Class: Preprocessor

Inherits:
Object show all
Defined in:
ext/rubypp.rb

Instance Method Summary collapse

Constructor Details

#initialize(input, output, filename) ⇒ Preprocessor

Returns a new instance of Preprocessor.



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# File 'ext/rubypp.rb', line 2

def initialize(input, output, filename)
  @input = input
  @output = output
  @filename = filename
  @linenum = 1
end

Instance Method Details

#evaluate(str, linenum) ⇒ Object 



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# File 'ext/rubypp.rb', line 61

def evaluate(str, linenum)
  result = eval(str, TOPLEVEL_BINDING, @filename, linenum)
  success = true
  return result
end

#getline ⇒ Object 



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# File 'ext/rubypp.rb', line 9

def getline
  line = @input.gets
  @linenum += 1 if not line.nil?
  return line
end

#preprocess ⇒ Object 



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# File 'ext/rubypp.rb', line 15

def preprocess
  success = false
  begin
    loop do
      line = getline
      break if line.nil?
      case line
      when /(.*[^\\]|^)\#\{(.*?)\}(.*)/
        puts "#{$1}#{evaluate($2, @linenum)}#{$3}"
      when /^\#ruby\s+<<(.*)/
        marker = $1
        str = ''
        evalstart = @linenum
        loop do
          line = getline
          if line.nil? then
            raise "End of input without #{marker}"
          end
          break if line.chomp == marker
          str << line
        end
        result = evaluate(str, evalstart)
        puts result if not result.nil?
      when /^\#ruby\s+(.*)/
        str = line = $1
        while line[-1] == ?\\
          str.chop!
          line = getline
          break if line.nil?
          line.chomp!
          str << line
        end
        result = evaluate(str, @linenum)
        puts result if not result.nil?
      else
        puts line
      end
    end
    success = true
  ensure
    if not success then
      $stderr.puts "Error on line #{@linenum}:"
    end
  end
end

#puts(line) ⇒ Object 



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# File 'ext/rubypp.rb', line 67

def puts(line)
  @output.puts(line)
end