory_pso2_h
+
+#include <stdint.h>
+
+#include "memory/header.h"
+#include "payloads/cons.h"
+#include "payloads/free.h"
+#include "payloads/function.h"
+#include "payloads/integer.h"
+#include "payloads/keyword.h"
+#include "payloads/lambda.h"
+#include "payloads/nlambda.h"
+#include "payloads/read_stream.h"
+#include "payloads/special.h"
+#include "payloads/string.h"
+#include "payloads/symbol.h"
+#include "payloads/time.h"
+#include "payloads/vector_pointer.h"
+#include "payloads/write_stream.h"
+
+/**
+ * @brief A paged space object of size class 2, four words total, two words
+ * payload.
+ * 
+ */
+struct pso2 {
+    struct pso_header header;
+    union {
+        char bytes[16];
+        uint64_t words[2];
+        struct cons_payload cons;
+        struct free_payload free;
+        struct function_payload function;
+        struct integer_payload integer;
+        struct lambda_payload lambda;
+//        struct special_payload special;
+        struct stream_payload stream;
+        struct time_payload time;
+        struct vectorp_payload vectorp;
+    } payload;
+};
+
+#endif
diff --git a/src/c/memory/pso3.h b/src/c/memory/pso3.h
new file mode 100644
index 0000000..c4975b1
--- /dev/null
+++ b/src/c/memory/pso3.h
@@ -0,0 +1,37 @@
+/**
+ *  memory/pso3.h
+ *
+ *  Paged space object of size class 3, 8 words total, 6 words payload.
+ *
+ *  (c) 2026 Simon Brooke <simon@journeyman.cc>
+ *  Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#ifndef __psse_memory_pso3_h
+#define __psse_memory_pso3_h
+
+#include <stdint.h>
+
+#include "memory/header.h"
+#include "payloads/exception.h"
+#include "payloads/free.h"
+#include "payloads/mutex.h"
+
+
+/**
+ * @brief A paged space object of size class 3, 8 words total, 6 words
+ * payload.
+ * 
+ */
+struct pso3 {
+    struct pso_header header;
+    union {
+        char bytes[48];
+        uint64_t words[6];
+        struct exception_payload exception;
+        struct free_payload free;
+        struct mutex_payload mutex;
+    } payload;
+};
+
+#endif
diff --git a/src/c/memory/pso4.h b/src/c/memory/pso4.h
new file mode 100644
index 0000000..9ffc337
--- /dev/null
+++ b/src/c/memory/pso4.h
@@ -0,0 +1,34 @@
+/**
+ *  memory/pso4.h
+ *
+ *  Paged space object of size class 4, 16 words total, 14 words payload.
+ *
+ *  (c) 2026 Simon Brooke <simon@journeyman.cc>
+ *  Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#ifndef __psse_memory_pso4_h
+#define __psse_memory_pso4_h
+
+#include <stdint.h>
+
+#include "memory/header.h"
+#include "payloads/free.h"
+#include "payloads/stack.h"
+
+/**
+ * @brief A paged space object of size class 4, 16 words total, 14 words
+ * payload.
+ * 
+ */
+struct pso4 {
+    struct pso_header header;
+    union {
+        char bytes[112];
+        uint64_t words[14];
+        struct free_payload free;
+        struct stack_frame_payload stack_frame;
+    } payload;
+};
+
+#endif
diff --git a/src/c/memory/pso5.h b/src/c/memory/pso5.h
new file mode 100644
index 0000000..585332c
--- /dev/null
+++ b/src/c/memory/pso5.h
@@ -0,0 +1,32 @@
+/**
+ *  memory/pso5.h
+ *
+ *  Paged space object of size class 5, 32 words total, 30 words payload.
+ *
+ *  (c) 2026 Simon Brooke <simon@journeyman.cc>
+ *  Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#ifndef __psse_memory_pso5_h
+#define __psse_memory_pso5_h
+
+#include <stdint.h>
+
+#include "memory/header.h"
+#include "payloads/free.h"
+
+/**
+ * @brief A paged space object of size class 5, 32 words total, 30 words
+ * payload.
+ * 
+ */
+struct pso5 {
+    struct pso_header header;
+    union {
+        char bytes[240];
+        uint64_t words[30];
+        struct free_payload free;
+    } payload;
+};
+
+#endif
diff --git a/src/c/memory/pso6.h b/src/c/memory/pso6.h
new file mode 100644
index 0000000..3bd9290
--- /dev/null
+++ b/src/c/memory/pso6.h
@@ -0,0 +1,32 @@
+/**
+ *  memory/pso6.h
+ *
+ *  Paged space object of size class 6, 64 words total, 62 words payload.
+ *
+ *  (c) 2026 Simon Brooke <simon@journeyman.cc>
+ *  Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#ifndef __psse_memory_pso6_h
+#define __psse_memory_pso6_h
+
+#include <stdint.h>
+
+#include "memory/header.h"
+#include "payloads/free.h"
+
+/**
+ * @brief A paged space object of size class 6, 64 words total, 62 words
+ * payload.
+ * 
+ */
+struct pso6 {
+    struct pso_header header;
+    union {
+        char bytes[496];
+        uint64_t words[62];
+        struct free_payload free;
+    } payload;
+};
+
+#endif
diff --git a/src/c/memory/pso7.h b/src/c/memory/pso7.h
new file mode 100644
index 0000000..04ee61b
--- /dev/null
+++ b/src/c/memory/pso7.h
@@ -0,0 +1,32 @@
+/**
+ *  memory/pso7.h
+ *
+ *  Paged space object of size class 7, 128 words total, 126 words payload.
+ *
+ *  (c) 2026 Simon Brooke <simon@journeyman.cc>
+ *  Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#ifndef __psse_memory_pso7_h
+#define __psse_memory_pso7_h
+
+#include <stdint.h>
+
+#include "memory/header.h"
+#include "payloads/free.h"
+
+/**
+ * @brief A paged space object of size class 7, 128 words total, 126 words
+ * payload.
+ * 
+ */
+struct pso7 {
+    struct pso_header header;
+    union {
+        char bytes[1008];
+        uint64_t words[126];
+        struct free_payload free;
+    } payload;
+};
+
+#endif
diff --git a/src/c/memory/pso8.h b/src/c/memory/pso8.h
new file mode 100644
index 0000000..b3a00bc
--- /dev/null
+++ b/src/c/memory/pso8.h
@@ -0,0 +1,32 @@
+/**
+ *  memory/pso8.h
+ *
+ *  Paged space object of size class 8, 256 words total, 254 words payload.
+ *
+ *  (c) 2026 Simon Brooke <simon@journeyman.cc>
+ *  Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#ifndef __psse_memory_pso8_h
+#define __psse_memory_pso8_h
+
+#include <stdint.h>
+
+#include "memory/header.h"
+#include "payloads/free.h"
+
+/**
+ * @brief A paged space object of size class 8, 256 words total, 254 words
+ * payload.
+ * 
+ */
+struct pso8 {
+    struct pso_header header;
+    union {
+        char bytes[2032];
+        uint64_t words[254];
+        struct free_payload free;
+    } payload;
+};
+
+#endif
diff --git a/src/c/memory/pso9.h b/src/c/memory/pso9.h
new file mode 100644
index 0000000..3fa5eab
--- /dev/null
+++ b/src/c/memory/pso9.h
@@ -0,0 +1,32 @@
+/**
+ *  memory/pso9.h
+ *
+ *  Paged space object of size class 9, 512 words total, 510 words payload.
+ *
+ *  (c) 2026 Simon Brooke <simon@journeyman.cc>
+ *  Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#ifndef __psse_memory_pso9_h
+#define __psse_memory_pso9_h
+
+#include <stdint.h>
+
+#include "memory/header.h"
+#include "payloads/free.h"
+
+/**
+ * @brief A paged space object of size class 9, 512 words total, 510 words
+ * payload.
+ * 
+ */
+struct pso9 {
+    struct pso_header header;
+    union {
+        char bytes[4080];
+        uint64_t words[510];
+        struct free_payload free;
+    } payload;
+};
+
+#endif
diff --git a/src/c/memory/psoa.h b/src/c/memory/psoa.h
new file mode 100644
index 0000000..1c8e9c7
--- /dev/null
+++ b/src/c/memory/psoa.h
@@ -0,0 +1,32 @@
+/**
+ *  memory/psoa.h
+ *
+ *  Paged space object of size class a, 1024 words total, 1022 words payload.
+ *
+ *  (c) 2026 Simon Brooke <simon@journeyman.cc>
+ *  Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#ifndef __psse_memory_psoa_h
+#define __psse_memory_psoa_h
+
+#include <stdint.h>
+
+#include "memory/header.h"
+#include "payloads/free.h"
+
+/**
+ * @brief A paged space object of size class a, 1024 words total, 1022 words
+ * payload.
+ * 
+ */
+struct psoa {
+    struct pso_header header;
+    union {
+        char bytes[8176];
+        uint64_t words[1022];
+        struct free_payload free;
+    } payload;
+};
+
+#endif
diff --git a/src/c/memory/psob.h b/src/c/memory/psob.h
new file mode 100644
index 0000000..d6b235a
--- /dev/null
+++ b/src/c/memory/psob.h
@@ -0,0 +1,32 @@
+/**
+ *  memory/psob.h
+ *
+ *  Paged space object of size class b, 2048 words total, 2046 words payload.
+ *
+ *  (c) 2026 Simon Brooke <simon@journeyman.cc>
+ *  Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#ifndef __psse_memory_psob_h
+#define __psse_memory_psob_h
+
+#include <stdint.h>
+
+#include "memory/header.h"
+#include "payloads/free.h"
+
+/**
+ * @brief A paged space object of size class b, 2048 words total, 2046 words
+ * payload.
+ * 
+ */
+struct psob {
+    struct pso_header header;
+    union {
+        char bytes[16368];
+        uint64_t words[2046];
+        struct free_payload free;
+    } payload;
+};
+
+#endif
diff --git a/src/c/memory/psoc.h b/src/c/memory/psoc.h
new file mode 100644
index 0000000..934c8b3
--- /dev/null
+++ b/src/c/memory/psoc.h
@@ -0,0 +1,32 @@
+/**
+ *  memory/psoc.h
+ *
+ *  Paged space object of size class c, 4096 words total, 4094 words payload.
+ *
+ *  (c) 2026 Simon Brooke <simon@journeyman.cc>
+ *  Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#ifndef __psse_memory_psoc_h
+#define __psse_memory_psoc_h
+
+#include <stdint.h>
+
+#include "memory/header.h"
+#include "payloads/free.h"
+
+/**
+ * @brief A paged space object of size class c, 4096 words total, 4094 words
+ * payload.
+ * 
+ */
+struct psoc {
+    struct pso_header header;
+    union {
+        char bytes[32752];
+        uint64_t words[4094];
+        struct free_payload free;
+    } payload;
+};
+
+#endif
diff --git a/src/c/memory/psod.h b/src/c/memory/psod.h
new file mode 100644
index 0000000..5ed7711
--- /dev/null
+++ b/src/c/memory/psod.h
@@ -0,0 +1,32 @@
+/**
+ *  memory/psod.h
+ *
+ *  Paged space object of size class d, 8192 words total, 8190 words payload.
+ *
+ *  (c) 2026 Simon Brooke <simon@journeyman.cc>
+ *  Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#ifndef __psse_memory_psod_h
+#define __psse_memory_psod_h
+
+#include <stdint.h>
+
+#include "memory/header.h"
+#include "payloads/free.h"
+
+/**
+ * @brief A paged space object of size class d, 8192 words total, 8190 words
+ * payload.
+ * 
+ */
+struct psod {
+    struct pso_header header;
+    union {
+        char bytes[65520];
+        uint64_t words[8190];
+        struct free_payload free;
+    } payload;
+};
+
+#endif
diff --git a/src/c/memory/psoe.h b/src/c/memory/psoe.h
new file mode 100644
index 0000000..5f2b619
--- /dev/null
+++ b/src/c/memory/psoe.h
@@ -0,0 +1,32 @@
+/**
+ *  memory/psoe.h
+ *
+ *  Paged space object of size class e, 16384 words total, 16382 words payload.
+ *
+ *  (c) 2026 Simon Brooke <simon@journeyman.cc>
+ *  Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#ifndef __psse_memory_psoe_h
+#define __psse_memory_psoe_h
+
+#include <stdint.h>
+
+#include "memory/header.h"
+#include "payloads/free.h"
+
+/**
+ * @brief A paged space object of size class e, 16384 words total, 16382 words
+ * payload.
+ * 
+ */
+struct psoe {
+    struct pso_header header;
+    union {
+        char bytes[131056];
+        uint64_t words[16382];
+        struct free_payload free;
+    } payload;
+};
+
+#endif
diff --git a/src/c/memory/psof.h b/src/c/memory/psof.h
new file mode 100644
index 0000000..58615de
--- /dev/null
+++ b/src/c/memory/psof.h
@@ -0,0 +1,32 @@
+/**
+ *  memory/psof.h
+ *
+ *  Paged space object of size class f, 32768 words total, 32766 words payload.
+ *
+ *  (c) 2026 Simon Brooke <simon@journeyman.cc>
+ *  Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#ifndef __psse_memory_psof_h
+#define __psse_memory_psof_h
+
+#include <stdint.h>
+
+#include "memory/header.h"
+#include "payloads/free.h"
+
+/**
+ * @brief A paged space object of size class f, 32768 words total, 32766 words
+ * payload.
+ * 
+ */
+struct psof {
+    struct pso_header header;
+    union {
+        char bytes[262128];
+        uint64_t words[32766];
+        struct free_payload free;
+    } payload;
+};
+
+#endif
diff --git a/src/c/payloads/function.h b/src/c/payloads/function.h
index 2ef45c4..2f43bef 100644
--- a/src/c/payloads/function.h
+++ b/src/c/payloads/function.h
@@ -11,7 +11,7 @@
 #define __psse_payloads_function_h
 
 #include "memory/pointer.h"
-#include "memory/pso.h"
+#include "memory/pso4.h"
 
 /**
  * @brief Tag for an ordinary Lisp function - one whose arguments are pre-evaluated.
@@ -41,7 +41,7 @@ struct function_payload {
      * a cons pointer (representing its result).
      * \todo check this documentation is current!
      */
-    struct pso_pointer ( *executable ) ( struct pso4 *,
+    struct pso_pointer ( *executable ) ( struct pso4*,
                                           struct pso_pointer,
                                           struct pso_pointer );
 };
diff --git a/src/c/payloads/hashtable.h b/src/c/payloads/hashtable.h
index 86664e5..3619847 100644
--- a/src/c/payloads/hashtable.h
+++ b/src/c/payloads/hashtable.h
@@ -45,11 +45,11 @@
  * i.e. either an assoc list or a further hashtable.
  */
 struct hashtable_payload {
-    struct cons_pointer hash_fn;    /* function for hashing values in this hashtable, or `NIL` to use
+    struct pso_pointer hash_fn;    /* function for hashing values in this hashtable, or `NIL` to use
                                      the default hashing function */
     uint32_t n_buckets;             /* number of hash buckets */
-    struct cons_pointer buckets[];  /* actual hash buckets, which should be `NIL`
+    struct pso_pointer buckets[];  /* actual hash buckets, which should be `NIL`
                                      * or assoc lists or (possibly) further hashtables. */
 };
 
-#endif
\ No newline at end of file
+#endif
diff --git a/src/c/payloads/namespace.h b/src/c/payloads/namespace.h
index b494e93..bb1b1b3 100644
--- a/src/c/payloads/namespace.h
+++ b/src/c/payloads/namespace.h
@@ -48,17 +48,17 @@
  * i.e. either an assoc list or a further namespace.
  */
 struct namespace_payload {
-    struct cons_pointer hash_fn;    /* function for hashing values in this namespace, or 
+    struct pso_pointer hash_fn;    /* function for hashing values in this namespace, or 
                                      * `NIL` to use the default hashing function */
     uint32_t n_buckets;             /* number of hash buckets */
     uint32_t unused;                /* for word alignment and possible later expansion */
-    struct cons_pointer write_acl;  /* it seems to me that it is likely that the
+    struct pso_pointer write_acl;  /* it seems to me that it is likely that the
                                      * principal difference between a hashtable and a
                                      * namespace is that a hashtable has a write ACL
                                      * of `NIL`, meaning not writeable by anyone */
-    struct cons_pointer mutex;      /* the mutex to lock when modifying this namespace.*/
-    struct cons_pointer buckets[];  /* actual hash buckets, which should be `NIL`
+    struct pso_pointer mutex;      /* the mutex to lock when modifying this namespace.*/
+    struct pso_pointer buckets[];  /* actual hash buckets, which should be `NIL`
                                      * or assoc lists or (possibly) further hashtables. */
 };
 
-#endif
\ No newline at end of file
+#endif
diff --git a/src/c/payloads/read_stream.h b/src/c/payloads/read_stream.h
index e271489..ef2f5cc 100644
--- a/src/c/payloads/read_stream.h
+++ b/src/c/payloads/read_stream.h
@@ -14,6 +14,7 @@
 
 #include <curl/curl.h>
 
+#include "io/fopen.h"
 #include "memory/pointer.h"
 
 /**
@@ -31,7 +32,7 @@ struct stream_payload {
     /** metadata on the stream (e.g. its file attributes if a file, its HTTP
      * headers if a URL, etc). Expected to be an association, or nil. Not yet
      * implemented. */
-    struct cons_pointer meta;
+    struct pso_pointer meta;
 };
 
 #endif
diff --git a/src/c/payloads/special.h b/src/c/payloads/special.h
index 4c64545..4dcf7c2 100644
--- a/src/c/payloads/special.h
+++ b/src/c/payloads/special.h
@@ -11,6 +11,7 @@
 #define __psse_payloads_special_h
 
 #include "memory/pointer.h"
+#include "memory/pso4.h"
 
 /**
  * A special form - one whose arguments are not pre-evaluated but passed as
@@ -20,25 +21,25 @@
 #define SPECIALTAG  "SFM"
 #define SPECIALTV   5064275
 
-/**
- * @brief Payload of a special form cell. 
- *
- * Currently identical to the payload of a function cell.
- * \see function_payload
- */
-struct special_payload {
-    /**
-     * pointer to the source from which the special form was compiled, or NIL
-     * if it is a primitive.
-     */
-    struct pso_pointer meta;
-    /**  pointer to a function which takes a cons pointer (representing
-     * its argument list) and a cons pointer (representing its environment) and a
-     * stack frame (representing the previous stack frame) as arguments and returns
-     * a cons pointer (representing its result). */
-    struct pso_pointer ( *executable ) ( struct pso4 *,
-                                          struct pso_pointer,
-                                          struct pso_pointer );
-};
+// /**
+//  * @brief Payload of a special form cell. 
+//  *
+//  * Currently identical to the payload of a function cell.
+//  * \see function_payload
+//  */
+// struct special_payload {
+//     /**
+//      * pointer to the source from which the special form was compiled, or NIL
+//      * if it is a primitive.
+//      */
+//     struct pso_pointer meta;
+//     /**  pointer to a function which takes a cons pointer (representing
+//      * its argument list) and a cons pointer (representing its environment) and a
+//      * stack frame (representing the previous stack frame) as arguments and returns
+//      * a cons pointer (representing its result). */
+//     struct pso_pointer ( *executable ) ( struct pso4*,
+//                                           struct pso_pointer,
+//                                           struct pso_pointer );
+// };
 
 #endif
diff --git a/src/c/payloads/stack.c b/src/c/payloads/stack.c
index a814699..484c13d 100644
--- a/src/c/payloads/stack.c
+++ b/src/c/payloads/stack.c
@@ -11,6 +11,9 @@
 #include "memory/pso.h"
 #include "payloads/stack.h"
 
+#define STACKTAG "STK"
+#define STACKTV  4936787
+
 /** 
  * @brief The maximum depth of stack before we throw an exception.
  *
diff --git a/src/c/payloads/stack.h b/src/c/payloads/stack.h
index ba0abd8..23fb8e5 100644
--- a/src/c/payloads/stack.h
+++ b/src/c/payloads/stack.h
@@ -13,6 +13,8 @@
 #define __psse_payloads_stack_h
 
 #include "memory/pointer.h"
+#include "memory/pso2.h"
+#include "memory/pso4.h"
 
 /*
  * number of arguments stored in a stack frame
diff --git a/src/c/payloads/time.h b/src/c/payloads/time.h
index d9870b4..fd67716 100644
--- a/src/c/payloads/time.h
+++ b/src/c/payloads/time.h
@@ -10,6 +10,8 @@
 #ifndef __psse_payloads_cons_h
 #define __psse_payloads_cons_h
 
+#include <stdint.h>
+
 #include "memory/pointer.h"
 
 /**
diff --git a/src/c/payloads/vector_pointer.h b/src/c/payloads/vector_pointer.h
index b5e5f1c..8fda0f3 100644
--- a/src/c/payloads/vector_pointer.h
+++ b/src/c/payloads/vector_pointer.h
@@ -16,6 +16,7 @@
  * A pointer to an object in vector space.
  */
 #define VECTORPOINTTAG  "VSP"
+#define VECTORPOINTTV   5264214
 
 /**
  * @brief payload of a vector pointer cell.
diff --git a/src/c/payloads/write_stream.h b/src/c/payloads/write_stream.h
index deda598..1197d73 100644
--- a/src/c/payloads/write_stream.h
+++ b/src/c/payloads/write_stream.h
@@ -10,6 +10,7 @@
 #ifndef __psse_payloads_write_stream_h
 #define __psse_payloads_write_stream_h
 
+#include "io/fopen.h"
 #include "memory/pointer.h"
 
 /**