Class: Patm::Pattern::Arr

Inherits:
Patm::Pattern show all
Defined in:
lib/patm.rb

Instance Method Summary collapse

Methods inherited from Patm::Pattern

#&, #[], build_from, #compile, #opt, #opt?, #rest?

Constructor Details

#initialize(head, rest = nil, tail = []) ⇒ Arr

Returns a new instance of Arr.



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# File 'lib/patm.rb', line 187

def initialize(head, rest = nil, tail = [])
  @head = head
  @rest = rest
  @tail = tail
end

Instance Method Details

#compile_internal(free_index, target_name = "_obj") ⇒ Object 



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# File 'lib/patm.rb', line 214

def compile_internal(free_index, target_name = "_obj")
  i = free_index
  srcs = []
  ctxs = []

  srcs << "#{target_name}.is_a?(::Array)"

  size_min = @head.size + @tail.size
  if @rest
    srcs << "#{target_name}.size >= #{size_min}"
  else
    srcs << "#{target_name}.size == #{size_min}"
  end

  elm_target_name = "#{target_name}_elm"
  @head.each_with_index do|h, hi|
    s, c, i = h.compile_internal(i, elm_target_name)
    srcs << "(#{elm_target_name} = #{target_name}[#{hi}]; #{s})" if s
    ctxs << c
  end

  unless @tail.empty?
    srcs << "(#{target_name}_t = #{target_name}[(-#{@tail.size})..-1]; true)"
    @tail.each_with_index do|t, ti|
      s, c, i = t.compile_internal(i, elm_target_name)
      srcs << "(#{elm_target_name} = #{target_name}_t[#{ti}]; #{s})" if s
      ctxs << c
    end
  end

  if @rest
    tname = "#{target_name}_r"
    s, c, i = @rest.compile_internal(i, tname)
    srcs << "(#{tname} = #{target_name}[#{@head.size}..-(#{@tail.size+1})];#{s})" if s
    ctxs << c
  end

  [
    srcs.compact.map{|s| "(#{s})"}.join(" &&\n"),
    ctxs.flatten(1),
    i
  ]
end

#execute(mmatch, obj) ⇒ Object 



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# File 'lib/patm.rb', line 193

def execute(mmatch, obj)
  size_min = @head.size + @tail.size
  return false unless obj.is_a?(Array)
  return false unless @rest ? (obj.size >= size_min) :  (obj.size == size_min)
  @head.zip(obj[0..(@head.size - 1)]).all? {|pat, o|
    pat.execute(mmatch, o)
  } &&
  @tail.zip(obj[(-@tail.size)..-1]).all? {|pat, o|
    pat.execute(mmatch, o)
  } &&
  (!@rest || @rest.execute(mmatch, obj[@head.size..-(@tail.size+1)]))
end

#inspect ⇒ Object 



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# File 'lib/patm.rb', line 206

def inspect
  if @rest
    (@head + [@rest] + @tail).inspect
  else
    (@head + @tail).inspect
  end
end