removed more debug prints

eg.
```lua
local err, file = os.open("LICENSE.md")
if err then
    // do error handling stuff
end

// passing "a" to read() will read the whole file
print(file:read("a"))
```

Makefile

@@ -1,7 +1,7 @@
 # make clean && make && ./bin/cosmo
 
 CC=clang
-CFLAGS=-fPIE -Wall -Isrc -O3 -std=c99 #-g -fsanitize=address
+CFLAGS=-fPIE -Wall -Isrc -O3 #-g -fsanitize=address
 LDFLAGS=-lm #-fsanitize=address
 OUT=bin/cosmo
 

docs/stdlib.md

@@ -59,7 +59,12 @@ Includes functions that interact with the operating system.
 
 | Name         | Type                                             | Behavior                                                                 | Example                  |
 | ------------ | ------------------------------------------------ | ------------------------------------------------------------------------ | ------------------------ |
-| os.read      | `(path<string>)` -> `<string>` or `<nil>`        | Returns a file's contents or nil if it doesn't exist/an error occurred   | `os.read("path")` -> `Hello, World!`|
+| os.open | `(path<string>)` -> `<bool>, <obj>` | Opens a file at `path` and returns a file object. If the file does not exist, it will be created. | `os.open("test.txt")` -> `true, <file>` |
 | os.time      | `()` -> `<number>`                               | Returns the system time in Epoch format                                  | `os.time()` -> `1.61691e+09` |
 | os.system    | `(cmd<string>)` -> `<number>`                    | Runs a system command as if it were a terminal and returns the exit code | `os.system("mkdir test")` -> `0`  |
 > -> means 'returns'
+
+File objects have the following methods:
+| Name         | Type                                             | Behavior                                                                 | Example                  |
+| ------------ | ------------------------------------------------ | ------------------------------------------------------------------------ | ------------------------ |
+| file:read | `(amt<number> or "a")` -> `<string>` | Reads `amt` bytes from the file and returns them as a string. If `"a"` is passed, the entire file is read. | `file:read("a")` -> `"Hello world!"` |

examples/reader.cosmo

@@ -0,0 +1,9 @@
+
+local err, file = os.open("LICENSE.md")
+print("made file")
+if err then
+  print("failed to open file")
+end
+
+print(file)
+print(file:read("a"))

main.c

@@ -75,7 +75,7 @@ static void repl(CState *state)
     cosmoV_pushString(state, "input");
     cosmoV_pushCFunction(state, cosmoB_input);
 
-    cosmoV_register(state, 2);
+    cosmoV_addGlobals(state, 2);
 
     while (_ACTIVE) {
         if (!(line = linenoise("> "))) { // better than gets()
@@ -130,7 +130,7 @@ static bool runFile(CState *state, const char *fileName)
     cosmoV_pushString(state, "input");
     cosmoV_pushCFunction(state, cosmoB_input);
 
-    cosmoV_register(state, 1);
+    cosmoV_addGlobals(state, 1);
 
     ret = interpret(state, script, fileName);
 

src/cbaselib.c

@@ -69,7 +69,7 @@ int cosmoB_pcall(CState *state, int nargs, CValue *args)
     bool res = cosmoV_pcall(state, nargs - 1, 1);
 
     // insert false before the result
-    cosmo_insert(state, 0, cosmoV_newBoolean(res));
+    cosmoV_insert(state, 0, cosmoV_newBoolean(res));
     return 2;
 }
 
@@ -105,7 +105,7 @@ int cosmoB_loadstring(CState *state, int nargs, CValue *args)
     CObjString *str = cosmoV_readString(args[0]);
     bool res = cosmoV_compileString(state, str->str, "");
 
-    cosmo_insert(state, 0, cosmoV_newBoolean(res));
+    cosmoV_insert(state, 0, cosmoV_newBoolean(res));
     return 2; // <boolean>, <closure> or <error>
 }
 
@@ -139,7 +139,7 @@ void cosmoB_loadLibrary(CState *state)
     }
 
     // register all the pushed c functions and the strings as globals
-    cosmoV_register(state, i);
+    cosmoV_addGlobals(state, i);
 
     // load other libraries
     cosmoB_loadObjLib(state);
@@ -230,52 +230,129 @@ COSMO_API void cosmoB_loadObjLib(CState *state)
     cosmoV_registerProtoObject(state, COBJ_OBJECT, obj);
 
     // register "object" to the global table
-    cosmoV_register(state, 1);
+    cosmoV_addGlobals(state, 1);
 }
 
 // ================================================================ [OS.*]
 
-// os.read()
-int cosmoB_osRead(CState *state, int nargs, CValue *args)
+int fileB_read(CState *state, int nargs, CValue *args)
 {
+    if (nargs != 2) {
+        cosmoV_error(state, "file:read() expected 2 arguments, got %d!", nargs);
+    }
+
+    if (!cosmoV_isValueUserType(state, args[0], COSMO_USER_FILE)) {
+        cosmoV_typeError(state, "file:read()", "<file>, <number> or \"a\"", "%s, %s",
+                         cosmoV_typeStr(args[0]), cosmoV_typeStr(args[1]));
+    }
+
+    CObjObject *fileObj = cosmoV_readObject(args[0]);
+    FILE *file = cosmoO_getUserP(fileObj);
+
+    if (IS_NUMBER(args[1])) {
+        cosmo_Number length = cosmoV_readNumber(args[1]);
+
+        // make sure the length is within the bounds of the file
+        if (length < 0) {
+            cosmoV_error(state, "file:read() expected length to be >= 0, got %d!", length);
+        }
+
+        // allocate a buffer for the read data
+        char *buffer = cosmoM_xmalloc(state, length + 1);
+
+        // read the data
+        fread(buffer, sizeof(char), length, file);
+
+        // push the read data
+        CValue temp = cosmoV_newRef(cosmoO_takeString(state, buffer, length));
+        cosmoV_pushValue(state, temp);
+    } else if (IS_STRING(args[1])) {
+        if (strcmp(cosmoV_readCString(args[1]), "a") == 0) {
+            // get the length of the file
+            fseek(file, 0, SEEK_END);
+            long length = ftell(file);
+            fseek(file, 0, SEEK_SET);
+
+            // allocate a buffer for the read data
+            char *buffer = cosmoM_xmalloc(state, length + 1);
+
+            // read the data
+            fread(buffer, sizeof(char), length, file);
+
+            buffer[length] = '\0'; // write the NULL terminator
+
+            // push the read data
+            CValue temp = cosmoV_newRef(cosmoO_takeString(state, buffer, length));
+            cosmoV_pushValue(state, temp);
+        } else {
+            cosmoV_error(state, "file:read() expected \"a\" or <number>, got %s!",
+                         cosmoV_readCString(args[1]));
+        }
+    } else {
+        cosmoV_typeError(state, "file:read()", "<file>, <number> or \"a\"", "%s, %s",
+                         cosmoV_typeStr(args[0]), cosmoV_typeStr(args[1]));
+    }
+
+    return 1;
+}
+
+int fileB_gc(CState *state, int nargs, CValue *args) {
     if (nargs != 1) {
-        cosmoV_error(state, "os.read() expected 1 argument, got %d!", nargs);
+        cosmoV_error(state, "file:read() expected 1 argument, got %d!", nargs);
+    }
+
+    if (!cosmoV_isValueUserType(state, args[0], COSMO_USER_FILE)) {
+        cosmoV_typeError(state, "file:__gc()", "<file>", "%s",
+                         cosmoV_typeStr(args[0]));
+    }
+
+    CObjObject *fileObj = cosmoV_readObject(args[0]);
+    FILE *file = cosmoO_getUserP(fileObj);
+
+    fclose(file);
+    return 0;
+}
+
+CObjObject *pushFileObj(CState *state, FILE *file)
+{
+    CObjObject *fileObj = cosmoO_newObject(state);
+    cosmoV_pushRef(state, (CObj *)fileObj);
+    cosmoO_setUserP(fileObj, file);
+    cosmoO_setUserT(fileObj, COSMO_USER_FILE);
+
+    // grab and set proto
+    cosmoV_pushRef(state, (CObj *)fileObj);
+    cosmoV_pushString(state, "file");
+    cosmoV_getRegistry(state);
+    cosmoV_setProto(state);
+
+    cosmoO_lock(fileObj);
+    return fileObj;
+}
+
+int cosmoB_osOpen(CState *state, int nargs, CValue *args)
+{
+    FILE *file;
+
+    if (nargs != 1) {
+        cosmoV_error(state, "os.open() expected 1 argument, got %d!", nargs);
     }
 
     if (!IS_STRING(args[0])) {
-        cosmoV_typeError(state, "os.read()", "<string>", "%s", cosmoV_typeStr(args[0]));
+        cosmoV_typeError(state, "os.open()", "<string>", "%s", cosmoV_typeStr(args[0]));
     }
 
-    CObjString *str = cosmoV_readString(args[0]);
-
-    // open file
-    FILE *file = fopen(str->str, "rb");
-    char *buf;
-    size_t size, bRead;
-
+    const char *filePath = cosmoV_readCString(args[0]);
+    file = fopen(filePath, "rb");
     if (file == NULL) {
-        // return nil, file doesn't exist
-        return 0;
+        cosmoV_pushBoolean(state, true);
+        cosmoV_pushFString(state, "Failed to open %s!", filePath);
+        return 2;
     }
 
-    // grab the size of the file
-    fseek(file, 0L, SEEK_END);
-    size = ftell(file);
-    rewind(file);
-
-    buf = cosmoM_xmalloc(state, size + 1);        // +1 for the NULL terminator
-    bRead = fread(buf, sizeof(char), size, file); // read the file into the buffer
-
-    if (bRead < size) {
-        // an error occured! we don't need to really throw an error, returning a nil is good enough
-        return 0;
-    }
-
-    buf[bRead] = '\0'; // place the NULL terminator at the end of the buffer
-
-    // push the string to the stack to return
-    cosmoV_pushValue(state, cosmoV_newRef(cosmoO_takeString(state, buf, bRead)));
-    return 1;
+    cosmoV_pushBoolean(state, false);
+    pushFileObj(state, file);
+    return 2;
 }
 
 // os.time()
@@ -309,9 +386,8 @@ int cosmoB_osSystem(CState *state, int nargs, CValue *args)
 
 COSMO_API void cosmoB_loadOS(CState *state)
 {
-    const char *identifiers[] = {"read", "time", "system"};
-
-    CosmoCFunction osLib[] = {cosmoB_osRead, cosmoB_osTime, cosmoB_osSystem};
+    const char *identifiers[] = {"open", "time", "system"};
+    CosmoCFunction osLib[] = {cosmoB_osOpen, cosmoB_osTime, cosmoB_osSystem};
 
     cosmoV_pushString(state, "os");
 
@@ -322,7 +398,25 @@ COSMO_API void cosmoB_loadOS(CState *state)
     }
 
     cosmoV_makeObject(state, i);
-    cosmoV_register(state, 1); // register the os.* object to the global table
+    cosmoV_addGlobals(state, 1); // register the os.* object to the global table
+
+    // make file proto
+    cosmoV_pushString(state, "file");
+
+    CObjObject *fileProto = cosmoO_newObject(state);
+    cosmoV_pushRef(state, (CObj *)fileProto);
+
+    cosmoV_pushRef(state, (CObj *)fileProto);
+    cosmoV_pushString(state, "read");
+    cosmoV_pushCFunction(state, fileB_read);
+    cosmoV_set(state);
+
+    cosmoV_pushRef(state, (CObj *)fileProto);
+    cosmoV_pushString(state, "__gc");
+    cosmoV_pushCFunction(state, fileB_gc);
+    cosmoV_set(state);
+
+    cosmoV_addRegistry(state, 1);
 }
 
 // ================================================================ [STRING.*]
@@ -578,7 +672,7 @@ void cosmoB_loadStrLib(CState *state)
     cosmoV_registerProtoObject(state, COBJ_STRING, obj);
 
     // register "string" to the global table
-    cosmoV_register(state, 1);
+    cosmoV_addGlobals(state, 1);
 }
 
 // ================================================================ [MATH]
@@ -773,7 +867,7 @@ void cosmoB_loadMathLib(CState *state)
 
     // make the object and register it as a global to the state
     cosmoV_makeObject(state, i);
-    cosmoV_register(state, 1);
+    cosmoV_addGlobals(state, 1);
 }
 
 // ================================================================ [VM.*]
@@ -924,5 +1018,5 @@ void cosmoB_loadVM(CState *state)
     cosmoV_makeObject(state, 5); // makes the vm object
 
     // register "vm" to the global table
-    cosmoV_register(state, 1);
+    cosmoV_addGlobals(state, 1);
 }

src/cbaselib.h

@@ -3,6 +3,13 @@
 
 #include "cstate.h"
 
+enum
+{
+    COSMO_USER_NONE, // CObjObject is not a userdata object
+    COSMO_USER_FILE, // CObjObject is a file object (see cosmoB_osOpen)
+    COSMO_USER_START // the first user type for user-defined userdata
+};
+
 /* loads all of the base library, including:
     - base library ("print", "assert", "type", "pcall", "loadstring", etc.)
     - object library

src/cmem.c

@@ -6,6 +6,7 @@
 #include "cstate.h"
 #include "ctable.h"
 #include "cvalue.h"
+#include "cvm.h"
 
 // realloc wrapper
 void *cosmoM_reallocate(CState *state, void *buf, size_t oldSize, size_t newSize)
@@ -246,22 +247,23 @@ static void sweep(CState *state)
                 prev->next = object;
             }
 
+            // call __gc on the object
+            CObjObject *protoObject = cosmoO_grabProto(oldObj);
+            CValue res;
+
+            // use user-defined __gc
+            if (protoObject != NULL && cosmoO_getIString(state, protoObject, ISTRING_GC, &res)) {
+                cosmoV_pushValue(state, res);
+                cosmoV_pushRef(state, (CObj *)oldObj);
+                cosmoV_call(state, 1, 0);
+            }
+
+
             cosmoO_free(state, oldObj);
         }
     }
 }
 
-static void markUserRoots(CState *state)
-{
-    CObj *root = state->userRoots;
-
-    // traverse userRoots and mark all the object
-    while (root != NULL) {
-        markObject(state, root);
-        root = root->nextRoot;
-    }
-}
-
 static void markRoots(CState *state)
 {
     // mark all values on the stack
@@ -285,8 +287,7 @@ static void markRoots(CState *state)
     for (int i = 0; i < ISTRING_MAX; i++)
         markObject(state, (CObj *)state->iStrings[i]);
 
-    // mark the user defined roots
-    markUserRoots(state);
+    markTable(state, &state->registry);
 
     for (int i = 0; i < COBJ_MAX; i++)
         markObject(state, (CObj *)state->protoObjects[i]);
@@ -323,44 +324,3 @@ COSMO_API void cosmoM_updateThreshhold(CState *state)
 {
     state->nextGC = state->allocatedBytes * HEAP_GROW_FACTOR;
 }
-
-COSMO_API void cosmoM_addRoot(CState *state, CObj *newRoot)
-{
-    // first, check and make sure this root doesn't already exist in the list
-    CObj *root = state->userRoots;
-    while (root != NULL) {
-        if (root == newRoot) // found in the list, abort
-            return;
-
-        root = root->nextRoot;
-    }
-
-    // adds root to userRoot linked list
-    newRoot->nextRoot = state->userRoots;
-    state->userRoots = newRoot;
-}
-
-COSMO_API void cosmoM_removeRoot(CState *state, CObj *oldRoot)
-{
-    CObj *prev = NULL;
-    CObj *root = state->userRoots;
-
-    // traverse the userRoot linked list
-    while (root != NULL) {
-        if (root == oldRoot) { // found root in list
-
-            // remove from the linked list
-            if (prev == NULL) {
-                state->userRoots = root->nextRoot;
-            } else {
-                prev->nextRoot = root->nextRoot;
-            }
-
-            root->nextRoot = NULL;
-            break;
-        }
-
-        prev = root;
-        root = root->nextRoot;
-    }
-}

src/cmem.h

@@ -67,13 +67,6 @@ COSMO_API bool cosmoM_checkGarbage(CState *state,
 COSMO_API void cosmoM_collectGarbage(CState *state);
 COSMO_API void cosmoM_updateThreshhold(CState *state);
 
-// lets the VM know you are holding a reference to a CObj and to not free it
-// NOTE: prefer to use the stack when possible
-COSMO_API void cosmoM_addRoot(CState *state, CObj *newRoot);
-
-// lets the VM know this root is no longer held in a reference and is able to be freed
-COSMO_API void cosmoM_removeRoot(CState *state, CObj *oldRoot);
-
 // wrapper for cosmoM_reallocate so we can track our memory usage
 static inline void *cosmoM_xmalloc(CState *state, size_t sz)
 {

src/cobj.c

@@ -31,7 +31,6 @@ CObj *cosmoO_allocateBase(CState *state, size_t sz, CObjType type)
     obj->next = state->objects;
     state->objects = obj;
 
-    obj->nextRoot = NULL;
 #ifdef GC_DEBUG
     printf("allocated %s %p\n", cosmoO_typeStr(obj), obj);
 #endif
@@ -51,9 +50,9 @@ void cosmoO_free(CState *state, CObj *obj)
         break;
     }
     case COBJ_OBJECT: {
-        CObjObject *objTbl = (CObjObject *)obj;
-        cosmoT_clearTable(state, &objTbl->tbl);
-        cosmoM_free(state, CObjObject, objTbl);
+        CObjObject *objObj = (CObjObject *)obj;
+        cosmoT_clearTable(state, &objObj->tbl);
+        cosmoM_free(state, CObjObject, objObj);
         break;
     }
     case COBJ_TABLE: {
@@ -492,6 +491,7 @@ void cosmoO_unlock(CObjObject *object)
     object->isLocked = false;
 }
 
+
 bool rawgetIString(CState *state, CObjObject *object, int flag, CValue *val)
 {
     if (readFlag(object->istringFlags, flag))

src/cobj.h

@@ -34,7 +34,6 @@ typedef int (*CosmoCFunction)(CState *state, int argCount, CValue *args);
 struct CObj
 {
     struct CObj *next;
-    struct CObj *nextRoot;    // for the root linked list
     struct CObjObject *proto; // protoobject, describes the behavior of the object
     CObjType type;
     bool isMarked; // for the GC

src/cstate.c

@@ -12,6 +12,7 @@ CPanic *cosmoV_newPanic(CState *state)
     CPanic *panic = cosmoM_xmalloc(state, sizeof(CPanic));
     panic->top = state->top;
     panic->frameCount = state->frameCount;
+    panic->freezeGC = state->freezeGC;
     panic->prev = state->panic;
     state->panic = panic;
 
@@ -41,7 +42,6 @@ CState *cosmoV_newState()
 
     // GC
     state->objects = NULL;
-    state->userRoots = NULL;
     state->grayStack.count = 0;
     state->grayStack.capacity = 2;
     state->grayStack.array = NULL;
@@ -61,11 +61,13 @@ CState *cosmoV_newState()
         state->iStrings[i] = NULL;
 
     cosmoT_initTable(state, &state->strings, 16); // init string table
+    cosmoT_initTable(state, &state->registry, 16);
 
     state->globals = cosmoO_newTable(state); // init global table
 
     // setup all strings used by the VM
     state->iStrings[ISTRING_INIT] = cosmoO_copyString(state, "__init", 6);
+    state->iStrings[ISTRING_GC] = cosmoO_copyString(state, "__gc", 4);
     state->iStrings[ISTRING_TOSTRING] = cosmoO_copyString(state, "__tostring", 10);
     state->iStrings[ISTRING_TONUMBER] = cosmoO_copyString(state, "__tonumber", 10);
     state->iStrings[ISTRING_INDEX] = cosmoO_copyString(state, "__index", 7);
@@ -119,6 +121,8 @@ void cosmoV_freeState(CState *state)
     // free our string table (the string table includes the internal VM strings)
     cosmoT_clearTable(state, &state->strings);
 
+    cosmoT_clearTable(state, &state->registry);
+
     // free our gray stack & finally free the state structure
     cosmoM_freeArray(state, CObj *, state->grayStack.array, state->grayStack.capacity);
 
@@ -132,7 +136,7 @@ void cosmoV_freeState(CState *state)
 }
 
 // expects 2*pairs values on the stack, each pair should consist of 1 key and 1 value
-void cosmoV_register(CState *state, int pairs)
+void cosmoV_addGlobals(CState *state, int pairs)
 {
     for (int i = 0; i < pairs; i++) {
         StkPtr key = cosmoV_getTop(state, 1);
@@ -145,6 +149,48 @@ void cosmoV_register(CState *state, int pairs)
     }
 }
 
+// expects 2*pairs values on the stack, each pair should consist of 1 key and 1 value
+void cosmoV_addRegistry(CState *state, int pairs)
+{
+    for (int i = 0; i < pairs; i++) {
+        StkPtr key = cosmoV_getTop(state, 1);
+        StkPtr val = cosmoV_getTop(state, 0);
+
+        CValue *oldVal = cosmoT_insert(state, &state->registry, *key);
+        *oldVal = *val;
+
+        cosmoV_setTop(state, 2); // pops the 2 values off the stack
+    }
+}
+
+// expects 1 key on the stack, pushes result
+void cosmoV_getRegistry(CState *state) {
+    CValue key = *cosmoV_pop(state);
+    CValue val;
+
+    if (!cosmoT_get(state, &state->registry, key, &val)) {
+        cosmoV_error(state, "failed to grab %s from registry", cosmoV_typeStr(key));
+    }
+
+    cosmoV_pushValue(state, val);
+}
+
+void cosmoV_setProto(CState *state) {
+    StkPtr objVal = cosmoV_getTop(state, 1);
+    StkPtr protoVal = cosmoV_getTop(state, 0);
+
+    if (!IS_REF(*objVal) || !IS_OBJECT(*protoVal)) {
+        cosmoV_error(state, "cannot set %s to proto of type %s", cosmoV_typeStr(*objVal), cosmoV_typeStr(*protoVal));
+    }
+
+    // actually set the protos
+    CObj *obj = cosmoV_readRef(*objVal);
+    CObjObject *proto = cosmoV_readObject(*protoVal);
+    obj->proto = proto;
+
+    cosmoV_setTop(state, 2);
+}
+
 void cosmoV_printStack(CState *state)
 {
     printf("==== [[ stack dump ]] ====\n");

src/cstate.h

@@ -18,6 +18,7 @@ struct CCallFrame
 typedef enum IStringEnum
 {
     ISTRING_INIT,     // __init
+    ISTRING_GC,       // __gc
     ISTRING_TOSTRING, // __tostring
     ISTRING_TONUMBER, // __tonumber
     ISTRING_EQUAL,    // __equals
@@ -46,6 +47,7 @@ typedef struct CPanic
     StkPtr top;
     struct CPanic *prev;
     int frameCount;
+    int freezeGC;
 } CPanic;
 
 struct CState
@@ -55,6 +57,7 @@ struct CState
     CObjObject *protoObjects[COBJ_MAX]; // proto object for each COBJ type [NULL = no default proto]
     CObjString *iStrings[ISTRING_MAX];  // strings used internally by the VM, eg. __init, __index
     CTable strings;
+    CTable registry;
     ArrayCObj grayStack; // keeps track of which objects *haven't yet* been traversed in our GC, but
                          // *have been* found
 
@@ -62,14 +65,12 @@ struct CState
     CObjTable *globals;
     CValue *top;     // top of the stack
     CObj *objects;   // tracks all of our allocated objects
-    CObj *userRoots; // user definable roots, this holds CObjs that should be considered "roots",
-                     // lets the VM know you are holding a reference to a CObj in your code
     CPanic *panic;
 
-    int freezeGC; // when > 0, GC events will be ignored (for internal use)
-    int frameCount;
     size_t allocatedBytes;
     size_t nextGC; // when allocatedBytes reaches this threshhold, trigger a GC event
+    int freezeGC; // when > 0, GC events will be ignored (for internal use)
+    int frameCount;
 };
 
 CPanic *cosmoV_newPanic(CState *state);
@@ -79,7 +80,16 @@ COSMO_API CState *cosmoV_newState();
 COSMO_API void cosmoV_freeState(CState *state);
 
 // expects 2*pairs values on the stack, each pair should consist of 1 key and 1 value
-COSMO_API void cosmoV_register(CState *state, int pairs);
+COSMO_API void cosmoV_addGlobals(CState *state, int pairs);
+
+// expects 2*pairs values on the stack, each pair should consist of 1 key and 1 value
+COSMO_API void cosmoV_addRegistry(CState *state, int pairs);
+
+// expects 1 key on the stack, pushes result
+COSMO_API void cosmoV_getRegistry(CState *state);
+
+// expects <object>->proto = <object> (2 total) to be on the stack
+COSMO_API void cosmoV_setProto(CState *state);
 
 COSMO_API void cosmoV_printStack(CState *state);
 

src/cvm.c

@@ -12,7 +12,7 @@
 
 #define cosmoV_protect(panic) setjmp(panic->jmp) == 0
 
-COSMO_API void cosmoV_pushFString(CState *state, const char *format, ...)
+void cosmoV_pushFString(CState *state, const char *format, ...)
 {
     va_list args;
     va_start(args, format);
@@ -21,7 +21,7 @@ COSMO_API void cosmoV_pushFString(CState *state, const char *format, ...)
 }
 
 // inserts val at state->top - indx - 1, moving everything else up
-COSMO_API void cosmo_insert(CState *state, int indx, CValue val)
+void cosmoV_insert(CState *state, int indx, CValue val)
 {
     StkPtr tmp = cosmoV_getTop(state, indx);
 
@@ -33,7 +33,7 @@ COSMO_API void cosmo_insert(CState *state, int indx, CValue val)
     state->top++;
 }
 
-COSMO_API bool cosmoV_undump(CState *state, cosmo_Reader reader, const void *ud)
+bool cosmoV_undump(CState *state, cosmo_Reader reader, const void *ud)
 {
     CObjFunction *func;
 
@@ -54,7 +54,7 @@ COSMO_API bool cosmoV_undump(CState *state, cosmo_Reader reader, const void *ud)
 
 // returns false if failed, error will be on the top of the stack. true if successful, closure will
 // be on the top of the stack
-COSMO_API bool cosmoV_compileString(CState *state, const char *src, const char *name)
+bool cosmoV_compileString(CState *state, const char *src, const char *name)
 {
     CObjFunction *func;
     CPanic *panic = cosmoV_newPanic(state);
@@ -77,7 +77,7 @@ COSMO_API bool cosmoV_compileString(CState *state, const char *src, const char *
     return false;
 }
 
-COSMO_API void cosmoV_printError(CState *state, CObjError *err)
+void cosmoV_printError(CState *state, CObjError *err)
 {
     // print stack trace
     for (int i = 0; i < err->frameCount; i++) {
@@ -122,6 +122,7 @@ void cosmoV_throw(CState *state)
     if (state->panic) {
         state->top = state->panic->top;
         state->frameCount = state->panic->frameCount;
+        state->freezeGC = state->panic->freezeGC;
         cosmoV_pushValue(state, val);
         longjmp(state->panic->jmp, 1);
     } else {
@@ -438,7 +439,7 @@ static inline bool isFalsey(StkPtr val)
     return IS_NIL(*val) || (IS_BOOLEAN(*val) && !cosmoV_readBoolean(*val));
 }
 
-COSMO_API CObjObject *cosmoV_makeObject(CState *state, int pairs)
+CObjObject *cosmoV_makeObject(CState *state, int pairs)
 {
     StkPtr key, val;
     CObjObject *newObj = cosmoO_newObject(state);
@@ -459,7 +460,7 @@ COSMO_API CObjObject *cosmoV_makeObject(CState *state, int pairs)
     return newObj;
 }
 
-COSMO_API bool cosmoV_registerProtoObject(CState *state, CObjType objType, CObjObject *obj)
+bool cosmoV_registerProtoObject(CState *state, CObjType objType, CObjObject *obj)
 {
     bool replaced = state->protoObjects[objType] != NULL;
     state->protoObjects[objType] = obj;
@@ -468,7 +469,7 @@ COSMO_API bool cosmoV_registerProtoObject(CState *state, CObjType objType, CObjO
     CObj *curr = state->objects;
     while (curr != NULL) {
         // update the proto
-        if (curr->type == objType && curr->proto != NULL) {
+        if (curr != (CObj *)obj && curr->type == objType && curr->proto != NULL) {
             curr->proto = obj;
         }
         curr = curr->next;
@@ -477,7 +478,7 @@ COSMO_API bool cosmoV_registerProtoObject(CState *state, CObjType objType, CObjO
     return replaced;
 }
 
-COSMO_API void cosmoV_makeTable(CState *state, int pairs)
+void cosmoV_makeTable(CState *state, int pairs)
 {
     StkPtr key, val;
     CObjTable *newObj = cosmoO_newTable(state);
@@ -529,7 +530,7 @@ void cosmoV_rawset(CState *state, CObj *_obj, CValue key, CValue val)
     cosmoO_setRawObject(state, object, key, val, _obj);
 }
 
-COSMO_API void cosmoV_get(CState *state)
+void cosmoV_get(CState *state)
 {
     CValue val;
     StkPtr obj = cosmoV_getTop(state, 1); // object was pushed first
@@ -547,7 +548,7 @@ COSMO_API void cosmoV_get(CState *state)
 }
 
 // yes, this would technically make it possible to set fields of types other than <string>. go crazy
-COSMO_API void cosmoV_set(CState *state)
+void cosmoV_set(CState *state)
 {
     StkPtr obj = cosmoV_getTop(state, 2); // object was pushed first
     StkPtr key = cosmoV_getTop(state, 1); // then the key
@@ -563,7 +564,7 @@ COSMO_API void cosmoV_set(CState *state)
     cosmoV_setTop(state, 3);
 }
 
-COSMO_API void cosmoV_getMethod(CState *state, CObj *obj, CValue key, CValue *val)
+void cosmoV_getMethod(CState *state, CObj *obj, CValue key, CValue *val)
 {
     cosmoV_rawget(state, obj, key, val);
 
@@ -577,6 +578,19 @@ COSMO_API void cosmoV_getMethod(CState *state, CObj *obj, CValue key, CValue *va
     }
 }
 
+bool cosmoV_isValueUserType(CState *state, CValue val, int userType) {
+    if (!IS_OBJECT(val)) {
+        return false;
+    }
+
+    CObjObject *obj = cosmoV_readObject(val);
+    if (obj->userT != userType) {
+        return false;
+    }
+
+    return true;
+}
+
 int _tbl__next(CState *state, int nargs, CValue *args)
 {
     if (nargs != 1) {
@@ -835,7 +849,8 @@ int cosmoV_execute(CState *state)
 
                 CObj *obj = cosmoV_readRef(*temp);
                 CObjObject *proto = cosmoO_grabProto(obj);
-                CValue val; // to hold our value
+                CValue val = cosmoV_newNil();          // to hold our value
+
 
                 if (proto != NULL) {
                     // check for __index metamethod
@@ -906,7 +921,7 @@ int cosmoV_execute(CState *state)
             }
             CASE(OP_GETOBJECT) :
             {
-                CValue val;                            // to hold our value
+                CValue val = cosmoV_newNil();          // to hold our value
                 StkPtr temp = cosmoV_getTop(state, 0); // that should be the object
                 uint16_t ident = READUINT(frame);      // use for the key
 
@@ -924,7 +939,7 @@ int cosmoV_execute(CState *state)
             }
             CASE(OP_GETMETHOD) :
             {
-                CValue val;                            // to hold our value
+                CValue val = cosmoV_newNil();          // to hold our value
                 StkPtr temp = cosmoV_getTop(state, 0); // that should be the object
                 uint16_t ident = READUINT(frame);      // use for the key
 

src/cvm.h

@@ -36,11 +36,11 @@ COSMO_API void cosmoV_pushFString(CState *state, const char *format, ...);
 COSMO_API void cosmoV_printError(CState *state, CObjError *err);
 COSMO_API void cosmoV_throw(CState *state);
 COSMO_API void cosmoV_error(CState *state, const char *format, ...);
-COSMO_API void cosmo_insert(CState *state, int indx, CValue val);
+COSMO_API void cosmoV_insert(CState *state, int indx, CValue val);
 
 /*
     Sets the default proto objects for the passed objType. Also walks through the object heap and
-   updates protos for the passed objType if that CObj* has no proto.
+    updates protos for the passed objType if that CObj* has no proto.
 
     returns true if replacing a previously registered proto object for this type
 */
@@ -72,13 +72,16 @@ COSMO_API bool cosmoV_undump(CState *state, cosmo_Reader reader, const void *ud)
 COSMO_API void cosmoV_get(CState *state);
 
 /*
-    expects object to be pushed, then the key, and finally the new value. pops the key & object
+    expects object to be pushed, then the key, and finally the new value. pops the object, key & value
 */
 COSMO_API void cosmoV_set(CState *state);
 
 // wraps the closure into a CObjMethod, so the function is called as an invoked method
 COSMO_API void cosmoV_getMethod(CState *state, CObj *obj, CValue key, CValue *val);
 
+// check if the value at the top of the stack is a <obj> user type
+COSMO_API bool cosmoV_isValueUserType(CState *state, CValue val, int userType);
+
 // nice to have wrappers
 
 // pushes a raw CValue to the stack, might throw an error if the stack is overflowed (with the