Module | Comparable |
In: |
compar.c
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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]
Compares two objects based on the receiver‘s <=> method, returning true if it returns -1.
/* * 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; }
Compares two objects based on the receiver‘s <=> method, returning true if it returns -1 or 0.
/* * 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; }
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.
/* * 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); }
Compares two objects based on the receiver‘s <=> method, returning true if it returns 1.
/* * 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; }
Compares two objects based on the receiver‘s <=> method, returning true if it returns 0 or 1.
/* * 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; }
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
/* * 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; }