Find commented out code in C/C++ files

find-code-in-comments.rb

#!/usr/bin/env ruby
# Tool that attempts to find commented out C++ code
#
# Basic strategy:
#  - look for keywords (see CheckRE) in commented out code
#  - ignore doxygen comment blocks
#
# Usage: find-code-in-comments.rb <files...>
#
# Author: Stephan Beyer

CheckRE = [
	/\balignas\b/,
	/\balignof\b/,
	/\basm\b/,
	/\bbool\b/,
	/\bbreak\b\s*;/,
	/\bcase\b/,
	/\bcatch\b/,
	/\bchar\b/,
	/\bcompl\b/,
	/\bconst\b/,
	/\bconst_cast\b/,
	/\bconstexpr\b/,
	/\bcontinue\b\s*;/,
	/\bdecltype\b/,
	/\belse\b/,
	/\benum\b/,
	/\bfloat\b/,
	/\bfor\b\s*\(/,
	/\bgoto\b/,
	/\bif\b\s*\(/,
	/\bmutable\b/,
	/\bnullptr\b/,
	/\breturn\b.*;/,
	/\bstatic\b/,
	/\bstatic_assert\b/,
	/\bstruct\b/,
	/\bswitch\b\(/,
	/\btemplate\b\s*</,
	/\bthrow\b/,
	/\btry\b\s*{/,
	/\btypedef\b/,
	/\btypeid\b/,
	/\btypename\b/,
	/\busing\b.*;/,
	/\bvoid\b/,
	/\bwhile\b\s*\(/,
	/_cast\b/,
]

def check_for_code(filename, lineno, comment)
	# ignore doxygen
	return if (comment[0] == '*' and comment[1] != '*') or comment[0] == '!'

	notcode = true
	CheckRE.each do |regex|
		notcode &= (comment =~ regex).nil?
	end
	puts "#{filename}:#{lineno}" unless notcode
end

def find_code_in_comments(filename)
	content = File.open(filename, 'rb') do |file|
		file.read
	end

	line = 1
	while not (pos = content =~ %r(/)).nil?
		line += content[0..pos].scan(/\n/).length
		content.slice!(0..pos)
		case content[0]
		when '/'
			endpos = content =~ /\n/
			endpos = -1 if endpos.nil?
			check_for_code(filename, line, content[1...endpos])
			content.slice!(0...endpos)
		when '*'
			endpos = content[1..-1] =~ /\*\//
			endpos = -1 if endpos.nil?
			check_for_code(filename, line, content[1...endpos])
			line += content[1..endpos+1].scan(/\n/).length
			content.slice!(0..endpos+2)
		end
	end
end

ARGV.each do |filename|
	find_code_in_comments(filename)
end