Class: ASMREPL::Lexer

Inherits:
Object
  • Object
show all
Defined in:
lib/asmrepl/parser.rb

Constant Summary collapse

INTEGER = 
/(?:[-+]?0b[0-1_,]+               (?# base 2)
|[-+]?(?:0(?!x)|[1-9][0-9_,]*) (?# base 10)
|[-+]?0x[0-9a-fA-F_,]+         (?# base 16))/x
REGISTERS = 
Set.new Fisk::Registers.constants.map(&:to_s)
INSTRUCTIONS = 
Set.new Fisk::Instructions.constants.map(&:to_s)

Instance Method Summary collapse

Constructor Details

#initialize(input) ⇒ Lexer

Returns a new instance of Lexer.



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# File 'lib/asmrepl/parser.rb', line 13

def initialize input
  @input = input
  @scanner = StringScanner.new input
end

Instance Method Details

#next_token ⇒ Object 



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# File 'lib/asmrepl/parser.rb', line 21

def next_token
  return if @scanner.eos?

  if @scanner.scan(INTEGER)
    [:on_int, @scanner.matched]
  elsif @scanner.scan(/\[/)
    [:on_lbracket, @scanner.matched]
  elsif @scanner.scan(/\]/)
    [:on_rbracket, @scanner.matched]
  elsif @scanner.scan(/,/)
    [:on_comma, @scanner.matched]
  elsif @scanner.scan(/qword/)
    [:qword, @scanner.matched]
  elsif @scanner.scan(/dword/)
    [:dword, @scanner.matched]
  elsif @scanner.scan(/word/)
    [:word, @scanner.matched]
  elsif @scanner.scan(/byte/)
    [:byte, @scanner.matched]
  elsif @scanner.scan(/ptr/)
    [:ptr, @scanner.matched]
  elsif @scanner.scan(/rip/i)
    [:on_rip, @scanner.matched]
  elsif @scanner.scan(/int/i)
    [:on_instruction, Fisk::Instructions::INT]
  elsif @scanner.scan(/movabs/i)
    [:on_instruction, Fisk::Instructions::MOV]
  elsif @scanner.scan(/\w+/)
    ident = @scanner.matched
    if INSTRUCTIONS.include?(ident.upcase)
      [:on_instruction, Fisk::Instructions.const_get(ident.upcase)]
    elsif REGISTERS.include?(ident.upcase)
      [:on_register, Fisk::Registers.const_get(ident.upcase)]
    else
      [:on_ident, @scanner.matched]
    end
  elsif @scanner.scan(/\s+/)
    [:on_sp, @scanner.matched]
  elsif @scanner.scan(/\+/)
    [:plus, @scanner.matched]
  elsif @scanner.scan(/-/)
    [:minus, @scanner.matched]
  else
    raise
  end
end