Class: RuboCop::AST::NodePattern::LexerRex

Inherits:
Object
  • Object
show all
Defined in:
lib/rubocop/ast/node_pattern/lexer.rex.rb

Overview

The generated lexer RuboCop::AST::NodePattern::LexerRex

Direct Known Subclasses

Lexer

Defined Under Namespace

Classes: LexerError, ScanError

Constant Summary collapse

CONST_NAME =

:stopdoc:

/[A-Z:][a-zA-Z_:]+/
SYMBOL_NAME = 
/[\w+@*\/?!<>=~|%^&-]+|\[\]=?/
IDENTIFIER = 
/[a-z][a-zA-Z0-9_]*/
NODE_TYPE = 
/[a-z][a-zA-Z0-9_-]*/
CALL = 
/(?:#{CONST_NAME}\.)?#{IDENTIFIER}[!?]?/
REGEXP_BODY = 
/(?:[^\/]|\\\/)*/
REGEXP = 
/\/(#{REGEXP_BODY})(?<!\\)\/([imxo]*)/

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#filename ⇒ Object

The file name / path



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# File 'lib/rubocop/ast/node_pattern/lexer.rex.rb', line 43

def filename
  @filename
end

#ss ⇒ Object Also known as: match

The StringScanner for this lexer.



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# File 'lib/rubocop/ast/node_pattern/lexer.rex.rb', line 48

def ss
  @ss
end

#state ⇒ Object

The current lexical state.



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# File 'lib/rubocop/ast/node_pattern/lexer.rex.rb', line 53

def state
  @state
end

Instance Method Details

#action ⇒ Object

Yields on the current action.



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# File 'lib/rubocop/ast/node_pattern/lexer.rex.rb', line 69

def action
  yield
end

#location ⇒ Object

The current location in the parse.



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# File 'lib/rubocop/ast/node_pattern/lexer.rex.rb', line 103

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

#matches ⇒ Object

The match groups for the current scan.



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# File 'lib/rubocop/ast/node_pattern/lexer.rex.rb', line 60

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

#next_token ⇒ Object

Lex the next token.



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# File 'lib/rubocop/ast/node_pattern/lexer.rex.rb', line 112

def next_token

  token = nil

  until ss.eos? or token do
    token =
      case state
      when nil then
        case
        when ss.skip(/\s+/) then
          # do nothing
        when ss.skip(/:(#{SYMBOL_NAME})/o) then
          action { emit :tSYMBOL, &:to_sym }
        when ss.skip(/"(.+?)"/) then
          action { emit :tSTRING }
        when ss.skip(/[-+]?\d+\.\d+/) then
          action { emit :tNUMBER, &:to_f }
        when ss.skip(/[-+]?\d+/) then
          action { emit :tNUMBER, &:to_i }
        when ss.skip(/#{Regexp.union(
                  %w"( ) { | } [ ] < > $ ! ^ ` ... + * ? ,"
                )}/o) then
          action { emit ss.matched, &:to_sym }
        when ss.skip(/#{REGEXP}/o) then
          action { emit_regexp }
        when ss.skip(/%?(#{CONST_NAME})/o) then
          action { emit :tPARAM_CONST }
        when ss.skip(/%([a-z_]+)/) then
          action { emit :tPARAM_NAMED }
        when ss.skip(/%(\d*)/) then
          action { emit(:tPARAM_NUMBER) { |s| s.empty? ? 1 : s.to_i } } # Map `%` to `%1`
        when ss.skip(/_(#{IDENTIFIER})/o) then
          action { emit :tUNIFY }
        when ss.skip(/_/o) then
          action { emit :tWILDCARD }
        when ss.skip(/\#(#{CALL})/o) then
          action { @state = :ARG; emit :tFUNCTION_CALL, &:to_sym }
        when ss.skip(/#{IDENTIFIER}\?/o) then
          action { @state = :ARG; emit :tPREDICATE, &:to_sym }
        when ss.skip(/#{NODE_TYPE}/o) then
          action { emit :tNODE_TYPE, &:to_sym }
        when ss.skip(/\#.*/) then
          action { emit_comment }
        else
          text = ss.string[ss.pos .. -1]
          raise ScanError, "can not match (#{state.inspect}) at #{location}: '#{text}'"
        end
      when :ARG then
        case
        when ss.skip(/\(/) then
          action { @state = nil; emit :tARG_LIST }
        when ss.skip(//) then
          action { @state = nil }
        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

Parse the given string.



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# File 'lib/rubocop/ast/node_pattern/lexer.rex.rb', line 83

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

  do_parse
end

#parse_file(path) ⇒ Object

Read in and parse the file at path.



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# File 'lib/rubocop/ast/node_pattern/lexer.rex.rb', line 93

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

#scanner_class ⇒ Object

The current scanner class. Must be overridden in subclasses.



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# File 'lib/rubocop/ast/node_pattern/lexer.rex.rb', line 76

def scanner_class
  StringScanner
end