Changelog

The implementation for the original Moonscript language 0.5.0 can be found in the 0.5.0 branch of Yuescript. The Moonscript with fixes and new features is in the main branch of Yuescript. Here are the changelogs for each Yuescript version.

v0.20.2

Added Features

Added chaining comparisons and list syntax [] with disallowing key value pairs in it.

x = 2
res = 1 < x < 3  -- true in Yuescript, like Python.
print res

list_with_only_one_element = [1,]
list = [
  1
  2
  3
  abc: 123 -- will report error here
]
[a = 1, b = 2] = tab_to_be_destructured

Added from "module" import ... syntax.

from "CS" import
  System
  UnityEngine

from UnityEngine import
  Object
  GameObject
  Transform
  MonoBehaviour
  Vector3
  Quaternion

Added import ... from "module" syntax.
```
import a, b, c from "module"
```

Fixed Issues

Fixed issue #150. Cannot use pipes on new line with const declarations.
Fixed issue #148. No output when running code in online compiler.
Fixed inline variable renaming rule to prevent naming conflicts.

v0.19.1

Added Features

Added unicode identifier support.

🌛 = 🏷️: "月之脚本"
print 🌛.🏷️

Implemented '...' for variable declaration within scope using anonymous functions.

ok, ... = fn!
if ok
  print select '#', ...
  print select 1, ...

Added close-variables support for Lua version targets below 5.4.

v0.17.10

Added Features

Added In-expression syntax to do range checking. In-expression can be used in switch statement as a new clause.

a = 5
if a in [1, 10] or a in (20, 30) or a in {77, 88} or a not in {100, 200}
  print "(1 <= a <= 10) or (20 < a < 30) or (a == 77 or a == 88) or not (a == 100 or a == 200)"

switch a when not in [1, 10]
  print "not (1 <= a <= 10)"

if item in list
	print "item existed in a list"

Added metamethod name checking for chain expression.
Added feature to reformat the expressions passed as macro function arguments to the formated code strings.
Added -r option to rewrite compiled Lua code output to match original Yuescript code line numbers.

Fixed Issues

Fixed a LuaJIT module loading issue.
Fixed built-in $FILE macro does not escape backslash on Windows.
Fixed more ambiguous Lua codes generation cases.
Fixed syntax error should throw for invalid interpolation.
Fixed an AST object life expired before accessing issue.

v0.16.4

Added Features

Added -w option for Yuescript tool to recursively watch file changes under a target path and get codes recompiled.
Added different metamethod name literals checking for different Lua target versions.
Added checks for not using break statement in a for-loop scope.

Added compiler option for preserving comments before statements. Using command line tool:

yue -c file.yue

Using Lua lib:

local yue = require("yue")
print yue.to_lua([[
-- a comment
f = ->
]], {reserve_comment = true})

Added yue.check() function to get compile errors in Lua table {{type, msg, line, col}}.
Added support for extending script search paths using yue.options.path.

Added new module export syntax for exporting items without creating local variables.

export.<name> = "My module"
export.<call> = (...) -> -- ...

compiles to:

local _module_0 = setmetatable({ }, { })
getmetatable(_module_0).__name = "My module"
getmetatable(_module_0).__call = function(...) end
return _module_0

Fixed Issues

Reduced max parser call stack size.
Refactored some syntax rules to speed up parsing.
Fixed default value issue when doing metatable destructuring.
Fixed a class syntax ambiguous issue when writting table block after a class declaration.
Improve number literal syntax to support hexadecimal point values, positive decimal exponents and hexadecimal exponents.
Prevented accessing scoped declared global variables multiple times when generating Lua codes.
Fixed parser running exponentially slow issue when parsing nested expressions.
Fixed exposing yue module as global variable by default.
Fixed a stack overflow issue in yue.to_ast().
Fixed flatten level > 0 getting wrong AST issue in yue.to_ast() function.
Fixed missing indent check for comments in the beginning of in_block syntax rule.
Prevented yue.loadfile() throwing errors to match Lua loadfile() function behavior.
Fixed yue module registering issue for Lua 5.1 and LuaJIT.

v0.15.12

Added Features

yue.to_ast(): Reserve comment nodes followed by a statement in AST structures.

Added while clause line decorator.

reader\parse_line! until reader\eof!

compiles to:

 while not reader:eof() do
   reader:parse_line()
 end

Supported underscores in number literal. 1_000_000, 0xFF_EF_06
Refactored some error messages with details instead of just "syntax error".
Added chaining assignment. a = b = c = 0

Fixed Issues

Change metable accessing operator to <> instead of postfix #.

<>: mt = tb
mt = tb.<>
a = <>: mt, value: 1
b = :<add>, value: 2
close _ = <close>: -> print "out of scope"

compiles to:

local mt = getmetatable(tb)
mt = getmetatable(tb)
local a = setmetatable({
  value = 1
}, mt)
local b = setmetatable({
  value = 2
}, {
  __add = add
})
local _ <close> = setmetatable({ }, {
  __close = function()
    return print("out of scope")
  end
})

Refactor continue keyword implementation with goto statement when targeting Lua version 5.2 and higher.
Skip utf-8 bom in parser.
Fixed classes don't inherits metamethods properly.

v0.14.5

Added Features

Added -g option for Yuescript CMD tool.
Added option --target=5.1 to generate Lua 5.1 compatible codes.

Added const destructuring and imported item is now const by default.

const :width, :height = View.size
const {:x = 0.0, :y = 0.0} = point
import a from b
-- report compiler error when doing width = nil or x = nil or a = nil

Added left and right side item numbers check in assignments.

a, b, c = 1 -- report error instead of implicitly assigning nil to extra variables
a, b, c = f! -- expecting function call to return multiple values is accepted
a = 1, 2 -- report error instead of ignoring extra values

Fixed Issues

Fix missing checks and issues related to doing destrucuring to if/switch expressions that returns values in multiple clauses.

v0.13.4

Added Features

Added update syntax support for var //= 5.

Added metamethod syntax support for class block.

class Foo
  new: (x) => @x = x
  mul#: (y) => @x * y
  ["abc"]#: 123
  :add
  :add#

Added support with block access with [key] syntax.

with tb
  [1] = [2]\func!
  print [3]
  with [abc]
    [4] = 1
  [] = "abc"

Added table pattern matching syntax.

items =
  * x: 100
    y: 200
  * width: 300
    height: 400

for item in *items
  switch item
    when :x, :y
      print "Vec2 #{x}, #{y}"
    when :width, :height
      print "size #{width}, #{height}"

Fixed Issues

Fix import X as {_} generates invalid Lua code.

Fix attribute syntax with line decorator compiles to unexpected codes.

const a = 1 if true

now compiles to:

local a <const> = (function()
  if true then
    return 1
  end
end)()

Fix continue in repeat loop gives invalid code.
Fix variables with attributes "const" and "close" should both get constant check in compiler.
Fix ambiguous syntax starting with [[. Expressions starting with [[ will now be always treated like raw strings other than nested list comprehensions.
Fix module can export both macros and normal values. The macro exporting module can now only allow macro definition, macro importing and macro expansion in place for better compiler performance.

v0.10.17

Added Features

Yuescript to AST function (yue.to_ast)

yue.p yue.to_ast(
  "print 123"
  2 --[[ast flatten level, can only be 0, 1, 2]]
)

Prints:

{
  [1] = "file"
  [2] = {
    [1] = "callable"
    [2] = "print"
  }
  [3] = {
    [1] = "invoke_args"
    [2] = "123"
  }
}

v0.10.16

Fixed Issues

Prevent text mode macros from inserting line numbers into generated code.

macro text = (code) -> {
  :code
  type: "text"
}

$text[[#!yue -e]]
nil

Compiles to:

#!yue -e
return nil -- 8

v0.10.15

Fixed Issues

Fix ambiguous syntax caused by argument table block.
Fix an issue using import as table destructuring with meta methods.
Fix a case combining the use of existential operator and metatable operator.
Raise error when use existential operator in the left part of an assignment.
Fix the way update assignment is implemented to reduce unnecessary table indexing.
Fix more cases that global variables are not being cached.
Fix Yuescript loader insertion order.
Fix Yuescript not found error messages.

Added Features

Builtin macros $FILE, $LINE to get the source file names and code line numbers.

Table appending operator.

tb = {}
tb[] = 1

Compiles to:

local tb = { }
tb[#tb + 1] = 1

Class mixing function by keyword using.

class A using B
-- If B is a Yuescript class object (which has a field named __base),
-- only fields that are not meta method will be added to class object A
-- If B is a plain table, all the fields will be added to class object A
-- so that you can change the behavior of Yuescript class' meta method __index.

Try catch syntax.

try
  func 1, 2, 3
catch err
  print yue.traceback err

success, result = try func 1, 2, 3

Compiles to:

xpcall(function()
  return func(1, 2, 3)
end, function(err)
  return print(yue.traceback(err))
end)
local success, result = pcall(func, 1, 2, 3)

Add nil coalescing operator.

local a, b, c
a = b ?? c
a ??= false

Compiles to:

local a, b, c
if b ~= nil then
  a = b
else
  a = c
end
if a == nil then
  a = false
end

Add a global variable "arg" for Yuescipt tool CLI execution.

Add placeholder support for list destructuring.

{_, b, _, d} = tb

Compiles to:

local b, d
do
  local _obj_0 = tb
  b, d = _obj_0[2], _obj_0[4]
end

Add table spread syntax.

copy = {...other}

Compiles to:

local copy
do
  local _tab_0 = { }
  local _idx_0 = 1
  for _key_0, _value_0 in pairs(other) do
    if _idx_0 == _key_0 then
      _tab_0[#_tab_0 + 1] = _value_0
      _idx_0 = _idx_0 + 1
    else
      _tab_0[_key_0] = _value_0
    end
  end
  copy = _tab_0
end

v0.8.5

Fixed Issues

Simplify and extend import syntax.
Report an error when destructuring nil item.

Added Features

Nil coalescing operator.

local a, b, c, d
a = b ?? c ?? d
func a ?? {}

a ??= false

Compiles to:

local a, b, c, d
if b ~= nil then
  a = b
else
  if c ~= nil then
    a = c
  else
    a = d
  end
end
func((function()
  if a ~= nil then
    return a
  else
    return { }
  end
end)())
if a == nil then
  a = false
end

New metatable syntax.

#: mt = tb
mt = tb.#
a = #: mt, value: 1
b = :add#, value: 2
close _ = close#: -> print "out of scope"

compiles to:

local mt = getmetatable(tb)
mt = getmetatable(tb)
local a = setmetatable({
  value = 1
}, mt)
local b = setmetatable({
  value = 2
}, {
  __add = add
})
local _ <close> = setmetatable({ }, {
  __close = function()
    return print("out of scope")
  end
})

Aliasing symbol :: with \ for writing colon chain items.
```
tb\func1()::func2()
```
compiles to:
```
tb:func1():func2()
```

Add until statement.

a = 3
until a == 0
  a -= 1

compiles to:

local a = 3
while not (a == 0) do
  a = a - 1
end

Add existential check syntax for function argument as a shortcut feature to assign self field.
```
tb\func1()::func2()
```
compiles to:
```
tb:func1():func2()
```

Add default value support for destructure syntax.

{:name = "nameless", :job = "jobless"} = person

compiles to:

local name, job
do
  local _obj_0 = person
  name, job = _obj_0.name, _obj_0.job
end
if name == nil then
  name = "nameless"
end
if job == nil then
  job = "jobless"
end

v0.6.7

Fixed Issues

Simplify macro syntax. A macro function can either return a Yuescript string or a config table containing Lua codes.

macro localFunc = (var)-> "local #{var} = ->"
$localFunc f1
f1 = -> "another function"

-- or

macro localFunc = (var)->
  {
    codes: "local function #{var}() end"
    type: "lua"
    locals: {var}
  }
$localFunc f2
f2 = -> "another function"

Compiles to:

local f1
f1 = function() end
f1 = function()
  return "another function"
end
local function f2() end
f2 = function()
  return "another function"
end

Change the Yuescript file extension to '.yue' because some of the Moonscript syntax is no longer supported and some codes written in Yuescript syntax won't be accepted by the Moonscript compiler.
Disable the use of local and global statements with wildcard operators.

Change the backcall operator syntax, extra parentheses for multiline chains are no longer needed.

readFile "example.txt"
  |> extract language, {}
  |> parse language
  |> emit
  |> render
  |> print

Compiles to:

return print(render(emit(parse(extract(readFile("example.txt"), language, { }), language))))

Added Features

Supporting multiline chaining function call syntax.

result = origin
  .transform.root
  .gameObject
  \Parents!
  \Descendants!
  \SelectEnable!
  \SelectVisible!
  \TagEqual "fx"
  \Where (x)->
    if x\IsTargeted!
      return false
    x.name\EndsWith "(Clone)"
  \Destroy!

origin.transform.root.gameObject
  \Parents!\Descendants!
  \SelectEnable!
  \SelectVisible!
  \TagEqual "fx"
  \Where (x)-> x.name\EndsWith "(Clone)"
  \Destroy!

Compiles to:

local result = origin.transform.root.gameObject:Parents():Descendants():SelectEnable():SelectVisible():TagEqual("fx"):Where(function(x)
  if x:IsTargeted() then
    return false
  end
  return x.name:EndsWith("(Clone)")
end):Destroy()
return origin.transform.root.gameObject:Parents():Descendants():SelectEnable():  SelectVisible():TagEqual("fx"):Where(function(x)
  return x.name:EndsWith("(Clone)")
end):Destroy()

v0.4.16

Fixed Issues

Remove support for escape newline symbol, binary operator expressions can now be written multiline without escape newline symbol.
Fix an issue when extending class without a name.
Fix an issue when using return with an export statement.
Fix issues when declaring table key with Lua multiline string and indexing expressions with Lua multiline string.

Make simple table and table block appear at the end of function arguments merged into one table.

-- function arguments end with a simple table followed by table block
another hello, one,
  two, three, four, yeah: man
  okay: yeah
  fine: alright

-- compiled in original Moonscript compiler
-- get two tables as arguments
another(hello, one, two, three, four, {
  yeah = man
}, {
  okay = yeah,
  fine = alright
})
-- compiled in fixed Yuescript compiler
-- get one table as argument
another(hello, one, two, three, four, {
  yeah = man,
  okay = yeah,
  fine = alright
})

Added Features

Add implicit objects support for table block syntax.

inventory =
  equipment:
    * "sword"
    * "shield"
  items:
    * name: "potion"
      count: 10
    * name: "bread"
      count: 3

Compiles to:

local inventory = {
  equipment = {
    "sword",
    "shield"
  },
  items = {
    {
      name = "potion",
      count = 10
    },
    {
      name = "bread",
      count = 3
    }
  }
}

Add support for local variable declared with attribute 'close' and 'const' for Lua 5.4.

close a = setmetatable {}, __close: =>
const b = if var then 123 else 'abc'

Compiles to:

local a <close> = setmetatable({ }, {
  __close = function(self) end
})
local b <const> = (function()
 if var then
   return 123
 else
   return 'abc'
 end
end)()

v0.4.0

Fixed Issues

Fix issues of the unary and binary operator "~".
Fix Moonscript issue 416: ambiguous Lua output in some cases.
Fix errors when explicitly declaring global or local variable initialized with table block.
Fix macro type mismatch issue.
Fix line break issue in macro, disable macro declaration outside the root scope.
Fix existential operator issue when used in an operator-valued list.
Fix assignment with backcall expressions in not well-handled cases.
Fix destructure case assigning one table variable to an operator-valued expression.
Fix simple chain value with Lua keyword colon chain item.

Added Features

Change operator precedence to
- [1] ^
- [2] unary operators (not, #, -, ~)
- [3] |>
- [4] *, /, //, %, ...

Add existential operator support for with statement.

with? io.open "test.txt", "w"
  \write "hello"
  \close!

Compiles to:

local _with_0 = io.open("test.txt", "w")
if _with_0 ~= nil then
  _with_0:write("hello")
  _with_0:close()
end

Add repeat until statement support.
Allow implicitly returning block macro.
Add support for macro system expanding to Lua codes directly.
Add goto statement support.
Add variadic arguments declaration check.
yue now supports recursively traversing any directory and compiling any moon file in the path.
yue now supports REPL functions for Moonscript.
Add useSpaceOverTab function to yue.
Add Lua codes minify function to yue.

Changed Behaviors

Remove else clause support from if-else line decorator syntax which makes users confused.

v0.3.0

Added Features

Add macro functions.

-- file 'macro.mp'
export macro config = (debugging = true)->
  global debugMode = debugging == "true"
  ""

export macro asserts = (cond)->
  debugMode and "assert #{cond}" or ""

export macro assert = (cond)->
  debugMode and "assert #{cond}" or "#{cond}"

$config!

-- file 'main.mp'
import 'macro' as {:$config, :$assert, :$asserts}

macro and = (...)-> "#{ table.concat {...}, ' and ' }"

$asserts item ~= nil
$config false
value = $assert item

if $and f1!, f2!, f3!
  print "OK"

Compiles to:

-- file 'macro.mp'
local _module_0 = { }
return _module_0

-- file 'main.mp'
assert(item ~= nil)
local value = item
if (f1() and f2() and f3()) then
  print("OK")
end

v0.2.0

Fixed Issues

Fix some cases when using backcall with an assignment.
Fix a case that complier crashes with an empty code body.
Force forward declaration of a variable for assigning local function.

From the original Moonscript compiler:

#390 Many lists are not allowed to be multiline

Added Features

Allow value lists in for and local statement to be multiline.
yue now compiles source files in multiple threads to speed up compilation.
Add placeholder support for backcall operator.
Add placeholder support for backcall statement.
Add fat arrow support for backcall statement.
Add option to compile Yuescript as a Lua C lib. Got Yuescript released to Luarocks.
Move old export statement functions to global statement to match the local statement.

Change export statement behavior to support module management. Moon codes with export statements can not explicitly return values in the root scope. And codes with export default can export only one value as the module content. Use cases:

-- file 'Config.mp'
export default {flag:1, value:"x"}

-- file 'Utils.mp'
export map = (items, func)-> [func item for item in *items]
export filter = (items, func)-> [item for item in *items when func item]

-- file 'main.mp'
import 'Config' as {:flag, :value}
import 'Utils' as {:map, :filter}

Compiles to:

-- file 'Config.mp'
local _module_0 = nil
_module_0 = {
  flag = 1,
  value = "x"
}
return _module_0

-- file 'Utils.mp'
local _module_0 = { }
local map
map = function(items, func)
  local _accum_0 = { }
  local _len_0 = 1
  for _index_0 = 1, #items do
    local item = items[_index_0]
    _accum_0[_len_0] = func(item)
    _len_0 = _len_0 + 1
  end
  return _accum_0
end
_module_0["map"] = map
local filter
filter = function(items, func)
  local _accum_0 = { }
  local _len_0 = 1
  for _index_0 = 1, #items do
    local item = items[_index_0]
    if func(item) then
      _accum_0[_len_0] = item
      _len_0 = _len_0 + 1
    end
  end
  return _accum_0
end
_module_0["filter"] = filter
return _module_0

-- file 'main.mp'
local flag, value
do
  local _obj_0 = require('Config')
  flag, value = _obj_0.flag, _obj_0.value
end
local map, filter
do
  local _obj_0 = require('Utils')
  map, filter = _obj_0.map, _obj_0.filter
end

v0.1.0

Fixed Issues

Fix issues in original Moonscript compiler:

#122 use of ? symbol
#155 wish moon could support: function?()
#156 About the 'import' statement
#375 assignment in line decorators
#384 The @ and @@ accessors do not escape Lua keywords

Added Features

Multi-line comment support.

Back call features with new operator and syntax. For example:

{1,2,3}
  |> map((x)-> x * 2)
  |> filter((x)-> x > 4)
  |> reduce(0, (a,b)-> a + b)
  |> print

do
  (data) <- http.get "ajaxtest"
  body[".result"]\html data
  (processed) <- http.post "ajaxprocess", data
  body[".result"]\append processed
  print "done"

will be compiled to:

print(reduce(filter(map({
  1,
  2,
  3
}, function(x)
  return x * 2
end), function(x)
  return x > 4
end), 0, function(a, b)
  return a + b
end))
do
  http.get("ajaxtest", function(data)
    body[".result"]:html(data)
    return http.post("ajaxprocess", data, function(processed)
      body[".result"]:append(processed)
      return print("done")
    end)
  end)
end

Existential operator support. Generate codes from:

func?!

x = tab?.value

print abc?["hello world"]?.xyz

if print and x?
  print x

to:

if func ~= nil then
  func()
end
local x
if tab ~= nil then
  x = tab.value
end
print((function()
  if abc ~= nil then
    local _obj_0 = abc["hello world"]
    if _obj_0 ~= nil then
      return _obj_0.xyz
    end
    return nil
  end
  return nil
end)())
if print and (x ~= nil) then
  print(x)
end

More usages for import keyword. Will compile codes from:

import 'module'
import "module.part"
import "d-a-s-h-e-s"
import "player" as Player
import "lpeg" as {:C, :Ct, :Cmt}

to:

local module = require('module')
local part = require("module.part")
local d_a_s_h_e_s = require("d-a-s-h-e-s")
local Player = require("player")
local C, Ct, Cmt
do
  local _obj_0 = require("lpeg")
  C, Ct, Cmt = _obj_0.C, _obj_0.Ct, _obj_0.Cmt
end

Can do slash call with Lua keywords. Generate codes from:

c.repeat.if\then("xyz")\else res

to:

local _call_3 = c["repeat"]["if"]
local _call_4 = _call_3["then"](_call_3, "xyz")
_call_4["else"](_call_4, res)

Changed Behaviors

Left part of update statement will now accept only one assignable expression.

Expression list appears in the middle of the code block is not allowed. For codes like:

-- Moonscript 0.5.0
f = (x)->
  "abc",123 -- valid meaningless codes
  x + 1

in original Moonscript compiles to:

local f
f = function(x)
 local _ = "abc", 123 -- report error in Yuescript
 return x + 1
end

This feature may lead to some silenced errors. For example:

-- expected codes
tree\addChild with Node!
  \addChild subNode

-- in original Moonscript, codes will still run
-- after adding a break by mistake
tree\addChild
with Node!
   \addChild subNode

The original Moonscript will compile these codes to:

-- expected codes
tree:addChild((function()
  do
    local _with_0 = Node()
    _with_0:addChild(subNode)
    return _with_0
  end
end)())

-- codes added with a break will still run
local _ -- report error in Yuescript instead of creating
do      -- an anonymous function to bind the object method
  local _base_0 = tree
  local _fn_0 = _base_0.addChild
  _ = function(...)
    return _fn_0(_base_0, ...)
  end
end
do
  local _with_0 = Node()
  _with_0:addChild(subNode)
end

Reusing variables which help generate reduced Lua codes. For example, Yuescript will generate codes from:

with leaf
  .world 1,2,3

with leaf
  g = .what.is.this
  print g

for x in *something
  print x

to:

leaf.world(1, 2, 3)
do
  local g = leaf.what.is.this
  print(g)
end
for _index_0 = 1, #something do
  local x = something[_index_0]
  print(x)
end

instead of:

do
  local _with_0 = leaf
  _with_0.world(1, 2, 3)
end
do
  local _with_0 = leaf
  local g = _with_0.what.is.this
end
local _list_0 = something
for _index_0 = 1, #_list_0 do
  local x = _list_0[_index_0]
  print(x)
end

v0.0.1

Implemented full features from Moonscript 0.5.0.

Files

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Changelog

v0.20.2

Added Features

Fixed Issues

v0.19.1

Added Features

v0.17.10

Added Features

Fixed Issues

v0.16.4

Added Features

Fixed Issues

v0.15.12

Added Features

Fixed Issues

v0.14.5

Added Features

Fixed Issues

v0.13.4

Added Features

Fixed Issues

v0.10.17

Added Features

v0.10.16

Fixed Issues

v0.10.15

Fixed Issues

Added Features

v0.8.5

Fixed Issues

Added Features

v0.6.7

Fixed Issues

Added Features

v0.4.16

Fixed Issues

Added Features

v0.4.0

Fixed Issues

Added Features

Changed Behaviors

v0.3.0

Added Features

v0.2.0

Fixed Issues

Added Features

v0.1.0

Fixed Issues

Added Features

Changed Behaviors

v0.0.1