allow destructure in for in names

moonscript/parse.lua

@@ -435,7 +435,7 @@ local build_grammar = wrap_env(function()
 		For = key"for" * DisableDo * ensure(Name * sym"=" * Ct(Exp * sym"," * Exp * (sym"," * Exp)^-1), PopDo) *
 			key"do"^-1 * Body / mark"for",
 
-		ForEach = key"for" * Ct(NameList) * key"in" * DisableDo * ensure(Ct(sym"*" * Exp / mark"unpack" + ExpList), PopDo) * key"do"^-1 * Body / mark"foreach",
+		ForEach = key"for" * Ct(AssignableNameList) * key"in" * DisableDo * ensure(Ct(sym"*" * Exp / mark"unpack" + ExpList), PopDo) * key"do"^-1 * Body / mark"foreach",
 
 		Do = key"do" * Body / mark"do",
 
@@ -575,7 +575,7 @@ local build_grammar = wrap_env(function()
 			(key"using" * Ct(NameList + Space * "nil") + Ct"") *
 			sym")" + Ct"" * Ct"",
 
-		FnArgDefList =  FnArgDef * (sym"," * FnArgDef)^0,
+		FnArgDefList = FnArgDef * (sym"," * FnArgDef)^0,
 		FnArgDef = Ct(Name * (sym"=" * Exp)^-1),
 
 		FunLit = FnArgsDef *
@@ -583,6 +583,9 @@ local build_grammar = wrap_env(function()
 			(Body + Ct"") / mark"fndef",
 
 		NameList = Name * (sym"," * Name)^0,
+		NameOrDestructure = Name + TableLit,
+		AssignableNameList = NameOrDestructure * (sym"," * NameOrDestructure)^0,
+
 		ExpList = Exp * (sym"," * Exp)^0,
 		ExpListLow = Exp * ((sym"," + sym";") * Exp)^0,
 

moonscript/transform.lua

@@ -2,7 +2,7 @@ local types = require("moonscript.types")
 local util = require("moonscript.util")
 local data = require("moonscript.data")
 local reversed = util.reversed
-local ntype, build, smart_node, is_slice, value_is_singular = types.ntype, types.build, types.smart_node, types.is_slice, types.value_is_singular
+local ntype, mtype, build, smart_node, is_slice, value_is_singular = types.ntype, types.mtype, types.build, types.smart_node, types.is_slice, types.value_is_singular
 local insert = table.insert
 local NameProxy, LocalName
 do
@@ -10,18 +10,6 @@ do
   NameProxy, LocalName = _table_0.NameProxy, _table_0.LocalName
 end
 local destructure = require("moonscript.transform.destructure")
-local mtype
-do
-  local moon_type = util.moon.type
-  mtype = function(val)
-    local t = type(val)
-    if "table" == t and rawget(val, "__class") then
-      return moon_type(val)
-    else
-      return t
-    end
-  end
-end
 local implicitly_return
 local Run
 do
@@ -670,6 +658,34 @@ local Statement = Transformer({
   foreach = function(self, node)
     smart_node(node)
     local source = unpack(node.iter)
+    local destructures = { }
+    node.names = (function()
+      local _accum_0 = { }
+      local _len_0 = 0
+      for i, name in ipairs(node.names) do
+        local _value_0
+        if ntype(name) == "table" then
+          do
+            local _with_0 = NameProxy("des")
+            local proxy = _with_0
+            local extracted = destructure.extract_assign_names(name)
+            insert(destructures, destructure.build_assign(extracted, proxy))
+            _value_0 = _with_0
+          end
+        else
+          _value_0 = name
+        end
+        if _value_0 ~= nil then
+          _len_0 = _len_0 + 1
+          _accum_0[_len_0] = _value_0
+        end
+      end
+      return _accum_0
+    end)()
+    if next(destructures) then
+      insert(destructures, build.group(node.body))
+      node.body = destructures
+    end
     if ntype(source) == "unpack" then
       local list = source[2]
       local index_name = NameProxy("index")

moonscript/transform.moon

@@ -4,22 +4,12 @@ util = require "moonscript.util"
 data = require "moonscript.data"
 
 import reversed from util
-import ntype, build, smart_node, is_slice, value_is_singular from types
+import ntype, mtype, build, smart_node, is_slice, value_is_singular from types
 import insert from table
 import NameProxy, LocalName from require "moonscript.transform.names"
 
 destructure = require "moonscript.transform.destructure"
 
-mtype = do
-  moon_type = util.moon.type
-  -- lets us check a smart node without throwing an error
-  (val) ->
-    t = type(val)
-    if "table" == t and rawget(val, "__class")
-      moon_type val
-    else
-      t
-
 local implicitly_return
 
 class Run
@@ -347,6 +337,19 @@ Statement = Transformer {
     smart_node node
     source = unpack node.iter
 
+    destructures = {}
+    node.names = for i, name in ipairs node.names
+      if ntype(name) == "table"
+        with proxy = NameProxy "des"
+          extracted = destructure.extract_assign_names name
+          insert destructures, destructure.build_assign extracted, proxy
+      else
+        name
+
+    if next destructures
+      insert destructures, build.group node.body
+      node.body = destructures
+
     if ntype(source) == "unpack"
       list = source[2]
 

moonscript/transform/destructure.lua

@@ -1,7 +1,7 @@
-local ntype, build
+local ntype, mtype, build
 do
   local _table_0 = require("moonscript.types")
-  ntype, build = _table_0.ntype, _table_0.build
+  ntype, mtype, build = _table_0.ntype, _table_0.mtype, _table_0.build
 end
 local NameProxy
 do
@@ -48,9 +48,31 @@ has_destructure = function(names)
 end
 local build_assign
 build_assign = function(extracted_names, receiver)
-  local obj = NameProxy("obj")
   local names = { }
   local values = { }
+  local inner = {
+    "assign",
+    names,
+    values
+  }
+  local obj
+  if mtype(receiver) == NameProxy then
+    obj = receiver
+  else
+    do
+      local _with_0 = NameProxy("obj")
+      obj = _with_0
+      inner = build["do"]({
+        build.assign_one(obj, receiver),
+        {
+          "assign",
+          names,
+          values
+        }
+      })
+      obj = _with_0
+    end
+  end
   local _list_0 = extracted_names
   for _index_0 = 1, #_list_0 do
     local tuple = _list_0[_index_0]
@@ -62,14 +84,7 @@ build_assign = function(extracted_names, receiver)
       "declare",
       names
     },
-    build["do"]({
+    inner
-      build.assign_one(obj, receiver),
-      {
-        "assign",
-        names,
-        values
-      }
-    })
   })
 end
 local extract_assign_names

moonscript/transform/destructure.moon

@@ -1,5 +1,5 @@
 
-import ntype, build from require "moonscript.types"
+import ntype, mtype, build from require "moonscript.types"
 import NameProxy from require "moonscript.transform.names"
 import insert from table
 
@@ -19,20 +19,27 @@ has_destructure = (names) ->
   false
 
 build_assign = (extracted_names, receiver) ->
-  obj = NameProxy "obj"
   names = {}
   values = {}
 
+  inner = {"assign", names, values}
+
+  obj = if mtype(receiver) == NameProxy
+    receiver
+  else
+    with obj = NameProxy "obj"
+      inner = build.do {
+        build.assign_one obj, receiver
+        {"assign", names, values}
+      }
+
   for tuple in *extracted_names
     insert names, tuple[1]
     insert values, obj\chain unpack tuple[2]
 
   build.group {
     {"declare", names}
-    build.do {
+    inner
-      build.assign_one obj, receiver
-      {"assign", names, values}
-    }
   }
 
 extract_assign_names = (name, accum={}, prefix={}) ->

moonscript/types.lua

@@ -26,6 +26,17 @@ ntype = function(node)
     return "value"
   end
 end
+local mtype
+do
+  local moon_type = util.moon.type
+  mtype = function(val)
+    local mt = getmetatable(val)
+    if mt and mt.smart_node then
+      return "table"
+    end
+    return moon_type(val)
+  end
+end
 local has_value
 has_value = function(node)
   if ntype(node) == "chain" then
@@ -260,27 +271,32 @@ build = setmetatable({
     return rawget(self, name)
   end
 })
+local smart_node_mt = setmetatable({ }, {
+  __index = function(self, node_type)
+    local index = key_table[node_type]
+    local mt = {
+      smart_node = true,
+      __index = function(node, key)
+        if index[key] then
+          return rawget(node, index[key])
+        elseif type(key) == "string" then
+          return error("unknown key: `" .. key .. "` on node type: `" .. ntype(node) .. "`")
+        end
+      end,
+      __newindex = function(node, key, value)
+        if index[key] then
+          key = index[key]
+        end
+        return rawset(node, key, value)
+      end
+    }
+    self[node_type] = mt
+    return mt
+  end
+})
 local smart_node
 smart_node = function(node)
-  local index = key_table[ntype(node)]
+  return setmetatable(node, smart_node_mt[ntype(node)])
-  if not index then
-    return node
-  end
-  return setmetatable(node, {
-    __index = function(node, key)
-      if index[key] then
-        return rawget(node, index[key])
-      elseif type(key) == "string" then
-        return error("unknown key: `" .. key .. "` on node type: `" .. ntype(node) .. "`")
-      end
-    end,
-    __newindex = function(node, key, value)
-      if index[key] then
-        key = index[key]
-      end
-      return rawset(node, key, value)
-    end
-  })
 end
 return {
   ntype = ntype,
@@ -292,5 +308,6 @@ return {
   cascading = cascading,
   value_is_singular = value_is_singular,
   comprehension_has_value = comprehension_has_value,
-  has_value = has_value
+  has_value = has_value,
+  mtype = mtype
 }

moonscript/types.moon

@@ -22,6 +22,14 @@ ntype = (node) ->
     else
       "value"
 
+mtype = do
+  moon_type = util.moon.type
+  -- lets us check a smart node without throwing an error
+  (val) ->
+    mt = getmetatable val
+    return "table" if mt and mt.smart_node
+    moon_type val
+
 -- does this always return a value
 has_value = (node) ->
   if ntype(node) == "chain"
@@ -142,25 +150,33 @@ build = setmetatable {
     rawget self, name
 }
 
+smart_node_mt = setmetatable {}, {
+  __index: (node_type) =>
+    index = key_table[node_type]
+    mt = {
+      smart_node: true
+
+      __index: (node, key) ->
+        if index[key]
+          rawget node, index[key]
+        elseif type(key) == "string"
+          error "unknown key: `"..key.."` on node type: `"..ntype(node).. "`"
+
+      __newindex: (node, key, value) ->
+        key = index[key] if index[key]
+        rawset node, key, value
+    }
+    self[node_type] = mt
+    mt
+}
+
 -- makes it so node properties can be accessed by name instead of index
 smart_node = (node) ->
-  index = key_table[ntype node]
+  setmetatable node, smart_node_mt[ntype node]
-  if not index then return node
-  setmetatable node, {
-    __index: (node, key) ->
-      if index[key]
-        rawget node, index[key]
-      elseif type(key) == "string"
-        error "unknown key: `"..key.."` on node type: `"..ntype(node).. "`"
-
-    __newindex: (node, key, value) ->
-      key = index[key] if index[key]
-      rawset node, key, value
-  }
-    
 
 {
   :ntype, :smart_node, :build, :is_value, :is_slice, :manual_return,
-  :cascading, :value_is_singular, :comprehension_has_value, :has_value
+  :cascading, :value_is_singular, :comprehension_has_value, :has_value,
+  :mtype
 }
 

tests/inputs/destructure.moon

@@ -43,3 +43,11 @@ print name, street, city
 
 { world: @world } = x
 
+--
+
+thing = {{1,2}, {3,4}}
+
+for {x,y} in *thing
+  print x,y
+
+

tests/outputs/destructure.lua

@@ -85,4 +85,20 @@ end
 do
   local _obj_0 = x
   self.world = _obj_0.world
+end
+thing = {
+  {
+    1,
+    2
+  },
+  {
+    3,
+    4
+  }
+}
+local _list_0 = thing
+for _index_0 = 1, #_list_0 do
+  local _des_0 = _list_0[_index_0]
+  x, y = _des_0[1], _des_0[2]
+  print(x, y)
 end