diff --git a/nomsu.lua b/nomsu.lua
index 11dd792..bd04c46 100644
--- a/nomsu.lua
+++ b/nomsu.lua
@@ -205,6 +205,10 @@ do
       self:write(...)
       return self:write("\n")
     end,
+    errorln = function(self, ...)
+      self:write_err(...)
+      return self:write_err("\n")
+    end,
     def = function(self, signature, thunk, src, is_macro)
       if is_macro == nil then
         is_macro = false
@@ -362,7 +366,7 @@ do
         end
         local ok, expr, statements = pcall(self.tree_to_lua, self, statement)
         if not ok then
-          self:writeln(tostring(colored.red("Error occurred in statement:")) .. "\n" .. tostring(colored.bright(colored.yellow(statement.src))))
+          self:errorln(tostring(colored.red("Error occurred in statement:")) .. "\n" .. tostring(colored.bright(colored.yellow(statement.src))))
           self:error(expr)
         end
         local code_for_statement = ([[                return (function(nomsu, vars)
@@ -390,8 +394,8 @@ do
           return_value = ret
         end
         if not ok then
-          self:writeln(tostring(colored.red("Error occurred in statement:")) .. "\n" .. tostring(colored.yellow(statement.src)))
-          self:writeln(debug.traceback())
+          self:errorln(tostring(colored.red("Error occurred in statement:")) .. "\n" .. tostring(colored.yellow(statement.src)))
+          self:errorln(debug.traceback())
           self:error(ret)
         end
         insert(buffer, tostring(statements or '') .. "\n" .. tostring(expr and "ret = " .. tostring(expr) or ''))
@@ -420,7 +424,7 @@ do
     tree_to_lua = function(self, tree)
       assert(tree, "No tree provided.")
       if not tree.type then
-        self:writeln(debug.traceback())
+        self:errorln(debug.traceback())
         self:error("Invalid tree: " .. tostring(repr(tree)))
       end
       local _exp_0 = tree.type
@@ -719,16 +723,16 @@ do
         end
       end))
     end,
-    error = function(self, ...)
-      self:writeln("ERROR!")
-      if select(1, ...) then
-        self:writeln(...)
+    error = function(self, msg)
+      self:errorln((colored.red("ERROR!")))
+      if msg then
+        self:errorln(colored.bright(colored.yellow(colored.onred(msg))))
       end
-      self:writeln("Callstack:")
+      self:errorln("Callstack:")
       for i = #self.callstack, 1, -1 do
-        self:writeln("    " .. tostring(self.callstack[i]))
+        self:errorln("    " .. tostring(self.callstack[i]))
       end
-      self:writeln("    <top level>")
+      self:errorln("    <top level>")
       self.callstack = { }
       return error()
     end,
@@ -809,6 +813,9 @@ do
       self.write = function(self, ...)
         return io.write(...)
       end
+      self.write_err = function(self, ...)
+        return io.stderr:write(...)
+      end
       self.defs = setmetatable({ }, {
         __index = parent and parent.defs
       })
diff --git a/nomsu.moon b/nomsu.moon
index 1695906..7e45d0d 100755
--- a/nomsu.moon
+++ b/nomsu.moon
@@ -184,6 +184,7 @@ nomsu = re.compile(nomsu, defs)
 class NomsuCompiler
     new:(parent)=>
         @write = (...)=> io.write(...)
+        @write_err = (...)=> io.stderr\write(...)
         @defs = setmetatable({}, {__index:parent and parent.defs})
         @callstack = {}
         @debug = false
@@ -197,6 +198,10 @@ class NomsuCompiler
         @write(...)
         @write("\n")
     
+    errorln:(...)=>
+        @write_err(...)
+        @write_err("\n")
+    
     def: (signature, thunk, src, is_macro=false)=>
         assert type(thunk) == 'function', "Bad thunk: #{repr thunk}"
         canonical_args = nil
@@ -293,7 +298,7 @@ class NomsuCompiler
                 @print_tree statement
             ok,expr,statements = pcall(@tree_to_lua, self, statement)
             if not ok
-                @writeln "#{colored.red "Error occurred in statement:"}\n#{colored.bright colored.yellow statement.src}"
+                @errorln "#{colored.red "Error occurred in statement:"}\n#{colored.bright colored.yellow statement.src}"
                 @error(expr)
             code_for_statement = ([[
                 return (function(nomsu, vars)
@@ -314,8 +319,8 @@ class NomsuCompiler
             ok,ret = pcall(run_statement, self, vars)
             if expr then return_value = ret
             if not ok
-                @writeln "#{colored.red "Error occurred in statement:"}\n#{colored.yellow statement.src}"
-                @writeln debug.traceback!
+                @errorln "#{colored.red "Error occurred in statement:"}\n#{colored.yellow statement.src}"
+                @errorln debug.traceback!
                 @error(ret)
             insert buffer, "#{statements or ''}\n#{expr and "ret = #{expr}" or ''}"
         
@@ -342,7 +347,7 @@ class NomsuCompiler
         -- Return <lua code for value>, <additional lua code>
         assert tree, "No tree provided."
         if not tree.type
-            @writeln debug.traceback()
+            @errorln debug.traceback()
             @error "Invalid tree: #{repr(tree)}"
         switch tree.type
             when "File"
@@ -537,14 +542,14 @@ class NomsuCompiler
         (var\gsub "%W", (verboten)->
             if verboten == "_" then "__" else ("_%x")\format(verboten\byte!))
 
-    error: (...)=>
-        @writeln "ERROR!"
-        if select(1, ...)
-            @writeln(...)
-        @writeln("Callstack:")
+    error: (msg)=>
+        @errorln (colored.red "ERROR!")
+        if msg
+            @errorln(colored.bright colored.yellow colored.onred msg)
+        @errorln("Callstack:")
         for i=#@callstack,1,-1
-            @writeln "    #{@callstack[i]}"
-        @writeln "    <top level>"
+            @errorln "    #{@callstack[i]}"
+        @errorln "    <top level>"
         @callstack = {}
         error!