Feature #6445
request for default length/position on string index
Description
would be nice if ruby has default for "rest or up to end of string"
eg
"hello"[2,] => should default to "hello"[2..-1]
or
"hello"[2..] => should default to "hello"[2..-1]
Updated by mame (Yusuke Endoh) over 8 years ago
- Status changed from Open to Assigned
- Assignee set to matz (Yukihiro Matsumoto)
Hello,
I created a patch that add a syntactic sugar from (arg..) to (arg..-1).
ary = [1, 2, 3, 4]
p ary[2..] #=> [3, 4]
Matz, what do you think?
diff --git a/parse.y b/parse.y
index 9f9093b..d272492 100644
--- a/parse.y
+++ b/parse.y
@@ -2168,6 +2168,18 @@ arg : lhs '=' arg
$$ = dispatch2(dot3, $1, $3);
%*/
}
- | arg tDOT2
- {
- /%%%/
- value_expr($1);
- $$ = NEW_DOT2($1, NEW_LIT(INT2FIX(-1)));
- if (nd_type($1) == NODE_LIT && FIXNUM_P($1->nd_lit)) {
- deferred_nodes = list_append(deferred_nodes, $$);
- }
- /*%
- $$ = dispatch2(dot2, $1, INT2FIX(-1));
- %*/
- } | arg '+' arg { /%%%/
--
Yusuke Endoh mame@tsg.ne.jp
Updated by knu (Akinori MUSHA) over 8 years ago
It would look nice and work fine with indexing strings and arrays, but if it were put in you would've come to want (1..).each {|i| .. } to work as well.
It might be better to default the omitted end to +Infinity and then make {Array,String,..}#[] understand +Infinity as an index, I guess?
Updated by yhara (Yutaka HARA) over 8 years ago
- Target version changed from 2.0.0 to 3.0
Updated by yhara (Yutaka HARA) over 8 years ago
- Target version changed from 3.0 to 2.6