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Fix Enumerator::Lazy#with_index

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* Make it correctly handle lambdas
* Make it iterate over the block if block is given

The original implementation was flawed, based on lazy_set_method
instead of lazy_add_method.

Note that there is no implicit map when passing a block, the return
value of the block passed to with_index is ignored, just as it
is for Enumerator#with_index. Also like Enumerator#with_index,
when called with a block, the return value is an enumerator without
the index.

Fixes [Bug #16414]
This commit is contained in:
Jeremy Evans 2019-12-10 13:38:12 -08:00
parent 8a80bfcfd4
commit 85e43e1dfe
Notes: git 2019-12-11 12:00:23 +09:00
2 changed files with 71 additions and 67 deletions
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121
enumerator.c
View file

@ -2645,6 +2645,62 @@ lazy_uniq(VALUE obj)
return lazy_add_method(obj, 0, 0, Qnil, Qnil, funcs);
}
static struct MEMO *
lazy_with_index_proc(VALUE proc_entry, struct MEMO* result, VALUE memos, long memo_index)
{
struct proc_entry *entry = proc_entry_ptr(proc_entry);
VALUE memo = rb_ary_entry(memos, memo_index);
VALUE argv[2];
if (NIL_P(memo)) {
memo = entry->memo;
}
argv[0] = result->memo_value;
argv[1] = memo;
if (entry->proc) {
rb_proc_call_with_block(entry->proc, 2, argv, Qnil);
LAZY_MEMO_RESET_PACKED(result);
} else {
LAZY_MEMO_SET_VALUE(result, rb_ary_new_from_values(2, argv));
LAZY_MEMO_SET_PACKED(result);
}
rb_ary_store(memos, memo_index, LONG2NUM(NUM2LONG(memo) + 1));
return result;
}
static const lazyenum_funcs lazy_with_index_funcs = {
lazy_with_index_proc, 0,
};
/*
* call-seq:
* lazy.with_index(offset = 0) {|(*args), idx| ... }
* lazy.with_index(offset = 0)
*
* If a block is given, iterates the given block for each element
* with an index, which starts from +offset+, and returns a
* lazy enumerator that yields the same values (without the index).
*
* If a block is not given, returns a new lazy enumerator that
* includes the index, starting from +offset+.
*
* +offset+:: the starting index to use
*
* see Enumerator#with_index.
*/
static VALUE
lazy_with_index(int argc, VALUE *argv, VALUE obj)
{
VALUE memo;
rb_scan_args(argc, argv, "01", &memo);
if (NIL_P(memo))
memo = LONG2NUM(0);
return lazy_add_method(obj, 0, 0, memo, rb_ary_new_from_values(1, &memo), &lazy_with_index_funcs);
}
#if 0 /* for RDoc */
/*
@ -3841,71 +3897,6 @@ arith_seq_size(VALUE self)
return len;
}
static VALUE
lazy_with_index_func(RB_BLOCK_CALL_FUNC_ARGLIST(val, offset))
{
VALUE yielder, memo, result;
VALUE e = rb_enum_values_pack(argc - 1, argv + 1);
long idx;
yielder = argv[0];
memo = rb_attr_get(yielder, id_memo);
if (NIL_P(memo))
memo = offset;
idx = NUM2LONG(memo);
result = rb_assoc_new(e, memo);
rb_funcall(yielder, idLTLT, 1, result);
rb_ivar_set(yielder, id_memo, LONG2NUM(++idx));
return Qnil;
}
static VALUE
lazy_with_index_iter(RB_BLOCK_CALL_FUNC_ARGLIST(val, offset))
{
VALUE yielder, memo, result;
VALUE e = rb_enum_values_pack(argc - 1, argv + 1);
long idx;
yielder = argv[0];
memo = rb_attr_get(yielder, id_memo);
if (NIL_P(memo))
memo = offset;
idx = NUM2LONG(memo);
result = rb_yield(rb_assoc_new(e, memo));
rb_funcall(yielder, idLTLT, 1, result);
rb_ivar_set(yielder, id_memo, LONG2NUM(++idx));
return Qnil;
}
/*
* call-seq:
* lazy.with_index(offset = 0) {|(*args), idx| ... }
* lazy.with_index(offset = 0)
*
* Iterates the given block for each element with an index, which
* starts from +offset+. If no block is given, returns a new
* lazy enumerator that includes the index, starting from +offset+
*
* +offset+:: the starting index to use
*
* see Enumerator#with_index.
*/
static VALUE
lazy_with_index(int argc, VALUE *argv, VALUE obj)
{
VALUE memo;
rb_scan_args(argc, argv, "01", &memo);
if (NIL_P(memo))
memo = LONG2NUM(0);
return lazy_set_method(rb_block_call(rb_cLazy, id_new, 1, &obj,
rb_block_given_p() ?
lazy_with_index_iter : lazy_with_index_func,
memo),
rb_ary_new_from_values(argc, argv), 0);
}
void
InitVM_Enumerator(void)
{

17
test/ruby/test_lazy_enumerator.rb
View file

@ -647,7 +647,7 @@ EOS
def test_with_index
feature7877 = '[ruby-dev:47025] [Feature #7877]'
leibniz = ->(n) {
(0..Float::INFINITY).lazy.with_index {|i, j|
(0..Float::INFINITY).lazy.with_index.map {|i, j|
raise IndexError, "limit exceeded (#{n})" unless j < n
((-1) ** j) / (2*i+1).to_f
}.take(n).reduce(:+)
@ -656,7 +656,20 @@ EOS
assert_in_epsilon(Math::PI/4, leibniz[1000])
}
ary = (0..Float::INFINITY).lazy.with_index(2) {|i, j| [i-1, j] }.take(2).to_a
a = []
ary = (0..Float::INFINITY).lazy.with_index(2) {|i, j| a << [i-1, j] }.take(2).to_a
assert_equal([[-1, 2], [0, 3]], a)
assert_equal([0, 1], ary)
a = []
ary = (0..Float::INFINITY).lazy.with_index(2, &->(i,j) { a << [i-1, j] }).take(2).to_a
assert_equal([[-1, 2], [0, 3]], a)
assert_equal([0, 1], ary)
ary = (0..Float::INFINITY).lazy.with_index(2).map {|i, j| [i-1, j] }.take(2).to_a
assert_equal([[-1, 2], [0, 3]], ary)
ary = (0..Float::INFINITY).lazy.with_index(2).map(&->(i, j) { [i-1, j] }).take(2).to_a
assert_equal([[-1, 2], [0, 3]], ary)
ary = (0..Float::INFINITY).lazy.with_index(2).take(2).to_a