add string interpolation to double quote string

moonscript/compile/value.lua

@@ -86,8 +86,13 @@ value_compile = {
     return self:line("(", self:value(node[2]), ")")
   end,
   string = function(self, node)
-    local _, delim, inner, delim_end = unpack(node)
-    return delim .. inner .. (delim_end or delim)
+    local _, delim, inner = unpack(node)
+    local end_delim = delim:gsub("%[", "]")
+    if inner then
+      return delim .. inner .. end_delim
+    else
+      return delim .. end_delim
+    end
   end,
   chain = function(self, node)
     local callee = node[2]

moonscript/compile/value.moon

@@ -44,8 +44,12 @@ value_compile =
     @line "(", @value(node[2]), ")"
 
   string: (node) =>
-    _, delim, inner, delim_end = unpack node
-    delim..inner..(delim_end or delim)
+    _, delim, inner = unpack node
+    end_delim = delim\gsub "%[", "]"
+    if inner
+      delim..inner..end_delim
+    else
+      delim..end_delim
 
   chain: (node) =>
     callee = node[2]

moonscript/parse.lua

@@ -148,10 +148,17 @@ local function symx(chars)
 	return chars
 end
 
-local function simple_string(delim, x)
-	return C(symx(delim)) * C((P('\\'..delim) +
-		"\\\\" +
-		(1 - S('\r\n'..delim)))^0) * sym(delim) / mark"string"
+local function simple_string(delim, allow_interpolation)
+	local inner = P('\\'..delim) + "\\\\" + (1 - S('\r\n'..delim))
+	if allow_interpolation then
+		inter = symx"#{" * V"Exp" * sym"}"
+		inner = (C((inner - inter)^1) + inter / mark"interpolate")^0
+	else
+		inner = C(inner^0)
+	end
+
+	return C(symx(delim)) *
+		inner * sym(delim) / mark"string"
 end
 
 local function wrap_func_arg(value)
@@ -384,11 +391,11 @@ local build_grammar = wrap_env(function()
 
 		String = Space * DoubleString + Space * SingleString + LuaString,
 		SingleString = simple_string("'"),
-		DoubleString = simple_string('"'),
+		DoubleString = simple_string('"', true),
 
 		LuaString = Cg(LuaStringOpen, "string_open") * Cb"string_open" * Break^-1 *
 			C((1 - Cmt(C(LuaStringClose) * Cb"string_open", check_lua_string))^0) *
-			C(LuaStringClose) / mark"string",
+			LuaStringClose / mark"string",
 
 		LuaStringOpen = sym"[" * P"="^0 * "[" / trim,
 		LuaStringClose = "]" * P"="^0 * "]",

moonscript/transform.lua

@@ -40,6 +40,9 @@ LocalName = (function()
     end
   })
   _base_0.__class = _class_0
+  if _parent_0 and _parent_0.__inherited then
+    _parent_0.__inherited(_parent_0, _class_0)
+  end
   return _class_0
 end)()
 NameProxy = (function()
@@ -127,6 +130,9 @@ NameProxy = (function()
     end
   })
   _base_0.__class = _class_0
+  if _parent_0 and _parent_0.__inherited then
+    _parent_0.__inherited(_parent_0, _class_0)
+  end
   return _class_0
 end)()
 Run = (function()
@@ -164,6 +170,9 @@ Run = (function()
     end
   })
   _base_0.__class = _class_0
+  if _parent_0 and _parent_0.__inherited then
+    _parent_0.__inherited(_parent_0, _class_0)
+  end
   return _class_0
 end)()
 local apply_to_last
@@ -303,6 +312,9 @@ Transformer = (function()
     end
   })
   _base_0.__class = _class_0
+  if _parent_0 and _parent_0.__inherited then
+    _parent_0.__inherited(_parent_0, _class_0)
+  end
   return _class_0
 end)()
 local construct_comprehension
@@ -1082,6 +1094,9 @@ Accumulator = (function()
     end
   })
   _base_0.__class = _class_0
+  if _parent_0 and _parent_0.__inherited then
+    _parent_0.__inherited(_parent_0, _class_0)
+  end
   return _class_0
 end)()
 local default_accumulator
@@ -1120,6 +1135,44 @@ Value = Transformer({
   ["for"] = default_accumulator,
   ["while"] = default_accumulator,
   foreach = default_accumulator,
+  string = function(self, node)
+    if #node <= 3 then
+      return node
+    end
+    local delim = node[2]
+    local convert_part
+    convert_part = function(part)
+      if part == nil then
+        return 
+      end
+      if type(part) == "string" then
+        return {
+          "string",
+          delim,
+          part
+        }
+      else
+        return build.chain({
+          base = "tostring",
+          {
+            "call",
+            {
+              part[2]
+            }
+          }
+        })
+      end
+    end
+    local e = {
+      "exp",
+      convert_part(node[3])
+    }
+    for i = 4, #node do
+      insert(e, "..")
+      insert(e, convert_part(node[i]))
+    end
+    return e
+  end,
   comprehension = function(self, node)
     local a = Accumulator()
     node = self.transform.statement(node, function(exp)

moonscript/transform.moon

@@ -593,6 +593,24 @@ Value = Transformer {
   while: default_accumulator
   foreach: default_accumulator
 
+  string: (node) =>
+    return node if #node <= 3
+    delim = node[2]
+
+    convert_part = (part) ->
+      return if part == nil
+      if type(part) == "string"
+        {"string", delim, part}
+      else
+        build.chain { base: "tostring", {"call", {part[2]}} }
+
+    e = {"exp", convert_part node[3]}
+
+    for i=4,#node
+      insert e, ".."
+      insert e, convert_part node[i]
+    e
+
   comprehension: (node) =>
     a = Accumulator!
     node = @transform.statement node, (exp) ->

tests/inputs/string.moon

@@ -31,3 +31,27 @@ x = "\\"
 x = "a\\b"
 x = "\\\n"
 x = "\""
+
+-- 
+
+a = "hello #{hello} hello"
+b = "#{hello} hello"
+c = "hello #{hello}"
+d = ""
+
+y = "hello" .. "world"
+
+y = [[hello world]]
+
+--
+
+a = 'hello #{hello} hello'
+b = '#{hello} hello'
+c = 'hello #{hello}'
+d = ''
+
+y = 'hello' .. 'world'
+
+y = [[hello world]]
+
+

tests/outputs/string.lua

@@ -16,3 +16,15 @@ local x = "\\"
 x = "a\\b"
 x = "\\\n"
 x = "\""
+local a = "hello " .. tostring(hello) .. " hello"
+local b = tostring(hello) .. " hello"
+local c = "hello " .. tostring(hello)
+local d = ""
+local y = "hello" .. "world"
+y = [[hello world]]
+a = 'hello #{hello} hello'
+b = '#{hello} hello'
+c = 'hello #{hello}'
+d = ''
+y = 'hello' .. 'world'
+y = [[hello world]]