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|
module Puppet::Parser::Functions
newfunction(
:try_get_value,
:type => :rvalue,
:arity => -2,
:doc => <<-eos
Looks up into a complex structure of arrays and hashes and returns a value
or the default value if nothing was found.
Key can contain slashes to describe path components. The function will go down
the structure and try to extract the required value.
$data = {
'a' => {
'b' => [
'b1',
'b2',
'b3',
]
}
}
$value = try_get_value($data, 'a/b/2', 'not_found', '/')
=> $value = 'b3'
a -> first hash key
b -> second hash key
2 -> array index starting with 0
not_found -> (optional) will be returned if there is no value or the path did not match. Defaults to nil.
/ -> (optional) path delimiter. Defaults to '/'.
In addition to the required "key" argument, "try_get_value" accepts default
argument. It will be returned if no value was found or a path component is
missing. And the fourth argument can set a variable path separator.
eos
) do |args|
path_lookup = lambda do |data, path, default|
debug "Try_get_value: #{path.inspect} from: #{data.inspect}"
if data.nil?
debug "Try_get_value: no data, return default: #{default.inspect}"
break default
end
unless path.is_a? Array
debug "Try_get_value: wrong path, return default: #{default.inspect}"
break default
end
unless path.any?
debug "Try_get_value: value found, return data: #{data.inspect}"
break data
end
unless data.is_a? Hash or data.is_a? Array
debug "Try_get_value: incorrect data, return default: #{default.inspect}"
break default
end
key = path.shift
if data.is_a? Array
begin
key = Integer key
rescue ArgumentError
debug "Try_get_value: non-numeric path for an array, return default: #{default.inspect}"
break default
end
end
path_lookup.call data[key], path, default
end
data = args[0]
path = args[1] || ''
default = args[2]
separator = args[3] || '/'
path = path.split separator
path_lookup.call data, path, default
end
end
|
