Hello world works
This commit is contained in:
parent
3ecceb8902
commit
5963b99c3e
GPG Key ID:
B715679E3A361BE6
2
Makefile
2
Makefile
|
|
@ -1,4 +1,4 @@
|
|||
CFLAGS = -std=gnu99 -Wall
|
||||
CFLAGS = -std=gnu99 -Wall -Wextra -ggdb
|
||||
all: ell
|
||||
ell: ell.c
|
||||
$(CC) $(CFLAGS) $< -o $@
|
||||
|
|
|
|||
254
ell.c
254
ell.c
|
|
@ -644,7 +644,7 @@ parse (const char *s, size_t len, char **e) {
|
|||
// --- Runtime -----------------------------------------------------------------
|
||||
|
||||
struct context;
|
||||
typedef bool (*handler_fn) (struct context *);
|
||||
typedef bool (*handler_fn) (struct context *, struct item *, struct item **);
|
||||
|
||||
struct native_fn {
|
||||
struct native_fn *next; ///< The next link in the chain
|
||||
|
|
@ -696,6 +696,42 @@ context_free (struct context *ctx) {
|
|||
free (ctx->error);
|
||||
}
|
||||
|
||||
static struct item *
|
||||
get (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;
|
||||
}
|
||||
|
||||
// FIXME: cloning and removing
|
||||
static bool
|
||||
set (struct context *ctx, const char *name, struct item *value) {
|
||||
struct item *iter, *key = NULL, *pair = NULL;
|
||||
for (iter = ctx->variables; iter; iter = iter->next)
|
||||
if (!strcmp (iter->head->value, name))
|
||||
break;
|
||||
if (iter) {
|
||||
item_free (iter->head->next);
|
||||
iter->head->next = value;
|
||||
return true;
|
||||
}
|
||||
if ((key = new_string (name, strlen (name)))
|
||||
&& (pair = new_list (NULL))) {
|
||||
(pair->head = key)->next = value;
|
||||
pair->next = ctx->variables;
|
||||
ctx->variables = pair;
|
||||
return true;
|
||||
} else {
|
||||
item_free_list (key);
|
||||
item_free_list (pair);
|
||||
ctx->memory_failure = true;
|
||||
return false;
|
||||
}
|
||||
}
|
||||
|
||||
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
|
||||
|
||||
static bool
|
||||
set_error (struct context *ctx, const char *format, ...) {
|
||||
free (ctx->error);
|
||||
|
|
@ -710,48 +746,106 @@ set_error (struct context *ctx, const char *format, ...) {
|
|||
return false;
|
||||
}
|
||||
|
||||
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 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))
|
||||
rename_arguments (struct context *ctx, struct item *names) {
|
||||
size_t i = 0;
|
||||
for (; names; names = names->next) {
|
||||
char buf[64];
|
||||
(void) snprintf (buf, sizeof buf, "%zu", i++);
|
||||
struct item *value = get (ctx, buf);
|
||||
|
||||
if (names->type != ITEM_STRING)
|
||||
continue;
|
||||
if (value)
|
||||
set (ctx, names->value, new_clone (value));
|
||||
else
|
||||
set (ctx, names->value, NULL);
|
||||
}
|
||||
return true;
|
||||
}
|
||||
|
||||
static bool execute (struct context *ctx, struct item *body, struct item **);
|
||||
|
||||
// TODO: we should probably maintain arguments in a separate list,
|
||||
// either that or at least remember the count so that we can reset them
|
||||
static bool
|
||||
execute_statement
|
||||
(struct context *ctx, struct item *statement, struct item **result) {
|
||||
if (statement->type == ITEM_STRING) {
|
||||
if ((*result = new_clone (statement)))
|
||||
return true;
|
||||
} else if (body->type == ITEM_STRING) {
|
||||
return set_error (ctx, "strings aren't callable: %s", name);
|
||||
} else if (execute (ctx, body))
|
||||
ctx->memory_failure = true;
|
||||
return false;
|
||||
}
|
||||
|
||||
// XXX: should this ever happen and what are the consequences?
|
||||
// Shouldn't we rather clone the empty list?
|
||||
struct item *body;
|
||||
if (!(body = statement->head))
|
||||
return true;
|
||||
|
||||
const char *name = "(anonymous)";
|
||||
if (body->type == ITEM_STRING) {
|
||||
name = body->value;
|
||||
if (!strcmp (name, "quote")) {
|
||||
if ((*result = new_clone_list (body->next)))
|
||||
return true;
|
||||
ctx->memory_failure = true;
|
||||
return false;
|
||||
}
|
||||
if (!strcmp (name, "arg"))
|
||||
return rename_arguments (ctx, body->next);
|
||||
|
||||
if (!(body = get (ctx, body->value))) {
|
||||
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);
|
||||
|
||||
struct item *args = NULL, **tail = &args;
|
||||
for (struct item *arg = statement->head->next;
|
||||
arg; arg = arg->next) {
|
||||
struct item *evaluated = NULL;
|
||||
if (!execute_statement (ctx, arg, &evaluated))
|
||||
return false;
|
||||
|
||||
if (evaluated) {
|
||||
item_free_list (evaluated->next);
|
||||
evaluated->next = NULL;
|
||||
*tail = evaluated;
|
||||
tail = &evaluated->next;
|
||||
}
|
||||
}
|
||||
bool ok = fn->handler (ctx, args, result);
|
||||
item_free_list (args);
|
||||
if (ok)
|
||||
return true;
|
||||
goto error;
|
||||
}
|
||||
}
|
||||
// Recursion could be pretty fatal, let's not do that
|
||||
if (body->type == ITEM_STRING)
|
||||
return new_clone (body);
|
||||
|
||||
size_t i = 0;
|
||||
for (struct item *arg = statement->head->next; arg; arg = arg->next) {
|
||||
struct item *evaluated = NULL;
|
||||
if (!execute_statement (ctx, arg, &evaluated))
|
||||
return false;
|
||||
|
||||
item_free_list (evaluated->next);
|
||||
evaluated->next = NULL;
|
||||
|
||||
char buf[64];
|
||||
(void) snprintf (buf, sizeof buf, "%zu", i++);
|
||||
set (ctx, buf, evaluated);
|
||||
}
|
||||
if (execute (ctx, body->head, result))
|
||||
return true;
|
||||
|
||||
error:
|
||||
// In this case, `error' is NULL
|
||||
if (ctx->memory_failure)
|
||||
return false;
|
||||
|
|
@ -764,55 +858,32 @@ call_function (struct context *ctx, const char *name) {
|
|||
return false;
|
||||
}
|
||||
|
||||
static struct item *execute (struct context *ctx, struct item *script);
|
||||
|
||||
static struct item *
|
||||
execute_one (struct context *ctx, struct item *statement) {
|
||||
if (!statement->head)
|
||||
return NULL;
|
||||
|
||||
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);
|
||||
}
|
||||
|
||||
// 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) {
|
||||
assert (script->type == ITEM_LIST);
|
||||
item_free_list (result);
|
||||
result = execute_one (ctx, script);
|
||||
static bool
|
||||
execute (struct context *ctx, struct item *body, struct item **result) {
|
||||
for (; body; body = body->next) {
|
||||
item_free_list (*result);
|
||||
*result = NULL;
|
||||
if (!execute_statement (ctx, body, result))
|
||||
return false;
|
||||
}
|
||||
return result;
|
||||
return true;
|
||||
}
|
||||
|
||||
// --- Runtime library ---------------------------------------------------------
|
||||
|
||||
#define defn(name) static bool name (struct context *ctx)
|
||||
#define defn(name) static bool name \
|
||||
(struct context *ctx, struct item *args, struct item **result)
|
||||
|
||||
static bool
|
||||
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 {
|
||||
const char *name; ///< Name of the function
|
||||
const char *definition; ///< The defining script
|
||||
} functions[] = {
|
||||
{ "greet", "arg _name\n" "print (.. 'hello ' (.. @_name))" },
|
||||
{ "greet", "arg _name\n" "print (.. 'hello ' @_name '\\n')" },
|
||||
};
|
||||
|
||||
for (size_t i = 0; i < N_ELEMENTS (functions); i++) {
|
||||
|
|
@ -830,9 +901,25 @@ init_runtime_library_scripts (struct context *ctx) {
|
|||
return ok;
|
||||
}
|
||||
|
||||
defn (fn_set) {
|
||||
struct item *name = args;
|
||||
if (!name || name->type != ITEM_STRING)
|
||||
return (void *) set_error (ctx, "first argument must be string");
|
||||
|
||||
struct item *value;
|
||||
if ((value = name->next))
|
||||
return set (ctx, name->value, value);
|
||||
|
||||
// FIXME: how do we represent a nil value here?
|
||||
*result = get (ctx, name->value);
|
||||
return true;
|
||||
}
|
||||
|
||||
defn (fn_print) {
|
||||
(void) result;
|
||||
|
||||
struct buffer buf = BUFFER_INITIALIZER;
|
||||
struct item *item = var (ctx, "1");
|
||||
struct item *item = args;
|
||||
buffer_append (&buf, item->value, item->len);
|
||||
buffer_append_c (&buf, '\0');
|
||||
if (buf.memory_failure) {
|
||||
|
|
@ -846,7 +933,17 @@ defn (fn_print) {
|
|||
}
|
||||
|
||||
defn (fn_concatenate) {
|
||||
// TODO: concatenate string arguments, error on list
|
||||
// TODO: error on list
|
||||
struct buffer buf = BUFFER_INITIALIZER;
|
||||
for (; args; args = args->next)
|
||||
buffer_append (&buf, args->value, args->len);
|
||||
buffer_append_c (&buf, '\0');
|
||||
if (buf.memory_failure) {
|
||||
ctx->memory_failure = true;
|
||||
return false;
|
||||
}
|
||||
*result = new_string (buf.s, buf.len);
|
||||
free (buf.s);
|
||||
return true;
|
||||
}
|
||||
|
||||
|
|
@ -854,6 +951,7 @@ static bool
|
|||
init_runtime_library (void)
|
||||
{
|
||||
return register_native ("..", fn_concatenate)
|
||||
&& register_native ("set", fn_set)
|
||||
&& register_native ("print", fn_print);
|
||||
}
|
||||
|
||||
|
|
@ -871,7 +969,7 @@ free_runtime_library (void) {
|
|||
int
|
||||
main (int argc, char *argv[]) {
|
||||
// TODO: load the entirety of stdin
|
||||
const char *program = "print 'hello world\\n'";
|
||||
const char *program = "greet 'world'";
|
||||
|
||||
char *e = NULL;
|
||||
struct item *tree = parse (program, strlen (program), &e);
|
||||
|
|
@ -887,7 +985,9 @@ main (int argc, char *argv[]) {
|
|||
|| !init_runtime_library_scripts (&ctx))
|
||||
printf ("%s\n", "runtime library initialization failed");
|
||||
ctx.user_data = NULL;
|
||||
item_free_list (execute (&ctx, tree));
|
||||
struct item *result = NULL;
|
||||
(void) execute (&ctx, tree->head, &result);
|
||||
item_free_list (result);
|
||||
item_free_list (tree);
|
||||
|
||||
const char *failure = NULL;
|
||||
|
|
|
|||
Loading…
Reference in New Issue