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class SymbolTable < Hash
def initialize(hash=nil)
super()
merge!(hash) unless hash.nil?
end
# Returns +true+ if the given key may be used in this table.
def valid_key?(key)
key.respond_to?(:to_sym)
end
# Returns +true+ if this table contains the given +key+.
def key?(key)
valid_key?(key) && super(key.to_sym)
end
# Retrieves the value of the given +key+.
def [](key)
super(key.to_sym) if valid_key?(key)
end
# Sets the value of the given +key+ to +val+.
def store(key, val)
if valid_key?(key)
val = self.class.new(val) if Hash === val && !(SymbolTable === val)
super(key.to_sym, val)
end
end
alias []= store
# Merges the values from +other_hash+ into this table.
def merge!(other_hash)
raise ArgumentError unless Hash === other_hash
other_hash.each do |k, v|
if block_given? && key?(k)
self[k] = yield(k, self[k], v)
else
self[k] = v
end
end
end
alias update merge!
# Allows values to be retrieved and set using Ruby's dot method syntax.
def method_missing(sym, *args)
if sym.to_s =~ /(.+)=$/
self[$1] = args[0]
elsif args.empty?
self[sym]
else
super(sym, *args)
end
end
# Returns a Hash
def to_hash
Hash[self]
end
end
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