Merge pull request #6 from CPunch/chunk-loading

Chunk loading

Makefile

@@ -19,6 +19,8 @@ CHDR=\
 	src/cvm.h\
 	src/cobj.h\
 	src/cbaselib.h\
+	src/cdump.h\
+	src/cundump.h\
 
 CSRC=\
 	src/cchunk.c\
@@ -33,6 +35,8 @@ CSRC=\
 	src/cvm.c\
 	src/cobj.c\
 	src/cbaselib.c\
+	src/cdump.c\
+	src/cundump.c\
 	main.c\
 
 COBJ=$(CSRC:.c=.o)

main.c

@@ -1,21 +1,29 @@
-#include "cosmo.h"
+#include "cbaselib.h"
 #include "cchunk.h"
 #include "cdebug.h"
-#include "cvm.h"
+#include "cdump.h"
-#include "cparse.h"
-#include "cbaselib.h"
-
 #include "cmem.h"
+#include "cosmo.h"
+#include "cparse.h"
+#include "cundump.h"
+#include "cvm.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <getopt.h>
 
 static bool _ACTIVE = false;
 
-int cosmoB_quitRepl(CState *state, int nargs, CValue *args) {
+int cosmoB_quitRepl(CState *state, int nargs, CValue *args)
+{
     _ACTIVE = false;
 
     return 0; // we don't return anything
 }
 
-int cosmoB_input(CState *state, int nargs, CValue *args) {
+int cosmoB_input(CState *state, int nargs, CValue *args)
+{
     // input() accepts the same params as print()!
     for (int i = 0; i < nargs; i++) {
         CObjString *str = cosmoV_toString(state, args[i]);
@@ -26,12 +34,14 @@ int cosmoB_input(CState *state, int nargs, CValue *args) {
     char line[1024];
     fgets(line, sizeof(line), stdin);
 
-    cosmoV_pushRef(state, (CObj*)cosmoO_copyString(state, line, strlen(line)-1)); // -1 for the \n
+    cosmoV_pushRef(state,
+                   (CObj *)cosmoO_copyString(state, line, strlen(line) - 1)); // -1 for the \n
 
     return 1; // 1 return value
 }
 
-static bool interpret(CState *state, const char *script, const char *mod) {
+static bool interpret(CState *state, const char *script, const char *mod)
+{
     bool ret;
 
     // cosmoV_compileString pushes the result onto the stack (COBJ_ERROR or COBJ_CLOSURE)
@@ -50,15 +60,11 @@ static bool interpret(CState *state, const char *script, const char *mod) {
     return !ret;
 }
 
-static void repl() {
+static void repl(CState *state)
+{
     char line[1024];
     _ACTIVE = true;
 
-    CState *state = cosmoV_newState();
-    cosmoB_loadLibrary(state);
-    cosmoB_loadOSLib(state);
-    cosmoB_loadVM(state);
-
     // add our custom REPL functions
     cosmoV_pushString(state, "quit");
     cosmoV_pushCFunction(state, cosmoB_quitRepl);
@@ -78,11 +84,10 @@ static void repl() {
 
         interpret(state, line, "REPL");
     }
-
-    cosmoV_freeState(state);
 }
 
-static char *readFile(const char* path) {
+static char *readFile(const char *path)
+{
     FILE *file = fopen(path, "rb");
     if (file == NULL) {
         fprintf(stderr, "Could not open file \"%s\".\n", path);
@@ -114,12 +119,10 @@ static char *readFile(const char* path) {
     return buffer;
 }
 
-static bool runFile(const char* fileName) {
+static bool runFile(CState *state, const char *fileName)
+{
     bool ret;
     char *script = readFile(fileName);
-    CState *state = cosmoV_newState();
-    cosmoB_loadLibrary(state);
-    cosmoB_loadOSLib(state);
 
     // add our input() function to the global table
     cosmoV_pushString(state, "input");
@@ -129,21 +132,119 @@ static bool runFile(const char* fileName) {
 
     ret = interpret(state, script, fileName);
 
-    cosmoV_freeState(state);
     free(script);
     return ret; // let the caller know if the script failed
 }
 
-int main(int argc, const char *argv[]) {
+int fileWriter(CState *state, const void *data, size_t size, const void *ud)
-    if (argc == 1) {
+{
-        repl();
+    return !fwrite(data, size, 1, (FILE *)ud);
-    } else if (argc >= 2) { // they passed a file (or more lol)
+}
-        for (int i = 1; i < argc; i++) {
+
-            if (!runFile(argv[i])) {
+int fileReader(CState *state, void *data, size_t size, const void *ud)
+{
+    return fread(data, size, 1, (FILE *)ud) != 1;
+}
+
+void compileScript(CState *state, const char *in, const char *out)
+{
+    char *script = readFile(in);
+
+    FILE *fout = fopen(out, "wb");
+
+    if (cosmoV_compileString(state, script, in)) {
+        CObjFunction *func = cosmoV_readClosure(*cosmoV_getTop(state, 0))->function;
+        cosmoD_dump(state, func, fileWriter, (void *)fout);
+    } else {
+        cosmoV_pop(state); // pop the error off the stack
+        cosmoV_printError(state, state->error);
+    }
+
+    free(script);
+    fclose(fout);
+
+    printf("[!] compiled %s to %s successfully!\n", in, out);
+}
+
+void loadScript(CState *state, const char *in)
+{
+    FILE *file;
+
+    file = fopen(in, "rb");
+    if (!cosmoV_undump(state, fileReader, file)) {
+        cosmoV_pop(state); // pop the error off the stack
+        cosmoV_printError(state, state->error);
+        return;
+    };
+
+    printf("[!] loaded %s!\n", in);
+    COSMOVMRESULT res = cosmoV_call(state, 0, 0); // 0 args being passed, 0 results expected
+
+    if (res == COSMOVM_RUNTIME_ERR)
+        cosmoV_printError(state, state->error);
+
+    fclose(file);
+}
+
+void printUsage(const char *name)
+{
+    printf("Usage: %s [-clsr] [args]\n\n", name);
+    printf("available options are:\n"
+           "-c <in> <out>\tcompile <in> and dump to <out>\n"
+           "-l <in>\t\tload dump from <in>\n"
+           "-s <in...>\tcompile and run <in...> script(s)\n"
+           "-r\t\tstart the repl\n\n");
+}
+
+int main(int argc, char *const argv[])
+{
+    CState *state = cosmoV_newState();
+    cosmoB_loadLibrary(state);
+    cosmoB_loadOSLib(state);
+    cosmoB_loadVM(state);
+
+    int opt;
+    bool isValid = false;
+    while ((opt = getopt(argc, argv, "clsr")) != -1) {
+        switch (opt) {
+        case 'c':
+            if (optind >= argc - 1) {
+                printf("Usage: %s -c <in> <out>\n", argv[0]);
+                exit(EXIT_FAILURE);
+            } else {
+                compileScript(state, argv[optind], argv[optind + 1]);
+            }
+            isValid = true;
+            break;
+        case 'l':
+            if (optind >= argc) {
+                printf("Usage: %s -l <in>\n", argv[0]);
+                exit(EXIT_FAILURE);
+            } else {
+                loadScript(state, argv[optind]);
+            }
+            isValid = true;
+            break;
+        case 's':
+            for (int i = optind; i < argc; i++) {
+                if (!runFile(state, argv[i])) {
+                    printf("failed to run %s!\n", argv[i]);
                     exit(EXIT_FAILURE);
                 }
             }
+            isValid = true;
+            break;
+        case 'r':
+            repl(state);
+            isValid = true;
+            break;
+        }
     }
 
+    if (!isValid) {
+        printUsage(argv[0]);
+    }
+
+    cosmoV_freeState(state);
     return 0;
 }

src/cbaselib.c

@@ -980,6 +980,4 @@ void cosmoB_loadVM(CState *state)
 
     // register "vm" to the global table
     cosmoV_register(state, 1);
-
-    printf("[WARNING] the vm.* library has been loaded!\n");
 }

src/cdump.c

@@ -0,0 +1,204 @@
+#include "cdump.h"
+
+#include "cdebug.h"
+#include "cmem.h"
+#include "cobj.h"
+#include "cvalue.h"
+#include "cvm.h"
+
+typedef struct
+{
+    CState *state;
+    const void *userData;
+    cosmo_Writer writer;
+    int writerStatus;
+} DumpState;
+
+static bool writeCValue(DumpState *dstate, CValue val);
+
+#define check(e)                                                                                   \
+    if (!e) {                                                                                      \
+        return false;                                                                              \
+    }
+
+static void initDumpState(CState *state, DumpState *dstate, cosmo_Writer writer,
+                          const void *userData)
+{
+    dstate->state = state;
+    dstate->userData = userData;
+    dstate->writer = writer;
+    dstate->writerStatus = 0;
+}
+
+static bool writeBlock(DumpState *dstate, const void *data, size_t size)
+{
+    if (dstate->writerStatus == 0) {
+        dstate->writerStatus = dstate->writer(dstate->state, data, size, dstate->userData);
+    }
+
+    return dstate->writerStatus == 0;
+}
+
+static bool writeu8(DumpState *dstate, uint8_t d)
+{
+    return writeBlock(dstate, &d, sizeof(uint8_t));
+}
+
+static bool writeu32(DumpState *dstate, uint32_t d)
+{
+    return writeBlock(dstate, &d, sizeof(uint32_t));
+}
+
+static bool writeSize(DumpState *dstate, size_t d)
+{
+    return writeBlock(dstate, &d, sizeof(size_t));
+}
+
+static bool writeVector(DumpState *dstate, const void *data, size_t size, size_t count)
+{
+    check(writeSize(dstate, count));
+    check(writeBlock(dstate, data, size * count));
+
+    return true;
+}
+
+static bool writeHeader(DumpState *dstate)
+{
+    check(writeBlock(dstate, COSMO_MAGIC, COSMO_MAGIC_LEN));
+
+    /* after the magic, we write some platform information */
+    check(writeu8(dstate, cosmoD_isBigEndian()));
+    check(writeu8(dstate, sizeof(cosmo_Number)));
+    check(writeu8(dstate, sizeof(size_t)));
+    check(writeu8(dstate, sizeof(int)));
+
+    return true;
+}
+
+static bool writeCObjString(DumpState *dstate, CObjString *obj)
+{
+    if (obj == NULL) { /* this is in case cobjfunction's name or module strings are null */
+        check(writeu32(dstate, 0));
+        return true;
+    }
+
+    /* write string length */
+    check(writeu32(dstate, obj->length));
+
+    /* write string data */
+    check(writeBlock(dstate, obj->str, obj->length));
+
+    return true;
+}
+
+static bool writeCObjFunction(DumpState *dstate, CObjFunction *obj)
+{
+    check(writeCObjString(dstate, obj->name));
+    check(writeCObjString(dstate, obj->module));
+
+    check(writeu32(dstate, obj->args));
+    check(writeu32(dstate, obj->upvals));
+    check(writeu8(dstate, obj->variadic));
+
+    /* write chunk info */
+    check(writeVector(dstate, obj->chunk.buf, sizeof(uint8_t), obj->chunk.count));
+
+    /* write line info */
+    check(writeVector(dstate, obj->chunk.lineInfo, sizeof(int), obj->chunk.count));
+
+    /* write constants */
+    check(writeSize(dstate, obj->chunk.constants.count));
+    for (int i = 0; i < obj->chunk.constants.count; i++) {
+        check(writeCValue(dstate, obj->chunk.constants.values[i]));
+    }
+
+    return true;
+}
+
+static bool writeCObj(DumpState *dstate, CObj *obj)
+{
+    /*
+        we can kind of cheat here since our parser only emits a few very limited CObjs...
+        CChunks will only ever have the following CObj's in their constant table:
+        - COBJ_STRING
+        - COBJ_FUNCTION
+
+        the rest of the objects are created during runtime. yay!
+    */
+    CObjType t = cosmoO_readType(obj);
+
+    /* write cobj type */
+    writeu8(dstate, t);
+
+    /* write object payload/body */
+    switch (t) {
+    case COBJ_STRING:
+        check(writeCObjString(dstate, (CObjString *)obj));
+        break;
+    case COBJ_FUNCTION:
+        check(writeCObjFunction(dstate, (CObjFunction *)obj));
+        break;
+    default:
+        cosmoV_error(dstate->state, "invalid cobj type: %d", t);
+        return false;
+    }
+
+    return true;
+}
+
+#define WRITE_VAR(dstate, type, expression)                                                        \
+    {                                                                                              \
+        type _tmp = expression;                                                                    \
+        check(writeBlock(dstate, &_tmp, sizeof(_tmp)));                                            \
+        break;                                                                                     \
+    }
+
+static bool writeCValue(DumpState *dstate, CValue val)
+{
+    CosmoType t = GET_TYPE(val);
+
+    /* write value type */
+    writeu8(dstate, t);
+
+    /* write value payload/body */
+    switch (t) {
+    case COSMO_TNUMBER:
+        WRITE_VAR(dstate, cosmo_Number, cosmoV_readNumber(val))
+    case COSMO_TBOOLEAN:
+        WRITE_VAR(dstate, bool, cosmoV_readBoolean(val))
+    case COSMO_TREF:
+        check(writeCObj(dstate, cosmoV_readRef(val)));
+        break;
+    case COSMO_TNIL: /* no body */
+        break;
+    default:
+        cosmoV_error(dstate->state, "invalid value type: %d", t);
+        return false;
+    }
+
+    return true;
+}
+
+#undef WRITE_VAR
+
+bool cosmoD_isBigEndian()
+{
+    union
+    {
+        uint32_t i;
+        uint8_t c[4];
+    } _indxint = {0xDEADB33F};
+
+    return _indxint.c[0] == 0xDE;
+}
+
+int cosmoD_dump(CState *state, CObjFunction *func, cosmo_Writer writer, const void *userData)
+{
+    DumpState dstate;
+    initDumpState(state, &dstate, writer, userData);
+
+    check(writeHeader(&dstate));
+    check(writeCObjFunction(&dstate, func));
+
+    return dstate.writerStatus;
+}

src/cdump.h

@@ -0,0 +1,17 @@
+#ifndef COSMO_DUMP_H
+#define COSMO_DUMP_H
+
+#include "cobj.h"
+#include "cosmo.h"
+
+#include <stdio.h>
+
+#define COSMO_MAGIC     "COS\x12"
+#define COSMO_MAGIC_LEN 4
+
+bool cosmoD_isBigEndian();
+
+/* returns non-zero on error */
+int cosmoD_dump(CState *state, CObjFunction *func, cosmo_Writer writer, const void *userData);
+
+#endif

src/cosmo.h

@@ -45,6 +45,9 @@ typedef struct CObjClosure CObjClosure;
 
 typedef uint8_t INSTRUCTION;
 
+typedef int (*cosmo_Reader)(CState *state, void *data, size_t size, const void *ud);
+typedef int (*cosmo_Writer)(CState *state, const void *data, size_t size, const void *ud);
+
 #define COSMOMAX_UPVALS 80
 #define FRAME_MAX       64
 #define STACK_MAX       (256 * FRAME_MAX)

src/cundump.c

@@ -0,0 +1,219 @@
+#include "cundump.h"
+
+#include "cchunk.h"
+#include "cdump.h"
+#include "cmem.h"
+#include "cvm.h"
+
+typedef struct
+{
+    CState *state;
+    const void *userData;
+    cosmo_Reader reader;
+    int readerStatus;
+} UndumpState;
+
+static bool readCValue(UndumpState *udstate, CValue *val);
+
+#define check(e)                                                                                   \
+    if (!e) {                                                                                      \
+        return false;                                                                              \
+    }
+
+static void initUndumpState(CState *state, UndumpState *udstate, cosmo_Reader reader,
+                            const void *userData)
+{
+    udstate->state = state;
+    udstate->userData = userData;
+    udstate->reader = reader;
+    udstate->readerStatus = 0;
+}
+
+static bool readBlock(UndumpState *udstate, void *data, size_t size)
+{
+    if (udstate->readerStatus == 0) {
+        /* if reader returns 1, we expect an error was thrown */
+        udstate->readerStatus = udstate->reader(udstate->state, data, size, udstate->userData);
+    }
+
+    return udstate->readerStatus == 0;
+}
+
+static bool readu8(UndumpState *udstate, uint8_t *d)
+{
+    return readBlock(udstate, d, sizeof(uint8_t));
+}
+
+static bool readu32(UndumpState *udstate, uint32_t *d)
+{
+    return readBlock(udstate, d, sizeof(uint32_t));
+}
+
+static bool readSize(UndumpState *udstate, size_t *d)
+{
+    return readBlock(udstate, d, sizeof(size_t));
+}
+
+static bool readVector(UndumpState *udstate, void **data, size_t size, size_t *count)
+{
+    check(readSize(udstate, count));
+    *data = cosmoM_xmalloc(udstate->state, (*count) * size);
+    return readBlock(udstate, *data, (*count) * size);
+}
+
+#define checku8(udstate, d, tmp)                                                                   \
+    check(readu8(udstate, &tmp));                                                                  \
+    if (d != tmp) {                                                                                \
+        cosmoV_error(udstate->state, "bad header!");                                               \
+        return false;                                                                              \
+    }
+
+static bool checkHeader(UndumpState *udstate)
+{
+    char magic[COSMO_MAGIC_LEN];
+    uint8_t tmp;
+
+    /* check header */
+    check(readBlock(udstate, magic, COSMO_MAGIC_LEN));
+    if (memcmp(magic, COSMO_MAGIC, COSMO_MAGIC_LEN) != 0) {
+        cosmoV_error(udstate->state, "bad header!");
+        return false;
+    }
+
+    /* after the magic, we read some platform information */
+    checku8(udstate, cosmoD_isBigEndian(), tmp);
+    checku8(udstate, sizeof(cosmo_Number), tmp);
+    checku8(udstate, sizeof(size_t), tmp);
+    checku8(udstate, sizeof(int), tmp);
+
+    return true;
+}
+
+#undef checku8
+
+static bool readCObjString(UndumpState *udstate, CObjString **str)
+{
+    uint32_t size;
+    char *data;
+
+    check(readu32(udstate, (uint32_t *)&size));
+    if (size == 0) { /* empty string */
+        *str = NULL;
+        return true;
+    }
+
+    data = cosmoM_xmalloc(udstate->state, size + 1);
+    check(readBlock(udstate, (void *)data, size));
+    data[size] = '\0'; /* add NULL-terminator */
+
+    *str = cosmoO_takeString(udstate->state, data, size);
+    return true;
+}
+
+static bool readCObjFunction(UndumpState *udstate, CObjFunction **func)
+{
+    size_t constants;
+    CValue val;
+
+    *func = cosmoO_newFunction(udstate->state);
+
+    /* make sure our GC can see that we're currently using this function (and the values it uses) */
+    cosmoV_pushRef(udstate->state, (CObj *)*func);
+
+    check(readCObjString(udstate, &(*func)->name));
+    check(readCObjString(udstate, &(*func)->module));
+
+    check(readu32(udstate, (uint32_t *)&(*func)->args));
+    check(readu32(udstate, (uint32_t *)&(*func)->upvals));
+    check(readu8(udstate, (uint8_t *)&(*func)->variadic));
+
+    /* read chunk info */
+    check(
+        readVector(udstate, (void **)&(*func)->chunk.buf, sizeof(uint8_t), &(*func)->chunk.count));
+    check(
+        readVector(udstate, (void **)&(*func)->chunk.lineInfo, sizeof(int), &(*func)->chunk.count));
+
+    /* read constants */
+    check(readSize(udstate, &constants));
+    for (int i = 0; i < constants; i++) {
+        check(readCValue(udstate, &val));
+        addConstant(udstate->state, &(*func)->chunk, val);
+    }
+
+    /* pop function off stack */
+    cosmoV_pop(udstate->state);
+    return true;
+}
+
+static bool readCObj(UndumpState *udstate, CObj **obj)
+{
+    uint8_t type;
+    check(readu8(udstate, &type));
+
+    switch (type) {
+    case COBJ_STRING:
+        return readCObjString(udstate, (CObjString **)obj);
+    case COBJ_FUNCTION:
+        return readCObjFunction(udstate, (CObjFunction **)obj);
+    default:
+        cosmoV_error(udstate->state, "unknown object type!");
+        return false;
+    }
+
+    return true;
+}
+
+#define READ_VAR(udstate, val, type, creator)                                                      \
+    {                                                                                              \
+        type _tmp;                                                                                 \
+        check(readBlock(udstate, &_tmp, sizeof(type)));                                            \
+        *val = creator(_tmp);                                                                      \
+        break;                                                                                     \
+    }
+
+static bool readCValue(UndumpState *udstate, CValue *val)
+{
+    uint8_t t;
+    check(readu8(udstate, &t));
+
+    switch (t) {
+    case COSMO_TNUMBER:
+        READ_VAR(udstate, val, cosmo_Number, cosmoV_newNumber)
+    case COSMO_TBOOLEAN:
+        READ_VAR(udstate, val, bool, cosmoV_newBoolean)
+    case COSMO_TREF: {
+        CObj *obj;
+        check(readCObj(udstate, (CObj **)&obj));
+        *val = cosmoV_newRef(obj);
+        break;
+    }
+    case COSMO_TNIL:
+        *val = cosmoV_newNil();
+        break;
+    default:
+        cosmoV_error(udstate->state, "invalid value type: %d", t);
+        return false;
+    }
+
+    return true;
+}
+
+#undef READ_VAR
+#undef check
+
+int cosmoD_undump(CState *state, cosmo_Reader reader, const void *userData, CObjFunction **func)
+{
+    UndumpState udstate;
+    initUndumpState(state, &udstate, reader, userData);
+
+    if (!checkHeader(&udstate)) {
+        return 1;
+    }
+
+    if (!readCObjFunction(&udstate, func)) {
+        return 1;
+    }
+
+    cosmoV_pushRef(state, (CObj *)*func);
+    return udstate.readerStatus;
+}

src/cundump.h

@@ -0,0 +1,12 @@
+#ifndef COSMO_UNDUMP_H
+#define COSMO_UNDUMP_H
+
+#include "cobj.h"
+#include "cosmo.h"
+
+#include <stdio.h>
+
+/* returns non-zero on error */
+int cosmoD_undump(CState *state, cosmo_Reader reader, const void *userData, CObjFunction **func);
+
+#endif

src/cvm.c

@@ -4,6 +4,7 @@
 #include "cmem.h"
 #include "cparse.h"
 #include "cstate.h"
+#include "cundump.h"
 
 #include <math.h>
 #include <stdarg.h>
@@ -30,6 +31,28 @@ 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)
+{
+    CObjFunction *func;
+
+    if (cosmoD_undump(state, reader, ud, &func)) {
+        // fail recovery
+        state->panic = false;
+        cosmoV_pushRef(state, (CObj *)state->error);
+        return false;
+    };
+
+#ifdef VM_DEBUG
+    disasmChunk(&func->chunk, func->name ? func->name->str : UNNAMEDCHUNK, 0);
+#endif
+
+    // push function onto the stack so it doesn't it cleaned up by the GC, at the same stack
+    // location put our closure
+    cosmoV_pushRef(state, (CObj *)func);
+    *(cosmoV_getTop(state, 0)) = cosmoV_newRef(cosmoO_newClosure(state, func));
+    return true;
+}
+
 COSMO_API bool cosmoV_compileString(CState *state, const char *src, const char *name)
 {
     CObjFunction *func;
@@ -46,7 +69,7 @@ COSMO_API bool cosmoV_compileString(CState *state, const char *src, const char *
         return true;
     }
 
-    // fail
+    // fail recovery
     state->panic = false;
     cosmoV_pushRef(state, (CObj *)state->error);
     return false;

src/cvm.h

@@ -38,7 +38,7 @@ COSMO_API void cosmo_insert(CState *state, int indx, CValue val);
 COSMO_API bool cosmoV_registerProtoObject(CState *state, CObjType objType, CObjObject *obj);
 
 /*
-    compiles string into a <closure>, if successful, <closure> will be pushed onto the stack
+    compiles string into a <closure>. if successful, <closure> will be pushed onto the stack
    otherwise the <error> will be pushed.
 
     returns:
@@ -47,6 +47,16 @@ COSMO_API bool cosmoV_registerProtoObject(CState *state, CObjType objType, CObjO
 */
 COSMO_API bool cosmoV_compileString(CState *state, const char *src, const char *name);
 
+/*
+    loads a <closure> from a dump. if successful, <closure> will be pushed onto the stack
+   otherwise the <error> will be pushed.
+
+   returns:
+        false : <error> is at the top of the stack
+        true  : <closure> is at the top of the stack
+*/
+COSMO_API bool cosmoV_undump(CState *state, cosmo_Reader reader, const void *ud);
+
 /*
     expects object to be pushed, then the key.