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authorPřemysl Janouch <p.janouch@gmail.com>2017-05-18 18:01:57 +0200
committerPřemysl Janouch <p.janouch@gmail.com>2017-05-21 13:19:45 +0200
commit329f60420465161dcb2b8dfd85211129cb20ff4d (patch)
treed1fbb3075dd25ad7ac30f4f353ff1374c5cc7f13
parent44b97f61c17f9106a732bf7d8d38d9adbc97f970 (diff)
downloadell-329f60420465161dcb2b8dfd85211129cb20ff4d.tar.gz
ell-329f60420465161dcb2b8dfd85211129cb20ff4d.tar.xz
ell-329f60420465161dcb2b8dfd85211129cb20ff4d.zip
Split native functions from non-native
-rwxr-xr-xell.c210
1 files changed, 111 insertions, 99 deletions
diff --git a/ell.c b/ell.c
index 59f59ac..cb30ebf 100755
--- a/ell.c
+++ b/ell.c
@@ -643,6 +643,38 @@ parse (const char *s, size_t len, char **e) {
// --- Runtime -----------------------------------------------------------------
+struct context;
+typedef bool (*handler_fn) (struct context *);
+
+struct native_fn {
+ struct native_fn *next; ///< The next link in the chain
+ handler_fn handler; ///< Internal C handler, or NULL
+ char name[]; ///< The name of the function
+};
+
+struct native_fn *g_native; ///< Maps words to functions
+
+static bool
+register_native (const char *name, handler_fn handler) {
+ struct native_fn *fn = NULL;
+ for (fn = g_native; fn; fn = fn->next)
+ if (!strcmp (fn->name, name))
+ break;
+
+ if (!fn) {
+ if (!(fn = calloc (1, sizeof *fn + strlen (name) + 1)))
+ return false;
+ strcpy (fn->name, name);
+ fn->next = g_native;
+ g_native = fn;
+ }
+
+ fn->handler = handler;
+ return true;
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
struct context {
struct item *variables; ///< List of variables
@@ -653,19 +685,6 @@ struct context {
void *user_data; ///< User data
};
-/// Internal handler for a function
-typedef bool (*handler_fn) (struct context *);
-
-struct fn {
- struct fn *next; ///< The next link in the chain
-
- handler_fn handler; ///< Internal C handler, or NULL
- struct item *script; ///< Alternatively runtime code
- char name[]; ///< The name of the function
-};
-
-struct fn *g_functions; ///< Maps words to functions
-
static void
context_init (struct context *ctx) {
memset (ctx, 0, sizeof *ctx);
@@ -691,20 +710,46 @@ set_error (struct context *ctx, const char *format, ...) {
return false;
}
-static bool execute (struct context *, struct item *);
+static struct item *
+var (struct context *ctx, const char *name) {
+ for (struct item *iter = ctx->variables; iter; iter = iter->next)
+ if (!strcmp (iter->head->value, name))
+ return iter->head->next;
+ return NULL;
+}
+
+static void
+set (struct context *ctx, const char *name, struct item *value) {
+ for (struct item *iter = ctx->variables; iter; iter = iter->next)
+ if (!strcmp (iter->head->value, name)) {
+ item_free (iter->head->next);
+ iter->head->next = value;
+ return;
+ }
+ struct item *key = new_string (name, strlen (name));
+ key->next = value;
+ struct item *pair = new_list (key);
+ pair->next = ctx->variables;
+ ctx->variables = pair;
+}
+
+static struct item *execute (struct context *, struct item *);
static bool
call_function (struct context *ctx, const char *name) {
- struct fn *iter;
- for (iter = g_functions; iter; iter = iter->next)
- if (!strcmp (name, iter->name))
- goto found;
- return set_error (ctx, "unknown function: %s", name);
-
-found:
- if (iter->handler
- ? iter->handler (ctx)
- : execute (ctx, iter->script))
+ struct item *body = var (ctx, name);
+ if (!body) {
+ struct native_fn *fn;
+ for (fn = g_native; fn; fn = fn->next)
+ if (!strcmp (name, fn->name))
+ break;
+ if (!fn)
+ return set_error (ctx, "unknown function: %s", name);
+ if (fn->handler (ctx))
+ return true;
+ } else if (body->type == ITEM_STRING) {
+ return set_error (ctx, "strings aren't callable: %s", name);
+ } else if (execute (ctx, body))
return true;
// In this case, `error' is NULL
@@ -719,64 +764,38 @@ found:
return false;
}
-static void
-free_function (struct fn *fn) {
- item_free_list (fn->script);
- free (fn);
-}
+static struct item *execute (struct context *ctx, struct item *script);
-static void
-unregister_function (const char *name) {
- for (struct fn **iter = &g_functions; *iter; iter = &(*iter)->next)
- if (!strcmp ((*iter)->name, name)) {
- struct fn *tmp = *iter;
- *iter = tmp->next;
- free_function (tmp);
- break;
- }
-}
-
-static struct fn *
-prepend_new_fn (const char *name) {
- struct fn *fn = calloc (1, sizeof *fn + strlen (name) + 1);
- if (!fn)
+static struct item *
+execute_one (struct context *ctx, struct item *statement) {
+ if (!statement->head)
return NULL;
- strcpy (fn->name, name);
- fn->next = g_functions;
- return g_functions = fn;
-}
-
-static bool
-register_handler (const char *name, handler_fn handler) {
- unregister_function (name);
- struct fn *fn = prepend_new_fn (name);
- if (!fn)
- return false;
- fn->handler = handler;
- return true;
-}
-
-static bool
-register_script (const char *name, struct item *script) {
- unregister_function (name);
- struct fn *fn = prepend_new_fn (name);
- if (!fn)
- return false;
- fn->script = script;
- return true;
+ struct item *fn = statement->head->head;
+ if (statement->head->type == ITEM_STRING) {
+ if (!strcmp (statement->head->value, "quote")) {
+ return statement->head->next;
+ } else if (!strcmp (statement->head->value, "arg")) {
+ // TODO: rename \d+ variables to arguments
+ } else {
+ // TODO: resolve the string
+ fn = NULL;
+ }
+ }
+ // TODO: assign the rest of items to variables
+ return execute (ctx, fn);
}
-static bool
+// Execute a block and return whatever the last statement returned
+static struct item *
execute (struct context *ctx, struct item *script) {
+ struct item *result = NULL;
for (; script; script = script->next) {
- // TODO: this should be a list
- // -> if the first item is a STRING, resolve it
- // -> but handle special forms
- // -> assign the rest of the items to variables
- // -> recurse
+ assert (script->type == ITEM_LIST);
+ item_free_list (result);
+ result = execute_one (ctx, script);
}
- return true;
+ return result;
}
// --- Runtime library ---------------------------------------------------------
@@ -784,39 +803,33 @@ execute (struct context *ctx, struct item *script) {
#define defn(name) static bool name (struct context *ctx)
static bool
-init_runtime_library_scripts (void) {
+init_runtime_library_scripts (struct context *ctx) {
bool ok = true;
// It's much cheaper (and more fun) to define functions in terms of other
// ones. The "unit tests" serve a secondary purpose of showing the usage.
- struct script {
+ struct {
const char *name; ///< Name of the function
const char *definition; ///< The defining script
- } scripts[] = {
+ } functions[] = {
{ "greet", "arg _name\n" "print (.. 'hello ' (.. @_name))" },
};
- for (size_t i = 0; i < N_ELEMENTS (scripts); i++) {
+ for (size_t i = 0; i < N_ELEMENTS (functions); i++) {
char *e = NULL;
- struct item *script = parse (scripts[i].definition,
- strlen (scripts[i].definition), &e);
+ struct item *body = parse (functions[i].definition,
+ strlen (functions[i].definition), &e);
if (e) {
- printf ("error parsing internal script `%s': %s\n",
- scripts[i].definition, e);
+ printf ("error parsing internal function `%s': %s\n",
+ functions[i].definition, e);
free (e);
ok = false;
} else
- ok &= register_script (scripts[i].name, script);
+ set (ctx, functions[i].name, body);
}
return ok;
}
-static struct item *
-var (struct context *ctx, const char *name) {
- // TODO: go through the "ctx->variables" list of lists and look for "name"
- return NULL;
-}
-
defn (fn_print) {
struct buffer buf = BUFFER_INITIALIZER;
struct item *item = var (ctx, "1");
@@ -840,17 +853,16 @@ defn (fn_concatenate) {
static bool
init_runtime_library (void)
{
- return register_handler ("..", fn_concatenate)
- && register_handler ("print", fn_print)
- && init_runtime_library_scripts ();
+ return register_native ("..", fn_concatenate)
+ && register_native ("print", fn_print);
}
static void
free_runtime_library (void) {
- struct fn *next, *iter;
- for (iter = g_functions; iter; iter = next) {
+ struct native_fn *next, *iter;
+ for (iter = g_native; iter; iter = next) {
next = iter->next;
- free_function (iter);
+ free (iter);
}
}
@@ -858,9 +870,6 @@ free_runtime_library (void) {
int
main (int argc, char *argv[]) {
- if (!init_runtime_library ())
- printf ("%s\n", "runtime library initialization failed");
-
// TODO: load the entirety of stdin
const char *program = "print 'hello world\\n'";
@@ -874,8 +883,11 @@ main (int argc, char *argv[]) {
struct context ctx;
context_init (&ctx);
+ if (!init_runtime_library ()
+ || !init_runtime_library_scripts (&ctx))
+ printf ("%s\n", "runtime library initialization failed");
ctx.user_data = NULL;
- execute (&ctx, tree);
+ item_free_list (execute (&ctx, tree));
item_free_list (tree);
const char *failure = NULL;