Add untested code for loading dlls on windows.

Makefile

@@ -49,7 +49,7 @@ all: $(DST_TARGET)
 
 DST_CORE_SOURCES=$(addprefix core/,\
 				 abstract.c array.c asm.c buffer.c compile.c compile_specials.c\
-				 fiber.c gc.c io.c math.c parse.c sourcemap.c string.c\
+				 fiber.c gc.c io.c math.c native.c parse.c sourcemap.c string.c\
 				 stl.c strtod.c struct.c symcache.c table.c tuple.c util.c\
 				 value.c vm.c wrap.c)
 

core/native.c

@@ -0,0 +1,73 @@
+/*
+* Copyright (c) 2017 Calvin Rose
+*
+* Permission is hereby granted, free of charge, to any person obtaining a copy
+* of this software and associated documentation files (the "Software"), to
+* deal in the Software without restriction, including without limitation the
+* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+* sell copies of the Software, and to permit persons to whom the Software is
+* furnished to do so, subject to the following conditions:
+*
+* The above copyright notice and this permission notice shall be included in
+* all copies or substantial portions of the Software.
+*
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+* IN THE SOFTWARE.
+*/
+
+#include <dst/dst.h>
+
+/* Use LoadLibrary on windows or dlopen on posix to load dynamic libaries
+ * with native code. */
+#ifdef DST_WINDOWS
+#include <windows.h>
+typedef HINSTANCE Clib;
+#define load_clib(name) LoadLibrary((name))
+#define symbol_clib(lib, sym) GetProcAddress((lib), (sym))
+#define error_clib() "could not load dynamic library"
+#else
+#include <dlfcn.h>
+typedef void *Clib;
+#define load_clib(name) dlopen((name), RTLD_NOW)
+#define symbol_clib(lib, sym) dlsym((lib), (sym))
+#define error_clib() dlerror()
+#endif
+
+DstCFunction dst_native(const char *name, const uint8_t **error) {
+    Clib lib = load_clib(name);
+    DstCFunction init;
+    if (!lib) {
+        *error = dst_cstring(error_clib());
+        return NULL;
+    }
+    init = (DstCFunction) symbol_clib(lib, "_dst_init");
+    if (!init) {
+        *error = dst_cstring("could not find _dst_init symbol");
+        return NULL;
+    }
+    return init;
+}
+
+int dst_load_native(int32_t argn, Dst *argv, Dst *ret) {
+    DstCFunction init;
+    const uint8_t *error = NULL;
+    if (argn < 1) {
+        *ret = dst_cstringv("expected at least one argument");
+        return 1;
+    }
+    if (!dst_checktype(argv[0], DST_STRING)) {
+        *ret = dst_cstringv("expected string");
+        return 1;
+    }
+    init = dst_native((const char *)dst_unwrap_string(argv[0]), &error);
+    if (!init) {
+        *ret = dst_wrap_string(error);
+        return 1;
+    }
+    return init(argn, argv, ret);
+}

core/stl.c

@@ -23,31 +23,6 @@
 #include <dst/dst.h>
 #include <dst/dststl.h>
 
-#include <dlfcn.h>
-int dst_stl_loadc(int32_t argn, Dst *argv, Dst *ret) {
-    void *lib;
-    DstCFunction init;
-    if (argn < 1) {
-        *ret = dst_cstringv("expected at least on argument");
-        return 1;
-    }
-    if (!dst_checktype(argv[0], DST_STRING)) {
-        *ret = dst_cstringv("expected string");
-        return 1;
-    }
-    lib = dlopen((const char *)dst_unwrap_string(argv[0]), RTLD_NOW);
-    if (NULL == lib) {
-        *ret = dst_cstringv(dlerror());
-        return 1;
-    }
-    init = dlsym(lib, "_dst_init");
-    if (NULL == init) {
-        *ret = dst_cstringv("could not find lib init function");
-        return 1;
-    }
-    return init(argn, argv, ret);
-}
-
 int dst_stl_parse(int32_t argn, Dst *argv, Dst *ret) {
     const uint8_t *src;
     int32_t len;
@@ -410,7 +385,7 @@ DST_DEFINE_COMPARATOR(notdescending, > 0)
 DST_DEFINE_COMPARATOR(notascending, < 0)
 
 static DstReg stl[] = {
-    {"load-native", dst_stl_loadc},
+    {"load-native", dst_load_native},
     {"parse", dst_stl_parse},
     {"compile", dst_stl_compile},
     {"int", dst_int},

include/dst/dst.h

@@ -169,6 +169,10 @@ void dst_setindex(Dst ds, Dst value, int32_t index);
 DstParseResult dst_parse(const uint8_t *src, int32_t len);
 DstParseResult dst_parsec(const char *src);
 
+/* Native */
+DstCFunction dst_native(const char *name, const uint8_t **error);
+int dst_load_native(int32_t argn, Dst *argv, Dst *ret);
+
 /* VM functions */
 int dst_init();
 void dst_deinit();