Added character as a first class object. Stepped through a run; it all works.

src/c/memory/pso2.h

@@ -12,8 +12,8 @@
 
 #include <stdint.h>
 
-#include "../payloads/psse-string.h"
 #include "memory/header.h"
+#include "payloads/character.h"
 #include "payloads/cons.h"
 #include "payloads/free.h"
 #include "payloads/function.h"
@@ -22,9 +22,9 @@
 #include "payloads/lambda.h"
 #include "payloads/nlambda.h"
 #include "payloads/read_stream.h"
-#include "payloads/special.h"
+#include "payloads/psse-string.h"
 #include "payloads/symbol.h"
-// #include "payloads/time.h"
+#include "payloads/time.h"
 #include "payloads/vector_pointer.h"
 #include "payloads/write_stream.h"
 
@@ -38,13 +38,16 @@ struct pso2 {
     union {
         char bytes[16];
         uint64_t words[2];
+        struct character_payload character;
         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 function_payload special;
         struct stream_payload stream;
+        struct string_payload string;
+// TODO: this isn't working and I don't know why (error: field ‘time’ has incomplete type)
 //        struct time_payload time;
         struct vectorp_payload vectorp;
     } payload;

src/c/payloads/character.h

@@ -0,0 +1,39 @@
+/**
+ *  payloads/character.h
+ *
+ *  A character object.
+ *
+ *  Note that, instead of instantiating actual character objects, it would be
+ *  possible to reserve one special page index, outside the normal page range,
+ *  possibly even page 0, such that a character would be represented by a
+ *  pso_pointer {node, special_page, character_code}. The special page wouldn't
+ *  actually have to exist. This wouldn't prevent `nil` being 'the object at
+ *  {n, 0, 0}, since the UTF character with the index 0 is NULL, which feels
+ *  entirely compatible. UTF 1 is 'Start of heading', which is not used by
+ *  anything I'm aware of these days, and is canonically not NULL, so I don't
+ *  see why we should not continue to treat {n, 0, 1} as `t`.
+ *
+ *  (c) 2026 Simon Brooke <simon@journeyman.cc>
+ *  Licensed under GPL version 2.0, or, at your option, any later version.
+ */
+
+#ifndef __psse_payloads_character_h
+#define __psse_payloads_character_h
+/*
+ * wide characters
+ */
+#include <wchar.h>
+#include <wctype.h>
+
+
+#define CHARTAG "CHR"
+#define CHARTV  5392451
+
+/**
+ * @brief a single character, as returned by the reader.
+ */
+struct character_payload {
+    wchar_t character;
+};
+
+#endif

src/c/payloads/special.h

@@ -3,6 +3,9 @@
  *
  *  A special form.
  *
+ *  No payload here; it would be identical to function_payload, q.v., so
+ *  use that instead. 
+ *
  *  (c) 2026 Simon Brooke <simon@journeyman.cc>
  *  Licensed under GPL version 2.0, or, at your option, any later version.
  */
@@ -21,25 +24,4 @@
 #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 );
-// };
-
 #endif

src/c/payloads/time.h

@@ -10,7 +10,9 @@
 #ifndef __psse_payloads_cons_h
 #define __psse_payloads_cons_h
 
+#include <ctype.h>
 #include <stdint.h>
+#include <stdlib.h>
 
 #include "memory/pointer.h"
 
@@ -26,7 +28,7 @@
  * convenience, 14Bn years before 1st Jan 1970 (the UNIX epoch))
  */
 struct time_payload {
-    unsigned __int128_t value;
+    unsigned __int128 value;
 };
 
 #endif