print( string.find( 'alo alx 123 b\0o b\0o', '(..*) %1' ) )
print( string.find( 'aloALO', '%l*' ) )
print( string.find( ' \n isto � assim', '%S%S*' ) )

print( string.find( "", "" ) )
print( string.find( "ababaabbaba", "abb" ) )
print( string.find( "ababaabbaba", "abb", 7 ) )

print( string.match( "aabaa", "a*" ) )
print( string.match( "aabaa", "a*", 3 ) )
print( string.match( "aabaa", "a*b" ) )
print( string.match( "aabaa", "a*b", 3 ) )

print( string.match( "abbaaababaabaaabaa", "b(a*)b" ) )

print( string.match( "abbaaababaabaaabaa", "b(a*)()b" ) )
print( string.match( "abbaaababaabaaabaa", "b(a*)()b", 3 ) )
print( string.match( "abbaaababaabaaabaa", "b(a*)()b", 8 ) )
print( string.match( "abbaaababaabaaabaa", "b(a*)()b", 12 ) )

print( string.byte("hi", -3) )

print( tostring(1234567890123) )
print( tostring(1234567890124) )
print( tostring(1234567890125) )

function f1(s, p)
  print(p)
  p = string.gsub(p, "%%([0-9])", function (s) return "%" .. (s+1) end)
  print(p)
  p = string.gsub(p, "^(^?)", "%1()", 1)
  print(p)
  p = string.gsub(p, "($?)$", "()%1", 1)
  print(p)
  local t = {string.match(s, p)}
  return string.sub(s, t[1], t[#t] - 1)
end

print( f1('alo alx 123 b\0o b\0o', '(..*) %1') )

local function badpat()
	print( string.gsub( "alo", "(.)", "%2" ) )
end

print( pcall( badpat ) )

for k, v in string.gmatch("w=200&h=150", "(%w+)=(%w+)") do
    print(k, v)
end

-- string.sub
function t(str)
	local i = { 0, 1, 2, 8, -1 }
	for ki,vi in ipairs(i) do
		local s,v = pcall( string.sub, str, vi )
		print( 'string.sub("'..str..'",'..tostring(vi)..')='..tostring(s)..',"'..tostring(v)..'"' )
		local j = { 0, 1, 2, 4, 8, -1 }
		for kj,vj in ipairs(j) do
			local s,v = pcall( string.sub, str, vi, vj )
			print( 'string.sub("'..str..'",'..tostring(vi)..','..tostring(vj)..')='..tostring(s)..',"'..tostring(v)..'"' )
		end
	end
end
t( 'abcdefghijklmn' )
t( 'abcdefg' )
t( 'abcd' )
t( 'abc' )
t( 'ab' )
t( 'a' )
t( '' )