diff --git a/bin/moonc b/bin/moonc
index f18d43f..9410d2e 100755
--- a/bin/moonc
+++ b/bin/moonc
@@ -9,7 +9,7 @@ require "moonscript.util"
 require "alt_getopt"
 require "lfs"
 
-local opts, ind = alt_getopt.get_opts(arg, "vhwt:pTb", {
+local opts, ind = alt_getopt.get_opts(arg, "vhwt:pTXb", {
 	print = "p", tree = "T", version = "v", help = "h"
 })
 
@@ -24,6 +24,7 @@ local help = [[Usage: %s [options] files...
     -t path     Specify where to place compiled files
     -p          Write output to standard out
     -T          Write parse tree instead of code (to stdout)
+    -X          Write line rewrite map instead of code (to stdout)
     -b          Dump parse and compile time (doesn't write output)
     -v          Print version
 
@@ -122,10 +123,18 @@ function compile_file(text, fname)
 		return ""
 	else
 		local compile_time = gettime()
-		local code, err, pos = compile.tree(tree)
+		local code, posmap_or_err, err_pos = compile.tree(tree)
 		compile_time = gettime() - compile_time
+
 		if not code then
-			return nil, compile.format_error(err, pos, text)
+			return nil, compile.format_error(posmap_or_err, err_pos, text)
+		end
+
+		if opts.X then
+			opts.p = true
+			print("Pos", "Lua", ">>", "Moon")
+			print(util.debug_posmap(posmap_or_err, text, code))
+			return ""
 		end
 
 		if opts.b then
diff --git a/moonscript/compile.lua b/moonscript/compile.lua
index 1d47f57..075b473 100644
--- a/moonscript/compile.lua
+++ b/moonscript/compile.lua
@@ -594,47 +594,6 @@ Block = (function()
   end
   return _class_0
 end)()
-local debug_posmap
-debug_posmap = function(posmap, fname, lua_code)
-  if fname == nil then
-    fname = error("pass in input file")
-  end
-  local moon_code = io.open(fname):read("*a")
-  local tuples = (function()
-    local _accum_0 = { }
-    local _len_0 = 0
-    for k, v in pairs(posmap) do
-      _len_0 = _len_0 + 1
-      _accum_0[_len_0] = {
-        k,
-        v
-      }
-    end
-    return _accum_0
-  end)()
-  table.sort(tuples, function(a, b)
-    return a[1] < b[1]
-  end)
-  local lines = (function()
-    local _accum_0 = { }
-    local _len_0 = 0
-    local _list_0 = tuples
-    for _index_0 = 1, #_list_0 do
-      local pair = _list_0[_index_0]
-      local lua_line, pos = unpack(pair)
-      local moon_line = pos_to_line(moon_code, pos)
-      local lua_text = get_line(lua_code, lua_line)
-      local moon_text = get_closest_line(moon_code, moon_line)
-      local _value_0 = tostring(pos) .. "\t " .. tostring(lua_line) .. ":[ " .. tostring(trim(lua_text)) .. " ] >> " .. tostring(moon_line) .. ":[ " .. tostring(trim(moon_text)) .. " ]"
-      if _value_0 ~= nil then
-        _len_0 = _len_0 + 1
-        _accum_0[_len_0] = _value_0
-      end
-    end
-    return _accum_0
-  end)()
-  return concat(lines, "\n") .. "\n"
-end
 RootBlock = (function()
   local _parent_0 = Block
   local _base_0 = {
diff --git a/moonscript/compile.moon b/moonscript/compile.moon
index 2c86a3f..6538c97 100644
--- a/moonscript/compile.moon
+++ b/moonscript/compile.moon
@@ -351,24 +351,6 @@ class Block
     @_lines = Lines!
     @stms fn lines
 
-debug_posmap = (posmap, fname=error"pass in input file", lua_code) ->
-  moon_code = io.open(fname)\read "*a"
-
-  tuples = [{k, v} for k, v in pairs posmap]
-
-  table.sort tuples, (a, b) -> a[1] < b[1]
-
-  lines = for pair in *tuples
-    lua_line, pos = unpack pair
-    moon_line = pos_to_line moon_code, pos
-
-    lua_text = get_line lua_code, lua_line
-    moon_text = get_closest_line moon_code, moon_line
-
-    "#{pos}\t #{lua_line}:[ #{trim lua_text} ] >> #{moon_line}:[ #{trim moon_text} ]"
-
-  concat(lines, "\n") .. "\n"
-
 class RootBlock extends Block
   new: (...) =>
     @root = self
@@ -419,6 +401,5 @@ tree = (tree, scope=RootBlock!) ->
   else
     lua_code = scope\render!
     posmap = scope._lines\flatten_posmap!
-    -- print debug_posmap posmap, "scrap.moon", lua_code
     lua_code, posmap
 
diff --git a/moonscript/util.lua b/moonscript/util.lua
index d131a12..e9845e9 100644
--- a/moonscript/util.lua
+++ b/moonscript/util.lua
@@ -99,3 +99,39 @@ dump = function(what)
   end
   return _dump(what)
 end
+debug_posmap = function(posmap, moon_code, lua_code)
+  local tuples = (function()
+    local _accum_0 = { }
+    local _len_0 = 0
+    for k, v in pairs(posmap) do
+      _len_0 = _len_0 + 1
+      _accum_0[_len_0] = {
+        k,
+        v
+      }
+    end
+    return _accum_0
+  end)()
+  table.sort(tuples, function(a, b)
+    return a[1] < b[1]
+  end)
+  local lines = (function()
+    local _accum_0 = { }
+    local _len_0 = 0
+    local _list_0 = tuples
+    for _index_0 = 1, #_list_0 do
+      local pair = _list_0[_index_0]
+      local lua_line, pos = unpack(pair)
+      local moon_line = pos_to_line(moon_code, pos)
+      local lua_text = get_line(lua_code, lua_line)
+      local moon_text = get_closest_line(moon_code, moon_line)
+      local _value_0 = tostring(pos) .. "\t " .. tostring(lua_line) .. ":[ " .. tostring(trim(lua_text)) .. " ] >> " .. tostring(moon_line) .. ":[ " .. tostring(trim(moon_text)) .. " ]"
+      if _value_0 ~= nil then
+        _len_0 = _len_0 + 1
+        _accum_0[_len_0] = _value_0
+      end
+    end
+    return _accum_0
+  end)()
+  return concat(lines, "\n")
+end
diff --git a/moonscript/util.moon b/moonscript/util.moon
index 3a97ffe..7bbb8c1 100644
--- a/moonscript/util.moon
+++ b/moonscript/util.moon
@@ -4,7 +4,7 @@ module "moonscript.util", package.seeall
 export moon
 export pos_to_line, get_closest_line, get_line
 export reversed, trim, split
-export dump
+export dump, debug_posmap
 
 import concat from table
 
@@ -75,3 +75,19 @@ dump = (what) ->
   _dump what
 
 
+debug_posmap = (posmap, moon_code, lua_code) ->
+  tuples = [{k, v} for k, v in pairs posmap]
+  table.sort tuples, (a, b) -> a[1] < b[1]
+
+  lines = for pair in *tuples
+    lua_line, pos = unpack pair
+    moon_line = pos_to_line moon_code, pos
+
+    lua_text = get_line lua_code, lua_line
+    moon_text = get_closest_line moon_code, moon_line
+
+    "#{pos}\t #{lua_line}:[ #{trim lua_text} ] >> #{moon_line}:[ #{trim moon_text} ]"
+
+  concat(lines, "\n")
+
+