cascading assigns done through transformer

Author: leafo

moonscript/compile.lua

@@ -379,47 +379,14 @@ Block_ = (function()
       end
       return nil
     end,
-    ret_stms = function(self, stms, ret)
-      if ret == nil then
-        ret = error("missing return handler")
-      end
-      local last_exp_id = 0
-      for i = #stms, 1, -1 do
-        local stm = stms[i]
-        if stm and util.moon.type(stm) ~= transform.Run then
-          last_exp_id = i
-          break
-        end
-      end
-      for i, stm in ipairs(stms) do
-        if i == last_exp_id then
-          if cascading[ntype(stm)] then
-            self:stm(stm, ret)
-          elseif self:is_value(stm) then
-            local line = ret(stms[i])
-            if self:is_stm(line) then
-              self:stm(line)
-            else
-              error("got a value from implicit return")
-            end
-          else
-            self:stm(stm)
-          end
-        else
-          self:stm(stm)
-        end
-      end
-      return nil
-    end,
     stms = function(self, stms, ret)
       if ret then
-        self:ret_stms(stms, ret)
-      else
-        local _list_0 = stms
-        for _index_0 = 1, #_list_0 do
-          local stm = _list_0[_index_0]
-          self:stm(stm)
-        end
+        error("deprecated stms call, use transformer")
+      end
+      local _list_0 = stms
+      for _index_0 = 1, #_list_0 do
+        local stm = _list_0[_index_0]
+        self:stm(stm)
       end
       return nil
     end

moonscript/compile.moon

@@ -258,38 +258,9 @@ class Block_
       @add out if out
     nil
 
-  ret_stms: (stms, ret=error"missing return handler") =>
-    -- find last exp for explicit return
-    last_exp_id = 0
-    for i = #stms, 1, -1
-      stm = stms[i]
-      if stm and util.moon.type(stm) != transform.Run
-        last_exp_id = i
-        break
-
-    for i, stm in ipairs stms
-      if i == last_exp_id
-        if cascading[ntype(stm)]
-          @stm stm, ret
-        elseif @is_value stm
-          line = ret stms[i]
-          if @is_stm line
-            @stm line
-          else
-            error "got a value from implicit return"
-        else
-          -- nothing we can do with a statement except show it
-          @stm stm
-      else
-        @stm stm
-
-    nil
-
   stms: (stms, ret) =>
-    if ret
-      @ret_stms stms, ret
-    else
-      @stm stm for stm in *stms
+    error "deprecated stms call, use transformer" if ret
+    @stm stm for stm in *stms
     nil
 
 class RootBlock extends Block_

moonscript/compile/format.lua

@@ -19,15 +19,6 @@ user_error = function(...)
     ...
   })
 end
-local manual_return = Set({
-  "foreach",
-  "for",
-  "while"
-})
-cascading = Set({
-  "if",
-  "with"
-})
 moonlib = {
   bind = function(tbl, name)
     return concat({

moonscript/compile/format.moon

@@ -15,8 +15,8 @@ indent_char = "  "
 user_error = (...) ->
   error {"user-error", ...}
 
-manual_return = Set{"foreach", "for", "while"}
-cascading = Set{ "if", "with" }
+-- manual_return = Set{"foreach", "for", "while"}
+-- cascading = Set{ "if", "with" }
 
 -- TODO get RID OF THIAS
 moonlib =

moonscript/compile/line.lua

@@ -39,65 +39,47 @@ line_compile = {
     local _, names, values = unpack(node)
     local undeclared = self:declare(names)
     local declare = "local " .. concat(undeclared, ", ")
-    if #values == 1 and self:is_stm(values[1]) and cascading[ntype(values[1])] then
-      local stm = values[1]
-      if #undeclared > 0 then
-        self:add(declare)
+    local has_fndef = false
+    local i = 1
+    while i <= #values do
+      if ntype(values[i]) == "fndef" then
+        has_fndef = true
       end
-      local decorate
-      decorate = function(value)
-        return {
-          "assign",
-          names,
-          {
-            value
-          }
-        }
-      end
-      return self:stm(stm, decorate)
-    else
-      local has_fndef = false
-      local i = 1
-      while i <= #values do
-        if ntype(values[i]) == "fndef" then
-          has_fndef = true
-        end
-        i = i + 1
-      end
-      do
-        local _with_0 = self:line()
-        if #undeclared == #names and not has_fndef then
-          _with_0:append(declare)
-        else
-          if #undeclared > 0 then
-            self:add(declare)
-          end
-          _with_0:append_list((function()
-            local _accum_0 = { }
-            local _len_0 = 0
-            local _list_0 = names
-            for _index_0 = 1, #_list_0 do
-              local name = _list_0[_index_0]
-              _len_0 = _len_0 + 1
-              _accum_0[_len_0] = self:value(name)
-            end
-            return _accum_0
-          end)(), ", ")
+      i = i + 1
+    end
+    do
+      local _with_0 = self:line()
+      if #undeclared == #names and not has_fndef then
+        _with_0:append(declare)
+      else
+        if #undeclared > 0 then
+          self:add(declare)
         end
-        _with_0:append(" = ")
         _with_0:append_list((function()
           local _accum_0 = { }
           local _len_0 = 0
-          local _list_0 = values
+          local _list_0 = names
           for _index_0 = 1, #_list_0 do
-            local v = _list_0[_index_0]
+            local name = _list_0[_index_0]
             _len_0 = _len_0 + 1
-            _accum_0[_len_0] = self:value(v)
+            _accum_0[_len_0] = self:value(name)
           end
           return _accum_0
         end)(), ", ")
-        return _with_0
       end
+      _with_0:append(" = ")
+      _with_0:append_list((function()
+        local _accum_0 = { }
+        local _len_0 = 0
+        local _list_0 = values
+        for _index_0 = 1, #_list_0 do
+          local v = _list_0[_index_0]
+          _len_0 = _len_0 + 1
+          _accum_0[_len_0] = self:value(v)
+        end
+        return _accum_0
+      end)(), ", ")
+      return _with_0
     end
   end,
   update = function(self, node)
@@ -196,12 +178,12 @@ line_compile = {
       return _with_0
     end
   end,
-  ["if"] = function(self, node, ret)
+  ["if"] = function(self, node)
     local cond, block = node[2], node[3]
     local root
     do
       local _with_0 = self:block(self:line("if ", self:value(cond), " then"))
-      _with_0:stms(block, ret)
+      _with_0:stms(block)
       root = _with_0
     end
     local current = root
@@ -216,7 +198,7 @@ line_compile = {
         i = i + 1
         next = self:block(self:line("elseif ", self:value(clause[2]), " then"))
       end
-      next:stms(clause[i], ret)
+      next:stms(clause[i])
       current.next = next
       current = next
     end

moonscript/compile/line.moon

@@ -29,31 +29,22 @@ line_compile =
     undeclared = @declare names
     declare = "local "..concat(undeclared, ", ")
 
-    -- todo: tree transformation
-    if #values == 1 and @is_stm(values[1]) and cascading[ntype(values[1])]
-      stm = values[1]
-      @add declare if #undeclared > 0
-      decorate = (value) ->
-        {"assign", names, {value}}
-
-      @stm stm, decorate
-    else
-      has_fndef = false
-      i = 1
-      while i <= #values
-        if ntype(values[i]) == "fndef"
-          has_fndef = true
-        i = i +1
-
-      with @line!
-        if #undeclared == #names and not has_fndef
-          \append declare
-        else
-          @add declare if #undeclared > 0
-          \append_list [@value name for name in *names], ", "
-
-        \append " = "
-        \append_list [@value v for v in *values], ", "
+    has_fndef = false
+    i = 1
+    while i <= #values
+      if ntype(values[i]) == "fndef"
+        has_fndef = true
+      i = i +1
+
+    with @line!
+      if #undeclared == #names and not has_fndef
+        \append declare
+      else
+        @add declare if #undeclared > 0
+        \append_list [@value name for name in *names], ", "
+
+      \append " = "
+      \append_list [@value v for v in *values], ", "
 
   update: (node) =>
     _, name, op, exp = unpack node
@@ -100,10 +91,10 @@ line_compile =
       source = \init_free_var "table", source
       \stm {"assign", {name}, {get_value name}} for name in *final_names
 
-  if: (node, ret) =>
+  if: (node) =>
     cond, block = node[2], node[3]
     root = with @block @line "if ", @value(cond), " then"
-      \stms block, ret
+      \stms block
 
     current = root
     add_clause = (clause)->
@@ -115,7 +106,7 @@ line_compile =
         i += 1
         @block @line "elseif ", @value(clause[2]), " then"
 
-      next\stms clause[i], ret
+      next\stms clause[i]
 
       current.next = next
       current = next

moonscript/transform.lua

@@ -187,6 +187,34 @@ Transformer = function(transformers)
   })
 end
 Statement = Transformer({
+  assign = function(node)
+    local _, names, values = unpack(node)
+    if #values == 1 and types.cascading[ntype(values[1])] then
+      values[1] = Statement(values[1], function(stm)
+        local t = ntype(stm)
+        if is_value(stm) then
+          return {
+            "assign",
+            names,
+            {
+              stm
+            }
+          }
+        else
+          return stm
+        end
+      end)
+      return build.group({
+        {
+          "declare",
+          names
+        },
+        values[1]
+      })
+    else
+      return node
+    end
+  end,
   comprehension = function(node, action)
     local _, exp, clauses = unpack(node)
     action = action or function(exp)

moonscript/transform.moon

@@ -106,6 +106,24 @@ Transformer = (transformers) ->
   }
 
 Statement = Transformer {
+  assign: (node) ->
+    _, names, values = unpack node
+    -- bubble cascading assigns
+    if #values == 1 and types.cascading[ntype values[1]]
+      values[1] = Statement values[1], (stm) ->
+        t = ntype stm
+        if is_value stm
+          {"assign", names, {stm}}
+        else
+          stm
+
+      build.group {
+        {"declare", names}
+        values[1]
+      }
+    else
+      node
+
   comprehension: (node, action) ->
     _, exp, clauses = unpack node