Class: JsonPath::Expression

Inherits:
Object
  • Object
show all
Defined in:
lib/jsonpath/expression.rb

Instance Method Summary collapse

Constructor Details

#initialize(expression, object = nil) ⇒ Expression

Returns a new instance of Expression.



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# File 'lib/jsonpath/expression.rb', line 5

def initialize(expression, object = nil)
  scanner = StringScanner.new(expression)
  @path = []
  bracket_count = 0
  while not scanner.eos?
    token = scanner.scan_until(/($|\$|@|[a-zA-Z]+|\[.*?\]|\.\.|\.(?!\.))/)
    case token
    when '.'
      # do nothing
    when /^[a-zA-Z]+$/
      @path << "['#{token}']"
    else
      bracket_count == 0 && @path << token or @path[-1] += token
      bracket_count += token.count('[') - token.count(']')
    end
  end
  @object = object
end

Instance Method Details

#each(node = @object, pos = 0, options = {}, &blk) ⇒ Object 



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# File 'lib/jsonpath/expression.rb', line 41

def each(node = @object, pos = 0, options = {}, &blk)
  if pos == @path.size
    return blk.call(node)
  else
    case expr = @path[pos]
    when '*', '..'
      each(node, pos + 1, &blk) 
    when '$'
      each(node, pos + 1, &blk) if node == @object
    when '@'
      each(node, pos + 1, &blk)
    when /^\[(.*)\]$/
      expr[1,expr.size - 2].split(',').each do |sub_path|
        case sub_path[0]
        when ?', ?"
          if node.is_a?(Hash)
            key = sub_path[1,sub_path.size - 2]
            each(node[key], pos + 1, &blk) if node.key?(key) 
          end
        when ??
          (node.is_a?(Hash) ? node.keys : (0..node.size)).each do |e|
            ::JsonPath.path(sub_path[2,sub_path.size - 3]) do |jp|
              @obj = node[e]
              begin
                each(node[e], pos + 1, &blk) if jp.test?(node[e])
              rescue
                # ignore ..
              end
            end
          end
        else
          if node.is_a?(Array)
            @obj = node
            array_args = sub_path.gsub('@','@obj').split(':')
            start_idx = (array_args[0] && eval(array_args[0]) || 0) % node.size
            end_idx = (array_args[1] && eval(array_args[1]) || (sub_path.count(':') == 0 ? start_idx : -1)) % node.size
            step = array_args[2] && eval(array_args[2]) || 1
            (start_idx..end_idx).step(step) {|i| each(node[i], pos + 1, &blk)}
          end
        end
      end
    else
      blk.call(node) if pos == (@path.size - 1) && eval("node #{@path[pos]}")
    end
    
    if pos > 0 && @path[pos-1] == '..'
      case node
      when Hash
        node.values.each {|n| each(n, pos, &blk) }
      when Array
        node.each {|n| each(n, pos, &blk) }
      end
    end
  end
end

#map(node = @object) ⇒ Object 



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# File 'lib/jsonpath/expression.rb', line 35

def map(node = @object)
  store = []
  each(node) {|o| store << (yield o)}
  store
end

#test?(node = @object) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/jsonpath/expression.rb', line 24

def test?(node = @object)
  each(node) {|n| return true}
  false
end

#to_a(node = @object) ⇒ Object 



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# File 'lib/jsonpath/expression.rb', line 29

def to_a(node = @object)
  store = []
  each(node) {|o| store << o}
  store
end