..= for string concatenation update

moonscript/compile/line.lua

@@ -117,7 +117,7 @@ line_compile = {
   end,
   update = function(self, node)
     local _, name, op, exp = unpack(node)
-    local op_final = op:match("(.)=")
+    local op_final = op:match("^(.+)=$")
     if not op_final then
       error("Unknown op: " .. op)
     end

moonscript/compile/line.moon

@@ -66,7 +66,7 @@ line_compile =
 
   update: (node) =>
     _, name, op, exp = unpack node
-    op_final = op\match "(.)="
+    op_final = op\match "^(.+)=$"
     error "Unknown op: "..op if not op_final
     @stm {"assign", {name}, {{"exp", name, op_final, exp}}}
 

moonscript/parse.lua

@@ -305,7 +305,7 @@ local build_grammar = wrap(function()
 		CompClause = CompFor + key"when" * Exp / mark"when",
 
 		Assign = Ct(AssignableList) * sym"=" * (With + If + Ct(TableBlock + ExpListLow)) / mark"assign",
-		Update = Assignable * ((sym"+=" + sym"-=" + sym"*=" + sym"/=" + sym"%=")/trim) * Exp / mark"update",
+		Update = Assignable * ((sym"..=" + sym"+=" + sym"-=" + sym"*=" + sym"/=" + sym"%=")/trim) * Exp / mark"update",
 
 		-- we can ignore precedence for now
 		OtherOps = op"or" + op"and" + op"<=" + op">=" + op"~=" + op"!=" + op"==" + op".." + op"<" + op">",

tests/inputs/syntax.moon

@@ -138,7 +138,7 @@ j -= "hello"
 y *= 2
 y /= 100
 m %= 2
-
+hello ..= "world"
 
 x = 0
 (if ntype(v) == "fndef" then x += 1) for v in *values

tests/outputs/syntax.lua

@@ -142,6 +142,7 @@ local j = j - "hello"
 y = y * 2
 y = y / 100
 local m = m % 2
+local hello = hello .. "world"
 x = 0
 do
   local _item_0 = values
@@ -155,7 +156,7 @@ do
     end)())
   end
 end
-local hello = {
+hello = {
   something = world,
   ["if"] = "hello",
   ["else"] = 3434,