Simplified AST to just use a single moonscript class called "SyntaxTree"

instead of a different metatable for each type of syntax tree.

1 files changed, 96 insertions, 124 deletions

diff --git a/syntax_tree.lua b/syntax_tree.lua
index 63c24ee..92cee59 100644
--- a/syntax_tree.lua
+++ b/syntax_tree.lua
@@ -6,13 +6,6 @@ end
 local Source
 Source = require("code_obj").Source
 local unpack = unpack or table.unpack
-local AST = { }
-AST.is_syntax_tree = function(n, t)
-  if t == nil then
-    t = nil
-  end
-  return type(n) == 'table' and getmetatable(n) and getmetatable(n).__type == "Syntax Tree" and (t == nil or n.type == t)
-end
 local as_lua
 as_lua = function(self)
   if type(self) == 'number' then
@@ -31,40 +24,17 @@ as_lua = function(self)
   end
   return error("Not supported: " .. tostring(self))
 end
-local types = {
-  "Number",
-  "Var",
-  "Block",
-  "EscapedNomsu",
-  "Text",
-  "List",
-  "Dict",
-  "DictEntry",
-  "IndexChain",
-  "Action",
-  "FileChunks",
-  "Error",
-  "Comment"
-}
-for _index_0 = 1, #types do
-  local name = types[_index_0]
-  local cls = { }
-  do
-    cls.__class = cls
-    cls.__index = cls
-    cls.__name = name
-    cls.type = name
-    cls.__type = "Syntax Tree"
-    cls.is_instance = function(self, x)
-      return getmetatable(x) == self
-    end
-    cls.__tostring = function(self)
+local SyntaxTree
+do
+  local _class_0
+  local _base_0 = {
+    __tostring = function(self)
       local bits
       do
         local _accum_0 = { }
         local _len_0 = 1
-        for _index_1 = 1, #self do
-          local b = self[_index_1]
+        for _index_0 = 1, #self do
+          local b = self[_index_0]
           _accum_0[_len_0] = tostring(b)
           _len_0 = _len_0 + 1
         end
@@ -75,15 +45,29 @@ for _index_0 = 1, #types do
           table.insert(bits, "[ " .. tostring(tostring(k)) .. "]=" .. tostring(tostring(v)))
         end
       end
-      return tostring(self.type) .. "{" .. tostring(table.concat(bits, ", ")) .. "}"
-    end
-    cls.as_lua = function(self)
+      return "SyntaxTree{" .. tostring(table.concat(bits, ", ")) .. "}"
+    end,
+    __eq = function(self, other)
+      if type(self) ~= type(other) or #self ~= #other or getmetatable(self) ~= getmetatable(other) then
+        return false
+      end
+      for i = 1, #self do
+        if self[i] ~= other[i] then
+          return false
+        end
+      end
+      if self.target ~= other.target then
+        return false
+      end
+      return true
+    end,
+    as_lua = function(self)
       local bits
       do
         local _accum_0 = { }
         local _len_0 = 1
-        for _index_1 = 1, #self do
-          local b = self[_index_1]
+        for _index_0 = 1, #self do
+          local b = self[_index_0]
           _accum_0[_len_0] = as_lua(b)
           _len_0 = _len_0 + 1
         end
@@ -94,45 +78,32 @@ for _index_0 = 1, #types do
           table.insert(bits, "[ " .. tostring(as_lua(k)) .. "]=" .. tostring(as_lua(v)))
         end
       end
-      return tostring(self.type) .. "{" .. tostring(table.concat(bits, ", ")) .. "}"
-    end
-    cls.source_code_for_tree = setmetatable({ }, {
-      __index = function(self, t)
-        local s = t.source
-        local Files = require('files')
-        local f = Files.read(s.filename)
-        return f
-      end
-    })
-    cls.get_source_code = function(self)
-      return self.source_code_for_tree[self]
-    end
-    cls.map = function(self, fn)
+      return "SyntaxTree{" .. tostring(table.concat(bits, ", ")) .. "}"
+    end,
+    get_source_code = function(self)
+      return self.__class.source_code_for_tree[self]
+    end,
+    map = function(self, fn)
       local replacement = fn(self)
       if replacement == false then
         return nil
       end
       if replacement then
-        if AST.is_syntax_tree(replacement) then
-          replacement = setmetatable((function()
+        if SyntaxTree:is_instance(replacement) then
+          do
             local _tbl_0 = { }
             for k, v in pairs(replacement) do
               _tbl_0[k] = v
             end
-            return _tbl_0
-          end)(), getmetatable(replacement))
+            replacement = _tbl_0
+          end
           replacement.source = self.source
           if self.comments then
             replacement.comments = {
               unpack(self.comments)
             }
           end
-          do
-            local init = replacement.__init
-            if init then
-              init(replacement)
-            end
-          end
+          replacement = SyntaxTree(replacement)
         end
       else
         replacement = {
@@ -146,7 +117,7 @@ for _index_0 = 1, #types do
           local _continue_0 = false
           repeat
             replacement[k] = v
-            if AST.is_syntax_tree(v) then
+            if SyntaxTree:is_instance(v) then
               local r = v:map(fn)
               if r == v or r == nil then
                 _continue_0 = true
@@ -164,74 +135,75 @@ for _index_0 = 1, #types do
         if not (changes) then
           return self
         end
-        replacement = setmetatable(replacement, getmetatable(self))
-        do
-          local init = replacement.__init
-          if init then
-            init(replacement)
-          end
-        end
+        replacement = SyntaxTree(replacement)
       end
       return replacement
-    end
-    cls.__eq = function(self, other)
-      if type(self) ~= type(other) or #self ~= #other or getmetatable(self) ~= getmetatable(other) then
-        return false
-      end
-      for i = 1, #self do
-        if self[i] ~= other[i] then
-          return false
+    end,
+    get_args = function(self)
+      assert(self.type == "Action", "Only actions have arguments")
+      local _accum_0 = { }
+      local _len_0 = 1
+      for _index_0 = 1, #self do
+        local tok = self[_index_0]
+        if type(tok) ~= 'string' then
+          _accum_0[_len_0] = tok
+          _len_0 = _len_0 + 1
         end
       end
-      if self.target ~= other.target then
-        return false
-      end
-      return true
-    end
-  end
-  AST[name] = setmetatable(cls, {
-    __tostring = function(self)
-      return self.__name
+      return _accum_0
     end,
-    __call = function(self, t)
-      if type(t.source) == 'string' then
-        t.source = Source:from_string(t.source)
-      end
-      setmetatable(t, self)
-      do
-        local init = t.__init
-        if init then
-          init(t)
+    get_stub = function(self)
+      local stub_bits = { }
+      local arg_i = 1
+      for _index_0 = 1, #self do
+        local a = self[_index_0]
+        if type(a) == 'string' then
+          stub_bits[#stub_bits + 1] = a
+        else
+          stub_bits[#stub_bits + 1] = tostring(arg_i)
+          arg_i = arg_i + 1
         end
       end
-      return t
+      return concat(stub_bits, " ")
+    end
+  }
+  _base_0.__index = _base_0
+  _class_0 = setmetatable({
+    __init = function() end,
+    __base = _base_0,
+    __name = "SyntaxTree"
+  }, {
+    __index = _base_0,
+    __call = function(cls, ...)
+      local _self_0 = setmetatable({}, _base_0)
+      cls.__init(_self_0, ...)
+      return _self_0
     end
   })
-end
-AST.Action.__init = function(self)
-  local stub_bits = { }
-  local arg_i = 1
-  for _index_0 = 1, #self do
-    local a = self[_index_0]
-    if type(a) == 'string' then
-      stub_bits[#stub_bits + 1] = a
-    else
-      stub_bits[#stub_bits + 1] = tostring(arg_i)
-      arg_i = arg_i + 1
+  _base_0.__class = _class_0
+  local self = _class_0
+  self.__type = "Syntax Tree"
+  self.source_code_for_tree = setmetatable({ }, {
+    __index = function(self, t)
+      local s = t.source
+      local Files = require('files')
+      local f = Files.read(s.filename)
+      return f
     end
+  })
+  self.is_instance = function(self, t)
+    return type(t) == 'table' and getmetatable(t) == self.__base
   end
-  self.stub = concat(stub_bits, " ")
+  SyntaxTree = _class_0
 end
-AST.Action.get_args = function(self)
-  local _accum_0 = { }
-  local _len_0 = 1
-  for _index_0 = 1, #self do
-    local tok = self[_index_0]
-    if type(tok) ~= 'string' then
-      _accum_0[_len_0] = tok
-      _len_0 = _len_0 + 1
-    end
+getmetatable(SyntaxTree).__call = function(self, t)
+  if type(t.source) == 'string' then
+    t.source = Source:from_string(t.source)
+  end
+  setmetatable(t, self.__base)
+  if t.type == 'Action' then
+    t.stub = t:get_stub()
   end
-  return _accum_0
+  return t
 end
-return AST
+return SyntaxTree