Module Comparable
In: compar.c

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. Comparable uses <=> to implement the conventional comparison operators (<, <=, ==, >=, and >) and the method between?. 

   class SizeMatters
     include Comparable
     attr :str
     def <=>(anOther)
       str.size <=> anOther.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]

Methods

<   <=   ==   >   >=   between?  

Public Instance methods

obj < other => true or false

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

[Source]

/*
 *  call-seq:
 *     obj < other    => true or false
 *  
 *  Compares two objects based on the receiver's <code><=></code>
 *  method, returning true if it returns -1.
 */

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

    if (NIL_P(c)) return cmperr();
    if (rb_cmpint(c, x, y) < 0) return Qtrue;
    return Qfalse;
}
obj <= other => true or false

Compares two objects based on the receiver‘s <=> method, returning true if it returns -1 or 0.

[Source]

/*
 *  call-seq:
 *     obj <= other    => true or false
 *  
 *  Compares two objects based on the receiver's <code><=></code>
 *  method, returning true if it returns -1 or 0.
 */

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

    if (NIL_P(c)) return cmperr();
    if (rb_cmpint(c, x, y) <= 0) return Qtrue;
    return Qfalse;
}
obj == other => true or false

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.

[Source]

/*
 *  call-seq:
 *     obj == other    => true or false
 *  
 *  Compares two objects based on the receiver's <code><=></code>
 *  method, returning true if it returns 0. Also returns true if
 *  _obj_ and _other_ are the same object.
 */

static VALUE
cmp_equal(x, y)
    VALUE x, y;
{
    VALUE a[2];

    if (x == y) return Qtrue;

    a[0] = x; a[1] = y;
    return rb_rescue(cmp_eq, (VALUE)a, cmp_failed, 0);
}
obj > other => true or false

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

[Source]

/*
 *  call-seq:
 *     obj > other    => true or false
 *  
 *  Compares two objects based on the receiver's <code><=></code>
 *  method, returning true if it returns 1.
 */

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

    if (NIL_P(c)) return cmperr();
    if (rb_cmpint(c, x, y) > 0) return Qtrue;
    return Qfalse;
}
obj >= other => true or false

Compares two objects based on the receiver‘s <=> method, returning true if it returns 0 or 1.

[Source]

/*
 *  call-seq:
 *     obj >= other    => true or false
 *  
 *  Compares two objects based on the receiver's <code><=></code>
 *  method, returning true if it returns 0 or 1.
 */

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

    if (NIL_P(c)) return cmperr();
    if (rb_cmpint(c, x, y) >= 0) return Qtrue;
    return Qfalse;
}
obj.between?(min, max) => true or false

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

[Source]

/*
 *  call-seq:
 *     obj.between?(min, max)    => true or false
 *  
 *  Returns <code>false</code> if <i>obj</i> <code><=></code>
 *  <i>min</i> is less than zero or if <i>anObject</i> <code><=></code>
 *  <i>max</i> is greater than zero, <code>true</code> 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(x, min, max)
    VALUE x, min, max;
{
    if (RTEST(cmp_lt(x, min))) return Qfalse;
    if (RTEST(cmp_gt(x, max))) return Qfalse;
    return Qtrue;
}

[Validate]