100 lines
2.6 KiB
Ruby
100 lines
2.6 KiB
Ruby
#
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# values_at.rb
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#
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module Puppet::Parser::Functions
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newfunction(:values_at, :type => :rvalue, :doc => <<-EOS
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Finds value inside an array based on location.
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The first argument is the array you want to analyze, and the second element can
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be a combination of:
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* A single numeric index
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* A range in the form of 'start-stop' (eg. 4-9)
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* An array combining the above
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*Examples*:
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values_at(['a','b','c'], 2)
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Would return ['c'].
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values_at(['a','b','c'], ["0-1"])
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Would return ['a','b'].
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values_at(['a','b','c','d','e'], [0, "2-3"])
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Would return ['a','c','d'].
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EOS
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) do |arguments|
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raise(Puppet::ParseError, "values_at(): Wrong number of " +
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"arguments given (#{arguments.size} for 2)") if arguments.size < 2
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array = arguments.shift
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unless array.is_a?(Array)
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raise(Puppet::ParseError, 'values_at(): Requires array to work with')
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end
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indices = [arguments.shift].flatten() # Get them all ... Pokemon ...
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if not indices or indices.empty?
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raise(Puppet::ParseError, 'values_at(): You must provide ' +
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'at least one positive index to collect')
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end
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result = []
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indices_list = []
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indices.each do |i|
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i = i.to_s
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if m = i.match(/^(\d+)(\.\.\.?|\-)(\d+)$/)
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start = m[1].to_i
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stop = m[3].to_i
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type = m[2]
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if start > stop
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raise(Puppet::ParseError, 'values_at(): Stop index in ' +
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'given indices range is smaller than the start index')
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elsif stop > array.size - 1 # First element is at index 0 is it not?
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raise(Puppet::ParseError, 'values_at(): Stop index in ' +
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'given indices range exceeds array size')
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end
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range = case type
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when /^(\.\.|\-)$/ then (start .. stop)
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when /^(\.\.\.)$/ then (start ... stop) # Exclusive of last element ...
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end
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range.each { |i| indices_list << i.to_i }
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else
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# Only positive numbers allowed in this case ...
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if not i.match(/^\d+$/)
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raise(Puppet::ParseError, 'values_at(): Unknown format ' +
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'of given index')
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end
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# In Puppet numbers are often string-encoded ...
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i = i.to_i
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if i > array.size - 1 # Same story. First element is at index 0 ...
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raise(Puppet::ParseError, 'values_at(): Given index ' +
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'exceeds array size')
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end
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indices_list << i
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end
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end
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# We remove nil values as they make no sense in Puppet DSL ...
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result = indices_list.collect { |i| array[i] }.compact
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return result
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end
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end
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# vim: set ts=2 sw=2 et :
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