NAME

map.rb

SYNOPSIS

the awesome ruby container you've always wanted: a string/symbol indifferent
ordered hash that works in all rubies

maps are bitchin ordered hashes that are both ordered, string/symbol
indifferent, and have all sorts of sweetness like recursive conversion, more
robust implementation than HashWithIndifferentAccess, support for struct
like (map.foo) access, and support for option/keyword access which avoids

INSTALL

gem install map

URI

http://github.com/ahoward/map

DESCRIPTION

# maps are always ordered. constructing them in an ordered fashion builds # them that way, although the normal hash contructor is also supported #

m = Map[:k, :v, :key, :val]
m = Map(:k, :v, :key, :val)
m = Map.new(:k, :v, :key, :val)

m = Map[[:k, :v], [:key, :val]]
m = Map(:k => :v, :key => :val)  # ruh-oh, the input hash loses order!
m = Map.new(:k => :v, :key => :val)  # ruh-oh, the input hash loses order!

m = Map.new
m[:a] = 0
m[:b] = 1
m[:c] = 2

p m.keys   #=> ['a','b','c']  ### always ordered!
p m.values #=> [0,1,2]        ### always ordered!

# maps don't care about symbol vs.string keys #

p m[:a]  #=> 0
p m["a"] #=> 0

# even via deep nesting #

p m[:foo]['bar'][:baz]  #=> 42

# many functions operate in a way one would expect from an ordered container #

m.update(:k2 => :v2)
m.update(:k2, :v2)

key_val_pair = m.shift
key_val_pair = m.pop

# maps keep mapiness for even deep operations #

m.update :nested => {:hashes => {:are => :converted}}

# maps can give back clever little struct objects #

m = Map(:foo => {:bar => 42})
s = m.struct
p s.foo.bar #=> 42

# because option parsing is such a common use case for needing string/symbol # indifference map.rb comes out of the box loaded with option support #

def foo(*args, &block)
  opts = Map.options(args)
  a = opts.getopt(:a)
  b = opts.getopt(:b, :default => false)
end

opts = Map.options(:a => 42, :b => nil, :c => false)
opts.getopt(:a)                    #=> 42
opts.getopt(:b)                    #=> nil
opts.getopt(:b, :default => 42)    #=> 42 
opts.getopt(:c)                    #=> false
opts.getopt(:d, :default => false) #=> false

# this avoids such bugs as #

options = {:read_only => false}
read_only = options[:read_only] || true  # should be false but is true

# with options this becomes #

options = Map.options(:read_only => true)
read_only = options.getopt(:read_only, :default => false) #=> true

# maps support some really nice operators that hashes/orderedhashes do not #

m = Map.new
m.set(:h, :a, 0, 42)
m.has?(:h, :a)         #=> true
p m                    #=> {'h' => {'a' => [42]}} 
m.set(:h, :a, 1, 42.0)
p m                    #=> {'h' => {'a' => [42, 42.0]}} 

m.get(:h, :a, 1)       #=> 42.0
m.get(:x, :y, :z)      #=> nil
m[:x][:y][:z]          #=> raises exception!

m = Map.new(:array => [0,1])
defaults = {:array => [nil, nil, 2]}
m.apply!(defaults)
p m[:array]            #=> [0,1,2]

# they also support some different iteration styles #

m = Map.new

m.set(
  [:a, :b, :c, 0] => 0,
  [:a, :b, :c, 1] => 10,
  [:a, :b, :c, 2] => 20,
  [:a, :b, :c, 3] => 30
)

m.set(:x, :y, 42)
m.set(:x, :z, 42.0)

m.depth_first_each do |key, val|
  p key => val
end

#=> [:a, :b, :c, 0] => 0
#=> [:a, :b, :c, 1] => 10
#=> [:a, :b, :c, 2] => 20
#=> [:a, :b, :c, 3] => 30
#=> [:x, :y] => 42
#=> [:x, :z] => 42.0

USAGE

see lib/map.rb and test/map_test.rb

HISTORY

4.3.0:
  - support for dot keys. map.set('a.b.c' => 42) #=> {'a'=>{'b'=>{'c'=>42}}}