Class: N65::Label

Inherits:
Object
  • Object
show all
Defined in:
lib/n65/directives/label.rb

Overview

This class represents a label, and will create

an entry in the symbol table associated with 
the address it appears at.

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(symbol) ⇒ Label

Create a new label object



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# File 'lib/n65/directives/label.rb', line 24

def initialize(symbol)
  @symbol = symbol
end

Class Method Details

.parse(line) ⇒ Object

Try to parse as a label



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# File 'lib/n65/directives/label.rb', line 12

def self.parse(line)
  match_data = line.match(/^([a-zA-Z][a-zA-Z0-9_]+):$/)
  unless match_data.nil?
    label = match_data[1].to_sym
    return self.new(label)
  end
  nil
end

Instance Method Details

#exec(assembler) ⇒ Object

Create an entry in the symbol table for this label



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# File 'lib/n65/directives/label.rb', line 31

def exec(assembler)
  program_counter = assembler.program_counter
  assembler.symbol_table.define_symbol(@symbol, program_counter)
end

#to_s ⇒ Object

Display



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# File 'lib/n65/directives/label.rb', line 39

def to_s
  "#{@symbol}:"
end