From: aycabta@... Date: 2017-12-01T00:31:13+00:00 Subject: [ruby-core:84017] [Ruby trunk Feature#12753] Useful operator to check bit-flag is true or false Issue #12753 has been updated by aycabta (Code Ahss). phluid61 (Matthew Kerwin) wrote: > It introduces a strange paradox, though: > > ~~~ruby > a.allbits? 0 #��� true > a.nobits? 0 #��� true > ~~~ I discussed it with @watson1978 (Shizuo Fujita). We guess the behavior is not strange. The allbits? means "The receiver checks that all standing bits of the argument don't sit on itself". ~~~ruby a.allbits? 0 #��� true ~~~ In this case, "all standing bits of the argument don't sit on the receiver " because "all standing bits of argument" is nothing. So it returns true. I think this is correct. If I have to choose a word, it's reasonable specification. ~~~ruby a.nobits? 0 #��� true ~~~ I think this is correct in the same way. ---------------------------------------- Feature #12753: Useful operator to check bit-flag is true or false https://bugs.ruby-lang.org/issues/12753#change-68098 * Author: tagomoris (Satoshi TAGOMORI) * Status: Open * Priority: Normal * Assignee: * Target version: ---------------------------------------- Ruby's 0 is truthy value. It's useful for many cases, but it's confusing and I made many bugs when I'm writing code to handle binary data, because my thought is almost same with one to write C code in such situation. ```ruby n = get_integer_value if n & 0b10100000 # code for the case when flag is true else # never comes here :( end ``` IMO it's very useful to have methods for such use-cases, like `#and?` and `#xor?` (`#or?` looks not so useful... I can't imagine the use case of this operator, but it's better to have for consistency). ```ruby n = get_integer_value case when n.and?(0b10000000) # negative signed char when n.and?(0b01110000) # large positive else # small positive end ``` -- https://bugs.ruby-lang.org/ Unsubscribe: