Class: FAM::Syntax::Lexer

Inherits:
Object show all
Defined in:
lib/fam/syntax/lexer.rb

Direct Known Subclasses

Parser

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(string) ⇒ Lexer

Returns a new instance of Lexer.



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# File 'lib/fam/syntax/lexer.rb', line 7

def initialize string
  @raw = string
  @tokens = TokenStream.new
end

Instance Attribute Details

#tokens ⇒ Object (readonly)

Returns the value of attribute tokens.



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# File 'lib/fam/syntax/lexer.rb', line 5

def tokens
  @tokens
end

Class Method Details

.lex(string) ⇒ Object 



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# File 'lib/fam/syntax/lexer.rb', line 12

def self.lex string
  obj = self.new string
  obj.lexer
  obj
end

Instance Method Details

#lexer ⇒ Object 



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# File 'lib/fam/syntax/lexer.rb', line 18

def lexer
  puts "Lexing..." if $VERBOSE
  @raw << EOF unless @raw[-1] == EOF

  loc = {:line => 1, :col => 1}
  i = 0
  while i < @raw.size
    unread = @raw[i..-1]

    if ["\n", ";"].include? unread[0]
      loc[:line] += 1
      loc[:col] = 1
      @tokens << tokenize(unread[0], :TERMINATOR, loc)
      i += 1

    elsif unread[0] == ' '
      loc[:col] += 1
      i += 1

    elsif unread[/\A{{/, 0] || unread[/\A!/, 0]
      comment = unread[/\A{{/, 0] || unread[/\A!/, 0]
      comment_start = loc.clone
      j = 0
      if comment == '!'
        until unread[j] == "\n" || unread[j] == EOF
          i += 1
          j += 1
        end
        j -= 1
      else
        until unread[j..j+1] == '}}' || unread[j] == EOF
          i += 1
          loc[:col] += 1
          if unread[j] == "\n"
            loc[:line] += 1
            loc[:col] = 1
          end
          j += 1
        end
        j += 1
      end
      @tokens << tokenize(unread[0..j], :COMMENT, comment_start)

    elsif label = unread[/\A[a-zA-Z_]([a-zA-Z0-9_]+)?:/, 0]
      @tokens << tokenize(label, :LABEL, loc)
      loc[:col] += label.size
      i += label.size

    elsif numeric = unread[/\A(\-|\+)??((?=0x|0b)([0-9A-Za-z]+)|([0-9]+((e(\-|\+)?[0-9]+)?)))/, 0]
      @tokens << tokenize(numeric, :NUMERIC, loc)
      loc[:col] += numeric.size
      i += numeric.size

    elsif address = unread[/\A@[0-9]+/, 0]
      @tokens << tokenize(address, :ADDRESS, loc)
      loc[:col] += address.size
      i += address.size

    elsif register = unread[/\A&[a-zA-Z0-9]+/, 0]
      @tokens << tokenize(register, :REGISTER, loc)
      loc[:col] += register.size
      i += register.size

    elsif ident = unread[/\A[A-Za-z_]([A-Za-z0-9_]+)?/, 0]
      if Tokens::OPCODES.include? ident
        @tokens << tokenize(ident, :OPCODE, loc)
      else
        @tokens << tokenize(ident, :IDENT, loc)
      end

      loc[:col] += ident.size
      i += ident.size


    elsif op = unread[/\A[(\+)(\-)(\:)(\|)]/, 0]
      @tokens << tokenize(op, :OPERATOR, loc)
      loc[:col] += op.size
      i += op.size

    else
      i += 1
      loc[:col] += 1
    end

  end

  @tokens
end

#to_s ⇒ Object 



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# File 'lib/fam/syntax/lexer.rb', line 111

def to_s
  result = "LEXED TOKENS:\n"
  @tokens.tokens.each do |token|
    widest = @tokens.tokens.map(&:type).max
    result << "  :#{token.type}#{' ' * (widest.size - token.type.size)} :: " +
    "[#{token.line.to_s.rjust 3}:#{token.col.to_s.ljust 3}] " +
    "{ #{token.name.inspect.size > 10 ? (token.name[0..7] + '...').inspect : token.name.inspect} }\n"
  end
  result
end