From 578531395ecbabd8179e31520c2832ac7d6d3765 Mon Sep 17 00:00:00 2001
From: Matthew Sotoudeh <matthew@masot.net>
Date: Thu, 27 Jul 2023 12:06:17 -0700
Subject: add dynamic typing example

---
 .../dynamic_typing/runtime/dynamic_typing.c        | 72 ++++++++++++++++++++++
 .../dynamic_typing/runtime/dynamic_typing.h        | 48 +++++++++++++++
 2 files changed, 120 insertions(+)
 create mode 100644 python/examples/dynamic_typing/runtime/dynamic_typing.c
 create mode 100644 python/examples/dynamic_typing/runtime/dynamic_typing.h

(limited to 'python/examples/dynamic_typing/runtime')

diff --git a/python/examples/dynamic_typing/runtime/dynamic_typing.c b/python/examples/dynamic_typing/runtime/dynamic_typing.c
new file mode 100644
index 0000000..4e47bc9
--- /dev/null
+++ b/python/examples/dynamic_typing/runtime/dynamic_typing.c
@@ -0,0 +1,72 @@
+#include <stdlib.h>
+#include "dynamic_typing.h"
+
+struct entry {
+    void *start;
+    void *end;
+    struct type *type;
+};
+
+static struct entry *ENTRIES;
+static unsigned long N_ENTRIES;
+
+void annotate_type(void *ptr, struct type *type) {
+    ENTRIES = realloc(ENTRIES, (++N_ENTRIES) * sizeof(ENTRIES[0]));
+    ENTRIES[N_ENTRIES - 1] = (struct entry){
+        .start = ptr,
+        .end = ptr + 1,
+        .type = type,
+    };
+}
+
+struct type *dynamic_typeof(void *ptr) {
+    for (unsigned long i = N_ENTRIES; i --> 0;)
+        if (ENTRIES[i].start <= ptr && ptr < ENTRIES[i].end)
+            return ENTRIES[i].type;
+    return 0;
+}
+
+struct type *make_basic(const char *type, unsigned long size) {
+    struct type *t = calloc(1, sizeof(*t));
+    t->kind = TY_BASIC;
+    t->basic = type;
+    t->size = size;
+    return t;
+}
+
+struct type *make_array(struct type *base, unsigned long len) {
+    struct type *t = calloc(1, sizeof(*t));
+    t->kind = TY_ARRAY;
+    t->base = base;
+    t->length = len;
+    t->size = len * t->base->size;
+    return t;
+}
+
+struct type *make_pointer(struct type *base) {
+    struct type *t = calloc(1, sizeof(*t));
+    t->kind = TY_POINTER;
+    t->base = base;
+    t->size = sizeof(void*);
+    return t;
+}
+
+// function not supported yet
+// for struct & union, the members are initialized by the caller
+struct type *make_struct(unsigned long size) {
+    struct type *t = calloc(1, sizeof(*t));
+    t->kind = TY_STRUCT;
+    return t;
+}
+
+struct type *make_union(unsigned long size) {
+    struct type *t = calloc(1, sizeof(*t));
+    t->kind = TY_UNION;
+    return t;
+}
+void prepend_member(struct type *aggregate, struct type *member, const char *name, unsigned long offset) {
+    member->offset = offset;
+    member->next_member = aggregate->members;
+    member->field_name = name;
+    aggregate->members = member;
+}
diff --git a/python/examples/dynamic_typing/runtime/dynamic_typing.h b/python/examples/dynamic_typing/runtime/dynamic_typing.h
new file mode 100644
index 0000000..4f7b1aa
--- /dev/null
+++ b/python/examples/dynamic_typing/runtime/dynamic_typing.h
@@ -0,0 +1,48 @@
+#ifndef DYNAMIC_TYPING_
+#define DYNAMIC_TYPING_
+
+enum TYPE_KIND {
+    TY_BASIC,
+    TY_ARRAY,
+    TY_POINTER,
+    TY_FUNCTION,
+    TY_STRUCT,
+    TY_UNION,
+};
+
+struct type {
+    enum TYPE_KIND kind;
+    unsigned long size;
+
+    // basic types:
+    const char *basic;
+
+    // array & pointer types:
+    struct type *base;
+    unsigned long length;
+
+    // struct & union types
+    struct type *members;
+    struct type *next_member;
+    unsigned long offset;
+    const char *field_name;
+
+    // function types:
+    struct type *return_type;
+    struct type *params;
+    struct type *next_param;
+};
+
+struct type *dynamic_typeof(void *ptr);
+
+struct type *make_basic(const char *type, unsigned long size);
+struct type *make_array(struct type *base, unsigned long len);
+struct type *make_pointer(struct type *base);
+// function not supported yet
+// for struct & union, the members are initialized by the caller
+struct type *make_struct(unsigned long size);
+struct type *make_union(unsigned long size);
+void prepend_member(struct type *aggregate, struct type *member, const char *name, unsigned long offset);
+void annotate_type(void *ptr, struct type *type);
+
+#endif
-- 
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