binary assignment operator shorthand + misc

moonscript/compile2.lua

@@ -61,6 +61,7 @@ local moonlib = { bind = function(tbl, name) return concat({
       ")"
     }) end }
 local cascading = Set({ "if" })
+local non_atomic = Set({ "update" })
 local has_value
 has_value = function(node)
   if ntype(node) == "chain" then
@@ -70,6 +71,8 @@ has_value = function(node)
     return true
   end
 end
+local is_non_atomic
+is_non_atomic = function(node) return non_atomic[ntype(node)] end
 local line_compile = {
   assign = function(self, node)
     local _, names, values = unpack(node)
@@ -145,7 +148,21 @@ local line_compile = {
       end
     end
   end,
+  update = function(self, node)
+    local _, name, op, exp = unpack(node)
+    local op_final = op:match("(.)=")
+    if not op_final then
+      _ = error("unknown op: ") .. op
+    end
+    return self:stm({ "assign", { name }, { {
+          "exp",
+          name,
+          op_final,
+          exp
+        } } })
+  end,
   ["return"] = function(self, node) return self:add_line("return", self:value(node[2])) end,
+  ["break"] = function(self, node) return self:add_line("break") end,
   ["import"] = function(self, node)
     local _, names, source = unpack(node)
     local to_bind = {  }
@@ -237,8 +254,13 @@ local line_compile = {
   end,
   ["while"] = function(self, node)
     local _, cond, block = unpack(node)
-    self:add_line("while", self:value(cond), "do")
     local inner = self:block()
+    if is_non_atomic(cond) then
+      self:add_line("while", "true", "do")
+      inner:stm({ "if", { "not", cond }, { { "break" } } })
+    else
+      self:add_line("while", self:value(cond), "do")
+    end
     inner:stms(block)
     self:add_line(inner:render())
     return self:add_line("end")
@@ -315,6 +337,11 @@ local value_compile = {
       return _moon_0
     end)(), " ")
   end,
+  update = function(self, node)
+    local _, name = unpack(node)
+    self:stm(node)
+    return self:name(name)
+  end,
   explist = function(self, node) return concat((function()
       local _moon_0 = {}
       for i, v in ipairs(node) do

moonscript/compile2.moon

@@ -43,6 +43,9 @@ moonlib =
 
 cascading = Set{ "if" }
 
+-- an action that can't be completed in a single line
+non_atomic = Set{ "update" }
+
 -- does this always return a value
 has_value = (node) ->
   if ntype(node) == "chain"
@@ -51,6 +54,9 @@ has_value = (node) ->
   else
     true
 
+is_non_atomic = (node) ->
+  non_atomic[ntype(node)]
+
 line_compile =
   assign: (node) =>
     _, names, values = unpack node
@@ -89,9 +95,18 @@ line_compile =
         @add_line declare if #undeclared > 0
         @add_line concat([@value n for n in *names], ", ").." = "..values
 
+  update: (node) =>
+    _, name, op, exp = unpack node
+    op_final = op:match"(.)="
+    error"unknown op: "..op if not op_final
+    @stm {"assign", {name}, {{"exp", name, op_final, exp}}}
+
   ["return"]: (node) =>
     @add_line "return", @value node[2]
 
+  ["break"]: (node) =>
+    @add_line "break"
+
   ["import"]: (node) =>
     _, names, source = unpack node
 
@@ -162,8 +177,13 @@ line_compile =
   ["while"]: (node) =>
     _, cond, block = unpack node
 
-    @add_line "while", @value(cond), "do"
     inner = @block()
+    if is_non_atomic cond
+      @add_line "while", "true", "do"
+      inner:stm {"if", {"not", cond}, {{"break"}}}
+    else
+      @add_line "while", @value(cond), "do"
+
     inner:stms block
 
     @add_line inner:render()
@@ -231,6 +251,11 @@ value_compile =
     -- ugly
     concat [_comp i,v for i,v in ipairs node when i > 1], " "
 
+  update: (node) =>
+    _, name = unpack node
+    @stm node
+    @name name
+
   explist: (node) =>
     concat [@value v for i,v in ipairs node when i > 1], ", "
 

moonscript/parse.lua

@@ -227,7 +227,7 @@ local build_grammar = wrap(function()
 		Block = Ct(Line * (Break^1 * Line)^0),
 		Line = Cmt(Indent, check_indent) * Statement + _Space * Comment,
 
-		Statement = (Import + If + While + Ct(ExpList) / flatten_or_mark"explist" * Space) * (
+		Statement = (Import + While + BreakLoop + Ct(ExpList) / flatten_or_mark"explist" * Space) * (
 				-- statement decorators
 				key"if" * Exp * (key"else" * Exp)^-1 * Space / mark"if" +
 				CompInner / mark"comprehension"
@@ -244,6 +244,8 @@ local build_grammar = wrap(function()
 
 		NameList = Name * (sym"," * Name)^0,
 
+		BreakLoop = Ct(key"break"/trim),
+
 		If = key"if" * Exp * key"then"^-1 * Body *
 			((Break * Cmt(Indent, check_indent))^-1 * key"elseif" * Exp * key"then"^-1 * Body / mark"elseif")^0 *
 			((Break * Cmt(Indent, check_indent))^-1 * key"else" * Body / mark"else")^-1 / mark"if",
@@ -256,7 +258,8 @@ local build_grammar = wrap(function()
 		CompFor = key"for" * Ct(NameList) * key"in" * (sym"*" * Exp / mark"unpack" + Exp) / mark"for",
 		CompClause = CompFor + key"when" * Exp / mark"when",
 
-		Assign = Ct(AssignableList) * sym"=" * (Ct(TableBlock + ExpListLow) + If) / mark"assign",
+		Assign = Ct(AssignableList) * sym"=" * (If + Ct(TableBlock + ExpListLow)) / mark"assign",
+		Update = Assignable * ((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">",
@@ -271,6 +274,7 @@ local build_grammar = wrap(function()
 		-- Term = Ct(Value * (TermOp * Value)^0) / flatten_or_mark"exp",
 
 		Value =
+			If +
 			sym"-" * Exp / mark"minus" +
 			sym"#" * Exp / mark"length" +
 			sym"not" * Exp / mark"not" +
@@ -278,7 +282,7 @@ local build_grammar = wrap(function()
 			Comprehension +
 			ColonChain * Ct(ExpList^0) / flatten_func + -- have precedence over open table
 			Ct(KeyValueList) / mark"table" +
-			Assign + FunLit + String +
+			Assign + Update + FunLit + String +
 			((Chain + Callable) * Ct(ExpList^0)) / flatten_func +
 			Num,
 

tests/inputs/syntax.moon

@@ -139,3 +139,11 @@ something:hello what
 something.hello:world a,b
 something.hello:world(1,2,3) a,b
 
+x = 1232
+x += 10 + 3
+j -= "hello"
+y *= 2
+y /= 100
+m %= 2
+
+

tests/outputs/syntax.lua

@@ -94,4 +94,10 @@ _ = hello, world
 something:hello(what)(a, b)
 something:hello(what)
 something.hello:world(a, b)
-something.hello:world(1, 2, 3)(a, b)
+something.hello:world(1, 2, 3)(a, b)
+x = 1232
+x = x + 10 + 3
+local j = j - "hello"
+y = y * 2
+y = y / 100
+local m = m % 2