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Reimplements Range#first
Range#first shouldn't call `Range#to_a` on infinity range.
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ksss committed Nov 21, 2016
1 parent a3f8206 commit 682237be6ecabe9f35e7a7a1cb16a1eb54b69fb9
Showing 3 changed files with 32 additions and 27 deletions.
@@ -0,0 +1,31 @@
class Range
##
# call-seq:
# rng.first -> obj
# rng.first(n) -> an_array
#
# Returns the first object in the range, or an array of the first +n+
# elements.
#
# (10..20).first #=> 10
# (10..20).first(3) #=> [10, 11, 12]
#
def first(*args)
return self.begin if args.empty?

raise ArgumentError, "wrong number of arguments (given #{args.length}, expected 1)" unless args.length == 1
nv = args[0]
raise TypeError, "no implicit conversion from nil to integer" unless nv.nil?.!
raise TypeError, "no implicit conversion of #{nv.class} into Integer" unless nv.respond_to?(:to_int)
n = nv.to_int
raise TypeError, "no implicit conversion of #{nv.class} into Integer" unless n.kind_of?(Integer)
raise ArgumentError, "negative array size (or size too big)" unless 0 <= n
ary = []
each do |i|
break if n <= 0
ary.push(i)
n -= 1
end
ary
end
end
@@ -66,32 +66,6 @@ mrb_range_cover(mrb_state *mrb, mrb_value range)
return mrb_false_value();
}

/*
* call-seq:
* rng.first -> obj
* rng.first(n) -> an_array
*
* Returns the first object in the range, or an array of the first +n+
* elements.
*
* (10..20).first #=> 10
* (10..20).first(3) #=> [10, 11, 12]
*/
static mrb_value
mrb_range_first(mrb_state *mrb, mrb_value range)
{
mrb_int num;
mrb_value array;
struct RRange *r = mrb_range_ptr(range);

if (mrb_get_args(mrb, "|i", &num) == 0) {
return r->edges->beg;
}

array = mrb_funcall(mrb, range, "to_a", 0);
return mrb_funcall(mrb, array, "first", 1, mrb_fixnum_value(num));
}

/*
* call-seq:
* rng.last -> obj
@@ -193,7 +167,6 @@ mrb_mruby_range_ext_gem_init(mrb_state* mrb)
struct RClass * s = mrb_class_get(mrb, "Range");

mrb_define_method(mrb, s, "cover?", mrb_range_cover, MRB_ARGS_REQ(1));
mrb_define_method(mrb, s, "first", mrb_range_first, MRB_ARGS_OPT(1));
mrb_define_method(mrb, s, "last", mrb_range_last, MRB_ARGS_OPT(1));
mrb_define_method(mrb, s, "size", mrb_range_size, MRB_ARGS_NONE());
}
@@ -10,6 +10,7 @@
assert('Range#first') do
assert_equal 10, (10..20).first
assert_equal [10, 11, 12], (10..20).first(3)
assert_equal [0, 1, 2], (0..Float::INFINITY).first(3)
end

assert('Range#last') do

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