2 # Merges two or more hashes together or hashes resulting from iteration, and returns
5 # @example Using merge()
6 # $hash1 = {'one' => 1, 'two', => 2}
7 # $hash2 = {'two' => 'dos', 'three', => 'tres'}
8 # $merged_hash = merge($hash1, $hash2) # $merged_hash = {'one' => 1, 'two' => 'dos', 'three' => 'tres'}
10 # When there is a duplicate key, the key in the rightmost hash will "win."
12 # Note that since Puppet 4.0.0 the same merge can be achieved with the + operator.
13 # `$merged_hash = $hash1 + $hash2`
15 # If merge is given a single Iterable (Array, Hash, etc.) it will call a given block with
16 # up to three parameters, and merge each resulting Hash into the accumulated result. All other types
17 # of values returned from the block (typically undef) are skipped (not merged).
19 # The codeblock can take 2 or three parameters:
20 # * with two, it gets the current hash (as built to this point), and each value (for hash the value is a [key, value] tuple)
21 # * with three, it gets the current hash (as built to this point), the key/index of each value, and then the value
23 # If the iterable is empty, or no hash was returned from the given block, an empty hash is returned. In the given block, a call to `next()`
24 # will skip that entry, and a call to `break()` will end the iteration.
26 # @example counting occurrences of strings in an array
27 # ['a', 'b', 'c', 'c', 'd', 'b'].merge | $hsh, $v | { { $v => $hsh[$v].lest || { 0 } + 1 } } # results in { a => 1, b => 2, c => 2, d => 1 }
29 # @example skipping values for entries that are longer than 1 char
30 # ['a', 'b', 'c', 'c', 'd', 'b', 'blah', 'blah'].merge | $hsh, $v | { if $v =~ String[1,1] { { $v => $hsh[$v].lest || { 0 } + 1 } } } # results in { a => 1, b => 2, c => 2, d => 1 }
32 # The iterative `merge()` has an advantage over doing the same with a general `reduce()` in that the constructed hash
33 # does not have to be copied in each iteration and thus will perform much better with large inputs.
34 Puppet::Functions.create_function(:merge) do
36 # Repeated Param - The hashes that are to be merged
40 dispatch :merge2hashes do
41 repeated_param 'Variant[Hash, Undef, String[0,0]]', :args # this strange type is backwards compatible
46 # Repeated Param - The hashes that are to be merged
49 # A block placed on the repeatable param `args`
53 dispatch :merge_iterable3 do
54 repeated_param 'Iterable', :args
55 block_param 'Callable[3,3]', :block
60 # Repeated Param - The hashes that are to be merged
63 # A block placed on the repeatable param `args`
67 dispatch :merge_iterable2 do
68 repeated_param 'Iterable', :args
69 block_param 'Callable[2,2]', :block
73 def merge2hashes(*hashes)
75 hashes.each { |h| accumulator.merge!(h) if h.is_a?(Hash) }
79 def merge_iterable2(iterable)
81 enum = Puppet::Pops::Types::Iterable.asserted_iterable(self, iterable)
83 r = yield(accumulator, v)
84 accumulator.merge!(r) if r.is_a?(Hash)
89 def merge_iterable3(iterable)
91 enum = Puppet::Pops::Types::Iterable.asserted_iterable(self, iterable)
94 r = yield(accumulator, *entry)
95 accumulator.merge!(r) if r.is_a?(Hash)
101 r = yield(accumulator, index, enum.next)
102 accumulator.merge!(r) if r.is_a?(Hash)
105 rescue StopIteration # rubocop:disable Lint/HandleExceptions