Class: Eymiha::MethodicHash

Inherits:
Hash
  • Object
show all
Defined in:
lib/eymiha/util/methodic_hash.rb

Overview

The MethodicHash is some method_missing magic that uses method names as hash keys, so hash assignment and lookup appear to be attribute writing and reading. For instance, if

mh = MethodicHash.new
mh['four']  = 'iv'
mh[:seven]  = 'vii'
mh.eighteen = 'xviii'

then

mh['four']     ---> 'iv'
mh[:four]      ---> 'iv'
mh.four        ---> 'iv'
mh['seven']    ---> 'vii'
mh[:seven]     ---> 'vii'
mh.seven       ---> 'vii'
mh['eighteen'] ---> 'xviii'
mh[:eighteen]  ---> 'xviii'
mh.eighteen    ---> 'xviii'

This allows access to simply declared facts to be embedded in Ruby code and leverages the possibility of hashing procs.

Note that if the hash uses anything but strings or symbols as keys, the magic stands a good chance of failing, raising an error or acting in a bizarre manner. Note also that methods of the Hash cannot be used as ‘attribute’ names.

Instance Method Summary collapse

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args) ⇒ Object

A missing method is assummed to be the assignment of a value of a key, or the lookup of a value with a key.



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# File 'lib/eymiha/util/methodic_hash.rb', line 59

def method_missing(method,*args)
  string = method.to_s
  if string[string.length-1,1] == '='
    self[string[0,string.length-1].to_sym] = args[0]
  else
    self[method]
  end
end

Instance Method Details

#[](key) ⇒ Object

Try to look up using a key directly, or if that fails as a string, or as a symbol as last resort. If a symbol conversion doesn’t exists, rescue with a nil.



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# File 'lib/eymiha/util/methodic_hash.rb', line 36

def [](key)
  begin
    super(key) || super(key.to_s) || super(key.to_sym)
  rescue
    nil
  end
end

#delete(key, &block) ⇒ Object

Deletes and returns the key-value pairs from hash whose keys are equal to key.to_s or key.to_sym. If both key.to_s and key.to_sym are in the hash, then both values are returned in an Array, respectively. If neither key is found, the delete is deferred to the Hash.



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# File 'lib/eymiha/util/methodic_hash.rb', line 48

def delete(key,&block)
  values = [key.to_s, key.to_sym].collect {|k| super(k){ nil } }.compact
  case values.size
  when 0 then super(key,&block)
  when 1 then values[0]
  when 2 then values
  end
end