module Comparable - Documentation for Ruby 2.3.0 (original) (raw)

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
s4.between?(s1, s3)
s4.between?(s3, s5)
[ s3, s2, s5, s4, s1 ].sort

Public Instance Methods

obj < other → true or false click to toggle source

Compares two objects based on the receiver's <=> method, returning true if it returns -1.

static VALUE cmp_lt(VALUE x, VALUE y) { VALUE c = rb_funcall(x, cmp, 1, y);

if (rb_cmpint(c, x, y) < 0) return Qtrue;
return Qfalse;

}

obj <= other → true or false click to toggle source

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) { VALUE c = rb_funcall(x, cmp, 1, y);

if (rb_cmpint(c, x, y) <= 0) return Qtrue;
return Qfalse;

}

obj == other → true or false click to toggle source

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;

}

obj > other → true or false click to toggle source

Compares two objects based on the receiver's <=> method, returning true if it returns 1.

static VALUE cmp_gt(VALUE x, VALUE y) { VALUE c = rb_funcall(x, cmp, 1, y);

if (rb_cmpint(c, x, y) > 0) return Qtrue;
return Qfalse;

}

obj >= other → true or false click to toggle source

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) { VALUE c = rb_funcall(x, cmp, 1, y);

if (rb_cmpint(c, x, y) >= 0) return Qtrue;
return Qfalse;

}

between?(min, max) → true or false click to toggle source

Returns false if obj <=> min is less than zero or if anObject <=> max is greater than zero, true otherwise.

3.between?(1, 5)
6.between?(1, 5)
'cat'.between?('ant', 'dog')
'gnu'.between?('ant', 'dog')

static VALUE cmp_between(VALUE x, VALUE min, VALUE max) { if (RTEST(cmp_lt(x, min))) return Qfalse; if (RTEST(cmp_gt(x, max))) return Qfalse; return Qtrue; }