Mirana

Mirana is an extension to lua. It compiles to lua before running. Full grammar is in grammar/mirana.g4.

Features

• Easy lambda expression: Lambda expressions composed by a parameter list (can be embraced by a pair of parenthesis or not), an arrow, and an expression block, embraced by braces. Lambdas can also be moved out of the parenthesis when used as the last parameter of a function call. For example:

  a { (v1, v2, ...) -> 15 }
  a(3, 7) { -> 8 }
  

  Normal lua function declarations can also use an expression together with an arrow as the return value of the function.

  function(t) -> t:GetUnitName()
  

  compiles to

  function(t) return t:GetUnitName() end

• Operator lambda: Most operators (+,-,*,/,%,^,==,~=,..,and,or,not,&&,||,++,~~) can be used as lambda expression when surrounded by braces.

  local a,b = {>},{not}
  

  compiles to

  local a,b = function(opv_1, opv_2) return opv_1 > opv_2 end, function(opv_1) return not opv_1 end

• If integrated variable declaration: a local variable declaration can be inserted before the predicate of an if statement and separated by a comma. The predicate in this way can be omitted if the variable itself is to be checked (semantically, neither nil nor false in lua). Throughout Mirana files, you can use elif instead of elseif.

  if local target = a:GetTarget() then
    ShootAt(target)
  elif local health = f:GetHealth(); health > 1000 then -- elif equals to elseif
    ...
  end
  

  compiles to

  do
    local target = a:GetTarget()
    if target then
      ShootAt(target)
    else
      local health = f:GetHealth()
      if health > 1000 then
        print(health)
      end
    end
  end

• If expression: use if, elif, else and braces as keywords to write if expressions. The else branch can be omitted, and in this case the else branch is evaluated to nil. Variables can be integrated into if and elif predicates. For example:

  local c = if t > 3 {
    15
  } elif local target = GetBot() {
    "else"
  } else {
    b
  }
  

• operator ++, ~~: They can only be used as statements and in prefix form at this time.

  ~~a
  ++a.b()[1]:c()[2]
  

  compiles to

  a = a - 1
  local __mira_locvar_1 = a.b()[1]:c()
  __mira_locvar_1[2] = __mira_locvar_1[2] + 1

  also operator +=, -=, *=.

Usage

Require .NET 5.0 to build and run. Call from command-line with MiranaCompiler. Parameters are either path to .mira file or path to folder that contains .mira files.

Alternatively, you can call the Mirana compiler from C# or any other .NET languages. For example:

using MiranaCompiler;

Compiler compiler = new();
await compiler.CompileAsync(new [] {
  "path_to_mira_files",
  "path_to_mira_file",
});