module Comparable - RDoc Documentation (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 a value less than 0, returning 0, or returning a value greater than 0, 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 a value less than 0.

static VALUE cmp_lt(VALUE x, VALUE y) { if (cmpint(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 a value less than or equal to 0.

static VALUE cmp_le(VALUE x, VALUE y) { if (cmpint(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 a value greater than 0.

static VALUE cmp_gt(VALUE x, VALUE y) { if (cmpint(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 a value greater than or equal to 0.

static VALUE cmp_ge(VALUE x, VALUE y) { if (cmpint(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 obj <=> 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 (cmpint(x, min) < 0) return Qfalse; if (cmpint(x, max) > 0) return Qfalse; return Qtrue; }

clamp(min, max) → obj click to toggle source

clamp(range) → obj

In (min, max) form, returns min if obj <=> min is less than zero, max if obj <=> max is greater than zero, and obj otherwise.

12.clamp(0, 100)
523.clamp(0, 100)
-3.123.clamp(0, 100)

'd'.clamp('a', 'f')
'z'.clamp('a', 'f')

In (range) form, returns range.begin if obj <=> range.begin is less than zero, range.end if obj <=> range.end is greater than zero, and obj otherwise.

12.clamp(0..100)
523.clamp(0..100)
-3.123.clamp(0..100)

'd'.clamp('a'..'f')
'z'.clamp('a'..'f')

If range.begin is nil, it is considered smaller than obj, and if range.end is nil, it is considered greater than obj.

-20.clamp(0..)
523.clamp(..100)

When range.end is excluded and not nil, an exception is raised.

100.clamp(0...100)

static VALUE cmp_clamp(int argc, VALUE *argv, VALUE x) { VALUE min, max; int c, excl = 0;

if (rb_scan_args(argc, argv, "11", &min, &max) == 1) {
    VALUE range = min;
    if (!rb_range_values(range, &min, &max, &excl)) {
        rb_raise(rb_eTypeError, "wrong argument type %s (expected Range)",
                 rb_builtin_class_name(range));
    }
    if (!NIL_P(max)) {
        if (excl) rb_raise(rb_eArgError, "cannot clamp with an exclusive range");
    }
}
if (!NIL_P(min) && !NIL_P(max) && cmpint(min, max) > 0) {
    rb_raise(rb_eArgError, "min argument must be smaller than max argument");
}

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

}