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Replace for/break with a try/throw mechanism

This commit is contained in:
Přemysl Eric Janouch 2017-05-25 13:52:41 +02:00
parent aa4b4391f3
commit 1de758b6d6
Signed by: p
GPG Key ID: B715679E3A361BE6
2 changed files with 14 additions and 41 deletions
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47
ell.c
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@ -852,18 +852,6 @@ set_single_argument (struct context *ctx, struct item *item) {
return true;
}
#define E_BREAK "_break"
static bool
eat_error (struct context *ctx, const char *name) {
if (!ctx->error || strcmp (ctx->error, name))
return false;
free (ctx->error);
ctx->error = NULL;
return true;
}
static struct item *
new_number (double n) {
char *s;
@ -946,31 +934,6 @@ defn (fn_if) {
return true;
}
defn (fn_for) {
struct item *list = args, *body;
if (!list || list->type != ITEM_LIST)
return set_error (ctx, "first argument must be a list");
if (!(body = list->next) || body->type != ITEM_LIST)
return set_error (ctx, "second argument must be a function");
(void) result;
for (struct item *v = list->head; v; v = v->next) {
struct item *res = NULL;
bool ok = set_single_argument (ctx, v)
&& execute (ctx, body->head, &res);
item_free_list (res);
if (eat_error (ctx, E_BREAK))
break;
if (!ok)
return false;
}
return true;
}
defn (fn_break) {
(void) args; (void) result; return set_error (ctx, E_BREAK);
}
defn (fn_map) {
struct item *body = args, *values;
if (!body || body->type != ITEM_LIST)
@ -1214,8 +1177,12 @@ init_runtime_library (struct context *ctx) {
const char *definition; ///< The defining script
} functions[] = {
{ "unless", "arg _cond _body; if (not (@_cond)) @_body" },
{ "filter", "arg _body _list; map {"
"arg _item; if (@_body @_item) { @_item } } @_list" },
{ "filter", "arg _body _list;"
"map { arg _i; if (@_body @_i) { @_i } } @_list" },
{ "for", "arg _list _body;"
"try { map {arg _i; @_body @_i } @_list"
"} { arg _e; if (ne? @_e _break) { throw @e } }" },
{ "break", "throw _break" },
// TODO: we should be able to apply them to all arguments
{ "ne?", "arg _ne1 _ne2; not (eq? @_ne1 @_ne2)" },
{ "ge?", "arg _ge1 _ge2; not (lt? @_ge1 @_ge2)" },
@ -1251,8 +1218,6 @@ init_runtime_library (struct context *ctx) {
&& native_register (ctx, "set", fn_set)
&& native_register (ctx, "list", fn_list)
&& native_register (ctx, "if", fn_if)
&& native_register (ctx, "for", fn_for)
&& native_register (ctx, "break", fn_break)
&& native_register (ctx, "map", fn_map)
&& native_register (ctx, "print", fn_print)
&& native_register (ctx, "..", fn_concatenate)

8
greet.ell
View File

@ -2,10 +2,18 @@ set greet {
arg _name
print 'hello ' @_name '\n'
}
set decr {
arg _name
set @_name (- @@_name 1)
}
set limit 2
for (map { arg _x; .. @_x ! } [
world
creator
'darkness, my old friend'
]) {
arg _whom
greet @_whom
if (= 0 (decr limit)) { break }
}