The Comparable
mixin is used by classes whose objects may be ordered. The class must define the <=>
operator, which compares the receiver against another object, returning -1, 0, or +1 depending on whether the receiver is less than, equal to, or greater than the other object. If the other object is not comparable then the <=>
operator should return nil. Comparable
uses <=>
to implement the conventional comparison operators (<
, <=
, ==
, >=
, and >
) and the method between?
.
class SizeMatters include Comparable attr :str def <=>(other) str.size <=> other.str.size end def initialize(str) @str = str end def inspect @str end end s1 = SizeMatters.new("Z") s2 = SizeMatters.new("YY") s3 = SizeMatters.new("XXX") s4 = SizeMatters.new("WWWW") s5 = SizeMatters.new("VVVVV") s1 < s2 #=> true s4.between?(s1, s3) #=> false s4.between?(s3, s5) #=> true [ s3, s2, s5, s4, s1 ].sort #=> [Z, YY, XXX, WWWW, VVVVV]
Compares two objects based on the receiver's <=>
method, returning true if it returns -1.
static VALUE cmp_lt(VALUE x, VALUE y) { if (cmpint(x, y) < 0) return Qtrue; return Qfalse; }
Compares two objects based on the receiver's <=>
method, returning true if it returns -1 or 0.
static VALUE cmp_le(VALUE x, VALUE y) { if (cmpint(x, y) <= 0) return Qtrue; return Qfalse; }
Compares two objects based on the receiver's <=>
method, returning true if it returns 0. Also returns true if obj and other are the same object.
static VALUE cmp_equal(VALUE x, VALUE y) { VALUE c; if (x == y) return Qtrue; c = rb_exec_recursive_paired_outer(cmp_eq_recursive, x, y, y); if (NIL_P(c)) return Qfalse; if (rb_cmpint(c, x, y) == 0) return Qtrue; return Qfalse; }
Compares two objects based on the receiver's <=>
method, returning true if it returns 1.
static VALUE cmp_gt(VALUE x, VALUE y) { if (cmpint(x, y) > 0) return Qtrue; return Qfalse; }
Compares two objects based on the receiver's <=>
method, returning true if it returns 0 or 1.
static VALUE cmp_ge(VALUE x, VALUE y) { if (cmpint(x, y) >= 0) return Qtrue; return Qfalse; }
Returns false
if obj <=>
min is less than zero or if anObject <=>
max is greater than zero, true
otherwise.
3.between?(1, 5) #=> true 6.between?(1, 5) #=> false 'cat'.between?('ant', 'dog') #=> true 'gnu'.between?('ant', 'dog') #=> false
static VALUE cmp_between(VALUE x, VALUE min, VALUE max) { if (cmpint(x, min) < 0) return Qfalse; if (cmpint(x, max) > 0) return Qfalse; return Qtrue; }
Returns min if obj <=>
min is less than zero, max if obj <=>
max is greater than zero and obj 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; }