Class: Braingasm::Parser

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

Overview

Takes some input code and generates the program

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(input, compiler) ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/braingasm/parser.rb', line 10

def initialize(input, compiler)
  @input = input
  @compiler = compiler
  @program = []
end

Instance Attribute Details

#input ⇒ Object

Returns the value of attribute input.



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# File 'lib/braingasm/parser.rb', line 8

def input
  @input
end

#program ⇒ Object

Returns the value of attribute program.



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# File 'lib/braingasm/parser.rb', line 8

def program
  @program
end

Instance Method Details

#parse_next(tokens) ⇒ Object 



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# File 'lib/braingasm/parser.rb', line 25

def parse_next(tokens)
  token = tokens.next

  case token
  when :right
    @compiler.right
  when :left
    @compiler.left
  when :increment
    @compiler.inc
  when :decrement
    @compiler.dec
  when :multiply
    @compiler.multiply
  when :divide
    @compiler.divide
  when :print
    @compiler.print
  when :output
    @compiler.print_int
  when :read
    @compiler.read
  when :input
    @compiler.read_int
  when :compare
    @compiler.compare
  when :quit
    @compiler.quit
  when :tape_limit
    @compiler.tape_limit
  when :loop_start
    @compiler.loop_start(@program.size)
  when :loop_end
    @compiler.loop_end(@program.size)
  else
    case token
    when Integer, String
      @compiler.push_prefix token
    when :position
      @compiler.pos
    when :random
      @compiler.random
    when :zero
      @compiler.zero
    when :signed
      @compiler.signed
    when :parity
      @compiler.parity
    when :oddity
      @compiler.oddity
    end
    false
  end
rescue BraingasmError => e
  raise_parsing_error(e.message)
end

#parse_program ⇒ Object 



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# File 'lib/braingasm/parser.rb', line 16

def parse_program
  loop do
    push_instruction parse_next(@input)
  end

  raise_parsing_error("Unmatched `[`") unless @compiler.loop_stack.empty?
  @program
end

#push_instruction(instruction) ⇒ Object 



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# File 'lib/braingasm/parser.rb', line 82

def push_instruction(instruction)
  return unless instruction
  @program.push(*instruction)
  @program.size - 1
end

#raise_parsing_error(message) ⇒ Object

Raises:



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# File 'lib/braingasm/parser.rb', line 88

def raise_parsing_error(message)
  raise ParsingError.new(@input.line_numer, @input.column_number), message
end