[WIP] Implement pattern matching using Qo

[bolshakov]

See https://github.com/baweaver/qo

Some(42).match do |m|
  m.some { |x| x * 2 }
  m.none { 'none' }
end #=> 84

you can pass a conditions to #some method

Some(41).match do |m|
  m.some(:even?) { |x| x / 2 }
  m.some(:odd?, ->(v) { v > 0 }) { |x| x * 2 }
  m.none { 'none' }
end #=> 82

it raises Fear::MatchError if pattern match is not exhaustive

Some(42).match do |m|
  m.some(:odd?) { |x| x * 2 }
  m.none { 'none' }
end #=> raises Fear::MatchError

to avoid exception, you can pass #else branch

Some(42).match do |m|
  m.some(:odd?) { |x| x * 2 }
  m.else { 'nothing' }
end #=> nothing

Waiting the following PR to be released:

• Ensure precondition run before extractor baweaver/qo#24
• Document Qo::PatternMatchers::PatternMatch#default as private API baweaver/qo#25

[bolshakov]

Decided to implement in other way #28