Class: TlaParserS::Parser

Inherits:
Object
  • Object
show all
Includes:
Utils::MyLogger
Defined in:
lib/parser/parser.rb

Constant Summary collapse

PROGNAME =

Logger

"parser"
@@parser =

Load the Treetop grammar from the ‘sexp_parser’ file, and create a new instance of that parser as a class variable so we don’t have to re-create it every time we need to parse a string

nil

Constants included from Utils::MyLogger

Utils::MyLogger::LOGFILE

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Utils::MyLogger

#getLogger, #logfile

Constructor Details

#initialize(options = {}) ⇒ Parser

constructore



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# File 'lib/parser/parser.rb', line 41

def initialize( options = {} )
  @logger = getLogger( PROGNAME, options )
  @logger.info( "#{__method__} initialized" )
  
  self.loadParsers
end

Class Method Details

.version ⇒ Object 



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# File 'lib/parser/parser.rb', line 33

def self.version
  TlaParserS::version
end

Instance Method Details

#getTheParser ⇒ SexpParser

Returns static parser to use.

Returns:

  • (SexpParser) —

    static parser to use



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# File 'lib/parser/parser.rb', line 106

def getTheParser
  @@parser
end

#loadParsers ⇒ SexpParser

Returns cached parser from ‘parser_sexp.treetop’.

Returns:

  • (SexpParser) —

    cached parser from ‘parser_sexp.treetop’



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# File 'lib/parser/parser.rb', line 49

def loadParsers
  # cached
  return @@parser  unless @@parser.nil?
  base_path   = File.expand_path(File.dirname(__FILE__))
  parser_path = File.join( base_path, 'parser_sexp.treetop')
  @logger.info( "#{__method__} loading parser from parser path #{parser_path}" )
  Treetop.load( parser_path)
  @@parser = SbuilderSexpParser.new
  @@parser 
end

#parse(data, start = nil) ⇒ Object

Parameters:

  • start (symbol) (defaults to: nil) —

    treep grammar non-terminal to start iwth



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# File 'lib/parser/parser.rb', line 67

def parse( data, start = nil )
  return nil if data.nil?

  
  # to pass a file
  if data.respond_to? :read
    data = data.read
  # elsif ! data.respond_to? :lines
  #   data.lines = data.to_a
  end

  
  # Pass the data over to the parser instance
  parser = getTheParser
  tree = parser.parse(data, :root=>start )
  
  # If the AST is nil then there was an error during parsing
  # we need to report a simple error message to help the user
  if(tree.nil?)
    # adopted from http://whitequark.org/blog/2011/09/08/treetop-typical-errors/
    parser.failure_reason =~ /(Expected .*) after/m
    expected = $1.nil? ? parser.failure_reason : $1
    msg= <<-EOS
    Parse error:
    Line     : #{parser.failure_line}, offset   : #{parser.index}
    #{expected.gsub( "\n", '$NEWLINE')}
    #{data.lines.to_a[ parser.failure_line()-1 ]}
    #{'~' * (parser.failure_column-1)}^
    EOS
    # puts msg
    @logger.error( "#{__method__} #{msg}, for data #{data}" )
    raise ParseException.new msg
  end

  self.class.clean_tree( tree )
  return tree
end