diff --git a/parser.lua b/parser.lua
new file mode 100644
index 0000000..d48c435
--- /dev/null
+++ b/parser.lua
@@ -0,0 +1,164 @@
+local lpeg = require('lpeg')
+local re = require('re')
+lpeg.setmaxstack(10000)
+local P, R, V, S, Cg, C, Cp, B, Cmt, Carg
+P, R, V, S, Cg, C, Cp, B, Cmt, Carg = lpeg.P, lpeg.R, lpeg.V, lpeg.S, lpeg.Cg, lpeg.C, lpeg.Cp, lpeg.B, lpeg.Cmt, lpeg.Carg
+local utils = require('utils')
+local match, sub, rep, gsub, format, byte, find
+do
+  local _obj_0 = string
+  match, sub, rep, gsub, format, byte, match, find = _obj_0.match, _obj_0.sub, _obj_0.rep, _obj_0.gsub, _obj_0.format, _obj_0.byte, _obj_0.match, _obj_0.find
+end
+local AST = require("nomsu_tree")
+local NOMSU_DEFS
+do
+  local _with_0 = { }
+  _with_0.nl = P("\r") ^ -1 * P("\n")
+  _with_0.ws = S(" \t")
+  _with_0.tonumber = tonumber
+  local string_escapes = {
+    n = "\n",
+    t = "\t",
+    b = "\b",
+    a = "\a",
+    v = "\v",
+    f = "\f",
+    r = "\r"
+  }
+  local digit, hex = R('09'), R('09', 'af', 'AF')
+  _with_0.escaped_char = (P("\\") * S("xX") * C(hex * hex)) / function(self)
+    return string.char(tonumber(self, 16))
+  end
+  _with_0.escaped_char = _with_0.escaped_char + ((P("\\") * C(digit * (digit ^ -2))) / function(self)
+    return string.char(tonumber(self))
+  end)
+  _with_0.escaped_char = _with_0.escaped_char + ((P("\\") * C(S("ntbavfr"))) / string_escapes)
+  _with_0.operator_char = S("'`~!@$^&*-+=|<>?/")
+  _with_0.utf8_char = (R("\194\223") * R("\128\191") + R("\224\239") * R("\128\191") * R("\128\191") + R("\240\244") * R("\128\191") * R("\128\191") * R("\128\191"))
+  _with_0.ident_char = R("az", "AZ", "09") + P("_") + _with_0.utf8_char
+  _with_0.indent = Cmt(Carg(1), function(self, start, userdata)
+    local indented = userdata.indent .. '    '
+    if sub(self, start, start + #indented - 1) == indented then
+      userdata.indent = indented
+      return start + #indented
+    end
+  end)
+  _with_0.dedent = Cmt(Carg(1), function(self, start, userdata)
+    local dedented = sub(userdata.indent, 1, -5)
+    if #match(self, "^[ ]*", start) <= #dedented then
+      userdata.indent = dedented
+      return start
+    end
+  end)
+  _with_0.nodent = Cmt(Carg(1), function(self, start, userdata)
+    if sub(self, start, start + #userdata.indent - 1) == userdata.indent then
+      return start + #userdata.indent
+    end
+  end)
+  _with_0.userdata = Carg(1)
+  _with_0.error = function(src, end_pos, start_pos, err_msg, userdata)
+    local seen_errors = userdata.errors
+    if seen_errors[start_pos] then
+      return true
+    end
+    if utils.size(seen_errors) >= 10 then
+      seen_errors[start_pos + 1] = colored.bright(colored.yellow(colored.onred("Too many errors, canceling parsing...")))
+      return #src + 1
+    end
+    local err_pos = start_pos
+    local line_no = pos_to_line(src, err_pos)
+    src = FILE_CACHE[userdata.source.filename]
+    local line_starts = LINE_STARTS[src]
+    local prev_line = line_no == 1 and "" or src:sub(line_starts[line_no - 1] or 1, line_starts[line_no] - 2)
+    local err_line = src:sub(line_starts[line_no], (line_starts[line_no + 1] or 0) - 2)
+    local next_line = src:sub(line_starts[line_no + 1] or -1, (line_starts[line_no + 2] or 0) - 2)
+    local i = err_pos - line_starts[line_no]
+    local pointer = ("-"):rep(i) .. "^"
+    err_msg = colored.bright(colored.yellow(colored.onred((err_msg or "Parse error") .. " at " .. tostring(userdata.source.filename) .. ":" .. tostring(line_no) .. ":")))
+    if #prev_line > 0 then
+      err_msg = err_msg .. ("\n" .. colored.dim(prev_line))
+    end
+    err_line = colored.white(err_line:sub(1, i)) .. colored.bright(colored.red(err_line:sub(i + 1, i + 1))) .. colored.dim(err_line:sub(i + 2, -1))
+    err_msg = err_msg .. "\n" .. tostring(err_line) .. "\n" .. tostring(colored.red(pointer))
+    if #next_line > 0 then
+      err_msg = err_msg .. ("\n" .. colored.dim(next_line))
+    end
+    seen_errors[start_pos] = err_msg
+    return true
+  end
+  NOMSU_DEFS = _with_0
+end
+setmetatable(NOMSU_DEFS, {
+  __index = function(self, key)
+    local make_node
+    make_node = function(start, value, stop, userdata)
+      if userdata.source then
+        do
+          local _with_0 = userdata.source
+          value.source = Source(_with_0.filename, _with_0.start + start - 1, _with_0.start + stop - 1)
+        end
+      end
+      setmetatable(value, AST[key])
+      if value.__init then
+        value:__init()
+      end
+      for i = 1, #value do
+        assert(value[i])
+      end
+      return value
+    end
+    self[key] = make_node
+    return make_node
+  end
+})
+local NOMSU_PATTERN
+do
+  local peg_tidier = re.compile([[    file <- {~ %nl* (def/comment) (%nl+ (def/comment))* %nl* ~}
+    def <- anon_def / captured_def
+    anon_def <- ({ident} (" "*) ":"
+        {((%nl " "+ [^%nl]*)+) / ([^%nl]*)}) -> "%1 <- %2"
+    captured_def <- ({ident} (" "*) "(" {ident} ")" (" "*) ":"
+        {((%nl " "+ [^%nl]*)+) / ([^%nl]*)}) -> "%1 <- (({} %3 {} %%userdata) -> %2)"
+    ident <- [a-zA-Z_][a-zA-Z0-9_]*
+    comment <- "--" [^%nl]*
+    ]])
+  local nomsu_peg = peg_tidier:match(FILE_CACHE["nomsu.peg"])
+  NOMSU_PATTERN = re.compile(nomsu_peg, NOMSU_DEFS)
+end
+local parse
+parse = function(nomsu_code, source)
+  if source == nil then
+    source = nil
+  end
+  nomsu_code = tostring(nomsu_code)
+  local userdata = {
+    indent = "",
+    errors = { },
+    source = source
+  }
+  local tree = NOMSU_PATTERN:match(nomsu_code, nil, userdata)
+  if not (tree) then
+    error("In file " .. tostring(colored.blue(tostring(source or "<unknown>"))) .. " failed to parse:\n" .. tostring(colored.onyellow(colored.black(nomsu_code))))
+  end
+  if type(tree) == 'number' then
+    tree = nil
+  end
+  if next(userdata.errors) then
+    local keys = utils.keys(userdata.errors)
+    table.sort(keys)
+    local errors
+    do
+      local _accum_0 = { }
+      local _len_0 = 1
+      for _index_0 = 1, #keys do
+        local k = keys[_index_0]
+        _accum_0[_len_0] = userdata.errors[k]
+        _len_0 = _len_0 + 1
+      end
+      errors = _accum_0
+    end
+    error(table.concat(errors, "\n\n"), 0)
+  end
+  return tree
+end
+return parse
diff --git a/parser.moon b/parser.moon
new file mode 100644
index 0000000..cac126c
--- /dev/null
+++ b/parser.moon
@@ -0,0 +1,123 @@
+lpeg = require 'lpeg'
+re = require 're'
+lpeg.setmaxstack 10000
+{:P,:R,:V,:S,:Cg,:C,:Cp,:B,:Cmt,:Carg} = lpeg
+utils = require 'utils'
+{:match, :sub, :rep, :gsub, :format, :byte, :match, :find} = string
+{:NomsuCode, :LuaCode, :Source} = require "code_obj"
+AST = require "nomsu_tree"
+
+NOMSU_DEFS = with {}
+    -- Newline supports either windows-style CR+LF or unix-style LF
+    .nl = P("\r")^-1 * P("\n")
+    .ws = S(" \t")
+    .tonumber = tonumber
+    string_escapes = n:"\n", t:"\t", b:"\b", a:"\a", v:"\v", f:"\f", r:"\r"
+    digit, hex = R('09'), R('09','af','AF')
+    .escaped_char = (P("\\")*S("xX")*C(hex*hex)) / => string.char(tonumber(@, 16))
+    .escaped_char += (P("\\")*C(digit*(digit^-2))) / => string.char(tonumber @)
+    .escaped_char += (P("\\")*C(S("ntbavfr"))) / string_escapes
+    .operator_char = S("'`~!@$^&*-+=|<>?/")
+    .utf8_char = (
+        R("\194\223")*R("\128\191") +
+        R("\224\239")*R("\128\191")*R("\128\191") +
+        R("\240\244")*R("\128\191")*R("\128\191")*R("\128\191"))
+    .ident_char = R("az","AZ","09") + P("_") + .utf8_char
+
+    -- If the line begins with #indent+4 spaces, the pattern matches *those* spaces
+    -- and adds them to the current indent (not any more).
+    .indent = Cmt Carg(1), (start, userdata)=>
+        indented = userdata.indent..'    '
+        if sub(@, start, start+#indented-1) == indented
+            userdata.indent = indented
+            return start + #indented
+    -- If the number of leading space characters is <= the number of spaces in the current
+    -- indent minus 4, this pattern matches and decrements the current indent exactly once.
+    .dedent = Cmt Carg(1), (start, userdata)=>
+        dedented = sub(userdata.indent, 1, -5)
+        if #match(@, "^[ ]*", start) <= #dedented
+            userdata.indent = dedented
+            return start
+    -- If the number of leading space characters is >= the number of spaces in the current
+    -- indent, this pattern matches and does not modify the indent.
+    .nodent = Cmt Carg(1), (start, userdata)=>
+        if sub(@, start, start+#userdata.indent-1) == userdata.indent
+            return start + #userdata.indent
+
+    .userdata = Carg(1)
+
+    .error = (src,end_pos,start_pos,err_msg,userdata)->
+        seen_errors = userdata.errors
+        if seen_errors[start_pos]
+            return true
+        if utils.size(seen_errors) >= 10
+            seen_errors[start_pos+1] = colored.bright colored.yellow colored.onred "Too many errors, canceling parsing..."
+            return #src+1
+        err_pos = start_pos
+        line_no = pos_to_line(src, err_pos)
+        src = FILE_CACHE[userdata.source.filename]
+        line_starts = LINE_STARTS[src]
+        prev_line = line_no == 1 and "" or src\sub(line_starts[line_no-1] or 1, line_starts[line_no]-2)
+        err_line = src\sub(line_starts[line_no], (line_starts[line_no+1] or 0)-2)
+        next_line = src\sub(line_starts[line_no+1] or -1, (line_starts[line_no+2] or 0)-2)
+        i = err_pos-line_starts[line_no]
+        pointer = ("-")\rep(i) .. "^"
+        err_msg = colored.bright colored.yellow colored.onred (err_msg or "Parse error").." at #{userdata.source.filename}:#{line_no}:"
+        if #prev_line > 0 then err_msg ..= "\n"..colored.dim(prev_line)
+        err_line = colored.white(err_line\sub(1, i))..colored.bright(colored.red(err_line\sub(i+1,i+1)))..colored.dim(err_line\sub(i+2,-1))
+        err_msg ..= "\n#{err_line}\n#{colored.red pointer}"
+        if #next_line > 0 then err_msg ..= "\n"..colored.dim(next_line)
+        --error(err_msg)
+        seen_errors[start_pos] = err_msg
+        return true
+
+setmetatable(NOMSU_DEFS, {__index:(key)=>
+    make_node = (start, value, stop, userdata)->
+        if userdata.source
+            with userdata.source
+                value.source = Source(.filename, .start + start-1, .start + stop-1)
+        setmetatable(value, AST[key])
+        if value.__init then value\__init!
+        for i=1,#value do assert(value[i])
+        return value
+
+    self[key] = make_node
+    return make_node
+})
+
+NOMSU_PATTERN = do
+    -- Just for cleanliness, I put the language spec in its own file using a slightly modified
+    -- version of the lpeg.re syntax.
+    peg_tidier = re.compile [[
+    file <- {~ %nl* (def/comment) (%nl+ (def/comment))* %nl* ~}
+    def <- anon_def / captured_def
+    anon_def <- ({ident} (" "*) ":"
+        {((%nl " "+ [^%nl]*)+) / ([^%nl]*)}) -> "%1 <- %2"
+    captured_def <- ({ident} (" "*) "(" {ident} ")" (" "*) ":"
+        {((%nl " "+ [^%nl]*)+) / ([^%nl]*)}) -> "%1 <- (({} %3 {} %%userdata) -> %2)"
+    ident <- [a-zA-Z_][a-zA-Z0-9_]*
+    comment <- "--" [^%nl]*
+    ]]
+    nomsu_peg = peg_tidier\match(FILE_CACHE["nomsu.peg"])
+    re.compile(nomsu_peg, NOMSU_DEFS)
+
+parse = (nomsu_code, source=nil)->
+    nomsu_code = tostring(nomsu_code)
+    userdata = {
+        indent: "", errors: {}, :source
+    }
+    tree = NOMSU_PATTERN\match(nomsu_code, nil, userdata)
+    unless tree
+        error "In file #{colored.blue tostring(source or "<unknown>")} failed to parse:\n#{colored.onyellow colored.black nomsu_code}"
+    if type(tree) == 'number'
+        tree = nil
+
+    if next(userdata.errors)
+        keys = utils.keys(userdata.errors)
+        table.sort(keys)
+        errors = [userdata.errors[k] for k in *keys]
+        error(table.concat(errors, "\n\n"), 0)
+    
+    return tree
+
+return parse