Class: Poetics::Parser

Inherits:
Object
  • Object
show all
Includes:
Syntax
Defined in:
lib/poetics/parser/parser.rb,
lib/poetics/parser.rb

Defined Under Namespace

Classes: LeftRecursive, MemoEntry, ParseError, RuleInfo

Constant Summary collapse

Rules = 
{}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Syntax

#false_value, #hexadecimal, #null_value, #number, #string_value, #true_value, #undefined_value

Constructor Details

#initialize(str, debug = false) ⇒ Parser

This is distinct from setup_parser so that a standalone parser can redefine #initialize and still have access to the proper parser setup code.



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# File 'lib/poetics/parser/parser.rb', line 18

def initialize(str, debug=false)
  setup_parser(str, debug)
end

Instance Attribute Details

#column ⇒ Object (readonly)

Returns the value of attribute column.



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# File 'lib/poetics/parser.rb', line 15

def column
  @column
end

#failed_rule ⇒ Object (readonly)

Returns the value of attribute failed_rule.



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# File 'lib/poetics/parser/parser.rb', line 144

def failed_rule
  @failed_rule
end

#failing_rule_offset ⇒ Object (readonly)

Returns the value of attribute failing_rule_offset.



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# File 'lib/poetics/parser/parser.rb', line 23

def failing_rule_offset
  @failing_rule_offset
end

#line ⇒ Object (readonly)

Returns the value of attribute line.



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# File 'lib/poetics/parser.rb', line 15

def line
  @line
end

#pos ⇒ Object

Returns the value of attribute pos.



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# File 'lib/poetics/parser/parser.rb', line 24

def pos
  @pos
end

#result ⇒ Object (readonly)

Returns the value of attribute result.



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# File 'lib/poetics/parser/parser.rb', line 23

def result
  @result
end

#string ⇒ Object (readonly)

Returns the value of attribute string.



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# File 'lib/poetics/parser/parser.rb', line 22

def string
  @string
end

Class Method Details

.parse_to_sexp(string) ⇒ Object 



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# File 'lib/poetics/parser.rb', line 6

def self.parse_to_sexp(string)
  parser = new string
  unless parser.parse
    parser.raise_error
  end

  parser.result.to_sexp
end

.rule_info(name, rendered) ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 310

def self.rule_info(name, rendered)
  RuleInfo.new(name, rendered)
end

Instance Method Details

#__hyphen_ ⇒ Object

  • (“ ” | “t” | “n”)*



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# File 'lib/poetics/parser/parser.rb', line 364

def __hyphen_
  while true

    _save1 = self.pos
    while true # choice
      _tmp = match_string(" ")
      break if _tmp
      self.pos = _save1
      _tmp = match_string("\t")
      break if _tmp
      self.pos = _save1
      _tmp = match_string("\n")
      break if _tmp
      self.pos = _save1
      break
    end # end choice

    break unless _tmp
  end
  _tmp = true
  set_failed_rule :__hyphen_ unless _tmp
  return _tmp
end

#_boolean ⇒ Object

boolean = position (true | false | null | undefined)



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# File 'lib/poetics/parser/parser.rb', line 410

def _boolean

  _save = self.pos
  while true # sequence
    _tmp = apply(:_position)
    unless _tmp
      self.pos = _save
      break
    end

    _save1 = self.pos
    while true # choice
      _tmp = apply(:_true)
      break if _tmp
      self.pos = _save1
      _tmp = apply(:_false)
      break if _tmp
      self.pos = _save1
      _tmp = apply(:_null)
      break if _tmp
      self.pos = _save1
      _tmp = apply(:_undefined)
      break if _tmp
      self.pos = _save1
      break
    end # end choice

    unless _tmp
      self.pos = _save
    end
    break
  end # end sequence

  set_failed_rule :_boolean unless _tmp
  return _tmp
end

#_column ⇒ Object

column = { current_column }



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# File 'lib/poetics/parser/parser.rb', line 819

def _column
  @result = begin;  current_column ; end
  _tmp = true
  set_failed_rule :_column unless _tmp
  return _tmp
end

#_digits ⇒ Object

digits = (“0” | /[1-9]/ /[0-9]/*)



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# File 'lib/poetics/parser/parser.rb', line 619

def _digits

  _save = self.pos
  while true # choice
    _tmp = match_string("0")
    break if _tmp
    self.pos = _save

    _save1 = self.pos
    while true # sequence
      _tmp = scan(/\A(?-mix:[1-9])/)
      unless _tmp
        self.pos = _save1
        break
      end
      while true
        _tmp = scan(/\A(?-mix:[0-9])/)
        break unless _tmp
      end
      _tmp = true
      unless _tmp
        self.pos = _save1
      end
      break
    end # end sequence

    break if _tmp
    self.pos = _save
    break
  end # end choice

  set_failed_rule :_digits unless _tmp
  return _tmp
end

#_end ⇒ Object

end = !.



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# File 'lib/poetics/parser/parser.rb', line 354

def _end
  _save = self.pos
  _tmp = get_byte
  _tmp = _tmp ? nil : true
  self.pos = _save
  set_failed_rule :_end unless _tmp
  return _tmp
end

#_false ⇒ Object

false = “false” Syntax#false_value



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# File 'lib/poetics/parser/parser.rb', line 470

def _false

  _save = self.pos
  while true # sequence
    _tmp = match_string("false")
    unless _tmp
      self.pos = _save
      break
    end
    @result = begin; false_value; end
    _tmp = true
    unless _tmp
      self.pos = _save
    end
    break
  end # end sequence

  set_failed_rule :_false unless _tmp
  return _tmp
end

#_hex ⇒ Object

hex = “0x” < hexdigits+ > hexadecimal(text)



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# File 'lib/poetics/parser/parser.rb', line 578

def _hex

  _save = self.pos
  while true # sequence
    _tmp = match_string("0x")
    unless _tmp
      self.pos = _save
      break
    end
    _text_start = self.pos
    _save1 = self.pos
    _tmp = apply(:_hexdigits)
    if _tmp
      while true
        _tmp = apply(:_hexdigits)
        break unless _tmp
      end
      _tmp = true
    else
      self.pos = _save1
    end
    if _tmp
      text = get_text(_text_start)
    end
    unless _tmp
      self.pos = _save
      break
    end
    @result = begin; hexadecimal(text); end
    _tmp = true
    unless _tmp
      self.pos = _save
    end
    break
  end # end sequence

  set_failed_rule :_hex unless _tmp
  return _tmp
end

#_hexdigits ⇒ Object

hexdigits = /[0-9A-Fa-f]/



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# File 'lib/poetics/parser/parser.rb', line 571

def _hexdigits
  _tmp = scan(/\A(?-mix:[0-9A-Fa-f])/)
  set_failed_rule :_hexdigits unless _tmp
  return _tmp
end

#_int ⇒ Object

int = < digits > number(text)



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# File 'lib/poetics/parser/parser.rb', line 655

def _int

  _save = self.pos
  while true # sequence
    _text_start = self.pos
    _tmp = apply(:_digits)
    if _tmp
      text = get_text(_text_start)
    end
    unless _tmp
      self.pos = _save
      break
    end
    @result = begin; number(text); end
    _tmp = true
    unless _tmp
      self.pos = _save
    end
    break
  end # end sequence

  set_failed_rule :_int unless _tmp
  return _tmp
end

#_line ⇒ Object

line = { current_line }



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# File 'lib/poetics/parser/parser.rb', line 811

def _line
  @result = begin;  current_line ; end
  _tmp = true
  set_failed_rule :_line unless _tmp
  return _tmp
end

#_null ⇒ Object

null = “null” Syntax#null_value



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# File 'lib/poetics/parser/parser.rb', line 492

def _null

  _save = self.pos
  while true # sequence
    _tmp = match_string("null")
    unless _tmp
      self.pos = _save
      break
    end
    @result = begin; null_value; end
    _tmp = true
    unless _tmp
      self.pos = _save
    end
    break
  end # end sequence

  set_failed_rule :_null unless _tmp
  return _tmp
end

#_number ⇒ Object

number = position (real | hex | int)



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# File 'lib/poetics/parser/parser.rb', line 536

def _number

  _save = self.pos
  while true # sequence
    _tmp = apply(:_position)
    unless _tmp
      self.pos = _save
      break
    end

    _save1 = self.pos
    while true # choice
      _tmp = apply(:_real)
      break if _tmp
      self.pos = _save1
      _tmp = apply(:_hex)
      break if _tmp
      self.pos = _save1
      _tmp = apply(:_int)
      break if _tmp
      self.pos = _save1
      break
    end # end choice

    unless _tmp
      self.pos = _save
    end
    break
  end # end sequence

  set_failed_rule :_number unless _tmp
  return _tmp
end

#_position ⇒ Object

position = line:l column:c { position(l, c) }



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# File 'lib/poetics/parser/parser.rb', line 827

def _position

  _save = self.pos
  while true # sequence
    _tmp = apply(:_line)
    l = @result
    unless _tmp
      self.pos = _save
      break
    end
    _tmp = apply(:_column)
    c = @result
    unless _tmp
      self.pos = _save
      break
    end
    @result = begin;  position(l, c) ; end
    _tmp = true
    unless _tmp
      self.pos = _save
    end
    break
  end # end sequence

  set_failed_rule :_position unless _tmp
  return _tmp
end

#_real ⇒ Object

real = < digits “.” digits (“e” /[-+]/? /[0-9]/+)? > number(text)



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# File 'lib/poetics/parser/parser.rb', line 681

def _real

  _save = self.pos
  while true # sequence
    _text_start = self.pos

    _save1 = self.pos
    while true # sequence
      _tmp = apply(:_digits)
      unless _tmp
        self.pos = _save1
        break
      end
      _tmp = match_string(".")
      unless _tmp
        self.pos = _save1
        break
      end
      _tmp = apply(:_digits)
      unless _tmp
        self.pos = _save1
        break
      end
      _save2 = self.pos

      _save3 = self.pos
      while true # sequence
        _tmp = match_string("e")
        unless _tmp
          self.pos = _save3
          break
        end
        _save4 = self.pos
        _tmp = scan(/\A(?-mix:[-+])/)
        unless _tmp
          _tmp = true
          self.pos = _save4
        end
        unless _tmp
          self.pos = _save3
          break
        end
        _save5 = self.pos
        _tmp = scan(/\A(?-mix:[0-9])/)
        if _tmp
          while true
            _tmp = scan(/\A(?-mix:[0-9])/)
            break unless _tmp
          end
          _tmp = true
        else
          self.pos = _save5
        end
        unless _tmp
          self.pos = _save3
        end
        break
      end # end sequence

      unless _tmp
        _tmp = true
        self.pos = _save2
      end
      unless _tmp
        self.pos = _save1
      end
      break
    end # end sequence

    if _tmp
      text = get_text(_text_start)
    end
    unless _tmp
      self.pos = _save
      break
    end
    @result = begin; number(text); end
    _tmp = true
    unless _tmp
      self.pos = _save
    end
    break
  end # end sequence

  set_failed_rule :_real unless _tmp
  return _tmp
end

#_root ⇒ Object

root = - value? - end



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# File 'lib/poetics/parser/parser.rb', line 318

def _root

  _save = self.pos
  while true # sequence
    _tmp = apply(:__hyphen_)
    unless _tmp
      self.pos = _save
      break
    end
    _save1 = self.pos
    _tmp = apply(:_value)
    unless _tmp
      _tmp = true
      self.pos = _save1
    end
    unless _tmp
      self.pos = _save
      break
    end
    _tmp = apply(:__hyphen_)
    unless _tmp
      self.pos = _save
      break
    end
    _tmp = apply(:_end)
    unless _tmp
      self.pos = _save
    end
    break
  end # end sequence

  set_failed_rule :_root unless _tmp
  return _tmp
end

#_string ⇒ Object

string = position “"” < /[^\“]*/ > ”"“ string_value(text)



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# File 'lib/poetics/parser/parser.rb', line 770

def _string

  _save = self.pos
  while true # sequence
    _tmp = apply(:_position)
    unless _tmp
      self.pos = _save
      break
    end
    _tmp = match_string("\"")
    unless _tmp
      self.pos = _save
      break
    end
    _text_start = self.pos
    _tmp = scan(/\A(?-mix:[^\\"]*)/)
    if _tmp
      text = get_text(_text_start)
    end
    unless _tmp
      self.pos = _save
      break
    end
    _tmp = match_string("\"")
    unless _tmp
      self.pos = _save
      break
    end
    @result = begin; string_value(text); end
    _tmp = true
    unless _tmp
      self.pos = _save
    end
    break
  end # end sequence

  set_failed_rule :_string unless _tmp
  return _tmp
end

#_true ⇒ Object

true = “true” Syntax#true_value



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# File 'lib/poetics/parser/parser.rb', line 448

def _true

  _save = self.pos
  while true # sequence
    _tmp = match_string("true")
    unless _tmp
      self.pos = _save
      break
    end
    @result = begin; true_value; end
    _tmp = true
    unless _tmp
      self.pos = _save
    end
    break
  end # end sequence

  set_failed_rule :_true unless _tmp
  return _tmp
end

#_undefined ⇒ Object

undefined = “undefined” Syntax#undefined_value



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# File 'lib/poetics/parser/parser.rb', line 514

def _undefined

  _save = self.pos
  while true # sequence
    _tmp = match_string("undefined")
    unless _tmp
      self.pos = _save
      break
    end
    @result = begin; undefined_value; end
    _tmp = true
    unless _tmp
      self.pos = _save
    end
    break
  end # end sequence

  set_failed_rule :_undefined unless _tmp
  return _tmp
end

#_value ⇒ Object

value = (string | number | boolean)



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# File 'lib/poetics/parser/parser.rb', line 389

def _value

  _save = self.pos
  while true # choice
    _tmp = apply(:_string)
    break if _tmp
    self.pos = _save
    _tmp = apply(:_number)
    break if _tmp
    self.pos = _save
    _tmp = apply(:_boolean)
    break if _tmp
    self.pos = _save
    break
  end # end choice

  set_failed_rule :_value unless _tmp
  return _tmp
end

#apply(rule) ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 247

def apply(rule)
  if m = @memoizations[rule][@pos]
    m.inc!

    prev = @pos
    @pos = m.pos
    if m.ans.kind_of? LeftRecursive
      m.ans.detected = true
      return nil
    end

    @result = m.result

    return m.ans
  else
    lr = LeftRecursive.new(false)
    m = MemoEntry.new(lr, @pos)
    @memoizations[rule][@pos] = m
    start_pos = @pos

    ans = __send__ rule

    m.move! ans, @pos, @result

    # Don't bother trying to grow the left recursion
    # if it's failing straight away (thus there is no seed)
    if ans and lr.detected
      return grow_lr(rule, start_pos, m)
    else
      return ans
    end

    return ans
  end
end

#current_column(target = pos) ⇒ Object

STANDALONE START



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# File 'lib/poetics/parser/parser.rb', line 27

def current_column(target=pos)
  if c = string.rindex("\n", target-1)
    return target - c - 1
  end

  target + 1
end

#current_line(target = pos) ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 35

def current_line(target=pos)
  cur_offset = 0
  cur_line = 0

  string.each_line do |line|
    cur_line += 1
    cur_offset += line.size
    return cur_line if cur_offset >= target
  end

  -1
end

#external_invoke(other, rule, *args) ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 227

def external_invoke(other, rule, *args)
  old_pos = @pos
  old_string = @string

  @pos = other.pos
  @string = other.string

  begin
    if val = __send__(rule, *args)
      other.pos = @pos
    else
      other.set_failed_rule "#{self.class}##{rule}"
    end
    val
  ensure
    @pos = old_pos
    @string = old_string
  end
end

#failure_caret ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 81

def failure_caret
  l = current_line @failing_rule_offset
  c = current_column @failing_rule_offset

  line = lines[l-1]
  "#{line}\n#{' ' * (c - 1)}^"
end

#failure_character ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 89

def failure_character
  l = current_line @failing_rule_offset
  c = current_column @failing_rule_offset
  lines[l-1][c-1, 1]
end

#failure_info ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 69

def failure_info
  l = current_line @failing_rule_offset
  c = current_column @failing_rule_offset

  if @failed_rule.kind_of? Symbol
    info = self.class::Rules[@failed_rule]
    "line #{l}, column #{c}: failed rule '#{info.name}' = '#{info.rendered}'"
  else
    "line #{l}, column #{c}: failed rule '#{@failed_rule}'"
  end
end

#failure_oneline ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 95

def failure_oneline
  l = current_line @failing_rule_offset
  c = current_column @failing_rule_offset

  char = lines[l-1][c-1, 1]

  if @failed_rule.kind_of? Symbol
    info = self.class::Rules[@failed_rule]
    "@#{l}:#{c} failed rule '#{info.name}', got '#{char}'"
  else
    "@#{l}:#{c} failed rule '#{@failed_rule}', got '#{char}'"
  end
end

#get_byte ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 167

def get_byte
  if @pos >= @string.size
    return nil
  end

  s = @string.getbyte @pos
  @pos += 1
  s
end

#get_text(start) ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 56

def get_text(start)
  @string[start..@pos-1]
end

#grow_lr(rule, start_pos, m) ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 283

def grow_lr(rule, start_pos, m)
  while true
    @pos = start_pos
    @result = m.result

    ans = __send__ rule
    return nil unless ans

    break if @pos <= m.pos

    m.move! ans, @pos, @result
  end

  @result = m.result
  @pos = m.pos
  return m.ans
end

#lines ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 48

def lines
  lines = []
  string.each_line { |l| lines << l }
  lines
end

#match_string(str) ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 146

def match_string(str)
  len = str.size
  if @string[pos,len] == str
    @pos += len
    return str
  end

  return nil
end

#parse(rule = nil) ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 188

def parse(rule=nil)
  if !rule
    _root ? true : false
  else
    # This is not shared with code_generator.rb so this can be standalone
    method = rule.gsub("-","_hyphen_")
    __send__("_#{method}") ? true : false
  end
end

#position(line, column) ⇒ Object 



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# File 'lib/poetics/parser.rb', line 17

def position(line, column)
  @line = line
  @column = column
end

#raise_error ⇒ Object

Raises:



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# File 'lib/poetics/parser/parser.rb', line 112

def raise_error
  raise ParseError, failure_oneline
end

#scan(reg) ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 156

def scan(reg)
  if m = reg.match(@string[@pos..-1])
    width = m.end(0)
    @pos += width
    return true
  end

  return nil
end

#set_failed_rule(name) ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 137

def set_failed_rule(name)
  if @pos > @failing_rule_offset
    @failed_rule = name
    @failing_rule_offset = @pos
  end
end

#setup_foreign_grammar ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 315

def setup_foreign_grammar; end

#setup_parser(str, debug = false) ⇒ Object

STANDALONE START



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# File 'lib/poetics/parser/parser.rb', line 3

def setup_parser(str, debug=false)
  @string = str
  @pos = 0
  @memoizations = Hash.new { |h,k| h[k] = {} }
  @result = nil
  @failed_rule = nil
  @failing_rule_offset = -1

  setup_foreign_grammar
end

#show_error(io = STDOUT) ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 116

def show_error(io=STDOUT)
  error_pos = @failing_rule_offset
  line_no = current_line(error_pos)
  col_no = current_column(error_pos)

  io.puts "On line #{line_no}, column #{col_no}:"

  if @failed_rule.kind_of? Symbol
    info = self.class::Rules[@failed_rule]
    io.puts "Failed to match '#{info.rendered}' (rule '#{info.name}')"
  else
    io.puts "Failed to match rule '#{@failed_rule}'"
  end

  io.puts "Got: #{string[error_pos,1].inspect}"
  line = lines[line_no-1]
  io.puts "=> #{line}"
  io.print(" " * (col_no + 3))
  io.puts "^"
end

#show_pos ⇒ Object 



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# File 'lib/poetics/parser/parser.rb', line 60

def show_pos
  width = 10
  if @pos < width
    "#{@pos} (\"#{@string[0,@pos]}\" @ \"#{@string[@pos,width]}\")"
  else
    "#{@pos} (\"... #{@string[@pos - width, width]}\" @ \"#{@string[@pos,width]}\")"
  end
end