Class: Fabulator::Grammar::Cursor

Inherits:
Object
  • Object
show all
Defined in:
lib/fabulator/grammar/cursor.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(g, ctx, s) ⇒ Cursor

Returns a new instance of Cursor.



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# File 'lib/fabulator/grammar/cursor.rb', line 6

def initialize(g,ctx,s)
  @source = s
  @grammar = g
  @start = 0
  @curpos = 0
  @end = @source.length-1
  @line = 0
  @col = 0
  @anchored = false
  @mode = :default
  @skip = nil
  @context = ctx.with_root(ctx.root.anon_node(nil))
  @context.root.roots['result'] = @context.root
  @context.root.axis = 'result'
end

Instance Attribute Details

#mode ⇒ Object

Returns the value of attribute mode.



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# File 'lib/fabulator/grammar/cursor.rb', line 4

def mode
  @mode
end

#skip ⇒ Object

Returns the value of attribute skip.



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# File 'lib/fabulator/grammar/cursor.rb', line 4

def skip
  @skip
end

#start ⇒ Object

Returns the value of attribute start.



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# File 'lib/fabulator/grammar/cursor.rb', line 4

def start
  @start
end

Instance Method Details

#advance_position(i) ⇒ Object 



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# File 'lib/fabulator/grammar/cursor.rb', line 40

def advance_position(i)
  @curpos += i if i > 0
end

#anchored ⇒ Object 



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# File 'lib/fabulator/grammar/cursor.rb', line 44

def anchored
  @anchored
end

#anchored=(t) ⇒ Object 



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# File 'lib/fabulator/grammar/cursor.rb', line 48

def anchored=(t)
  @anchored = t
end

#attempt(&block) ⇒ Object 



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# File 'lib/fabulator/grammar/cursor.rb', line 74

def attempt(&block)
  saved = self.point
  begin
    yield self
  rescue Fabulator::Grammar::RejectParse
    self.point = saved
    return nil
  end

  ret = @context.root.roots['result']
  @context.root = saved[:root]
  @context.root.roots['result'] = saved[:result]
  return ret
end

#context ⇒ Object 



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# File 'lib/fabulator/grammar/cursor.rb', line 22

def context
  @context
end

#data ⇒ Object 



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# File 'lib/fabulator/grammar/cursor.rb', line 136

def data
  @context
end

#do_skip ⇒ Object 



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# File 'lib/fabulator/grammar/cursor.rb', line 140

def do_skip
  if !@skip.nil?
    my_skip = @skip
    new_pos = @curpos
    self.attempt do |cursor|
      cursor.skip = nil
      cursor.anchored
      r = my_skip.parse(cursor)
      while !r.nil?
        r = my_skip.parse(cursor)
      end
      new_pos = cursor.pos
    end
    @curpos = new_pos
  end
end

#eof? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/fabulator/grammar/cursor.rb', line 36

def eof?
  @curpos > @end
end

#find_rule(nom) ⇒ Object 



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# File 'lib/fabulator/grammar/cursor.rb', line 128

def find_rule(nom)
  r = @grammar.get_rule(@mode, nom)
  if r.nil? && @mode.to_s != 'default'
    r = @grammar.get_rule('default', nom)
  end
  r
end

#grammar ⇒ Object 



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# File 'lib/fabulator/grammar/cursor.rb', line 52

def grammar
  @grammar
end

#match_token(regex) ⇒ Object 



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# File 'lib/fabulator/grammar/cursor.rb', line 157

def match_token(regex)
  do_skip
  if @source[@curpos .. @end] =~ %r{^(#{regex})}
    @context.root.value = $1.to_s
    @curpos += @context.root.value.length
  else
    raise Fabulator::Grammar::RejectParse
  end
end

#name_result(nom = nil) ⇒ Object 



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# File 'lib/fabulator/grammar/cursor.rb', line 100

def name_result(nom = nil)
  return if nom.nil?
  return if @context.root.value.nil? && @context.root.children.empty?
  if @context.root.value.nil?
    @context.root.name = nom
  else
    if @context.root.name.nil?
      @context.root.name = nom
    else
      n = @context.root.anon_node(nil)
      n.name = nom
      n.add_child(@context.root)
      @context.root = n
      @context.root.roots['result'] = @context.root
    end
  end
end

#point ⇒ Object 



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# File 'lib/fabulator/grammar/cursor.rb', line 56

def point
  r = { :curpos => @curpos, :line => @line, :col => @col, :root => @context.root, :mode => @mode, :anchored => @anchored, :skip => @skip, :result => @context.root.roots['result'] }
  @context.root.roots['result'] = r[:result].anon_node(nil)
  @context.root = @context.root.roots['result']
  r
end

#point=(p) ⇒ Object 



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# File 'lib/fabulator/grammar/cursor.rb', line 63

def point=(p)
  @curpos = p[:curpos]
  @line = p[:line]
  @col = p[:col]
  @mode = p[:mode]
  @anchored = p[:anchored]
  @skip = p[:skip]
  @context.root = p[:root]
  @context.root.roots['result'] = p[:result]
end

#pos ⇒ Object 



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# File 'lib/fabulator/grammar/cursor.rb', line 26

def pos
  @curpos
end

#rename_result(nom = nil) ⇒ Object 



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# File 'lib/fabulator/grammar/cursor.rb', line 118

def rename_result(nom = nil)
  return if nom.nil?
  return if @context.root.value.nil? && @context.root.children.empty?
#        if @context.root.children.select{ |c| !c.name.nil? }.empty?
#          @context.root.children.each { |c| c.name = nom }
#        else
    @context.root.name = nom
#        end
end

#resync(pat) ⇒ Object 



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# File 'lib/fabulator/grammar/cursor.rb', line 30

def resync(pat)
  until self.eof || @source[@curpos..@source.length-1] =~ %r{^#{pat}}
    @curpos += 1
  end
end

#set_result(r) ⇒ Object 



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# File 'lib/fabulator/grammar/cursor.rb', line 89

def set_result(r)
  r = [ r ] unless r.is_a?(Array)
  if r.size > 1
    @context.root = @context.root.anon_node(nil)
    r.each { |rr| @context.root.add_child(rr) }
  elsif !r.empty?
    @context.root = r.first
  end
  @context.root.roots['result'] = @context.root
end