simple stack rewriting

moon

@@ -8,6 +8,8 @@ require "moonscript.util"
 
 require "alt_getopt"
 
+require "lpeg"
+
 -- moonloader and repl
 local opts, ind = alt_getopt.get_opts(arg, "ch", { help = "h" })
 
@@ -43,11 +45,13 @@ local function create_moonpath(package_path)
 	return table.concat(paths, ";")
 end
 
+local line_tables = {}
 local function moon_chunk(file, file_path)
-	-- print("loading", file_path)
 	local tree, err = parse.string(file:read"*a")
 	if not tree then error("Parse error: "..err) end
-	local code = compile.tree(tree)
+	local code, ltable = compile.tree(tree)
+
+	line_tables[file_path] = ltable
 
 	return load(function()
 		local out = code
@@ -74,13 +78,64 @@ local function moon_loader(name)
 	return moon_chunk(file, file_path)
 end
 
-
 if not package.moonpath then
 	package.moonpath = create_moonpath(package.path)
 end
 
 table.insert(package.loaders, 2, moon_loader)
 
+local lookup_text = {}
+local function lookup_line(fname, pos)
+	if not lookup_text[fname] then
+		local f = io.open(fname)
+		lookup_text[fname] = f:read"*a"
+		f:close()
+	end
+
+	local sub = lookup_text[fname]:sub(1, pos)
+	local count = 1
+	for _ in sub:gmatch("\n") do
+		count = count + 1
+	end
+	return count
+end
+
+local function reverse_line(fname, line_table, line)
+	for i = line,0,-1 do
+		if line_table[i] then
+			return lookup_line(fname, line_table[i])
+		end
+	end
+	return "unknown"
+end
+
+local function rewrite_traceback(text, err)
+	local header_text = "stack traceback:"
+
+	local Header, Line = lpeg.V"Header", lpeg.V"Line"
+	local Break = lpeg.S"\n"
+	local g = lpeg.P {
+		Header,
+		Header = header_text * Break * lpeg.Ct(Line^1),
+		Line = "\t" * lpeg.C((1 -Break)^0) * (Break + -1)
+	}
+
+	local match = g:match(text)
+	table.insert(match, 1, err)
+	for i, trace in pairs(match) do
+		local fname, line, msg = trace:match('^%[string "(.-)"]:(%d+): (.*)$')
+		if fname then
+			if line_tables[fname] then
+				local table = line_tables[fname]
+				match[i] = fname .. ":" ..
+					reverse_line(fname, table, line) .. ": " .. msg
+			end
+		end
+	end
+
+	return header_text .. "\n\t" .. table.concat(match, "\n\t")
+end
+
 local file, err = io.open(script)
 if not file then error(err) end
 
@@ -92,4 +147,9 @@ local new_arg = {
 
 local chunk = moon_chunk(file, script)
 getfenv(chunk).arg = new_arg
-chunk(unpack(new_arg))
+
+local runner = coroutine.create(chunk)
+local success, err = coroutine.resume(runner, unpack(new_arg))
+if not success then
+	print(rewrite_traceback(debug.traceback(runner), err))
+end

moonscript/compile/format.lua

@@ -68,3 +68,10 @@ has_value = function(node)
   end
 end
 is_non_atomic = function(node) return non_atomic[ntype(node)] end
+count_lines = function(str)
+  local count = 1
+  for _ in str:gmatch("\n") do
+    count = count + 1
+  end
+  return count
+end

moonscript/compile/format.moon

@@ -8,6 +8,7 @@ import Set, ntype from data
 import concat, insert from table
 
 export indent_char, pretty, returner, moonlib, cascading, non_atomic, has_value, is_non_atomic
+export count_lines
 
 indent_char = "  "
 pretty = (lines, indent) ->
@@ -56,3 +57,9 @@ has_value = (node) ->
 
 is_non_atomic = (node) ->
   non_atomic[ntype(node)]
+
+count_lines = (str) ->
+  count = 1
+  count += 1 for _ in str\gmatch "\n"
+  count
+

moonscript/compile2.lua

@@ -179,6 +179,7 @@ local value_compile = {
 local Block
 Block = (function(_parent_0)
   local _base_0 = {
+    line_table = function(self) return self._posmap end,
     set = function(self, name, value) self._state[name] = value end,
     get = function(self, name) return self._state[name] end,
     set_indent = function(self, depth)
@@ -220,6 +221,7 @@ Block = (function(_parent_0)
       end
       return name
     end,
+    mark_pos = function(self, node) self._posmap[#self._lines + 1] = node[-1] end,
     add_lines = function(self, lines)
       local _item_0 = lines
       for _index_0=1,#_item_0 do
@@ -263,6 +265,7 @@ Block = (function(_parent_0)
       if not fn then
         error("Failed to compile value: " .. dump.value(node))
       end
+      self:mark_pos(node)
       return fn(self, node, ...)
     end,
     values = function(self, values, delim)
@@ -336,6 +339,7 @@ Block = (function(_parent_0)
       self.parent = parent
       self:set_indent(self.parent and self.parent.indent + 1 or 0)
       self._lines = {  }
+      self._posmap = {  }
       self._names = {  }
       self._state = {  }
       if self.parent then
@@ -360,5 +364,5 @@ tree = function(tree)
     local line = _item_0[_index_0]
     scope:stm(line)
   end
-  return scope:render()
+  return scope:render(), scope:line_table()
 end

moonscript/compile2.moon

@@ -163,6 +163,7 @@ class Block
   new: (@parent) =>
     @set_indent @parent and @parent.indent + 1 or 0
     @_lines = {}
+    @_posmap = {}
     @_names = {}
     @_state = {}
 
@@ -170,6 +171,9 @@ class Block
       setmetatable @_state, { __index: @parent._state }
       setmetatable @_names, { __index: @parent._names }
 
+  line_table: =>
+    @_posmap
+
   set: (name, value) =>
     @_state[name] = value
 
@@ -203,6 +207,9 @@ class Block
     @put_name name if not dont_put
     name
 
+  mark_pos: (node) =>
+    @_posmap[#@_lines + 1] = node[-1]
+
   add_lines: (lines) =>
     insert @_lines, line for line in *lines
     nil
@@ -244,6 +251,7 @@ class Block
     return tostring node if type(node) != "table"
     fn = value_compile[node[1]]
     error "Failed to compile value: "..dump.value node if not fn
+    @mark_pos node
     fn self, node, ...
 
   values: (values, delim) =>
@@ -303,5 +311,8 @@ build_compiler = ->
 tree = (tree) ->
   scope = Block!
   scope\stm line for line in *tree
-  scope\render!
+
+  -- print util.dump scope._posmap
+
+  scope\render!, scope\line_table!
 

moonscript/dump.lua

@@ -11,7 +11,9 @@ local function flat_value(op, depth)
 		table.insert(items, flat_value(item, depth+1))
 	end
 
-	return "{"..table.concat(items, ", ").."}"
+	local pos = op[-1]
+
+	return "{"..(pos and "["..pos.."] " or "")..table.concat(items, ", ").."}"
 end
 
 function value(op)

moonscript/parse.lua

@@ -75,6 +75,17 @@ local function mark(name)
 	end
 end
 
+local function insert_pos(pos, value)
+    if type(value) == "table" then
+        value[-1] = pos
+    end
+    return value
+end
+
+local function pos(patt)
+	return (lpeg.Cp() * patt) / insert_pos
+end
+
 local function got(what)
 	return Cmt("", function(str, pos, ...)
 		local cap = {...}
@@ -294,10 +305,10 @@ local build_grammar = wrap(function()
 		ChainValue =
 			((Chain + DotChain + Callable) * Ct(ExpList^0)) / flatten_func,
 
-		Value =
+		Value = pos(
 			SimpleValue +
 			Ct(KeyValueList) / mark"table" +
-			ChainValue,
+			ChainValue),
 
 		SliceValue = SimpleValue + ChainValue,
 
@@ -405,7 +416,6 @@ local build_grammar = wrap(function()
 				print("stopped at", line_no)
 				error(err)
 			end
-			
 
 			if not tree then
 				local line_no = pos_to_line(last_pos)