Class: Predicator::Lexer

Inherits:
Object
  • Object
show all
Defined in:
lib/predicator/lexer.rex.rb

Overview

– This file is automatically generated. Do not modify it. Generated by: oedipus_lex version 2.5.0. Source: lib/predicator/lexer.rex ++

Defined Under Namespace

Classes: LexerError, ScanError

Constant Summary collapse

SPACE = 
/[ \t\r\n]/
LPAREN = 
/\(/
RPAREN = 
/\)/
LBRACKET = 
/\[/
RBRACKET = 
/\]/
TRUE = 
/true\b/
FALSE = 
/false\b/
BETWEEN = 
/between\b/
IN = 
/in\b/
BANG = 
/!/
NOT = 
/not\b/
DOT = 
/\./
COMMA = 
/,/
AND = 
/and\b/
OR = 
/or\b/
EQ = 
/=/
GT = 
/>/
LT = 
/</
INTEGER = 
/[+-]?\d(_?\d)*\b/
STRING = 
/(["'])(?:\\?.)*?\1/
IDENTIFIER = 
/[a-z][A-Za-z0-9_]*\b/

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#filename ⇒ Object

Returns the value of attribute filename.



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# File 'lib/predicator/lexer.rex.rb', line 37

def filename
  @filename
end

#lineno ⇒ Object

Returns the value of attribute lineno.



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# File 'lib/predicator/lexer.rex.rb', line 36

def lineno
  @lineno
end

#old_pos ⇒ Object

Returns the value of attribute old_pos.



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# File 'lib/predicator/lexer.rex.rb', line 53

def old_pos
  @old_pos
end

#ss ⇒ Object Also known as: match

Returns the value of attribute ss.



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# File 'lib/predicator/lexer.rex.rb', line 38

def ss
  @ss
end

#state ⇒ Object

Returns the value of attribute state.



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# File 'lib/predicator/lexer.rex.rb', line 39

def state
  @state
end

Instance Method Details

#action ⇒ Object 



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# File 'lib/predicator/lexer.rex.rb', line 49

def action
  yield
end

#column ⇒ Object 



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# File 'lib/predicator/lexer.rex.rb', line 55

def column
  idx = ss.string.rindex("\n", old_pos) || -1
  old_pos - idx - 1
end

#do_parse ⇒ Object

def next_token



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# File 'lib/predicator/lexer.rex.rb', line 159

def do_parse; end

#location ⇒ Object 



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# File 'lib/predicator/lexer.rex.rb', line 79

def location
  [
    (filename || "<input>"),
    lineno,
    column,
  ].compact.join(":")
end

#matches ⇒ Object 



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# File 'lib/predicator/lexer.rex.rb', line 43

def matches
  m = (1..9).map { |i| ss[i] }
  m.pop until m[-1] or m.empty?
  m
end

#next_token ⇒ Object 



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# File 'lib/predicator/lexer.rex.rb', line 87

def next_token

  token = nil

  until ss.eos? or token do
    self.lineno += 1 if ss.peek(1) == "\n"
    self.old_pos = ss.pos
    token =
      case state
      when nil then
        case
        when ss.skip(/#{SPACE}/) then
          # do nothing
        when text = ss.scan(/#{LPAREN}/) then
          action { [:LPAREN, text] }
        when text = ss.scan(/#{RPAREN}/) then
          action { [:RPAREN, text] }
        when text = ss.scan(/#{LBRACKET}/) then
          action { [:LBRACKET, text] }
        when text = ss.scan(/#{RBRACKET}/) then
          action { [:RBRACKET, text] }
        when text = ss.scan(/#{TRUE}/) then
          action { [:TRUE, text] }
        when text = ss.scan(/#{FALSE}/) then
          action { [:FALSE, text] }
        when text = ss.scan(/#{BETWEEN}/) then
          action { [:BETWEEN, text] }
        when text = ss.scan(/#{IN}/) then
          action { [:IN, text] }
        when text = ss.scan(/#{BANG}/) then
          action { [:BANG, text] }
        when text = ss.scan(/#{NOT}/) then
          action { [:NOT, text] }
        when text = ss.scan(/#{DOT}/) then
          action { [:DOT, text] }
        when text = ss.scan(/#{COMMA}/) then
          action { [:COMMA, text] }
        when text = ss.scan(/#{AND}/) then
          action { [:AND, text] }
        when text = ss.scan(/#{OR}/) then
          action { [:OR, text] }
        when text = ss.scan(/#{EQ}/) then
          action { [:EQ, text] }
        when text = ss.scan(/#{GT}/) then
          action { [:GT, text] }
        when text = ss.scan(/#{LT}/) then
          action { [:LT, text] }
        when text = ss.scan(/#{INTEGER}/) then
          action { [:INTEGER, text] }
        when text = ss.scan(/#{STRING}/) then
          action { [:STRING, text[1...-1]] }
        when text = ss.scan(/#{IDENTIFIER}/) then
          action { [:IDENTIFIER, text] }
        else
          text = ss.string[ss.pos .. -1]
          raise ScanError, "can not match (#{state.inspect}) at #{location}: '#{text}'"
        end
      else
        raise ScanError, "undefined state at #{location}: '#{state}'"
      end # token = case state

    next unless token # allow functions to trigger redo w/ nil
  end # while

  raise LexerError, "bad lexical result at #{location}: #{token.inspect}" unless
    token.nil? || (Array === token && token.size >= 2)

  # auto-switch state
  self.state = token.last if token && token.first == :state

  token
end

#parse(str) ⇒ Object 



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# File 'lib/predicator/lexer.rex.rb', line 64

def parse str
  self.ss     = scanner_class.new str
  self.lineno = 1
  self.state  ||= nil

  do_parse
end

#parse_file(path) ⇒ Object 



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# File 'lib/predicator/lexer.rex.rb', line 72

def parse_file path
  self.filename = path
  open path do |f|
    parse f.read
  end
end

#scanner_class ⇒ Object 



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# File 'lib/predicator/lexer.rex.rb', line 60

def scanner_class
  StringScanner
end