destructure works with if assignment cond

moonscript/transform.lua

@@ -602,15 +602,32 @@ local Statement = Transformer({
   ["if"] = function(self, node, ret)
     if ntype(node[2]) == "assign" then
       local _, assign, body = unpack(node)
-      local name = assign[2][1]
-      return build["do"]({
-        assign,
-        {
-          "if",
-          name,
-          unpack(node, 3)
+      if destructure.has_destructure(assign[2]) then
+        local name = NameProxy("des")
+        body = {
+          destructure.build_assign(assign[2][1], name),
+          build.group(node[3])
         }
-      })
+        return build["do"]({
+          build.assign_one(name, assign[3][1]),
+          {
+            "if",
+            name,
+            body,
+            unpack(node, 4)
+          }
+        })
+      else
+        local name = assign[2][1]
+        return build["do"]({
+          assign,
+          {
+            "if",
+            name,
+            unpack(node, 3)
+          }
+        })
+      end
     end
     node = expand_elseif_assign(node)
     if ret then
@@ -668,8 +685,7 @@ local Statement = Transformer({
           do
             local _with_0 = NameProxy("des")
             local proxy = _with_0
-            local extracted = destructure.extract_assign_names(name)
-            insert(destructures, destructure.build_assign(extracted, proxy))
+            insert(destructures, destructure.build_assign(name, proxy))
             _value_0 = _with_0
           end
         else

moonscript/transform.moon

@@ -291,11 +291,24 @@ Statement = Transformer {
     -- expand assign in cond
     if ntype(node[2]) == "assign"
       _, assign, body = unpack node
-      name = assign[2][1]
-      return build["do"] {
-        assign
-        {"if", name, unpack node, 3}
-      }
+      if destructure.has_destructure assign[2]
+        name = NameProxy "des"
+
+        body = {
+          destructure.build_assign assign[2][1], name
+          build.group node[3]
+        }
+
+        return build.do {
+          build.assign_one name, assign[3][1]
+          {"if", name, body, unpack node, 4}
+        }
+      else
+        name = assign[2][1]
+        return build["do"] {
+          assign
+          {"if", name, unpack node, 3}
+        }
 
     node = expand_elseif_assign node
 
@@ -341,8 +354,7 @@ Statement = Transformer {
     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
+          insert destructures, destructure.build_assign name, proxy
       else
         name
 

moonscript/transform/destructure.lua

@@ -46,47 +46,6 @@ has_destructure = function(names)
   end
   return false
 end
-local build_assign
-build_assign = function(extracted_names, receiver)
-  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]
-    insert(names, tuple[1])
-    insert(values, obj:chain(unpack(tuple[2])))
-  end
-  return build.group({
-    {
-      "declare",
-      names
-    },
-    inner
-  })
-end
 local extract_assign_names
 extract_assign_names = function(name, accum, prefix)
   if accum == nil then
@@ -143,6 +102,48 @@ extract_assign_names = function(name, accum, prefix)
   end
   return accum
 end
+local build_assign
+build_assign = function(destruct_literal, receiver)
+  local extracted_names = extract_assign_names(destruct_literal)
+  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]
+    insert(names, tuple[1])
+    insert(values, obj:chain(unpack(tuple[2])))
+  end
+  return build.group({
+    {
+      "declare",
+      names
+    },
+    inner
+  })
+end
 local split_assign
 split_assign = function(assign)
   local names, values = unpack(assign, 2)
@@ -182,8 +183,7 @@ split_assign = function(assign)
           end)()
         })
       end
-      local extracted = extract_assign_names(n)
-      insert(g, build_assign(extracted, values[i]))
+      insert(g, build_assign(n, values[i]))
       start = i + 1
     end
   end
@@ -237,6 +237,5 @@ end
 return {
   has_destructure = has_destructure,
   split_assign = split_assign,
-  extract_assign_names = extract_assign_names,
   build_assign = build_assign
 }

moonscript/transform/destructure.moon

@@ -18,30 +18,6 @@ has_destructure = (names) ->
     return true if ntype(n) == "table"
   false
 
-build_assign = (extracted_names, receiver) ->
-  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}
-    inner
-  }
-
 extract_assign_names = (name, accum={}, prefix={}) ->
   i = 1
   for tuple in *name[2]
@@ -70,6 +46,32 @@ extract_assign_names = (name, accum={}, prefix={}) ->
 
   accum
 
+build_assign = (destruct_literal, receiver) ->
+  extracted_names = extract_assign_names destruct_literal
+
+  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}
+    inner
+  }
+
 -- applies to destructuring to a assign node
 split_assign = (assign) ->
   names, values = unpack assign, 2
@@ -93,8 +95,7 @@ split_assign = (assign) ->
             values[i]
         }
 
-      extracted = extract_assign_names n
-      insert g, build_assign extracted, values[i]
+      insert g, build_assign n, values[i]
 
       start = i + 1
 
@@ -113,4 +114,4 @@ split_assign = (assign) ->
 
   build.group g
 
-{ :has_destructure, :split_assign, :extract_assign_names, :build_assign }
+{ :has_destructure, :split_assign, :build_assign }

tests/inputs/destructure.moon

@@ -51,3 +51,28 @@ for {x,y} in *thing
   print x,y
 
 
+--
+
+with {a,b} = thing
+  print a, b
+
+
+--
+
+thing = nil
+if {a} = thing
+  print a
+else
+  print "nothing"
+
+thang = {1,2}
+if {a,b} = thang
+  print a,b
+
+if {a,b} = thing
+  print a,b
+elseif {c,d} = thang
+  print c,d
+else
+  print "NO"
+

tests/outputs/destructure.lua

@@ -101,4 +101,47 @@ 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
+do
+  local _with_0 = thing
+  a, b = _with_0[1], _with_0[2]
+  print(a, b)
+end
+thing = nil
+do
+  local _des_0 = thing
+  if _des_0 then
+    a = _des_0[1]
+    print(a)
+  else
+    print("nothing")
+  end
+end
+local thang = {
+  1,
+  2
+}
+do
+  local _des_0 = thang
+  if _des_0 then
+    a, b = _des_0[1], _des_0[2]
+    print(a, b)
+  end
+end
+do
+  local _des_0 = thing
+  if _des_0 then
+    a, b = _des_0[1], _des_0[2]
+    print(a, b)
+  else
+    do
+      local _des_1 = thang
+      if _des_1 then
+        c, d = _des_1[1], _des_1[2]
+        print(c, d)
+      else
+        return print("NO")
+      end
+    end
+  end
 end

todo

@@ -1,4 +1,9 @@
 # TODO
+#
+#
+#
+
+-- local * and local ^
 
 -- seems like running in moon messes up require order
 
@@ -8,19 +13,14 @@
 
 - or= and=
 
-- a do block for making a quick anon func and calling it
-
 - error with stray comma at end of line
-- ugly error if attempting to assign to rvalue like #hello
-
-- class expressions, x = class extends Hello do new: => print "hello"
 
 * multiline comments
 * table slices (almost)
 
 * combine for and if line decorators
 
-* export later?
+* export later? nah
 
 	x = 232
 	export x