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Comparable#clamp

* compar.c (cmp_clamp): Introduce Comparable#clamp.  [Feature #10594]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55863 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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nobu committed Aug 11, 2016
1 parent b8ad953 commit d5a0b8e3cc48632d0cb99553a7aaf233b22a1eac
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  1. +4 −0 ChangeLog
  2. +4 −0 NEWS
  3. +34 −0 compar.c
  4. +14 −0 test/ruby/test_comparable.rb
@@ -1,3 +1,7 @@
Thu Aug 11 16:24:23 2016 nerdinand <nerdinand@nerdinand.com>

* compar.c (cmp_clamp): Introduce Comparable#clamp. [Feature #10594]

Thu Aug 11 03:16:59 2016 Marc-Andre Lafortune <ruby-core@marc-andre.ca>

* lib/prime.rb: Optimize prime?
4 NEWS
@@ -30,6 +30,10 @@ with all sufficient information, see the ChangeLog file or Redmine
This is different from Enumerable#sum in that Array#sum doesn't depend on
the definition of each method.

* Comparable

* Comparable#clamp. [Feature #10594]

* Dir

* Dir.empty?. [Feature #10121]
@@ -173,6 +173,39 @@ cmp_between(VALUE x, VALUE min, VALUE max)
return Qtrue;
}

/*
* call-seq:
* obj.clamp(min, max) -> obj
*
* Returns <i>min</i> if <i>obj</i> <code><=></code> <i>min</i> is less
* than zero, <i>max</i> if <i>obj</i> <code><=></code> <i>max</i> is
* greater than zero and <i>obj</i> otherwise.
*
* 12.clamp(0, 100) #=> 12
* 523.clamp(0, 100) #=> 100
* -3.123.clamp(0, 100) #=> 0
*
* 'd'.clamp('a', 'f') #=> 'd'
* 'z'.clamp('a', 'f') #=> 'f'
*/

static VALUE
cmp_clamp(VALUE x, VALUE min, VALUE max)
{
int c;

if (cmpint(min, max) > 0) {
rb_raise(rb_eArgError, "min argument must be smaller than max argument");
}

c = cmpint(x, min);
if (c == 0) return x;
if (c < 0) return min;
c = cmpint(x, max);
if (c > 0) return max;
return x;
}

/*
* The <code>Comparable</code> mixin is used by classes whose objects
* may be ordered. The class must define the <code><=></code> operator,
@@ -225,4 +258,5 @@ Init_Comparable(void)
rb_define_method(rb_mComparable, "<", cmp_lt, 1);
rb_define_method(rb_mComparable, "<=", cmp_le, 1);
rb_define_method(rb_mComparable, "between?", cmp_between, 2);
rb_define_method(rb_mComparable, "clamp", cmp_clamp, 2);
}
@@ -76,6 +76,20 @@ def test_between
assert_equal(true, @o.between?(0, 0))
end

def test_clamp
cmp->(x) do 0 <=> x end
assert_equal(1, @o.clamp(1, 2))
assert_equal(-1, @o.clamp(-2, -1))
assert_equal(0, @o.clamp(-1, 3))

assert_equal(1, @o.clamp(1, 1))
assert_equal(0, @o.clamp(0, 0))

assert_raise_with_message(ArgumentError, 'min argument must be smaller than max argument') {
@o.clamp(2, 1)
}
end

def test_err
assert_raise(ArgumentError) { 1.0 < nil }
assert_raise(ArgumentError) { 1.0 < Object.new }

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