handing the transformation of decorator with implicit return in all cases

Author: leafo

moonscript/dump.lua

@@ -28,15 +28,9 @@ value = function(op)
   return flat_value(op)
 end
 tree = function(block)
-  return (function()
-    local _accum_0 = { }
-    local _len_0 = 0
-    local _list_0 = block
-    for _index_0 = 1, #_list_0 do
-      value = _list_0[_index_0]
-      _len_0 = _len_0 + 1
-      _accum_0[_len_0] = print(flat_value(value))
-    end
-    return _accum_0
-  end)()
+  local _list_0 = block
+  for _index_0 = 1, #_list_0 do
+    value = _list_0[_index_0]
+    print(flat_value(value))
+  end
 end

moonscript/transform.lua

@@ -376,32 +376,38 @@ construct_comprehension = function(inner, clauses)
 end
 Statement = Transformer({
   assign = function(self, node)
-    local _, names, values = unpack(node)
-    if #values == 1 and types.cascading[ntype(values[1])] then
-      values[1] = self.transform.statement(values[1], function(stm)
-        local t = ntype(stm)
-        if types.is_value(stm) then
-          return {
-            "assign",
-            names,
-            {
-              stm
-            }
-          }
-        else
-          return stm
-        end
-      end)
-      return build.group({
-        {
-          "declare",
-          names
-        },
-        values[1]
-      })
-    else
-      return node
+    local names, values = unpack(node, 2)
+    local transformed
+    if #values == 1 then
+      local value = values[1]
+      local t = ntype(value)
+      if t == "decorated" then
+        value = self.transform.statement(value)
+        t = ntype(value)
+      end
+      if types.cascading[t] then
+        transformed = build.group({
+          {
+            "declare",
+            names
+          },
+          self.transform.statement(value, function(stm)
+            if types.is_value(stm) then
+              return {
+                "assign",
+                names,
+                {
+                  stm
+                }
+              }
+            else
+              return stm
+            end
+          end)
+        })
+      end
     end
+    return transformed or node
   end,
   export = function(self, node)
     if #node > 2 then
@@ -1258,6 +1264,9 @@ Value = Transformer({
   ["for"] = default_accumulator,
   ["while"] = default_accumulator,
   foreach = default_accumulator,
+  decorated = function(self, node)
+    return self.transform.statement(node)
+  end,
   string = function(self, node)
     local delim = node[2]
     local convert_part

moonscript/transform.moon

@@ -160,22 +160,28 @@ construct_comprehension = (inner, clauses) ->
 
 Statement = Transformer {
   assign: (node) =>
-    _, names, values = unpack node
+    names, values = unpack node, 2
     -- bubble cascading assigns
-    if #values == 1 and types.cascading[ntype values[1]]
-      values[1] = @transform.statement values[1], (stm) ->
-        t = ntype stm
-        if types.is_value stm
-          {"assign", names, {stm}}
-        else
-          stm
+    transformed = if #values == 1
+      value = values[1]
+      t = ntype value
+
+      if t == "decorated"
+        value = @transform.statement value
+        t = ntype value
+
+      if types.cascading[t]
+        build.group {
+          {"declare", names}
+          @transform.statement value, (stm) ->
+            if types.is_value stm
+              {"assign", names, {stm}}
+            else
+              stm
+        }
+
+    transformed or node
 
-      build.group {
-        {"declare", names}
-        values[1]
-      }
-    else
-      node
 
   export: (node) =>
     -- assign values if they are included
@@ -655,6 +661,9 @@ Value = Transformer {
   while: default_accumulator
   foreach: default_accumulator
 
+  decorated: (node) =>
+    @transform.statement node
+
   string: (node) =>
     delim = node[2]
 

moonscript/types.moon

@@ -11,7 +11,9 @@ import insert from table
 -- implicit return does not work on these statements
 manual_return = data.Set{"foreach", "for", "while", "return"}
 
--- assigns and returns are bubbled into their bodies
+-- Assigns and returns are bubbled into their bodies.
+-- All cascading statement transform functions accept a second arugment that
+-- is the transformation to apply to the last statement in their body
 cascading = data.Set{ "if", "unless", "with", "switch" }
 
 is_value = (stm) ->

tests/inputs/lists.moon

@@ -71,3 +71,8 @@ print thing for thing in *test
 
 -> a = b for row in *rows
 
+-- testing implicit return
+-> x for x in *things
+-> [x for x in *things]
+
+

tests/outputs/lists.lua

@@ -278,4 +278,24 @@ _ = function()
     local row = _list_9[_index_0]
     a = b
   end
+end
+_ = function()
+  local _list_9 = things
+  for _index_0 = 1, #_list_9 do
+    x = _list_9[_index_0]
+    _ = x
+  end
+end
+_ = function()
+  return (function()
+    local _accum_0 = { }
+    local _len_0 = 0
+    local _list_9 = things
+    for _index_0 = 1, #_list_9 do
+      x = _list_9[_index_0]
+      _len_0 = _len_0 + 1
+      _accum_0[_len_0] = x
+    end
+    return _accum_0
+  end)()
 end

todo

@@ -55,3 +55,10 @@ not working right:
 
 * convert tree transformer to be depth first instead of breadth first (lazy)
 
+
+-- for searching?
+x = for thing in *things
+	if is_important thing
+		break thing 
+
+