diff options
| author | Tanaka Akira <[email protected]> | 2023-10-13 00:00:58 +0900 |
|---|---|---|
| committer | Tanaka Akira <[email protected]> | 2023-10-13 00:00:58 +0900 |
| commit | c23b25f75f6180b7428f9650e063b1e50fc161e2 (patch) | |
| tree | f4983a22426410499e2e3ef2be4bfe162a6ee098 /range.c | |
| parent | b2e1ddffa55463f1180af7f9b269a2d89140b131 (diff) | |
describe the assumption for Range#overlap?.
Range#overlap? assumes that there is no minimum value.
This assumption makes
+(...-Float::INFINITY).overlap?((...-Float::INFINITY))+ returns true
while +(...-Float::INFINITY)+ is empty.
Diffstat (limited to 'range.c')
| -rw-r--r-- | range.c | 13 |
1 files changed, 13 insertions, 0 deletions
@@ -2386,6 +2386,19 @@ empty_region_p(VALUE beg, VALUE end, int excl) * (1..2).overlap?(3..4) # => false * (1...3).overlap?(3..4) # => false * + * This method assumes that there is no minimum value because + * Ruby lacks a standard method for determining minimum values. + * This assumption is invalid. + * For example, there is no value smaller than +-Float::INFINITY+, + * making +(...-Float::INFINITY)+ an empty set. + * Consequently, +(...-Float::INFINITY)+ has no elements in common with itself, + * yet +(...-Float::INFINITY).overlap?((...-Float::INFINITY))+ returns + * true due to this assumption. + * In general, if +r = (...minimum); r.overlap?(r)+ returns +true+, + * where +minimum+ is a value that no value is smaller than. + * Such values include +-Float::INFINITY+, +[]+, +""+, and + * classes without subclasses. + * * Related: Range#cover?. */ |