From de9d7bcfdc2bf9272a3859df75c3ffd3a479378b Mon Sep 17 00:00:00 2001
From: bakpakin <calsrose@gmail.com>
Date: Sun, 9 Jul 2017 16:10:47 -0400
Subject: [PATCH] Update representation of an environment.

---
 core/stl.c        | 39 +++++++++++++++++++++++----------------
 core/util.c       | 40 ++++++++++++++++++++++++----------------
 include/gst/gst.h |  4 ----
 3 files changed, 47 insertions(+), 36 deletions(-)

diff --git a/core/stl.c b/core/stl.c
index fee77a91..a0e3a7ad 100644
--- a/core/stl.c
+++ b/core/stl.c
@@ -1088,22 +1088,29 @@ static const GstModuleItem std_module[] = {
     {NULL, NULL}
 };
 
-/* Load all libraries */
+/* Load stl library into the current environment. Create stl module object
+ * only if it is not yet created. */
 void gst_stl_load(Gst *vm) {
-    GstValue maybeEnv;
-    /* Load the normal c functions */
-    gst_module_mutable(vm, "std", std_module);
-    /* Wrap stdin and stdout */
-    FILE **inp = gst_userdata(vm, sizeof(FILE *), &gst_stl_filetype);
-    FILE **outp = gst_userdata(vm, sizeof(FILE *), &gst_stl_filetype);
-    FILE **errp = gst_userdata(vm, sizeof(FILE *), &gst_stl_filetype);
-    *inp = stdin;
-    *outp = stdout;
-    *errp = stderr;
-    gst_module_put(vm, "std", "stdin", gst_wrap_userdata(inp));
-    gst_module_put(vm, "std", "stdout", gst_wrap_userdata(outp));
-    gst_module_put(vm, "std", "stderr", gst_wrap_userdata(outp));
-    maybeEnv = gst_table_get(vm->modules, gst_string_cvs(vm, "std"));
-    if (maybeEnv.type == GST_TABLE)
+    GstValue maybeEnv = gst_table_get(vm->modules, gst_string_cvs(vm, "std"));
+    if (maybeEnv.type == GST_TABLE) {
+        /* Module already created, so merge into main vm. */
         gst_env_merge(vm, vm->env, maybeEnv.data.table);
+    } else {
+        /* Module not yet created */
+        /* Load the normal c functions */
+        gst_module_mutable(vm, "std", std_module);
+        /* Wrap stdin and stdout */
+        FILE **inp = gst_userdata(vm, sizeof(FILE *), &gst_stl_filetype);
+        FILE **outp = gst_userdata(vm, sizeof(FILE *), &gst_stl_filetype);
+        FILE **errp = gst_userdata(vm, sizeof(FILE *), &gst_stl_filetype);
+        *inp = stdin;
+        *outp = stdout;
+        *errp = stderr;
+        gst_module_put(vm, "std", "stdin", gst_wrap_userdata(inp));
+        gst_module_put(vm, "std", "stdout", gst_wrap_userdata(outp));
+        gst_module_put(vm, "std", "stderr", gst_wrap_userdata(outp));
+        // Now merge
+        maybeEnv = gst_table_get(vm->modules, gst_string_cvs(vm, "std"));
+        gst_env_merge(vm, vm->env, maybeEnv.data.table);
+    }
 }
diff --git a/core/util.c b/core/util.c
index e387294d..617dc427 100644
--- a/core/util.c
+++ b/core/util.c
@@ -343,9 +343,9 @@ int gst_callc(Gst *vm, GstCFunction fn, int numargs, ...) {
     return result;
 }
 
-static GstTable *gst_env_inttab(Gst *vm, GstTable *env, GstInteger i) {
+static GstTable *gst_env_keytab(Gst *vm, GstTable *env, const char *keyword) {
     GstTable *tab;
-    GstValue key = gst_wrap_integer(i);
+    GstValue key = gst_string_cv(vm, keyword);
     GstValue maybeTab = gst_table_get(env, key);
     if (maybeTab.type != GST_TABLE) {
         tab = gst_table(vm, 10);
@@ -357,11 +357,11 @@ static GstTable *gst_env_inttab(Gst *vm, GstTable *env, GstInteger i) {
 }
 
 GstTable *gst_env_nils(Gst *vm, GstTable *env) {
-    return gst_env_inttab(vm, env, GST_ENV_NILS);
+    return gst_env_keytab(vm, env, "nils");
 }
 
 GstTable *gst_env_meta(Gst *vm, GstTable *env) {
-    return gst_env_inttab(vm, env, GST_ENV_METADATA);
+    return gst_env_keytab(vm, env, "meta");
 }
 
 /* Add many global variables and bind to nil */
@@ -391,6 +391,18 @@ static void mergemeta(Gst *vm, GstTable *destEnv, GstTable *meta) {
     }
 }
 
+/* Simple strequal between gst string ans c string, no 0s in b allowed */
+static int streq(const char *str, const uint8_t *b) {
+    uint32_t len = gst_string_length(b);
+    uint32_t i;
+    const uint8_t *ustr = (const uint8_t *)str;
+    for (i = 0; i < len; ++i) {
+        if (ustr[i] != b[i])
+            return 0;
+    }
+    return 1;
+}
+
 /* Add many global variables */
 void gst_env_merge(Gst *vm, GstTable *destEnv, GstTable *srcEnv) {
     const GstValue *data = srcEnv->data;
@@ -399,18 +411,14 @@ void gst_env_merge(Gst *vm, GstTable *destEnv, GstTable *srcEnv) {
     for (i = 0; i < len; i += 2) {
         if (data[i].type == GST_SYMBOL) {
             gst_table_put(vm, destEnv, data[i], data[i + 1]);
-        } else if (data[i].type == GST_INTEGER) {
-            switch (data[i].data.integer) {
-                case GST_ENV_NILS:
-                    if (data[i + 1].type == GST_TABLE)
-                        mergenils(vm, destEnv, data[i + 1].data.table);
-                    break;
-                case GST_ENV_METADATA:
-                    if (data[i + 1].type == GST_TABLE)
-                        mergemeta(vm, destEnv, data[i + 1].data.table);
-                    break;
-                default:
-                    break;
+        } else if (data[i].type == GST_STRING) {
+            const uint8_t *k = data[i].data.string;
+            if (streq("nils", k)) {
+                if (data[i + 1].type == GST_TABLE)
+                    mergenils(vm, destEnv, data[i + 1].data.table);
+            } else if (streq("meta", k)) {
+               if (data[i + 1].type == GST_TABLE)
+                mergemeta(vm, destEnv, data[i + 1].data.table);
             }
         }
     }
diff --git a/include/gst/gst.h b/include/gst/gst.h
index e36cd408..2e3dc186 100644
--- a/include/gst/gst.h
+++ b/include/gst/gst.h
@@ -634,10 +634,6 @@ int gst_hashtable_view(GstValue tab, const GstValue **data, uint32_t *cap);
 /* Misc */
 /****/
 
-#define GST_ENV_NILS 0
-#define GST_ENV_METADATA 1
-#define GST_ENV_VARS 2
-
 int gst_read_real(const uint8_t *string, const uint8_t *end, double *ret, int forceInt);
 int gst_read_integer(const uint8_t *string, const uint8_t *end, int64_t *ret);
 GstReal gst_integer_to_real(GstInteger x);