But sub! always returns nil, even when it succeeds (in Perl, it will
return the number of substitutions made, enabling “next if
s/.$suf$//”)
Er, no it doesn’t.
irb(main):001:0> s=“aaabbb”
=> “aaabbb”
irb(main):002:0> s.sub!(/a+/,’’)
=> “bbb”
irb(main):003:0> s.sub!(/zzz/,’’)
=> nil
C:>ri String.sub!
------------------------------------------------------------ String#sub!
str.sub!(pattern, replacement) => str or nil
str.sub!(pattern) {|match| block } => str or nil