add destructuring assignment

moonscript/compile.lua

@@ -5,7 +5,11 @@ require("moonscript.compile.format")
 require("moonscript.compile.statement")
 require("moonscript.compile.value")
 local transform = require("moonscript.transform")
-local NameProxy, LocalName = transform.NameProxy, transform.LocalName
+local NameProxy, LocalName
+do
+  local _table_0 = require("moonscript.transform.names")
+  NameProxy, LocalName = _table_0.NameProxy, _table_0.LocalName
+end
 local Set
 do
   local _table_0 = require("moonscript.data")

moonscript/compile.moon

@@ -9,7 +9,7 @@ require "moonscript.compile.value"
 
 transform = require "moonscript.transform"
 
-import NameProxy, LocalName from transform
+import NameProxy, LocalName from require "moonscript.transform.names"
 import Set from require "moonscript.data"
 import ntype from require "moonscript.types"
 

moonscript/parse.lua

@@ -170,7 +170,8 @@ local _chain_assignable = { index = true, dot = true, slice = true }
 local function is_assignable(node)
 	local t = ntype(node)
 	return t == "self" or t == "value" or t == "self_class" or
-		t == "chain" and _chain_assignable[ntype(node[#node])]
+		t == "chain" and _chain_assignable[ntype(node[#node])] or
+		t == "table"
 end
 
 local function check_assignable(str, pos, value)

moonscript/transform.lua

@@ -5,6 +5,12 @@ 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 insert = table.insert
+local NameProxy, LocalName
+do
+  local _table_0 = require("moonscript.transform.names")
+  NameProxy, LocalName = _table_0.NameProxy, _table_0.LocalName
+end
+local destructure = require("moonscript.transform.destructure")
 local mtype
 do
   local moon_type = util.moon.type
@@ -18,136 +24,6 @@ do
   end
 end
 local implicitly_return
-do
-  local _parent_0 = nil
-  local _base_0 = {
-    get_name = function(self)
-      return self.name
-    end
-  }
-  _base_0.__index = _base_0
-  if _parent_0 then
-    setmetatable(_base_0, _parent_0.__base)
-  end
-  local _class_0 = setmetatable({
-    __init = function(self, name)
-      self.name = name
-      self[1] = "temp_name"
-    end,
-    __base = _base_0,
-    __name = "LocalName",
-    __parent = _parent_0
-  }, {
-    __index = function(cls, name)
-      local val = rawget(_base_0, name)
-      if val == nil and _parent_0 then
-        return _parent_0[name]
-      else
-        return val
-      end
-    end,
-    __call = function(cls, ...)
-      local _self_0 = setmetatable({}, _base_0)
-      cls.__init(_self_0, ...)
-      return _self_0
-    end
-  })
-  _base_0.__class = _class_0
-  if _parent_0 and _parent_0.__inherited then
-    _parent_0.__inherited(_parent_0, _class_0)
-  end
-  LocalName = _class_0
-end
-do
-  local _parent_0 = nil
-  local _base_0 = {
-    get_name = function(self, scope)
-      if not self.name then
-        self.name = scope:free_name(self.prefix, true)
-      end
-      return self.name
-    end,
-    chain = function(self, ...)
-      local items = {
-        ...
-      }
-      items = (function()
-        local _accum_0 = { }
-        local _len_0 = 0
-        local _list_0 = items
-        for _index_0 = 1, #_list_0 do
-          local i = _list_0[_index_0]
-          local _value_0
-          if type(i) == "string" then
-            _value_0 = {
-              "dot",
-              i
-            }
-          else
-            _value_0 = i
-          end
-          if _value_0 ~= nil then
-            _len_0 = _len_0 + 1
-            _accum_0[_len_0] = _value_0
-          end
-        end
-        return _accum_0
-      end)()
-      return build.chain({
-        base = self,
-        unpack(items)
-      })
-    end,
-    index = function(self, key)
-      return build.chain({
-        base = self,
-        {
-          "index",
-          key
-        }
-      })
-    end,
-    __tostring = function(self)
-      if self.name then
-        return ("name<%s>"):format(self.name)
-      else
-        return ("name<prefix(%s)>"):format(self.prefix)
-      end
-    end
-  }
-  _base_0.__index = _base_0
-  if _parent_0 then
-    setmetatable(_base_0, _parent_0.__base)
-  end
-  local _class_0 = setmetatable({
-    __init = function(self, prefix)
-      self.prefix = prefix
-      self[1] = "temp_name"
-    end,
-    __base = _base_0,
-    __name = "NameProxy",
-    __parent = _parent_0
-  }, {
-    __index = function(cls, name)
-      local val = rawget(_base_0, name)
-      if val == nil and _parent_0 then
-        return _parent_0[name]
-      else
-        return val
-      end
-    end,
-    __call = function(cls, ...)
-      local _self_0 = setmetatable({}, _base_0)
-      cls.__init(_self_0, ...)
-      return _self_0
-    end
-  })
-  _base_0.__class = _class_0
-  if _parent_0 and _parent_0.__inherited then
-    _parent_0.__inherited(_parent_0, _class_0)
-  end
-  NameProxy = _class_0
-end
 do
   local _parent_0 = nil
   local _base_0 = {
@@ -497,7 +373,11 @@ Statement = Transformer({
         })
       end
     end
-    return transformed or node
+    node = transformed or node
+    if destructure.has_destructure(names) then
+      return destructure.split_assign(node)
+    end
+    return node
   end,
   continue = function(self, node)
     local continue_name = self:send("continue")

moonscript/transform.moon

@@ -8,6 +8,9 @@ data = require "moonscript.data"
 import reversed from util
 import ntype, 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
@@ -19,48 +22,10 @@ mtype = do
     else
       t
 
-export Statement, Value, NameProxy, LocalName, Run
+export Statement, Value, Run
 
 local implicitly_return
 
--- always declares as local
-class LocalName
-  new: (@name) => self[1] = "temp_name"
-  get_name: => @name
-
-class NameProxy
-  new: (@prefix) =>
-    self[1] = "temp_name"
-
-  get_name: (scope) =>
-    if not @name
-      @name = scope\free_name @prefix, true
-    @name
-
-  chain: (...) =>
-    items = {...} -- todo: fix ... propagation
-    items = for i in *items
-      if type(i) == "string"
-        {"dot", i}
-      else
-        i
-
-    build.chain {
-      base: self
-      unpack items
-    }
-
-  index: (key) =>
-    build.chain {
-      base: self, {"index", key}
-    }
-
-  __tostring: =>
-    if @name
-      ("name<%s>")\format @name
-    else
-      ("name<prefix(%s)>")\format @prefix
-
 class Run
   new: (@fn) =>
     self[1] = "run"
@@ -228,7 +193,12 @@ Statement = Transformer {
           @transform.statement value, ret, node
         }
 
-    transformed or node
+    node = transformed or node
+
+    if destructure.has_destructure names
+      return destructure.split_assign node
+
+    node
 
   continue: (node) =>
     continue_name = @send "continue"

moonscript/transform/destructure.lua

@@ -0,0 +1,227 @@
+local ntype, build
+do
+  local _table_0 = require("moonscript.types")
+  ntype, build = _table_0.ntype, _table_0.build
+end
+local NameProxy
+do
+  local _table_0 = require("moonscript.transform.names")
+  NameProxy = _table_0.NameProxy
+end
+local insert = table.insert
+local user_error
+do
+  local _table_0 = require("moonscript.compile")
+  user_error = _table_0.user_error
+end
+local join
+join = function(...)
+  do
+    local _with_0 = { }
+    local out = _with_0
+    local i = 1
+    local _list_0 = {
+      ...
+    }
+    for _index_0 = 1, #_list_0 do
+      local tbl = _list_0[_index_0]
+      local _list_1 = tbl
+      for _index_1 = 1, #_list_1 do
+        local v = _list_1[_index_1]
+        out[i] = v
+        i = i + 1
+      end
+    end
+    return _with_0
+  end
+end
+local has_destructure
+has_destructure = function(names)
+  local _list_0 = names
+  for _index_0 = 1, #_list_0 do
+    local n = _list_0[_index_0]
+    if ntype(n) == "table" then
+      return true
+    end
+  end
+  return false
+end
+local build_assign
+build_assign = function(extracted_names, receiver)
+  local obj = NameProxy("obj")
+  local names = { }
+  local values = { }
+  local _list_0 = extracted_names
+  for _index_0 = 1, #_list_0 do
+    local tuple = _list_0[_index_0]
+    insert(names, tuple[1])
+    insert(values, obj:chain(unpack(tuple[2])))
+  end
+  return build.group({
+    {
+      "declare",
+      names
+    },
+    build["do"]({
+      build.assign_one(obj, receiver),
+      {
+        "assign",
+        names,
+        values
+      }
+    })
+  })
+end
+local extract_assign_names
+extract_assign_names = function(name, accum, prefix)
+  if accum == nil then
+    accum = { }
+  end
+  if prefix == nil then
+    prefix = { }
+  end
+  local i = 1
+  local _list_0 = name[2]
+  for _index_0 = 1, #_list_0 do
+    local tuple = _list_0[_index_0]
+    local value, suffix
+    if #tuple == 1 then
+      local s = {
+        "index",
+        {
+          "number",
+          i
+        }
+      }
+      i = i + 1
+      value, suffix = tuple[1], s
+    else
+      local key = tuple[1]
+      local s
+      if ntype(key) == "key_literal" then
+        s = {
+          "dot",
+          key[2]
+        }
+      else
+        s = {
+          "index",
+          key
+        }
+      end
+      value, suffix = tuple[2], s
+    end
+    suffix = join(prefix, {
+      suffix
+    })
+    local t = ntype(value)
+    if t == "value" or t == "chain" or t == "self" then
+      insert(accum, {
+        value,
+        suffix
+      })
+    elseif t == "table" then
+      extract_assign_names(value, accum, suffix)
+    else
+      user_error("Can't destructure value of type: " .. tostring(ntype(value)))
+    end
+  end
+  return accum
+end
+local split_assign
+split_assign = function(assign)
+  local names, values = unpack(assign, 2)
+  local g = { }
+  local total_names = #names
+  local total_values = #values
+  local start = 1
+  for i, n in ipairs(names) do
+    if ntype(n) == "table" then
+      if i > start then
+        local stop = i - 1
+        insert(g, {
+          "assign",
+          (function()
+            local _accum_0 = { }
+            local _len_0 = 0
+            for i = start, stop do
+              local _value_0 = names[i]
+              if _value_0 ~= nil then
+                _len_0 = _len_0 + 1
+                _accum_0[_len_0] = _value_0
+              end
+            end
+            return _accum_0
+          end)(),
+          (function()
+            local _accum_0 = { }
+            local _len_0 = 0
+            for i = start, stop do
+              local _value_0 = values[i]
+              if _value_0 ~= nil then
+                _len_0 = _len_0 + 1
+                _accum_0[_len_0] = _value_0
+              end
+            end
+            return _accum_0
+          end)()
+        })
+      end
+      local extracted = extract_assign_names(n)
+      insert(g, build_assign(extracted, values[i]))
+      start = i + 1
+    end
+  end
+  if total_names >= start or total_values >= start then
+    local name_slice
+    if total_names < start then
+      name_slice = {
+        "_"
+      }
+    else
+      name_slice = (function()
+        local _accum_0 = { }
+        local _len_0 = 0
+        for i = start, total_names do
+          local _value_0 = names[i]
+          if _value_0 ~= nil then
+            _len_0 = _len_0 + 1
+            _accum_0[_len_0] = _value_0
+          end
+        end
+        return _accum_0
+      end)()
+    end
+    local value_slice
+    if total_values < start then
+      value_slice = {
+        "nil"
+      }
+    else
+      value_slice = (function()
+        local _accum_0 = { }
+        local _len_0 = 0
+        for i = start, total_values do
+          local _value_0 = values[i]
+          if _value_0 ~= nil then
+            _len_0 = _len_0 + 1
+            _accum_0[_len_0] = _value_0
+          end
+        end
+        return _accum_0
+      end)()
+    end
+    insert(g, {
+      "assign",
+      name_slice,
+      value_slice
+    })
+  end
+  return build.group(g)
+end
+return {
+  has_destructure = has_destructure,
+  split_assign = split_assign,
+  extract_assign_names = extract_assign_names,
+  build_assign = build_assign
+}

moonscript/transform/destructure.moon

@@ -0,0 +1,109 @@
+
+import ntype, build from require "moonscript.types"
+import NameProxy from require "moonscript.transform.names"
+import insert from table
+
+import user_error from require "moonscript.compile"
+
+join = (...) ->
+  with out = {}
+    i = 1
+    for tbl in *{...}
+      for v in *tbl
+        out[i] = v
+        i += 1
+
+has_destructure = (names) ->
+  for n in *names
+    return true if ntype(n) == "table"
+  false
+
+build_assign = (extracted_names, receiver) ->
+  obj = NameProxy "obj"
+  names = {}
+  values = {}
+
+  for tuple in *extracted_names
+    insert names, tuple[1]
+    insert values, obj\chain unpack tuple[2]
+
+  build.group {
+    {"declare", names}
+    build.do {
+      build.assign_one obj, receiver
+      {"assign", names, values}
+    }
+  }
+
+extract_assign_names = (name, accum={}, prefix={}) ->
+  i = 1
+  for tuple in *name[2]
+    value, suffix = if #tuple == 1
+      s = {"index", {"number", i}}
+      i += 1
+      tuple[1], s
+    else
+      key = tuple[1]
+      s = if ntype(key) == "key_literal"
+        {"dot", key[2]}
+      else
+        {"index", key}
+
+      tuple[2], s
+
+    suffix = join prefix, {suffix}
+
+    t = ntype value
+    if t == "value" or t == "chain" or t == "self"
+      insert accum, {value, suffix}
+    elseif t == "table"
+      extract_assign_names value, accum, suffix
+    else
+      user_error "Can't destructure value of type: #{ntype value}"
+
+  accum
+
+-- applies to destructuring to a assign node
+split_assign = (assign) ->
+  names, values = unpack assign, 2
+
+  g = {}
+  total_names = #names
+  total_values = #values
+
+  -- We have to break apart the assign into groups of regular
+  -- assigns, and then the destructuring assignments
+  start = 1
+  for i, n in ipairs names
+    if ntype(n) == "table"
+      if i > start
+        stop = i - 1
+        insert g, {
+          "assign"
+          for i=start,stop
+            names[i]
+          for i=start,stop
+            values[i]
+        }
+
+      extracted = extract_assign_names n
+      insert g, build_assign extracted, values[i]
+
+      start = i + 1
+
+  if total_names >= start or total_values >= start
+    name_slice = if total_names < start
+      {"_"}
+    else
+      for i=start,total_names do names[i]
+
+    value_slice = if total_values < start
+      {"nil"}
+    else
+      for i=start,total_values do values[i]
+
+    insert g, {"assign", name_slice, value_slice}
+
+  build.group g
+
+{ :has_destructure, :split_assign, :extract_assign_names, :build_assign }

moonscript/transform/names.lua

@@ -0,0 +1,140 @@
+local build
+do
+  local _table_0 = require("moonscript.types")
+  build = _table_0.build
+end
+local LocalName
+do
+  local _parent_0 = nil
+  local _base_0 = {
+    get_name = function(self)
+      return self.name
+    end
+  }
+  _base_0.__index = _base_0
+  if _parent_0 then
+    setmetatable(_base_0, _parent_0.__base)
+  end
+  local _class_0 = setmetatable({
+    __init = function(self, name)
+      self.name = name
+      self[1] = "temp_name"
+    end,
+    __base = _base_0,
+    __name = "LocalName",
+    __parent = _parent_0
+  }, {
+    __index = function(cls, name)
+      local val = rawget(_base_0, name)
+      if val == nil and _parent_0 then
+        return _parent_0[name]
+      else
+        return val
+      end
+    end,
+    __call = function(cls, ...)
+      local _self_0 = setmetatable({}, _base_0)
+      cls.__init(_self_0, ...)
+      return _self_0
+    end
+  })
+  _base_0.__class = _class_0
+  if _parent_0 and _parent_0.__inherited then
+    _parent_0.__inherited(_parent_0, _class_0)
+  end
+  LocalName = _class_0
+end
+local NameProxy
+do
+  local _parent_0 = nil
+  local _base_0 = {
+    get_name = function(self, scope)
+      if not self.name then
+        self.name = scope:free_name(self.prefix, true)
+      end
+      return self.name
+    end,
+    chain = function(self, ...)
+      local items = (function(...)
+        local _accum_0 = { }
+        local _len_0 = 0
+        local _list_0 = {
+          ...
+        }
+        for _index_0 = 1, #_list_0 do
+          local i = _list_0[_index_0]
+          local _value_0
+          if type(i) == "string" then
+            _value_0 = {
+              "dot",
+              i
+            }
+          else
+            _value_0 = i
+          end
+          if _value_0 ~= nil then
+            _len_0 = _len_0 + 1
+            _accum_0[_len_0] = _value_0
+          end
+        end
+        return _accum_0
+      end)(...)
+      return build.chain({
+        base = self,
+        unpack(items)
+      })
+    end,
+    index = function(self, key)
+      return build.chain({
+        base = self,
+        {
+          "index",
+          key
+        }
+      })
+    end,
+    __tostring = function(self)
+      if self.name then
+        return ("name<%s>"):format(self.name)
+      else
+        return ("name<prefix(%s)>"):format(self.prefix)
+      end
+    end
+  }
+  _base_0.__index = _base_0
+  if _parent_0 then
+    setmetatable(_base_0, _parent_0.__base)
+  end
+  local _class_0 = setmetatable({
+    __init = function(self, prefix)
+      self.prefix = prefix
+      self[1] = "temp_name"
+    end,
+    __base = _base_0,
+    __name = "NameProxy",
+    __parent = _parent_0
+  }, {
+    __index = function(cls, name)
+      local val = rawget(_base_0, name)
+      if val == nil and _parent_0 then
+        return _parent_0[name]
+      else
+        return val
+      end
+    end,
+    __call = function(cls, ...)
+      local _self_0 = setmetatable({}, _base_0)
+      cls.__init(_self_0, ...)
+      return _self_0
+    end
+  })
+  _base_0.__class = _class_0
+  if _parent_0 and _parent_0.__inherited then
+    _parent_0.__inherited(_parent_0, _class_0)
+  end
+  NameProxy = _class_0
+end
+return {
+  NameProxy = NameProxy,
+  LocalName = LocalName
+}

moonscript/transform/names.moon

@@ -0,0 +1,43 @@
+
+import build from require "moonscript.types"
+
+-- always declares as local
+class LocalName
+  new: (@name) => self[1] = "temp_name"
+  get_name: => @name
+
+-- creates a unique name when used
+class NameProxy
+  new: (@prefix) =>
+    self[1] = "temp_name"
+
+  get_name: (scope) =>
+    if not @name
+      @name = scope\free_name @prefix, true
+    @name
+
+  chain: (...) =>
+    items = for i in *{...}
+      if type(i) == "string"
+        {"dot", i}
+      else
+        i
+
+    build.chain {
+      base: self
+      unpack items
+    }
+
+  index: (key) =>
+    build.chain {
+      base: self, {"index", key}
+    }
+
+  __tostring: =>
+    if @name
+      ("name<%s>")\format @name
+    else
+      ("name<prefix(%s)>")\format @prefix
+
+
+{ :NameProxy, :LocalName }

tests/inputs/destructure.moon

@@ -0,0 +1,45 @@
+
+{a, b} = hello
+
+{{a}, b, {c}} = hello
+
+{ :hello, :world } = value
+
+{ yes: no, thing } = world
+
+{:a,:b,:c,:d} = yeah
+
+{a} = one, two
+{b}, c = one
+{d}, e = one, two
+
+x, {y} = one, two
+
+xx, yy = 1, 2
+{yy, xx} = {xx, yy}
+
+{a, :b, c, :d, e, :f, g} = tbl
+
+--- 
+
+futurists =
+  sculptor: "Umberto Boccioni"
+  painter:  "Vladimir Burliuk"
+  poet:
+    name:   "F.T. Marinetti"
+    address: {
+      "Via Roma 42R"
+      "Bellagio, Italy 22021"
+    }
+
+{poet: {:name, address: {street, city}}} = futurists
+
+print name, street, city
+
+--
+
+{ @world } = x
+{ a.b, c.y, func!.z } = x
+
+{ world: @world } = x
+

tests/outputs/destructure.lua

@@ -0,0 +1,88 @@
+local a, b
+do
+  local _obj_0 = hello
+  a, b = _obj_0[1], _obj_0[2]
+end
+local c
+do
+  local _obj_0 = hello
+  a, b, c = _obj_0[1][1], _obj_0[2], _obj_0[3][1]
+end
+local hello, world
+do
+  local _obj_0 = value
+  hello, world = _obj_0.hello, _obj_0.world
+end
+local no, thing
+do
+  local _obj_0 = world
+  no, thing = _obj_0.yes, _obj_0[1]
+end
+local d
+do
+  local _obj_0 = yeah
+  a, b, c, d = _obj_0.a, _obj_0.b, _obj_0.c, _obj_0.d
+end
+do
+  local _obj_0 = one
+  a = _obj_0[1]
+end
+local _ = two
+do
+  local _obj_0 = one
+  b = _obj_0[1]
+end
+c = nil
+do
+  local _obj_0 = one
+  d = _obj_0[1]
+end
+local e = two
+local x = one
+local y
+do
+  local _obj_0 = two
+  y = _obj_0[1]
+end
+local xx, yy = 1, 2
+do
+  local _obj_0 = {
+    xx,
+    yy
+  }
+  yy, xx = _obj_0[1], _obj_0[2]
+end
+local f, g
+do
+  local _obj_0 = tbl
+  a, b, c, d, e, f, g = _obj_0[1], _obj_0.b, _obj_0[2], _obj_0.d, _obj_0[3], _obj_0.f, _obj_0[4]
+end
+local futurists = {
+  sculptor = "Umberto Boccioni",
+  painter = "Vladimir Burliuk",
+  poet = {
+    name = "F.T. Marinetti",
+    address = {
+      "Via Roma 42R",
+      "Bellagio, Italy 22021"
+    }
+  }
+}
+local name, street, city
+do
+  local _obj_0 = futurists
+  name, street, city = _obj_0.poet.name, _obj_0.poet.address[1], _obj_0.poet.address[2]
+end
+print(name, street, city)
+do
+  local _obj_0 = x
+  self.world = _obj_0[1]
+end
+do
+  local _obj_0 = x
+  a.b, c.y, func().z = _obj_0[1], _obj_0[2], _obj_0[3]
+end
+do
+  local _obj_0 = x
+  self.world = _obj_0.world
+end