cohen-carlisle / bihash Goto Github PK

• each_key
• each_value
• has_value?
• index
• invert
• key
• keys
• rassoc
• transform_values
• transform_values!
• value?
• values

Decide if Bihash should have merge methods.

If so, decide how to resolve collisions.

Merge methods:
#merge!
#update (alias of #merge!)
#merge

suggested changing impl to:

def fetch(key, *args, &block)
  (@forward.key?(key) ? @forward : @reverse).fetch(key, *args, &block)
end

Someday maybe improve serialization to not include redundant data.

Add logic to dup and freeze them instead of relying on the internal hashes to do it.

Current readme is unireadme

Suggested by Spike@StackExchange {

    def select!(&block)
      if block_given?
        raise_error_if_frozen
        old_size = size
        @forward.each { |k,v| delete(k) if !block.call(k,v) }
        old_size == size ? nil : self
      else
        to_enum(:select!)
      end
    end

The @forward.each line can be changed to keep_if(&block). Similarly for reject! and delete_if
}

However, this would also make redundant #block_given? and #raise_error_if_frozen checks

[:compact, :compact!]

bh = Bihash[1 => 2, 2=> 3]
bh[2] # => 3 ... but could equal 1 as well

• #<
• #<=
• #>
• #>=
• #dig
• #fetch_values
• #to_proc

found an edge case with rehash. Hash#rehash merges two pairs if their keys become equal, but not if their values become equal. Therefore the following code leaves a Bihash in an inconsistent state:

b = Bihash.new
key_a = ["a"]
key_b = ["b"]
key_c = ["c"]
b[key_a] = key_b
b[key_c] = key_c
key_a[0] = "c" # make key_a equal to key_c
b.rehash # @forward.size is now 1, but @reverse.size is still 2
puts b[["b"]].inspect # => ["c"] # found in @reverse
puts b[["c"]].inspect # => ["c"] # found in @forward

Bihash[1 => :one] == Bihash[:one => 1] should be true
Also fix #hash, #eql?